技术领域Technical field
本发明属于聚酰亚胺过滤薄膜技术领域，涉及一种具有双层过滤梯度的聚酰亚胺纸/纳米纤维复合膜及其制备方法和应用。The invention belongs to the technical field of polyimide filter membranes and relates to a polyimide paper/nanofiber composite membrane with a double-layer filtration gradient and its preparation method and application.
背景技术Background technique
聚酰亚胺(PI)是指主链上含有酰亚胺环(-CO-N-CO-)结构，同时又具有高密度芳杂环结构的一类高分子，其芳环中的碳氧双键与芳杂环相连产生共轭效应，分子间及分子内的相互作用易形成电荷转移络合物，这些分子结构特性赋予了PI纤维许多优异的性能，如高强高模、耐腐蚀、优良的热稳定性、低介电常数等，聚酰亚胺(PI)作为一种高性能材料，不仅具有优异的力学性能和热稳定性，而且具有较高的偶极矩(6.2D)，是迄今为止耐热等级最高的高分子材料，也是高温过滤的理想材料。因此，PI纤维被广泛应用于金属冶炼、发电厂及能源生产等行业的高温过滤。Polyimide (PI) refers to a type of polymer that contains an imide ring (-CO-N-CO-) structure on the main chain and a high-density aromatic heterocyclic structure. The carbon and oxygen in the aromatic ring Double bonds are connected to aromatic heterocycles to produce conjugation effects, and intermolecular and intramolecular interactions can easily form charge transfer complexes. These molecular structural characteristics give PI fibers many excellent properties, such as high strength and high modulus, corrosion resistance, and excellent Thermal stability, low dielectric constant, etc. As a high-performance material, polyimide (PI) not only has excellent mechanical properties and thermal stability, but also has a high dipole moment (6.2D). It is It is the polymer material with the highest heat resistance level so far and is also an ideal material for high temperature filtration. Therefore, PI fibers are widely used in high-temperature filtration in industries such as metal smelting, power plants, and energy production.
目前，制备聚酰亚胺耐高温过滤材料的方法历经了机织物与针织物、针刺、水刺、化学粘合法无纺布滤料、湿法抄造纸基滤料以及静电纺纳米纤维滤料等形式。其中，通过现代湿法造纸技术制备的纸基材料因其质轻、高孔隙率，独特的三维立体网状结构，在空气过滤材料领域具有重要的应用。与此同时，纤维直径在纳米级的静电纺纳米纤维膜具有可控的表面形态和丰富的孔隙结构以及更高的比表面积和孔体积，可以提高纤维对微细颗粒物的捕获能力，但通过该方法制得的过滤材料过滤范围小，过滤效率低，过滤材料的力学性能相对较差，难以承受高流速气体通过滤材时产生的冲击压力。At present, the methods for preparing polyimide high-temperature resistant filter materials have gone through woven fabrics and knitted fabrics, needle punching, spunlace, chemically bonded non-woven filter materials, wet paper-based filter materials, and electrospun nanofiber filters. Materials and other forms. Among them, paper-based materials prepared through modern wet papermaking technology have important applications in the field of air filtration materials because of their light weight, high porosity, and unique three-dimensional network structure. At the same time, electrospun nanofiber membranes with fiber diameters in the nanoscale have controllable surface morphology, rich pore structures, and higher specific surface area and pore volume, which can improve the fiber's ability to capture fine particles, but through this method The produced filter material has a small filtration range and low filtration efficiency. The mechanical properties of the filter material are relatively poor and it is difficult to withstand the impact pressure generated when high-flow gas passes through the filter material.
发明内容Contents of the invention
针对现有技术中存在的问题，本发明提供一种具有双层过滤梯度的聚酰亚胺纸/纳米纤维复合膜及其制备方法和应用，从而解决现有技术中空气过滤材料过滤尺度小、微细颗粒物过滤效率低、力学性能差的技术问题。In view of the problems existing in the prior art, the present invention provides a polyimide paper/nanofiber composite membrane with a double-layer filtration gradient and its preparation method and application, thereby solving the problem of small filtration scale of air filter materials in the prior art. Technical problems include low filtration efficiency of fine particles and poor mechanical properties.
本发明是通过以下技术方案来实现：The present invention is realized through the following technical solutions:
一种具有双层过滤梯度的聚酰亚胺纸/纳米纤维复合膜的制备方法，包括以下步骤：A method for preparing a polyimide paper/nanofiber composite membrane with a double-layer filtration gradient, including the following steps:
S1：首先使二酐单体和二胺单体进行缩聚得到聚酰胺酸溶液，然后经洗涤析出以及冷冻干燥后得到聚酰胺酸粉末；S1: First, the dianhydride monomer and the diamine monomer are polycondensed to obtain a polyamic acid solution, and then the polyamic acid powder is obtained after washing, precipitation and freeze-drying;
S2：在冰水浴下，将制得的聚酰胺酸粉末加入至强极性非质子溶剂中，搅拌至聚酰胺酸粉末充分溶解，得到聚酰胺酸纺丝液；S2: In an ice-water bath, add the prepared polyamic acid powder to a highly polar aprotic solvent, stir until the polyamic acid powder is fully dissolved, and obtain a polyamic acid spinning solution;
S3：通过静电纺丝法利用所述聚酰胺酸纺丝液制备聚酰胺酸纳米纤维膜；S3: Prepare a polyamic acid nanofiber membrane by using the polyamic acid spinning liquid through electrospinning method;
S4：将所述聚酰胺酸纳米纤维膜进行热亚胺化处理，制得聚酰亚胺纳米纤维膜；S4: Perform thermal imidization treatment on the polyamic acid nanofiber membrane to obtain a polyimide nanofiber membrane;
S5：将所述的聚酰亚胺纳米纤维膜与在聚酰胺酸溶液中浸渍后的聚酰亚胺纸进行热压成型，制得所述具有双层过滤梯度的聚酰亚胺纸/纳米纤维膜。S5: The polyimide nanofiber membrane and the polyimide paper soaked in the polyamic acid solution are hot-pressed to form the polyimide paper/nano with a double-layer filtration gradient. fiber membrane.
优选的，所述二酐单体为均苯四甲酸二酐、六氟二酐以及3,3’,4,4’-二苯酮四酸二酐中的一种或几种任意配比的混合物；所述二胺单体为4,4’-二氨基二苯醚、4,4’-二氨基联苯以及对苯二胺中的一种或几种任意配比的混合物。Preferably, the dianhydride monomer is one or more of pyromellitic dianhydride, hexafluorodianhydride and 3,3',4,4'-benzophenone tetracarboxylic dianhydride in any proportion. Mixture; the diamine monomer is one or a mixture of several of 4,4'-diaminodiphenyl ether, 4,4'-diaminobiphenyl and p-phenylenediamine in any proportion.
优选的，缩聚反应的反应温度为0～4℃，反应时间为4～6h。Preferably, the reaction temperature of the polycondensation reaction is 0 to 4°C, and the reaction time is 4 to 6 hours.
优选的，冷冻干燥的时间为24～48h。Preferably, the freeze-drying time is 24 to 48 hours.
优选的，所述二酐单体与二胺单体的摩尔比为(1～1.1):(0.95～1.05)。Preferably, the molar ratio of the dianhydride monomer to the diamine monomer is (1-1.1): (0.95-1.05).
优选的，所述聚酰胺酸纺丝液中聚酰胺酸的质量浓度为28％～30％。Preferably, the mass concentration of polyamic acid in the polyamic acid spinning solution is 28% to 30%.
优选的，所述静电纺丝的纺丝电压为20～25kV，纺丝液流速为0.010～0.017ml/min，针头距接收板的距离为10～20cm。Preferably, the electrospinning voltage is 20-25kV, the spinning liquid flow rate is 0.010-0.017ml/min, and the distance between the needle and the receiving plate is 10-20cm.
优选的，所述热亚胺化过程具体为，在5～10℃/min的升温速率下升温至100℃～150℃下，保温30～60min，然后在5～10℃/min的升温速率下升温至200℃～250℃，保温30～60min，最后在5～10℃/min的升温速率下升温至300℃～350℃，保温30～60min。Preferably, the thermal imidization process specifically includes heating to 100°C to 150°C at a heating rate of 5 to 10°C/min, maintaining the temperature for 30 to 60 min, and then heating at a heating rate of 5 to 10°C/min. Raise the temperature to 200℃~250℃, keep it warm for 30~60min, and finally raise the temperature to 300℃~350℃ at a heating rate of 5~10℃/min, and keep it warm for 30~60min.
一种具有双层过滤梯度的聚酰亚胺纸/纳米纤维复合膜，通过上述的方法制得；所述聚酰亚胺纸层的孔径为2～20μm，所述纳米纤维层的孔径为50～500nm；所述具有双层过滤梯度聚酰亚胺纸/纳米纤维膜的拉伸强度为4～15Mpa。A polyimide paper/nanofiber composite membrane with a double-layer filtration gradient, prepared by the above method; the pore diameter of the polyimide paper layer is 2 to 20 μm, and the pore diameter of the nanofiber layer is 50 ~500nm; the tensile strength of the polyimide paper/nanofiber membrane with double-layer filtration gradient is 4-15Mpa.
上述的一种具有双层过滤梯度的聚酰亚胺纸/纳米纤维复合膜在颗粒物过滤领域的应用。The application of the above-mentioned polyimide paper/nanofiber composite membrane with a double-layer filtration gradient in the field of particulate matter filtration.
与现有技术相比，本发明具有以下有益的技术效果：Compared with the existing technology, the present invention has the following beneficial technical effects:
一种具有双层过滤梯度的聚酰亚胺纸/纳米纤维复合膜的制备方法，首先选用二酐单体和二胺单体进行缩聚反应，再经过洗涤析出和冷冻干燥后得到聚酰胺酸粉末；然后配制不同浓度的聚酰胺酸纺丝液，进行静电纺丝过程，得到均匀的聚酰胺酸纳米纤维膜；最后经热亚胺化处理，制备得到黄色的聚酰亚胺纳米纤维膜，然后在聚酰亚胺纸上浸涂一层聚酰胺酸溶液，继而通过热压将聚酰亚胺纳米纤维膜与聚酰亚胺纸结合在一起，制得双层过滤梯度聚酰亚胺纸/纳米纤维膜。本发明采用聚酰亚胺纸与聚酰亚胺膜双层复合的方式提高了空气过滤材料的过滤尺度和对微细颗粒物的过滤效率，同时并没有明显增加过滤压降，而且聚酰亚胺纸还作为保护层提高了滤材的力学性能。本发明的另一个发明点在于，在材料的制备过程中，将聚酰亚胺纸在聚酰胺酸溶液中浸渍后，然后再与聚酰亚胺纳米纤维膜进行热压，这样操作有利于聚酰亚胺纸与聚酰亚胺膜更好的结合，进一步增加聚酰亚胺纸/纳米纤维膜复合材料的力学性能。因此，以聚酰亚胺纸为基底，在此基础上构筑聚酰亚胺纳米纤维膜，使其具有逐级过滤行为，即可实现对多分散PM颗粒的选择性逐级过滤，从而制备宽过滤范围、过滤效率高、力学性能强的高温空气过滤膜。该方法具有简单、高效、设备要求低、适用范围广且环境友好的优点，可有效避免传统高性能复合过滤膜难以制备的问题，所得的复合过滤膜在气体吸附、高温过滤等领域具有很高的潜在应用价值。A method for preparing a polyimide paper/nanofiber composite membrane with a double-layer filtration gradient. First, dianhydride monomer and diamine monomer are used for polycondensation reaction, and then polyamic acid powder is obtained after washing, precipitation and freeze-drying. ; Then prepare polyamic acid spinning solutions of different concentrations and perform an electrospinning process to obtain a uniform polyamic acid nanofiber membrane; finally undergo thermal imidization treatment to prepare a yellow polyimide nanofiber membrane, and then Dip-coat a layer of polyamic acid solution on the polyimide paper, and then combine the polyimide nanofiber membrane and the polyimide paper through hot pressing to prepare a double-layer filtration gradient polyimide paper/ Nanofiber membrane. The present invention adopts a double-layer composite method of polyimide paper and polyimide membrane to improve the filtration scale of the air filter material and the filtration efficiency of fine particles without significantly increasing the filtration pressure drop, and the polyimide paper It also serves as a protective layer to improve the mechanical properties of the filter material. Another invention point of the present invention is that during the preparation process of the material, the polyimide paper is soaked in the polyamic acid solution and then hot-pressed with the polyimide nanofiber membrane. This operation is beneficial to the polyimide nanofiber membrane. The better combination of imide paper and polyimide membrane further increases the mechanical properties of polyimide paper/nanofiber membrane composite materials. Therefore, by using polyimide paper as the base and constructing a polyimide nanofiber membrane to have step-by-step filtration behavior, selective step-by-step filtration of polydisperse PM particles can be achieved, thereby preparing a wide range of High-temperature air filtration membrane with high filtration range, high filtration efficiency and strong mechanical properties. This method has the advantages of simplicity, high efficiency, low equipment requirements, wide application range, and environmental friendliness. It can effectively avoid the problem of difficulty in preparing traditional high-performance composite filter membranes. The resulting composite filter membrane has high performance in gas adsorption, high-temperature filtration and other fields. potential application value.
进一步的，所述二酐单体为均苯四甲酸二酐、联苯四甲酸二酐以及3,3’,4,4’-二苯酮四酸二酐中的一种或几种任意配比的混合物，可使得聚合反应稳定易控制；二胺单体为4,4’-二氨基二苯醚、4,4’-二氨基联苯以及对苯二胺中的一种或几种任意配比的混合物，可使得聚合反应稳定易控制。Further, the dianhydride monomer is one or more of any combination of pyromellitic dianhydride, diphenyltetracarboxylic dianhydride and 3,3',4,4'-benzophenone tetracarboxylic dianhydride. The mixture of ratio can make the polymerization reaction stable and easy to control; the diamine monomer is one or more of 4,4'-diaminodiphenyl ether, 4,4'-diaminobiphenyl and p-phenylenediamine. The proportioned mixture can make the polymerization reaction stable and easy to control.
进一步的，步骤S1中，缩聚反应的反应温度为0～4℃，反应时间为4～6h，可使得反应过程中热量减少，粘度η达到了最大值。Further, in step S1, the reaction temperature of the polycondensation reaction is 0 to 4°C and the reaction time is 4 to 6 hours, which can reduce the heat during the reaction and the viscosity eta reaches the maximum value.
进一步的，冷冻干燥的时间为24～48h，可使得溶剂充分升华，PAA保持原有结构。Furthermore, the freeze-drying time is 24 to 48 hours, which allows the solvent to fully sublimate and the PAA to maintain its original structure.
进一步的，二酐单体与二胺单体的摩尔比为(1～1.1):(0.95～1.05)，可使得分子聚合度高，粘度大。Furthermore, the molar ratio of the dianhydride monomer to the diamine monomer is (1~1.1):(0.95~1.05), which can result in a high degree of molecular polymerization and high viscosity.
进一步的，聚酰胺酸纺丝液的浓度为28％～30％，可使得纤维中串珠结构减少，纤维更加均匀光滑。Furthermore, the concentration of the polyamic acid spinning liquid is 28% to 30%, which can reduce the bead structure in the fiber and make the fiber more uniform and smooth.
进一步的，静电纺丝的纺丝电压为20～25kV，纺丝液流速为0.010～0.017ml/min，针头距接收板的距离为10～20cm，可使得纤维出丝均匀且稳定，产出率高。Furthermore, the spinning voltage of electrospinning is 20~25kV, the flow rate of spinning solution is 0.010~0.017ml/min, and the distance between the needle and the receiving plate is 10~20cm, which can make the fiber output uniform and stable, and improve the output rate. high.
进一步的，所述热亚胺化过程具体为，在5～10℃/min的升温速率下升温至100℃～150℃下，保温30～60min，然后在5～10℃/min的升温速率下升温至200℃～250℃，保温30～60min，最后在5～10℃/min的升温速率下升温至300℃～350℃，保温30～60min，可使得聚酰胺酸完全转化成聚酰亚胺。Further, the thermal imidization process specifically includes heating to 100°C to 150°C at a heating rate of 5 to 10°C/min, maintaining the temperature for 30 to 60min, and then heating at a heating rate of 5 to 10°C/min. Raise the temperature to 200℃～250℃, keep it for 30～60min, and finally raise the temperature to 300℃～350℃ at a heating rate of 5～10℃/min, and keep it for 30～60min, which can completely convert polyamic acid into polyimide. .
附图说明Description of the drawings
为了更清楚地说明本发明实施例的技术方案，下面将对实施例中所需要使用的附图作简单地介绍，应当理解，以下附图仅示出了本发明的某些实施例，因此不应被看作是对范围的限定，对于本领域普通技术人员来讲，在不付出创造性劳动的前提下，还可以根据这些附图获得其他相关的附图。In order to explain the technical solutions of the embodiments of the present invention more clearly, the drawings required to be used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and therefore do not It should be regarded as a limitation of the scope. For those of ordinary skill in the art, other relevant drawings can be obtained based on these drawings without exerting creative efforts.
图1为本发明中一种具有双层过滤梯度聚酰亚胺纸/纳米纤维膜制备方法的流程示意图；Figure 1 is a schematic flow chart of a preparation method of a double-layer filtration gradient polyimide paper/nanofiber membrane in the present invention;
图2是本发明实施例1～3制得的聚酰亚胺纳米纤维膜的光学照片；Figure 2 is an optical photograph of the polyimide nanofiber membrane prepared in Examples 1 to 3 of the present invention;
图3是本发明对比例1～2以及实施例1～3制得的聚酰亚胺纳米纤维膜的SEM测试结果，其中，a、b分别对应对比例1～2，c、d、e分别对应实施例1～3；Figure 3 is the SEM test results of the polyimide nanofiber membranes prepared in Comparative Examples 1 to 2 and Examples 1 to 3 of the present invention, where a and b respectively correspond to Comparative Examples 1 to 2, and c, d and e respectively Corresponding to embodiments 1 to 3;
图4是本发明实施例1制得的具有双层过滤梯度的聚酰亚胺纸/纳米纤维膜复合膜截面的扫描电子显微镜图；Figure 4 is a scanning electron microscope image of the cross-section of the polyimide paper/nanofiber membrane composite membrane with a double-layer filtration gradient prepared in Example 1 of the present invention;
图5是本发明实施例1制得的具有双层过滤梯度的聚酰亚胺纸/纳米纤维膜上聚酰亚胺纸一侧的扫描电子显微镜图。Figure 5 is a scanning electron microscope image of the polyimide paper side of the polyimide paper/nanofiber membrane with a double-layer filtration gradient prepared in Example 1 of the present invention.
具体实施方式Detailed ways
为使本领域技术人员可了解本发明的特点及效果，以下谨就说明书及权利要求书中提及的术语及用语进行一般性的说明及定义。除非另有指明，否则文中使用的所有技术及科学上的字词，均为本领域技术人员对于本发明所了解的通常意义，当有冲突情形时，应以本说明书的定义为准。In order to enable those skilled in the art to understand the characteristics and effects of the present invention, the terms and expressions mentioned in the description and claims are generally described and defined below. Unless otherwise specified, all technical and scientific terms used in the text have their usual meanings as understood by those skilled in the art regarding the present invention. In the event of conflict, the definitions in this specification shall prevail.
本文描述和公开的理论或机制，无论是对或错，均不应以任何方式限制本发明的范围，即本发明内容可以在不为任何特定的理论或机制所限制的情况下实施。The theories or mechanisms described and disclosed herein, whether true or false, should not limit the scope of the invention in any way, that is, the invention may be implemented without being limited to any particular theory or mechanism.
本文中，所有以数值范围或百分比范围形式界定的特征如数值、数量、含量与浓度仅是为了简洁及方便。据此，数值范围或百分比范围的描述应视为已涵盖且具体公开所有可能的次级范围及范围内的个别数值(包括整数与分数)。In this article, all characteristics such as numerical values, quantities, contents, and concentrations defined in the form of numerical ranges or percentage ranges are for simplicity and convenience only. Accordingly, a description of a numerical range or percentage range shall be deemed to cover and specifically disclose all possible subranges and individual values within the range (including integers and fractions).
本文中，若无特别说明，“包含”、“包括”、“含有”、“具有”或类似用语涵盖了“由……组成”和“主要由……组成”的意思，例如“A包含a”涵盖了“A包含a和其他”和“A仅包含a”的意思。In this article, unless otherwise stated, "comprises", "includes", "contains", "has" or similar terms cover the meanings of "consisting of" and "consisting essentially of", for example, "A includes a ” covers the meaning of “A contains a and others” and “A contains only a”.
本文中，为使描述简洁，未对各个实施方案或实施例中的各个技术特征的所有可能的组合都进行描述。因此，只要这些技术特征的组合不存在矛盾，各个实施方案或实施例中的各个技术特征可以进行任意的组合，所有可能的组合都应当认为是本说明书记载的范围。Herein, in order to keep the description concise, not all possible combinations of each technical feature in each embodiment or example are described. Therefore, as long as there is no contradiction in the combination of these technical features, each technical feature in each embodiment or example can be combined in any way, and all possible combinations should be considered to be within the scope of this specification.
如图1所示，本发明提供了一种具有双层过滤梯度的聚酰亚胺纸/纳米纤维复合膜的制备方法，包括以下步骤：As shown in Figure 1, the present invention provides a method for preparing a polyimide paper/nanofiber composite membrane with a double-layer filtration gradient, which includes the following steps:
S1：首先使二酐和二胺进行缩聚得到聚酰胺酸溶液，然后经洗涤析出以及冷冻干燥后得到聚酰胺酸粉末；S1: First, the dianhydride and diamine are polycondensed to obtain a polyamic acid solution, and then the polyamic acid powder is obtained after washing, precipitation and freeze-drying;
其中，二酐单体为均苯四甲酸二酐、六氟二酐以及3,3’,4,4’-二苯酮四酸二酐中的一种或几种任意配比的混合物；二胺单体为4,4’-二氨基二苯醚、4,4’-二氨基联苯以及对苯二胺中的一种或几种任意配比的混合物。二酐单体与二胺单体的摩尔比为(1～1.1):(0.95～1.05)。缩聚反应的反应温度为0～4℃，反应时间为4～6h。冷冻干燥的时间为24～48h。Among them, the dianhydride monomer is one or a mixture of several of pyromellitic dianhydride, hexafluorodianhydride and 3,3',4,4'-benzophenone tetracarboxylic acid dianhydride in any proportion; The amine monomer is one or a mixture of several of 4,4'-diaminodiphenyl ether, 4,4'-diaminobiphenyl and p-phenylenediamine in any proportion. The molar ratio of dianhydride monomer to diamine monomer is (1~1.1): (0.95~1.05). The reaction temperature of the polycondensation reaction is 0 to 4°C, and the reaction time is 4 to 6 hours. The freeze-drying time is 24 to 48 hours.
S2：在冰水浴下，将制得的聚酰胺酸粉末加入至强极性非质子溶剂中，搅拌至聚酰胺酸粉末充分溶解，得到聚酰胺酸纺丝液，该聚酰胺酸纺丝液中聚酰胺酸的质量浓度为28％～30％。S2: In an ice-water bath, add the prepared polyamic acid powder to a strong polar aprotic solvent, stir until the polyamic acid powder is fully dissolved, and obtain a polyamic acid spinning liquid. In the polyamic acid spinning liquid The mass concentration of polyamic acid is 28% to 30%.
其中，强极性非质子溶剂为N,N’-二甲基甲酰胺、N,N’-二甲基乙酰胺、N-甲基吡咯烷酮、二甲基亚砜的一种或几种任意配比的混合物。Among them, the highly polar aprotic solvent is one or more arbitrary combinations of N,N'-dimethylformamide, N,N'-dimethylacetamide, N-methylpyrrolidone, and dimethyl sulfoxide. ratio mixture.
S3：通过静电纺丝法利用所述聚酰胺酸纺丝液制备聚酰胺酸纳米纤维膜；静电纺丝过程中静电纺丝的电压为20～25kV，纺丝液流速为0.010～0.017ml/min，针头距接收板的距离为10～20cm。S3: Use the polyamic acid spinning solution to prepare polyamic acid nanofiber membranes by electrospinning; the voltage of electrospinning during the electrospinning process is 20-25kV, and the flow rate of the spinning solution is 0.010-0.017ml/min. , the distance between the needle and the receiving plate is 10~20cm.
S4：将所述聚酰胺酸纳米纤维膜进行热亚胺化处理，制得聚酰亚胺纳米纤维膜；其中，热亚胺化过程具体为，在5～10℃/min的升温速率下升温至100℃～150℃下，保温30～60min，然后在5～10℃/min的升温速率下升温至200℃～250℃，保温30～60min，最后在5～10℃/min的升温速率下升温至300℃～350℃，保温30～60min。S4: The polyamic acid nanofiber membrane is subjected to thermal imidization treatment to obtain a polyimide nanofiber membrane; wherein, the thermal imidization process specifically includes heating at a heating rate of 5 to 10°C/min. to 100℃～150℃, keep it for 30～60min, then raise the temperature to 200℃～250℃ at a heating rate of 5～10℃/min, keep it for 30～60min, and finally heat it up at a heating rate of 5～10℃/min. Raise the temperature to 300℃~350℃ and keep it warm for 30~60min.
S5：将所述的聚酰亚胺纳米纤维膜与在聚酰胺酸溶液中浸渍后的聚酰亚胺纸进行热压成型，制得所述具有双层过滤梯度的聚酰亚胺纸/纳米纤维膜。S5: The polyimide nanofiber membrane and the polyimide paper soaked in the polyamic acid solution are hot-pressed to form the polyimide paper/nano with a double-layer filtration gradient. fiber membrane.
本发明还公开了通过上述的方法制得的双层过滤梯度的聚酰亚胺纸/纳米纤维复合膜；其中聚酰亚胺纸层的孔径为2～20μm，纳米纤维层的孔径为50～500nm；该具有双层过滤梯度聚酰亚胺纸/纳米纤维膜的拉伸强度为4～15Mpa。The invention also discloses a double-layer filtration gradient polyimide paper/nanofiber composite membrane prepared by the above method; wherein the pore size of the polyimide paper layer is 2 to 20 μm, and the pore size of the nanofiber layer is 50 to 50 μm. 500nm; the tensile strength of the polyimide paper/nanofiber membrane with double-layer filtration gradient is 4-15Mpa.
另外，本发明还公开了具有双层过滤梯度的聚酰亚胺纸/纳米纤维复合膜在颗粒物过滤领域的应用。In addition, the present invention also discloses the application of polyimide paper/nanofiber composite membrane with double-layer filtration gradient in the field of particulate matter filtration.
本发明中聚酰亚胺纸的制备过程为以聚酰亚胺短切纤维、对位芳纶沉析纤维为原料，通过纤维疏解机和纸页成型器抄造定量为60g/m2的聚酰亚胺纸。控制聚酰亚胺纤维与对位芳纶沉析纤维的比例为7:3，对其进行疏解分散后抄纸。The preparation process of the polyimide paper in the present invention is to use polyimide chopped fibers and para-aramid fibrid fibers as raw materials, and use a fiber deflasing machine and a paper sheet former to produce a polyimide paper with a quantitative value of 60g/m2 . imine paper. Control the ratio of polyimide fiber to para-aramid fibrid fiber to 7:3, loosen and disperse them and then make paper.
疏解方式具体为称取一定量的聚酰亚胺短切纤维和对位芳纶沉析纤维置于标准纤维疏解器中，再将一定量的水加入标准纤维疏解器中进行配浆，疏解转速为20000转，疏解时间为5min。The specific method of deflaking is to weigh a certain amount of polyimide chopped fibers and para-aramid fiber fibrids and place them in a standard fiber deflounderer, then add a certain amount of water to the standard fiber deflounderer to mix the pulp, and the deflaking speed is The speed is 20,000 rpm and the decomposition time is 5 minutes.
另外，本发明中拉伸强度的测试过程具体为：采用伺服材料多功能高低温控制试验机来测试材料的力学性能。测试条件为：拉伸速率为1mm/min，样品规格为20mmx5mm，夹距为5mm。In addition, the testing process of tensile strength in the present invention is specifically: using a servo material multifunctional high and low temperature control testing machine to test the mechanical properties of the material. The test conditions are: the tensile rate is 1mm/min, the sample specification is 20mmx5mm, and the clamping distance is 5mm.
下面结合具体实施例，进一步阐述本发明。应理解，这些实施例仅用于说明本发明而不用于限制本发明的范围。此外应理解，在阅读了本发明讲授的内容之后，本领域技术人员可以对本发明作各种改动或修改，这些等价形式同样落于本申请所附权利要求书所限定的范围。The present invention will be further described below in conjunction with specific embodiments. It should be understood that these examples are only used to illustrate the invention and are not intended to limit the scope of the invention. In addition, it should be understood that after reading the teachings of the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims of this application.
下列实施例中使用本领域常规的仪器设备。下列实施例中未注明具体条件的实验方法，通常按照常规条件，或按照制造厂商所建议的条件。下列实施例中使用各种原料，除非另作说明，都使用常规市售产品，其规格为本领域常规规格。在本发明的说明书以及下述实施例中，如没有特别说明，“％”都表示重量百分比，“份”都表示重量份，比例都表示重量比。In the following examples, conventional equipment in this field was used. Experimental methods without specifying specific conditions in the following examples usually follow conventional conditions or conditions recommended by the manufacturer. Various raw materials are used in the following examples. Unless otherwise stated, conventional commercially available products are used, and their specifications are conventional specifications in this field. In the description of the present invention and the following examples, unless otherwise specified, "%" means weight percentage, "part" means weight part, and proportion means weight ratio.
对比例1Comparative example 1
前驱体聚酰胺酸(PAA)固体的制备：在120mL的DMF溶液中，按照摩尔质量比为1.03:1，加入PMDA与ODA，其具体步骤如下：首先，量取100mL的DMF、称量10g的4,4’-二氨基二苯醚(ODA)加入三口烧瓶，在低温4℃下搅拌溶解，然后再称量11.22g均苯四甲酸酐(PMDA)分四次加入，每次间隔10min，用剩余的20mL的DMF冲洗烧杯和瓶壁，搅拌6h，出现爬杆效应后反应结束，制得PAA溶液。其中，当PAA溶液在搅拌过程中沿着搅拌轴被拉伸取向并缠绕在轴上时，即当出现爬杆效应后，将PAA缓慢倒入2L的去离子水中析出并进行多次洗涤后，放入冰箱中进行预冻，接着冷冻干燥24h，得到PAA固体，研磨后低温存放备用。Preparation of the precursor polyamic acid (PAA) solid: In 120 mL of DMF solution, add PMDA and ODA according to the molar mass ratio of 1.03:1. The specific steps are as follows: First, measure 100 mL of DMF, weigh 10 g of Add 4,4'-diaminodiphenyl ether (ODA) to the three-necked flask, stir and dissolve at a low temperature of 4°C, and then weigh 11.22g of pyromellitic anhydride (PMDA) and add it in four times, with an interval of 10 minutes each time. Rinse the beaker and bottle walls with the remaining 20 mL of DMF, and stir for 6 hours. The reaction ends after the rod climbing effect appears, and a PAA solution is obtained. Among them, when the PAA solution is stretched and oriented along the stirring axis during the stirring process and wrapped around the axis, that is, when the climbing rod effect occurs, the PAA is slowly poured into 2L of deionized water to precipitate and washed multiple times. Place it in the refrigerator for pre-freezing, then freeze-dry for 24 hours to obtain PAA solid, which is then ground and stored at low temperature for later use.
PAA纳米纤维膜的制备：调整纺丝液浓度，采用静电纺丝设备进行纺丝过程(环境湿度为30％，针尖距接收板距离为16cm)，来制备PAA纤维，具体过程如下：称取2.6g上述制备的PAA粉末溶于10mLDMF溶液中，低温搅拌4h后，获得质量浓度为26％的淡黄色PAA纺丝液，设置静电纺丝电压为24kV，流速为0.017mL/min，进行静电纺丝，获得PAA纳米纤维薄膜。Preparation of PAA nanofiber membrane: adjust the concentration of spinning liquid, use electrospinning equipment to perform the spinning process (environmental humidity is 30%, the distance between the needle tip and the receiving plate is 16cm) to prepare PAA fibers. The specific process is as follows: weigh 2.6 g The PAA powder prepared above was dissolved in 10 mL of DMF solution. After stirring at low temperature for 4 hours, a light yellow PAA spinning solution with a mass concentration of 26% was obtained. The electrospinning voltage was set to 24 kV and the flow rate was 0.017 mL/min for electrospinning. , to obtain PAA nanofiber film.
聚酰亚胺纸/聚酰亚胺纳米纤维膜的制备：将上述薄膜在高温管式炉中，N2环境下，进行阶段升温反应后处理：在10℃/min的升温速率下升温至150℃下，保温30min，然后在10℃/min的升温速率下升温至250℃，保温60min，最后在5℃/min的升温速率下升温至300℃，保温30min，制得聚酰亚胺纳米纤维膜；在聚酰亚胺纸上浸涂一层聚酰胺酸溶液，通过热压粘合工艺，将聚酰亚胺纸与聚酰亚胺纳米纤维膜结合在一起，得到双层过滤梯度聚酰亚胺纸/聚酰亚胺纳米纤维复合膜，即到双层过滤梯度聚酰亚胺纸/纳米纤维复合膜。Preparation of polyimide paper/polyimide nanofiber membrane: The above film is subjected to a staged temperature-raising reaction in a high-temperature tube furnace under anN2 environment. Post-processing: the temperature is raised to 150 at a heating rate of 10°C/min. ℃, keep the temperature for 30 minutes, then raise the temperature to 250°C at a heating rate of 10°C/min, keep the temperature for 60 minutes, and finally raise the temperature to 300°C at a heating rate of 5°C/min, and keep the temperature for 30 minutes to prepare polyimide nanofibers. Membrane; dip-coat a layer of polyamic acid solution on polyimide paper, and combine the polyimide paper and polyimide nanofiber membrane through a hot-pressing bonding process to obtain a double-layer filtration gradient polyamide Imine paper/polyimide nanofiber composite membrane, that is, double-layer filtration gradient polyimide paper/nanofiber composite membrane.
对比例2Comparative example 2
前驱体PAA固体的制备：在120mLDMF溶液中，按照摩尔质量比为1.03:1，加入PMDA与ODA，其具体步骤如下：首先，量取100mLDMF、称量10g的4,4’-二氨基二苯醚(ODA)加入三口烧瓶，在低温4℃下搅拌溶解，然后再称量11.22g均苯四甲酸酐(PMDA)分四次加入，每次间隔10min，用剩余的20mLDMF冲洗烧杯和瓶壁，搅拌6h，出现爬杆效应后反应结束，制得PAA溶液。然后将PAA缓慢倒入2L的去离子水中析出并进行多次洗涤后，放入冰箱中进行预冻，接着冷冻干燥24h，得到PAA固体，研磨后低温存放备用。Preparation of precursor PAA solid: In 120mLDMF solution, add PMDA and ODA according to the molar mass ratio of 1.03:1. The specific steps are as follows: First, weigh 100mLDMF and weigh 10g of 4,4'-diaminodiphenyl. Add ether (ODA) to the three-necked flask, stir and dissolve at low temperature of 4°C, then weigh 11.22g of pyromellitic anhydride (PMDA) and add it in four times with an interval of 10 minutes each time. Use the remaining 20mL of DMF to rinse the beaker and bottle walls. After stirring for 6 hours, the reaction ended after the rod climbing effect appeared, and a PAA solution was obtained. Then slowly pour the PAA into 2L of deionized water to precipitate, wash it multiple times, put it in the refrigerator for pre-freezing, and then freeze-dry for 24 hours to obtain the PAA solid, which is ground and stored at low temperature for later use.
PAA纳米纤维膜的制备：调整纺丝液浓度，采用静电纺丝设备进行纺丝过程(环境湿度为30％，针尖距接收板距离为16cm)，来制备PAA纤维，具体过程如下：称取2.7g上述制备的PAA粉末溶于10mLDMF溶液中，低温搅拌4h后，获得质量浓度为27％的淡黄色PAA纺丝液，设置静电纺丝电压为24kV，流速为0.017mL/min，进行静电纺丝，获得PAA纳米纤维薄膜。Preparation of PAA nanofiber membrane: adjust the concentration of the spinning liquid, use electrospinning equipment to perform the spinning process (environmental humidity is 30%, the distance between the needle tip and the receiving plate is 16cm) to prepare PAA fibers. The specific process is as follows: weigh 2.7 g The PAA powder prepared above was dissolved in 10 mL of DMF solution. After stirring at low temperature for 4 hours, a light yellow PAA spinning liquid with a mass concentration of 27% was obtained. The electrospinning voltage was set to 24 kV and the flow rate was 0.017 mL/min for electrospinning. , to obtain PAA nanofiber film.
聚酰亚胺纸/纳米纤维膜的制备：将上述薄膜在高温管式炉中，N2环境下，进行阶段升温反应后处理：在10℃/min的升温速率下升温至150℃下，保温30min，然后在10℃/min的升温速率下升温至250℃，保温60min，最后在5℃/min的升温速率下升温至300℃，保温30min，制得聚酰亚胺纳米纤维膜；在聚酰亚胺纸上浸涂一层聚酰胺酸溶液，通过热压粘合工艺，将聚酰亚胺纸与聚酰亚胺纳米纤维膜结合在一起，得到双层过滤梯度聚酰亚胺纸/纳米纤维膜。Preparation of polyimide paper/nanofiber membrane: The above film is carried out in a high-temperature tube furnace underN2 environment. Post-processing: heat up to 150°C at a heating rate of 10°C/min and keep warm. 30min, then heated to 250℃ at a heating rate of 10℃/min, kept for 60min, and finally heated to 300℃ at a heating rate of 5℃/min, kept for 30min, to obtain a polyimide nanofiber membrane; The imide paper is dip-coated with a layer of polyamic acid solution, and the polyimide paper and the polyimide nanofiber membrane are combined together through a hot-pressing bonding process to obtain a double-layer filtration gradient polyimide paper/ Nanofiber membrane.
实施例1Example 1
前驱体PAA固体的制备：在120mL的DMF溶液中，按照摩尔质量比为1.03:1，加入PMDA与ODA，其具体步骤如下：首先，量取100mLDMF、称量10g的4,4’-二氨基二苯醚(ODA)加入三口烧瓶，在低温4℃下搅拌溶解，然后再称量11.22g均苯四甲酸酐(PMDA)分四次加入，每次间隔10min，用剩余的20mLDMF冲洗烧杯和瓶壁，搅拌6h，出现爬杆效应后反应结束，制得PAA溶液。然后将PAA缓慢倒入2L的去离子水中析出并进行多次洗涤后，放入冰箱中进行预冻，接着冷冻干燥24h，得到PAA固体，研磨后低温存放备用。Preparation of precursor PAA solid: In 120 mL of DMF solution, add PMDA and ODA according to a molar mass ratio of 1.03:1. The specific steps are as follows: First, measure 100 mL of DMF and weigh 10 g of 4,4'-diamino. Add diphenyl ether (ODA) to the three-necked flask, stir and dissolve at a low temperature of 4°C, then weigh 11.22g of pyromellitic anhydride (PMDA) and add it in four times, with an interval of 10 minutes each time, and rinse the beaker and bottle with the remaining 20mL DMF. wall, stir for 6 hours, the reaction ends after the rod climbing effect appears, and a PAA solution is obtained. Then slowly pour the PAA into 2L of deionized water to precipitate, wash it multiple times, put it in the refrigerator for pre-freezing, and then freeze-dry for 24 hours to obtain the PAA solid, which is ground and stored at low temperature for later use.
PAA纳米纤维膜的制备：调整纺丝液浓度，采用静电纺丝设备进行纺丝过程(环境湿度为30％，针尖距接收板距离为16cm)，来制备PAA纤维，具体过程如下：称取2.8g上述制备的PAA粉末溶于10mLDMF溶液中，低温搅拌4h后，获得质量浓度为28％的淡黄色PAA纺丝液，设置静电纺丝电压为24kV，流速为0.017mL/min，进行静电纺丝，获得PAA纳米纤维薄膜。Preparation of PAA nanofiber membrane: adjust the concentration of the spinning liquid, use electrospinning equipment to perform the spinning process (environmental humidity is 30%, the distance between the needle tip and the receiving plate is 16cm) to prepare PAA fibers. The specific process is as follows: weigh 2.8 g The PAA powder prepared above was dissolved in 10 mL of DMF solution. After stirring at low temperature for 4 hours, a light yellow PAA spinning solution with a mass concentration of 28% was obtained. The electrospinning voltage was set to 24 kV and the flow rate was 0.017 mL/min for electrospinning. , to obtain PAA nanofiber film.
聚酰亚胺纸/纳米纤维膜的制备：将上述薄膜在高温管式炉中，N2环境下，进行阶段升温反应后处理：在10℃/min的升温速率下升温至150℃下，保温30min，然后在10℃/min的升温速率下升温至250℃，保温60min，最后在5℃/min的升温速率下升温至300℃，保温30min，制得聚酰亚胺纳米纤维膜；在聚酰亚胺纸上浸涂一层聚酰胺酸溶液，通过热压粘合工艺，将聚酰亚胺纸与聚酰亚胺纳米纤维膜结合在一起，得到双层过滤梯度聚酰亚胺纸/纳米纤维膜。Preparation of polyimide paper/nanofiber membrane: The above film is carried out in a high-temperature tube furnace underN2 environment. Post-processing: heat up to 150°C at a heating rate of 10°C/min and keep warm. 30min, then heated to 250℃ at a heating rate of 10℃/min, kept for 60min, and finally heated to 300℃ at a heating rate of 5℃/min, kept for 30min, to obtain a polyimide nanofiber membrane; The imide paper is dip-coated with a layer of polyamic acid solution, and the polyimide paper and the polyimide nanofiber membrane are combined together through a hot-pressing bonding process to obtain a double-layer filtration gradient polyimide paper/ Nanofiber membrane.
经本发明的拉伸强度测试方法测得本实施例制得的具有双层过滤梯度聚酰亚胺纸/纳米纤维膜的拉伸强度为15Mpa。The tensile strength of the polyimide paper/nanofiber membrane with double-layer filtration gradient produced in this example was measured by the tensile strength testing method of the present invention to be 15 MPa.
实施例2Example 2
前驱体PAA固体的制备：在120mLDMF溶液中，按照摩尔质量比为1.03:1，加入PMDA与ODA，其具体步骤如下：首先，量取100mLDMF、称量10g的4,4’-二氨基二苯醚(ODA)加入三口烧瓶，在低温4℃下搅拌溶解，然后再称量11.22g均苯四甲酸酐(PMDA)分四次加入，每次间隔10min，用剩余的20mLDMF冲洗烧杯和瓶壁，搅拌6h，出现爬杆效应后反应结束，制得PAA溶液。然后将PAA缓慢倒入2L的去离子水中析出并进行多次洗涤后，放入冰箱中进行预冻，接着冷冻干燥24h，得到PAA固体，研磨后低温存放备用。Preparation of precursor PAA solid: In 120mLDMF solution, add PMDA and ODA according to the molar mass ratio of 1.03:1. The specific steps are as follows: First, weigh 100mLDMF and weigh 10g of 4,4'-diaminodiphenyl. Add ether (ODA) to the three-necked flask, stir and dissolve at low temperature of 4°C, then weigh 11.22g of pyromellitic anhydride (PMDA) and add it in four times with an interval of 10 minutes each time. Use the remaining 20mL of DMF to rinse the beaker and bottle walls. After stirring for 6 hours, the reaction ended after the rod climbing effect appeared, and a PAA solution was obtained. Then slowly pour the PAA into 2L of deionized water to precipitate, wash it multiple times, put it in the refrigerator for pre-freezing, and then freeze-dry for 24 hours to obtain the PAA solid, which is ground and stored at low temperature for later use.
PAA纳米纤维膜的制备：调整纺丝液浓度，采用静电纺丝设备进行纺丝过程(环境湿度为30％，针尖距接收板距离为16cm)，来制备PAA纤维，具体过程如下：称取2.9g上述制备的PAA粉末溶于10mLDMF溶液中，低温搅拌4h后，获得质量浓度为29％的淡黄色PAA纺丝液，设置静电纺丝电压为24kV，流速为0.017mL/min，进行静电纺丝，获得PAA纳米纤维薄膜。Preparation of PAA nanofiber membrane: adjust the concentration of the spinning liquid, use electrospinning equipment to perform the spinning process (environmental humidity is 30%, the distance between the needle tip and the receiving plate is 16cm) to prepare PAA fibers. The specific process is as follows: weigh 2.9 g The PAA powder prepared above was dissolved in 10 mL of DMF solution. After stirring at low temperature for 4 hours, a light yellow PAA spinning solution with a mass concentration of 29% was obtained. The electrospinning voltage was set to 24 kV and the flow rate was 0.017 mL/min for electrospinning. , to obtain PAA nanofiber film.
酰亚胺纸/纳米纤维膜的制备：将上述薄膜在高温管式炉中，N2环境下，进行阶段升温反应后处理：在10℃/min的升温速率下升温至150℃下，保温30min，然后在10℃/min的升温速率下升温至250℃，保温60min，最后在5℃/min的升温速率下升温至300℃，保温30min，制得聚酰亚胺纳米纤维膜；在聚酰亚胺纸上浸涂一层聚酰胺酸溶液，通过热压粘合工艺，将聚酰亚胺纸与聚酰亚胺纳米纤维膜结合在一起，得到双层过滤梯度聚酰亚胺纸/纳米纤维膜。Preparation of imide paper/nanofiber membrane: perform a staged temperature-raising reaction on the above-mentioned film in a high-temperature tube furnace underN2 environment. Post-processing: raise the temperature to 150°C at a heating rate of 10°C/min and keep it warm for 30 minutes. , then raise the temperature to 250°C at a heating rate of 10°C/min, and keep it for 60 minutes, and finally heat it up to 300°C at a heating rate of 5°C/min and keep it for 30 minutes to prepare a polyimide nanofiber membrane; Dip-coat a layer of polyamic acid solution on the imide paper, and combine the polyimide paper and the polyimide nanofiber membrane through a hot-pressing bonding process to obtain a double-layer filter gradient polyimide paper/nano fiber membrane.
经本发明的拉伸强度测试方法测得本实施例制得的具有双层过滤梯度聚酰亚胺纸/纳米纤维膜的拉伸强度为15.2Mpa。The tensile strength of the polyimide paper/nanofiber membrane with double-layer filtration gradient produced in this example was measured by the tensile strength testing method of the present invention to be 15.2Mpa.
实施例3Example 3
前驱体PAA固体的制备：在120mLDMF溶液中，按照摩尔质量比为1.03:1，加入PMDA与ODA，其具体步骤如下：首先，量取100mLDMF、称量10g的4,4’-二氨基二苯醚(ODA)加入三口烧瓶，在低温4℃下搅拌溶解，然后再称量11.22g均苯四甲酸酐(PMDA)分四次加入，每次间隔10min，用剩余的20mLDMF冲洗烧杯和瓶壁，搅拌6h，出现爬杆效应后反应结束，制得PAA溶液。然后将PAA缓慢倒入2L的去离子水中析出并进行多次洗涤后，放入冰箱中进行预冻，接着冷冻干燥24h，得到PAA固体，研磨后低温存放备用。Preparation of precursor PAA solid: In 120mLDMF solution, add PMDA and ODA according to the molar mass ratio of 1.03:1. The specific steps are as follows: First, weigh 100mLDMF and weigh 10g of 4,4'-diaminodiphenyl. Add ether (ODA) to the three-necked flask, stir and dissolve at low temperature of 4°C, then weigh 11.22g of pyromellitic anhydride (PMDA) and add it in four times with an interval of 10 minutes each time. Use the remaining 20mL of DMF to rinse the beaker and bottle walls. After stirring for 6 hours, the reaction ended after the rod climbing effect appeared, and a PAA solution was obtained. Then slowly pour the PAA into 2L of deionized water to precipitate, wash it multiple times, put it in the refrigerator for pre-freezing, and then freeze-dry for 24 hours to obtain the PAA solid, which is ground and stored at low temperature for later use.
PAA纳米纤维膜的制备：调整纺丝液浓度，采用静电纺丝设备进行纺丝过程(环境湿度为30％，针尖距接收板距离为16cm)，来制备PAA纤维，具体过程如下：称取3g上述制备的PAA粉末溶于10mLDMF溶液中，低温搅拌4h后，获得质量浓度为30％的淡黄色PAA纺丝液，设置静电纺丝电压为24kV，流速为0.017mL/min，进行静电纺丝，获得PAA纳米纤维薄膜。Preparation of PAA nanofiber membrane: adjust the concentration of the spinning solution and use electrospinning equipment to perform the spinning process (environmental humidity is 30%, the distance between the needle tip and the receiving plate is 16cm) to prepare PAA fibers. The specific process is as follows: weigh 3g The PAA powder prepared above was dissolved in 10 mL of DMF solution. After stirring at low temperature for 4 hours, a light yellow PAA spinning solution with a mass concentration of 30% was obtained. The electrospinning voltage was set to 24 kV and the flow rate was 0.017 mL/min for electrospinning. PAA nanofiber films were obtained.
酰亚胺纸/纳米纤维膜的制备：将上述薄膜在高温管式炉中，N2环境下，进行阶段升温反应后处理：在10℃/min的升温速率下升温至150℃下，保温30min，然后在10℃/min的升温速率下升温至250℃，保温60min，最后在5℃/min的升温速率下升温至300℃，保温30min，制得聚酰亚胺纳米纤维膜；在聚酰亚胺纸上浸涂一层聚酰胺酸溶液，通过热压粘合工艺，将聚酰亚胺纸与聚酰亚胺纳米纤维膜结合在一起，得到双层过滤梯度聚酰亚胺纸/纳米纤维膜。Preparation of imide paper/nanofiber membrane: perform a staged temperature-raising reaction on the above-mentioned film in a high-temperature tube furnace underN2 environment. Post-processing: raise the temperature to 150°C at a heating rate of 10°C/min and keep it warm for 30 minutes. , then raise the temperature to 250°C at a heating rate of 10°C/min, and keep it for 60 minutes, and finally heat it up to 300°C at a heating rate of 5°C/min and keep it for 30 minutes to prepare a polyimide nanofiber membrane; Dip-coat a layer of polyamic acid solution on the imide paper, and combine the polyimide paper and the polyimide nanofiber membrane through a hot-pressing bonding process to obtain a double-layer filter gradient polyimide paper/nano fiber membrane.
经本发明的拉伸强度测试方法测得本实施例制得的具有双层过滤梯度聚酰亚胺纸/纳米纤维膜的拉伸强度为14.8Mpa。The tensile strength of the polyimide paper/nanofiber membrane with double-layer filtration gradient prepared in this example was measured by the tensile strength testing method of the present invention to be 14.8Mpa.
由图2可知，成功制备了固含量28％～30％的聚酰亚胺纳米纤维膜。As can be seen from Figure 2, a polyimide nanofiber membrane with a solid content of 28% to 30% was successfully prepared.
为了对本发明中制得的聚酰亚胺纳米纤维膜的微观结构进行表征，对对比例1～2以及实施例1～3中的聚酰亚胺纳米纤维膜进行的SEM表征测试，测试结果如图3所示，由图3可知，当聚酰胺酸纺丝液中聚酰亚胺的浓度较低时，为26％(对应对比例1)、27％(对比例2)时，即纺丝液粘度较低，纺丝过程不稳定，纤维在电纺过程中易形成串珠结构且形成的纤维粗细不均。随着纺丝液浓度的增加达到28％时，串珠结构消失，说明浓度增加有助于纺丝更稳定。当纺丝液浓度增加到29％时，纺丝过程可以持续稳定进行，并能制备出均匀光滑的纤维。当纺丝液浓度进一步增加到30％时，纺丝液粘度进一步增大，纺丝过程难度增大。而在实验过程中，发现当进一步增大聚酰胺酸纺丝液的浓度时，由于纺丝液粘度过大，纺丝的针头被堵塞，无法进行纺丝。因此，聚酰胺酸纺丝液的浓度为28％～30％可以有效使得成功纺丝的同时，纤维中串珠结构减少，纤维更加均匀光滑，进一步有效提高纤维对于颗粒物的过滤效率。同时，通过SEM可知，本发明制得的聚酰亚胺纳米纤维膜的孔径范围为50～500nm，该尺寸范围的纳米纤维膜可以有效对于小尺寸范围的颗粒物进行过滤，比如尺寸范围是纳米级的颗粒物。In order to characterize the microstructure of the polyimide nanofiber membrane produced in the present invention, SEM characterization tests were conducted on the polyimide nanofiber membranes in Comparative Examples 1 to 2 and Examples 1 to 3. The test results are as follows As shown in Figure 3, it can be seen from Figure 3 that when the concentration of polyimide in the polyamic acid spinning solution is low, 26% (corresponding to Comparative Example 1) and 27% (Comparative Example 2), that is, the spinning The liquid viscosity is low and the spinning process is unstable. The fiber easily forms a beaded structure during the electrospinning process and the resulting fiber is uneven in thickness. As the concentration of the spinning solution increases to 28%, the beaded structure disappears, indicating that the increase in concentration contributes to more stable spinning. When the concentration of the spinning solution is increased to 29%, the spinning process can continue and stably, and uniform and smooth fibers can be produced. When the concentration of the spinning solution is further increased to 30%, the viscosity of the spinning solution further increases and the difficulty of the spinning process increases. During the experiment, it was found that when the concentration of the polyamic acid spinning solution was further increased, the spinning needle was blocked due to the excessive viscosity of the spinning solution, making spinning impossible. Therefore, the polyamic acid spinning liquid concentration of 28% to 30% can effectively achieve successful spinning while reducing the bead structure in the fiber, making the fiber more uniform and smooth, and further effectively improving the fiber's filtration efficiency for particulate matter. At the same time, it can be seen from SEM that the pore size of the polyimide nanofiber membrane produced by the present invention ranges from 50 to 500 nm. The nanofiber membrane in this size range can effectively filter particles in a small size range, such as the size range is nanometer. of particulate matter.
本发明进一步对聚酰胺酸纺丝液浓度为28％时制得的聚酰亚胺纤维膜与聚酰亚胺纸复合后的复合膜，即实施例1得到的具有双层过滤梯度的聚酰亚胺纸/纳米纤维复合膜的截面进行了测试表征，测试结果如图4所示，由图4可知，经过热压处理聚酰亚胺纸与聚酰亚胺纳米纤维膜紧密结合，构成聚酰亚胺纸与纳米纤维的复合膜，该结构有效提高了聚酰亚胺纤维膜的结构强度以及力学强度。The present invention further studies the composite membrane of the polyimide fiber membrane and polyimide paper prepared when the polyamic acid spinning solution concentration is 28%, that is, the polyimide membrane with double-layer filtration gradient obtained in Example 1. The cross-section of the imide paper/nanofiber composite membrane was tested and characterized. The test results are shown in Figure 4. From Figure 4, it can be seen that after hot pressing treatment, the polyimide paper and the polyimide nanofiber membrane are closely combined to form a polyimide nanofiber membrane. A composite membrane of imide paper and nanofibers, this structure effectively improves the structural strength and mechanical strength of the polyimide fiber membrane.
进一步的为了观察本发明得到的聚酰亚胺纸的结构特征，对其进行了扫描电子显微镜测试，测试结果如图5所示，由图5可知，本发明中的聚酰亚胺纸具有良好的空隙结构，其孔径范围为2～20μm，该尺寸范围的纳米纤维膜可以有效对尺寸范围较大的颗粒物进行过滤，比如直径在2.5μm以上的大颗粒物。因此通过将聚酰亚胺纸与聚酰亚胺纳米纤维膜进行热压结合，有效的扩大了过滤膜的过滤尺寸范围，提高了过滤膜的过滤效果。Further, in order to observe the structural characteristics of the polyimide paper obtained in the present invention, a scanning electron microscope test was performed on it. The test results are shown in Figure 5. From Figure 5, it can be seen that the polyimide paper in the present invention has good The void structure has a pore size ranging from 2 to 20 μm. Nanofiber membranes in this size range can effectively filter particles with a larger size range, such as large particles with a diameter of more than 2.5 μm. Therefore, by hot-pressing the polyimide paper and the polyimide nanofiber membrane, the filtration size range of the filter membrane is effectively expanded and the filtration effect of the filter membrane is improved.
实施例4Example 4
一种具有双层过滤梯度的聚酰亚胺纸/纳米纤维复合膜的制备方法，包括以下步骤：A method for preparing a polyimide paper/nanofiber composite membrane with a double-layer filtration gradient, including the following steps:
S1：首先使摩尔比为1:0.95的均苯四甲酸二酐和4,4’-二氨基二苯醚在0℃缩聚4h，得到聚酰胺酸溶液，然后经洗涤析出，并冷冻干燥24h后得到聚酰胺酸粉末；S1: First, pyromellitic dianhydride and 4,4'-diaminodiphenyl ether with a molar ratio of 1:0.95 are polycondensed at 0°C for 4 hours to obtain a polyamic acid solution, which is then washed and precipitated, and freeze-dried for 24 hours. Obtain polyamic acid powder;
S2：在冰水浴下，将制得的聚酰胺酸粉末加入至N,N’-二甲基甲酰胺中，搅拌至聚酰胺酸粉末充分溶解，得到聚酰胺酸纺丝液，该聚酰胺酸纺丝液中聚酰胺酸的质量浓度为28.2％。S2: Add the prepared polyamic acid powder to N,N'-dimethylformamide under an ice-water bath, and stir until the polyamic acid powder is fully dissolved to obtain a polyamic acid spinning liquid. The polyamic acid The mass concentration of polyamic acid in the spinning solution is 28.2%.
S3：通过静电纺丝法利用所述聚酰胺酸纺丝液制备聚酰胺酸纳米纤维膜；静电纺丝过程中静电纺丝的电压为20kV，纺丝液流速为0.010ml/min，针头距接收板的距离为10cm。S3: Use the polyamic acid spinning solution to prepare polyamic acid nanofiber membranes by electrospinning; during the electrospinning process, the voltage of electrospinning is 20kV, the flow rate of the spinning solution is 0.010ml/min, and the needle distance is 0.010ml/min. The distance between the plates is 10cm.
S4：将所述聚酰胺酸纳米纤维膜进行热亚胺化处理，制得聚酰亚胺纳米纤维膜；其中，热亚胺化过程具体为，在5℃/min的升温速率下升温至100℃下，保温30min，然后在5℃/min的升温速率下升温至200℃，保温30min，最后在5℃/min的升温速率下升温至300℃，保温30min。S4: The polyamic acid nanofiber membrane is subjected to thermal imidization treatment to obtain a polyimide nanofiber membrane; wherein, the thermal imidization process is specifically: heating to 100°C at a heating rate of 5°C/min. ℃, keep it for 30 minutes, then raise it to 200°C at a heating rate of 5°C/min, keep it there for 30 minutes, and finally raise it to 300°C at a heating rate of 5°C/min, and keep it there for 30 minutes.
S5：将所述的聚酰亚胺纳米纤维膜与在聚酰胺酸溶液中浸渍后的聚酰亚胺纸在压力为10MPa，温度为220℃的条件下热压时间3min，制得所述具有双层过滤梯度的聚酰亚胺纸/纳米纤维膜。S5: Heat press the polyimide nanofiber membrane and the polyimide paper soaked in the polyamic acid solution for 3 minutes under the conditions of a pressure of 10 MPa and a temperature of 220°C to obtain the polyimide nanofiber membrane with Double layer filtration gradient polyimide paper/nanofiber membrane.
本实施例制得的聚酰亚胺纳米纤维层的孔径为50～80nm；该具有双层过滤梯度聚酰亚胺纸/纳米纤维膜的拉伸强度为4Mpa。The pore diameter of the polyimide nanofiber layer produced in this embodiment is 50-80 nm; the tensile strength of the polyimide paper/nanofiber membrane with double-layer filtration gradient is 4Mpa.
实施例5Example 5
一种具有双层过滤梯度的聚酰亚胺纸/纳米纤维复合膜的制备方法，包括以下步骤：A method for preparing a polyimide paper/nanofiber composite membrane with a double-layer filtration gradient, including the following steps:
S1：首先使摩尔比为1:1的六氟二酐和4,4’-二氨基联苯在2℃缩聚5h，得到聚酰胺酸溶液，然后经洗涤析出，并冷冻干燥30h后得到聚酰胺酸粉末；S1: First, hexafluorodianhydride and 4,4'-diaminobiphenyl with a molar ratio of 1:1 are polycondensed at 2°C for 5 hours to obtain a polyamic acid solution, which is then washed and precipitated, and freeze-dried for 30 hours to obtain polyamide. acid powder;
S2：在冰水浴下，将制得的聚酰胺酸粉末加入至N,N’-二甲基甲酰胺中，搅拌至聚酰胺酸粉末充分溶解，得到聚酰胺酸纺丝液，该聚酰胺酸纺丝液中聚酰胺酸的质量浓度为29.5％。S2: Add the prepared polyamic acid powder to N,N'-dimethylformamide under an ice-water bath, and stir until the polyamic acid powder is fully dissolved to obtain a polyamic acid spinning liquid. The polyamic acid The mass concentration of polyamic acid in the spinning solution is 29.5%.
S3：通过静电纺丝法利用所述聚酰胺酸纺丝液制备聚酰胺酸纳米纤维膜；静电纺丝过程中静电纺丝的电压为22kV，纺丝液流速为0.015ml/min，针头距接收板的距离为15cm。S3: Use the polyamic acid spinning solution to prepare polyamic acid nanofiber membranes by electrospinning; during the electrospinning process, the voltage of electrospinning is 22kV, the flow rate of the spinning solution is 0.015ml/min, and the needle distance is 0.015ml/min. The distance between the boards is 15cm.
S4：将所述聚酰胺酸纳米纤维膜进行热亚胺化处理，制得聚酰亚胺纳米纤维膜；其中，热亚胺化过程具体为，在8℃/min的升温速率下升温至120℃下，保温40min，然后在8℃/min的升温速率下升温至230℃，保温45min，最后在8℃/min的升温速率下升温至330℃，保温40min。S4: The polyamic acid nanofiber membrane is subjected to thermal imidization treatment to obtain a polyimide nanofiber membrane; wherein, the thermal imidization process is specifically: heating to 120°C at a heating rate of 8°C/min. ℃, keep the temperature for 40 minutes, then raise the temperature to 230°C at a heating rate of 8°C/min, keep it warm for 45 minutes, and finally raise the temperature to 330°C at a heating rate of 8°C/min and keep it warm for 40 minutes.
S5：将所述的聚酰亚胺纳米纤维膜与在聚酰胺酸溶液中浸渍后的聚酰亚胺纸在压力为10MPa，温度为220℃的条件下热压时间3min，制得所述具有双层过滤梯度的聚酰亚胺纸/纳米纤维膜。S5: Heat press the polyimide nanofiber membrane and the polyimide paper soaked in the polyamic acid solution for 3 minutes under the conditions of a pressure of 10 MPa and a temperature of 220°C to obtain the polyimide nanofiber membrane with Double layer filtration gradient polyimide paper/nanofiber membrane.
本实施例制得的聚酰亚胺纳米纤维层的孔径为70～200nm；该具有双层过滤梯度聚酰亚胺纸/纳米纤维膜的拉伸强度为10.5Mpa。The pore diameter of the polyimide nanofiber layer produced in this embodiment is 70-200 nm; the tensile strength of the polyimide paper/nanofiber membrane with double-layer filtration gradient is 10.5Mpa.
实施例6Example 6
一种具有双层过滤梯度的聚酰亚胺纸/纳米纤维复合膜的制备方法，包括以下步骤：A method for preparing a polyimide paper/nanofiber composite membrane with a double-layer filtration gradient, including the following steps:
S1：首先使摩尔比为1.1:1.05的二酐单体和二胺单体在4℃缩聚6h，得到聚酰胺酸溶液，然后经洗涤析出，并冷冻干燥48h后得到聚酰胺酸粉末；其中，二酐单体为均苯四甲酸二酐与六氟二酐的混合物，二胺单体为4,4’-二氨基二苯醚和对苯二胺的混合物。S1: First, dianhydride monomer and diamine monomer with a molar ratio of 1.1:1.05 are polycondensed at 4°C for 6 hours to obtain a polyamic acid solution, which is then precipitated by washing and freeze-dried for 48 hours to obtain polyamic acid powder; wherein, The dianhydride monomer is a mixture of pyromellitic dianhydride and hexafluorodianhydride, and the diamine monomer is a mixture of 4,4'-diaminodiphenyl ether and p-phenylenediamine.
S2：在冰水浴下，将制得的聚酰胺酸粉末加入至N-甲基吡咯烷酮和二甲基亚砜的混合溶液中，搅拌至聚酰胺酸粉末充分溶解，得到聚酰胺酸纺丝液，该聚酰胺酸纺丝液中聚酰胺酸的质量浓度为30％。S2: Add the prepared polyamic acid powder to the mixed solution of N-methylpyrrolidone and dimethyl sulfoxide under an ice-water bath, and stir until the polyamic acid powder is fully dissolved to obtain a polyamic acid spinning solution. The mass concentration of polyamic acid in the polyamic acid spinning solution is 30%.
S3：通过静电纺丝法利用所述聚酰胺酸纺丝液制备聚酰胺酸纳米纤维膜；静电纺丝过程中静电纺丝的电压为25kV，纺丝液流速为0.015ml/min，针头距接收板的距离为15cm。S3: Prepare polyamic acid nanofiber membrane by using the polyamic acid spinning liquid through electrospinning method; during the electrospinning process, the electrospinning voltage is 25kV, the spinning liquid flow rate is 0.015ml/min, and the needle distance is 0.015ml/min. The distance between the boards is 15cm.
S4：将所述聚酰胺酸纳米纤维膜进行热亚胺化处理，制得聚酰亚胺纳米纤维膜；其中，热亚胺化过程具体为，在8℃/min的升温速率下升温至150℃下，保温55min，然后在10℃/min的升温速率下升温至250℃，保温50min，最后在8℃/min的升温速率下升温至300℃，保温50min。S4: The polyamic acid nanofiber membrane is subjected to thermal imidization treatment to obtain a polyimide nanofiber membrane; wherein, the thermal imidization process is specifically: heating to 150°C at a heating rate of 8°C/min. ℃, keep the temperature for 55 minutes, then raise the temperature to 250°C at a heating rate of 10°C/min, keep the temperature for 50 minutes, and finally raise the temperature to 300°C at a heating rate of 8°C/min and keep the temperature for 50 minutes.
S5：将所述的聚酰亚胺纳米纤维膜与在聚酰胺酸溶液中浸渍后的聚酰亚胺纸在压力为10MPa，温度为220℃的条件下热压时间3min，制得所述具有双层过滤梯度的聚酰亚胺纸/纳米纤维膜。S5: Heat press the polyimide nanofiber membrane and the polyimide paper soaked in the polyamic acid solution for 3 minutes under the conditions of a pressure of 10 MPa and a temperature of 220°C to obtain the polyimide nanofiber membrane with Double layer filtration gradient polyimide paper/nanofiber membrane.
本实施例制得的聚酰亚胺纳米纤维层的孔径为70～220nm；该具有双层过滤梯度聚酰亚胺纸/纳米纤维膜的拉伸强度为13.5Mpa。The pore diameter of the polyimide nanofiber layer produced in this embodiment is 70-220 nm; the tensile strength of the polyimide paper/nanofiber membrane with double-layer filtration gradient is 13.5Mpa.
实施例7Example 7
一种具有双层过滤梯度的聚酰亚胺纸/纳米纤维复合膜的制备方法，包括以下步骤：A method for preparing a polyimide paper/nanofiber composite membrane with a double-layer filtration gradient, including the following steps:
S1：首先使摩尔比为1:1的3,3’,4,4’-二苯酮四酸二酐和对苯二胺在4℃缩聚6h，得到聚酰胺酸溶液，然后经洗涤析出，并冷冻干燥40h后得到聚酰胺酸粉末；S1: First, 3,3',4,4'-benzophenone tetra-acid dianhydride and p-phenylenediamine with a molar ratio of 1:1 are polycondensed at 4°C for 6 hours to obtain a polyamic acid solution, which is then washed and precipitated. And freeze-dry for 40 hours to obtain polyamic acid powder;
S2：在冰水浴下，将制得的聚酰胺酸粉末加入至N,N’-二甲基乙酰胺中，搅拌至聚酰胺酸粉末充分溶解，得到聚酰胺酸纺丝液，该聚酰胺酸纺丝液中聚酰胺酸的质量浓度为30％。S2: Add the prepared polyamic acid powder to N,N'-dimethylacetamide under an ice-water bath, and stir until the polyamic acid powder is fully dissolved to obtain a polyamic acid spinning liquid. The polyamic acid The mass concentration of polyamic acid in the spinning solution is 30%.
S3：通过静电纺丝法利用所述聚酰胺酸纺丝液制备聚酰胺酸纳米纤维膜；静电纺丝过程中静电纺丝的电压为25kV，纺丝液流速为0.017ml/min，针头距接收板的距离为20cm。S3: Prepare polyamic acid nanofiber membrane by using the polyamic acid spinning liquid through electrospinning method; during the electrospinning process, the electrospinning voltage is 25kV, the spinning liquid flow rate is 0.017ml/min, and the needle distance is 0.017ml/min. The distance between the boards is 20cm.
S4：将所述聚酰胺酸纳米纤维膜进行热亚胺化处理，制得聚酰亚胺纳米纤维膜；其中，热亚胺化过程具体为，在10℃/min的升温速率下升温至140℃下，保温55min，然后在10℃/min的升温速率下升温至230℃，保温50min，最后在10℃/min的升温速率下升温至350℃，保温50min。S4: The polyamic acid nanofiber membrane is subjected to thermal imidization treatment to obtain a polyimide nanofiber membrane; wherein, the thermal imidization process is specifically: heating to 140°C at a heating rate of 10°C/min. ℃, keep the temperature for 55 minutes, then raise the temperature to 230°C at a heating rate of 10°C/min, keep the temperature for 50 minutes, and finally raise the temperature to 350°C at a heating rate of 10°C/min and keep it warm for 50 minutes.
S5：将所述的聚酰亚胺纳米纤维膜与在聚酰胺酸溶液中浸渍后的聚酰亚胺纸在压力为10MPa，温度为220℃的条件下热压时间3min，制得所述具有双层过滤梯度的聚酰亚胺纸/纳米纤维膜。S5: Heat press the polyimide nanofiber membrane and the polyimide paper soaked in the polyamic acid solution for 3 minutes under the conditions of a pressure of 10 MPa and a temperature of 220°C to obtain the polyimide nanofiber membrane with Double layer filtration gradient polyimide paper/nanofiber membrane.
本实施例制得的聚酰亚胺纳米纤维层的孔径为200～500nm；该具有双层过滤梯度聚酰亚胺纸/纳米纤维膜的拉伸强度为14.8Mpa。The pore diameter of the polyimide nanofiber layer produced in this embodiment is 200-500 nm; the tensile strength of the polyimide paper/nanofiber membrane with double-layer filtration gradient is 14.8Mpa.
以上所述仅是本发明的优选实施方式，应当指出，对于本技术领域的普通技术人员来说，在不脱离本发明原理的前提下，还可以作出若干改进和润饰，这些改进和润饰也应视为本发明的保护范围。The above are only the preferred embodiments of the present invention. It should be pointed out that for those of ordinary skill in the art, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be made. regarded as the protection scope of the present invention.
最后所应当说明的是，以上实施例仅用以说明本发明的技术方案而非对本发明保护范围的限制，尽管参照较佳实施例对本发明作了详细说明，本领域的普通技术人员应当理解，可以对本发明的技术方案进行修改或者等同替换，而不脱离本发明技术方案的实质和范围。Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and do not limit the protection scope of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that The technical solution of the present invention may be modified or equivalently substituted without departing from the essence and scope of the technical solution of the present invention.
| Application Number | Priority Date | Filing Date | Title |
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| CN202310980009.2ACN116943448B (en) | 2023-08-04 | 2023-08-04 | A polyimide paper/nanofiber composite membrane with double-layer filtration gradient and its preparation method and application |
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| CN202310980009.2ACN116943448B (en) | 2023-08-04 | 2023-08-04 | A polyimide paper/nanofiber composite membrane with double-layer filtration gradient and its preparation method and application |
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| CN118496505A (en)* | 2024-06-13 | 2024-08-16 | 上海晋飞碳纤科技股份有限公司 | A trifluoromethyl-containing polyimide acid, preparation method and application thereof, colorless polyimide film, white polyimide film |
| CN119524652A (en)* | 2024-12-23 | 2025-02-28 | 陕西科技大学 | An ionic liquid modified polyimide nanofiber film and an air purification filter based thereon |
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| CN102747634A (en)* | 2012-07-27 | 2012-10-24 | 陕西科技大学 | Method for preparing modified polyimide fiber papers |
| CN104928937A (en)* | 2015-06-18 | 2015-09-23 | 中国地质大学（武汉） | Porous polyimide/electrospinning polyimide fibrous composite material and application thereof |
| CN109680552A (en)* | 2017-10-18 | 2019-04-26 | 江苏先诺新材料科技有限公司 | Polyimide/Nano fibre composite paper and preparation method thereof |
| CN115434160A (en)* | 2021-06-04 | 2022-12-06 | 上海晶顿科技有限公司 | Polyimide heating body and preparation method thereof |
| WO2023066342A1 (en)* | 2021-10-21 | 2023-04-27 | 北京宇程科技有限公司 | Modified composite separator and preparation method therefor |
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN102747634A (en)* | 2012-07-27 | 2012-10-24 | 陕西科技大学 | Method for preparing modified polyimide fiber papers |
| CN104928937A (en)* | 2015-06-18 | 2015-09-23 | 中国地质大学（武汉） | Porous polyimide/electrospinning polyimide fibrous composite material and application thereof |
| CN109680552A (en)* | 2017-10-18 | 2019-04-26 | 江苏先诺新材料科技有限公司 | Polyimide/Nano fibre composite paper and preparation method thereof |
| CN115434160A (en)* | 2021-06-04 | 2022-12-06 | 上海晶顿科技有限公司 | Polyimide heating body and preparation method thereof |
| WO2023066342A1 (en)* | 2021-10-21 | 2023-04-27 | 北京宇程科技有限公司 | Modified composite separator and preparation method therefor |
| Title |
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| 贾峰峰等: ""聚酰亚胺纤维及其纸基功能材料研究进展"", 《中国造纸学报》, 15 September 2022 (2022-09-15), pages 126 - 134* |
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| CN118496505A (en)* | 2024-06-13 | 2024-08-16 | 上海晋飞碳纤科技股份有限公司 | A trifluoromethyl-containing polyimide acid, preparation method and application thereof, colorless polyimide film, white polyimide film |
| CN119524652A (en)* | 2024-12-23 | 2025-02-28 | 陕西科技大学 | An ionic liquid modified polyimide nanofiber film and an air purification filter based thereon |
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| CN116943448B (en) | 2024-11-29 |
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