CN102718986B - Lignin-modified layered double hydroxide, preparation method thereof, and rubber composite material - Google Patents

Abstract

The invention relates to a lignin compound modified LDH and a preparation method thereof and to a rubber composite comprising the lignin compound modified LDH. The lignin compound in-situ modifies LDH to obtain the lignin compound modified LDH which comprises, by mass, 10% to 70% of water. The mass ratio of the lignin compound to LDH is 1:2 to 1:10. The lignin compound modified LDH can be used as a reinforcing agent to be uniformly dispersed in a rubber matrix, and has the advantages of low cost and no pollution to the environment.

Description

Lignin-modified layered double-hydroxide and preparation method thereof, rubber composite

Technical field

The present invention relates to field of compound material, relate in particular to compound-modified layered double-hydroxide of lignin and preparation method thereof, and using the rubber composite of the compound-modified layered double-hydroxide of this lignin as strengthening agent.

Background technology

Layered double-hydroxide (Layered double hydroxide, be called for short LDH), claims again anionic clay or hydrotalcite-based compound, its laminate by divalence (as Mg²⁺) and trivalent (as Al³⁺) metal hydroxides composition, positively charged, interlayer has tradable negatively charged ion (as NO₃^-or CO₃^2-) and crystal water molecule.Magnalium type LDH is owing to both having Mg (OH)₂the initial decomposition temperature that has when fire-retardant is high, caloric receptivity is large, press down the strong feature of cigarette ability, has again Al (OH)₃the promotion having when fire-retardant becomes charcoal, presses down the feature of cigarette, also has feature that the laminate of polynite intercepts and in widespread attention.If be applied to polymeric matrix as improved the flame retardant properties of polymeric matrix in rubber.Yet the granularity of LDH is less, surface has a large amount of activity hydroxies, easily in polymeric matrix, reunite, and LDH itself is kind of an inorganic materials, the interface compatibility of itself and most polymer material is poor, in polymeric matrix, be difficult for dispersedly, easily cause that stress distribution is uneven if be directly filled in polymeric matrix, material physical property is as mechanical properties decrease.Therefore, be necessary before use LDH to be carried out organically-modified, improve the consistency of itself and polymeric matrix, make it dispersed in polymeric matrix.

Summary of the invention

One embodiment of the invention provides compound-modified LDH of lignin and preparation method thereof, and using the compound-modified LDH of this lignin as loading material of rubber, is added into and in rubber matrix, prepares rubber composite.

In the compound-modified LDH of this lignin, by mass percentage, water content is 10%～70%, and the mass ratio of lignin compound and LDH is 1:2～1:10.

The compound-modified LDH of this lignin can make according to the following steps: under room temperature condition, it is that in 5%～30% sodium hydroxide solution, mechanical stirring 1h, makes lignin liquor that a certain amount of lignin compound is dissolved in to weight concentration; Described lignin compound comprises at least one in alkali lignin, vitriol xylogen, sulfonated lignin or hydroxymethylated lignin; The mixed aqueous solution that preparation contains divalent-metal ion and trivalent metal ion, wherein divalent-metal ion and trivalent metal ion mol ratio are 1:1～4:1, metal ion total concn is the mixed aqueous solution of 0.1～3 mol/L, and the mass ratio of metal ion and lignin compound is (12:1～3:5); Described divalent-metal ion can be Mg²⁺, Zn²⁺, Fe²⁺, Cu²⁺, Ca²⁺, Sn²⁺, Cr²⁺, Pb²⁺in a kind of, trivalent metal ion can be Al³⁺, Cr³⁺, Mn³⁺, Fe³⁺, Ti³⁺, Ga³⁺in a kind of; To drip the alkaline solution that described metal ion mixed aqueous solution and mass concentration are 5%～30% in described lignin liquor simultaneously, mechanical stirring to keep pH value be 7 ~ 13, until metallic ion mixed liquor drips off; Continue to stir 0.5～3h, be statically placed in crystallization 12～48h cold filtration in the water-bath of 50～90 ℃, with deionized water or distilled water wash solid, the dry water content that obtains is 10～70% lignin-modified LDH.

The compound-modified LDH of this lignin can be used as strengthening agent to be added in rubber, and the rubber mechanical property that not only can improve, can also reduce Rubber processing modification cost.

In the rubber composite that one embodiment of the invention provides, the modification LDH of lignin compound that comprises rubber matrix and be dispersed in this rubber matrix, wherein, in mass ratio, in pure LDH, the ratio that LDH modifies in rubber matrix Yu Gai lignin compound is 100:(10 ~ 30).

Compared with prior art, it is in-situ modified that the technical program utilizes lignin compound as anion surfactant, LDH to be carried out, and solved pure LDH at the not good key technical problem of rubber matrix dispersiveness.This lignin compound can be obtained by biomass material, and source is abundant, with low cost, simple with the technique of its modification LDH, and the modification LDH making can be uniformly dispersed in rubber matrix, has overcome that traditional rubber reinforcing filler cost is high, the shortcoming of contaminate environment.

Accompanying drawing explanation

The XRD schematic diagram of the pure LDH that in Fig. 1, a is non-modified, b is the XRD schematic diagram that sodium lignosulfonate is modified LDH (S-LDH);

In Fig. 2, a, b, c are respectively the scanning electron microscope (SEM) photograph of NBR, 10LDH/NBR, 10S-LDH/NBR.

Embodiment

In the compound-modified layered double-hydroxide of lignin provided by the invention, in mass ratio, water content is 10%～70%, and lignin compound and LDH mass ratio are 1:2～1:10, and it can make according to the following steps:

Under step 1, room temperature condition, it is that in 5%～30% sodium hydroxide solution, mechanical stirring 1h, makes lignin liquor that the xylogen of certain mass is dissolved in to weight concentration.

Described lignin compound comprises at least one in alkali lignin, vitriol xylogen, sulfonated lignin or hydroxymethylated lignin.Described alkaline solution can be sodium hydroxide solution or potassium hydroxide solution.

The mixed aqueous solution that step 2, preparation contain divalent-metal ion and trivalent metal ion, wherein divalent-metal ion and trivalent metal ion mol ratio are 4:1 ~ 1:1, metal ion total concn is the mixed aqueous solution of 0.1～3 mol/L, and the mass ratio of metal ion and lignin compound is (12:1～3:5).

Divalent-metal ion in described mixed aqueous solution is Mg²⁺, Zn²⁺, Fe²⁺, Cu²⁺, Ca²⁺, Sn²⁺, Cr²⁺, or Pb²⁺, trivalent metal ion is Al³⁺, Cr³⁺, Mn³⁺, Fe³⁺, Ti³⁺, Ga³⁺in a kind of.

Step 3, to drip the alkaline solution that described hybrid metal solion and mass concentration are 5%～30% in lignin liquor simultaneously, mechanical stirring to keep pH value be 7～13, until hybrid metal solion drips off, obtains lignin-modified LDH.

Step 4, drip rear continuation and stir 0.5～3h, be statically placed in crystallization 12～48h cold filtration in the water-bath of 50～90 ℃, with deionized water or distilled water wash solid, the dry water content that obtains is 10～70% lignin-modified LDH.

Below in conjunction with specific embodiments and the drawings, to compound-modified layered double-hydroxide of lignin provided by the invention and preparation method thereof, and rubber composite is done more detailed explanation.

Embodiment 1:

Prepare the magnesium nitrate of a certain amount of 0.50mol/L and the aluminum nitrate metallic ion mixed liquor of 0.25mol/L, Mg²⁺with Al³⁺mol ratio be 1:1.It is in 17% sodium hydroxide solution that 2g alkali lignin is dissolved in to 200mL weight concentration, makes lignin liquor.At room temperature with churned mechanically condition under, by metallic ion mixed liquor be added drop-wise to lentamente in lignin liquor to pH be 7, consume metallic ion mixed liquor 441g.Drip rear continuation and stir 1h, throw out is filtered, washes, is dried to water content after 65 ℃ of water-bath crystallization 24h and be 50% lignin-modified LDH, wherein the mass ratio of xylogen and LDH is about 1:10.By abovementioned steps, adjust the consumption of xylogen, make the mass ratio of xylogen and LDH be respectively 3:10 and 1:2, obtain the lignin-modified LDH of different xylogen/LDH mass ratioes, called after L-LDH.

By the L-LDH of the xylogen obtaining and LDH different mass ratio respectively with the blend in mill of styrene-butadiene rubber(SBR) matrix, melting temperature is 80～100 ℃, to constant weight, obtain three blocks of L-LDH/ styrene-butadiene rubber(SBR) rubber master batch, in every block of described rubber rubber master batch, the mass ratio of L-LDH and styrene-butadiene rubber(SBR) is 30/100.

The rubber ingredients such as zinc oxide, stearic acid, accelerant CZ and sulphur are joined in described styrene-butadiene rubber(SBR) rubber master batch successively by formula shown in table 1, at room temperature mixing.After mixing completing, gained rubber unvulcanizate is vulcanized with vulcanizing press at 160 ℃, obtain lignin-modified LDH/ styrene-butadiene rubber composite material, called after L-LDH/SBR, the matrix material of different xylogen/LDH mass ratioes is designated as respectively 3L-30LDH/SBR, 9L-30LDH/SBR, 15L-30LDH/SBR.

Table 1 styrene-butadiene rubber(SBR) formula

Component	Massfraction
		Styrene-butadiene rubber(SBR)	100
Zinc oxide	5
		Stearic acid	2
Accelerant CZ	1.5
		Sulphur	2.5

Embodiment 2:

The magnesium nitrate of 0.75mol/L and the aluminum nitrate metallic ion mixed liquor of 0.25mol/L that preparation total amount is 3000mL, Mg²⁺with Al³⁺mol ratio be 4:1.The sodium hydroxide solution that preparation 4000mL mass concentration is 5%.It is in 5% sodium hydroxide solution that 100g sodium lignosulfonate is dissolved in to 1000mL mass concentration, obtains lignin liquor.Under room temperature and churned mechanically condition, described metallic ion mixed liquor and sodium hydroxide solution are added drop-wise in described lignin liquor and keep pH value of solution=9～13 lentamente.After metallic ion mixed liquor drips, continue to stir 1h, throw out is filtered, washes, is dried to water content after 65 ℃ of water-bath crystallization 24h and be 50% sodium lignosulfonate modification LDH, called after S-LDH, wherein the massfraction of LDH is 70.5%.

By described S-LDH and paracril matrix by different mass ratioes, i.e. 10:100,20:100,30:100, blend in mill, melting temperature is 80～100 ℃, to constant weight, obtains S-LDH/ paracril rubber master batch.

The rubber ingredients such as zinc oxide, stearic acid, accelerant CZ and sulphur are joined in above-mentioned paracril rubber master batch successively by formula shown in table 2, at room temperature mixing.

Table 2 paracril formula

Component	Massfraction
		Paracril	100
Zinc oxide	5
		Stearic acid	2
Accelerant CZ	1.5
		Sulphur	2.5

Gained rubber unvulcanizate is vulcanized with vulcanizing press at 160 ℃, obtain lignin-modified LDH/ nitile-butadiene rubber composite material, called after S-LDH/NBR, press the difference of S-LDH content, gained rubber composite is designated as respectively 10S-LDH/NBR, 20S-LDH/NBR, 30S-LDH/NBR.

Comparative example 1:

At room temperature, by formula described in table 1, to styrene-butadiene rubber(SBR), add the rubber ingredients such as zinc oxide, stearic acid, accelerant CZ and sulphur, even with mill mixing, after being placed to 24h, vulcanizes with vulcanizing press at 160 ℃ rubber unvulcanizate.

Comparative example 2:

At room temperature, by formula shown in table 2, to paracril, add the rubber ingredients such as zinc oxide, stearic acid, accelerant CZ and sulphur, even with mill mixing, after being placed to 24h, vulcanizes with vulcanizing press at 160 ℃ rubber unvulcanizate.

Comparative example 3:

Prepare the magnesium nitrate of a certain amount of 0.50mol/L and the aluminum nitrate metallic ion mixed liquor of 0.25mol/L, Mg²⁺with Al³⁺mol ratio be 1: 1.The sodium hydroxide solution that preparation 200mL weight concentration is 17%.At room temperature with churned mechanically condition under, by metallic ion mixed liquor be added drop-wise to lentamente in lignin liquor to pH be 7, consume metallic ion mixed liquor 441g.Drip rear continuation and stir 1h, throw out is filtered, washes, is dried to water content after 65 ℃ of water-bath crystallization 24h and be 50% LDH.

By synthetic pure LDH and styrene-butadiene rubber(SBR) blend in mill, melting temperature is 80～100 ℃, to constant weight, obtains LDH/ styrene-butadiene rubber(SBR) rubber master batch.

The rubber ingredients such as zinc oxide, stearic acid, accelerant CZ and sulphur are joined in described styrene-butadiene rubber(SBR) rubber master batch successively by formula shown in table 1, at room temperature mixing.After mixing completing, gained rubber unvulcanizate is vulcanized with vulcanizing press at 160 ℃, obtain LDH/ styrene-butadiene rubber composite material, called after 0L-30LDH/SBR.

Comparative example 4:

The magnesium nitrate of 0.75mol/L and the aluminum nitrate metallic ion mixed liquor of 0.25mol/L that preparation total amount is 3000mL, Mg²⁺with Al³⁺mol ratio be 4:1.The sodium hydroxide solution that preparation 4000mL mass concentration is 5%, is designated as solution B.The sodium hydroxide solution that preparation 1000mL mass concentration is 5%, is designated as solution C.It is in 5% sodium hydroxide solution that 100g sodium lignosulfonate is dissolved in to 1000mL mass concentration, obtains lignin liquor.Under room temperature and churned mechanically condition, metallic ion mixed liquor and solution B are added drop-wise in solution C and lignin liquor and keep pH value of solution=9～11 lentamente.After metallic ion mixed liquor drips, continue to stir 1h, throw out is filtered, washes, is dried to water content after 65 ℃ of water-bath crystallization 24h and be 50% LDH.

Described LDH is pressed to different mass ratio blend in mill from paracril, and melting temperature is 80～100 ℃, to constant weight, obtains LDH/ paracril rubber master batch.

The rubber ingredients such as zinc oxide, stearic acid, accelerant CZ and sulphur are joined in above-mentioned paracril rubber master batch successively by formula shown in table 2, at room temperature mixing.

Gained rubber unvulcanizate is vulcanized with vulcanizing press at 160 ℃, obtains LDH/ nitile-butadiene rubber composite material, called after LDH/NBR, different loading levels be designated as respectively 10LDH/NBR, 20LDH/NBR, 30LDH/NBR.

Referring to Fig. 1, the XRD figure of the pure LDH that a is non-modified, b is the XRD figure that sodium lignosulfonate is modified LDH (S-LDH).As can be seen from Figure 1, compare with pure LDH, the diffraction peak position of S-LDH does not have considerable change, but the width at peak obviously increases and the intensity at peak obviously reduces, show that sodium lignosulfonate can suppress the accumulation of LDH lamella, make the size of LDH particle less, also reduced the degree of crystallinity of LDH simultaneously.

Referring to Fig. 2, a, b, c are respectively the scanning electron microscope (SEM) photograph of NBR, 10LDH/NBR, 10S-LDH/NBR.Contrast b and c are known, and S-LDH disperses more careful, even in NBR matrix, and the dispersiveness significantly better than pure LDH in NBR matrix shows to utilize lignin compound to carry out in-situ modifiedly significantly improving the dispersiveness of LDH in rubber matrix to LDH.

Referring to table 3 and table 4, the mechanical property of lignin-modified LDH/ styrene-butadiene rubber composite material and lignin-modified LDH/ paracril is shown respectively.From this two table, the lignin-modified LDH that the embodiment of the present invention provides can obviously improve the mechanical property of rubber matrix.

The performance of the lignin-modified LDH/ styrene-butadiene rubber composite material of table 3

The performance of table 4 sulfonated lignin LDH/ nitile-butadiene rubber composite material

Claims (2)

Translated fromChinese

1.一种木质素类化合物修饰LDH的制备方法，包括：于室温条件下，将木质素类化合物溶于重量浓度为5%～30%的碱溶液中，制得木质素溶液；配制含有二价金属离子和三价金属离子的混合水溶液，其中二价金属离子和三价金属离子摩尔比为1:1～4:1，金属离子总浓度为0.1～3摩尔/升的混合水溶液，金属离子与木质素类化合物的质量比为12：1～3：5；向所述木质素溶液中滴加所述金属离子混合水溶液和所述碱溶液，搅拌并保持pH值为7～13，直至金属离子混合溶液滴完；搅拌0.5～3h，静置于50～90℃的水浴中晶化12～48h冷却过滤，洗涤，干燥得到含水量为10～70%的木质素修饰LDH。1. A preparation method for modifying LDH with lignin compounds, comprising: at room temperature, dissolving lignin compounds in an alkali solution with a weight concentration of 5% to 30% to obtain a lignin solution; preparing a lignin solution containing two A mixed aqueous solution of valent metal ions and trivalent metal ions, wherein the molar ratio of divalent metal ions to trivalent metal ions is 1:1 to 4:1, and the total concentration of metal ions is 0.1 to 3 mol/liter. The mass ratio to the lignin compound is 12:1~3:5; add the metal ion mixed aqueous solution and the alkali solution dropwise to the lignin solution, stir and keep the pH value at 7~13 until the metal ion The ion mixed solution is dripped; stirred for 0.5-3 hours, placed in a water bath at 50-90°C for 12-48 hours, cooled and filtered, washed, and dried to obtain lignin-modified LDH with a water content of 10-70%.2.如权利要求1所述的木质素类化合物修饰LDH的制备方法，其特征是，所述木质素类化合物选自碱木质素、硫酸盐木质素、木质素磺酸盐或者羟甲基化木质素中的至少一种，所述二价金属离子为Mg²⁺、Zn²⁺、Fe²⁺、Cu²⁺、Ca²⁺、Sn²⁺、Cr²⁺、Pb²⁺中的一种，三价金属离子为Al³⁺、Cr³⁺、Mn³⁺、Fe³⁺、Ti³⁺、Ga³⁺中的一种。2. the preparation method of lignin compound modified LDH as claimed in claim 1, is characterized in that, described lignin compound is selected from alkali lignin, kraft lignin, lignosulfonate or hydroxymethylation At least one of lignin, the divalent metal ion is one of Mg²⁺ , Zn²⁺ , Fe²⁺ , Cu²⁺ , Ca²⁺ , Sn²⁺ , Cr²⁺ , Pb²⁺ , and the trivalent metal ion is one of Al³⁺ , Cr³⁺ , Mn³⁺ , Fe³⁺ , Ti³⁺ , and Ga³⁺ .

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