阅读说明：本技术 改性蛋白土、改性蛋白土复合材料及其制备方法和应用 (Modified opal, modified opal composite material, and preparation method and application thereof ) 是由 甄卫军 雷高伟 于 2020-06-09 设计创作，主要内容包括：本发明涉及聚乳酸复合材料技术领域,是一种改性蛋白土、改性蛋白土复合材料及其制备方法和应用,该改性蛋白土按下述方法得到：将蛋白土进行羧化改性,再将羧化蛋白土接枝聚丙交酯得到改性蛋白土。本发明通过采用本发明所述的改性蛋白土来制备本发明所述的聚乳酸-改性蛋白土复合材料,使得本发明聚乳酸-改性蛋白土复合材料较现有纯聚乳酸材料在力学性能和耐热性能均有明显提高,并且本发明聚乳酸-改性蛋白土复合材料的结晶性能和拉伸性能较现有纯聚乳酸材料有显著提高,从而拓展了聚乳酸复合材料的应用领域,另外,本发明对于蛋白土资源的高附加值开发具有重要的推动意义。(The invention relates to the technical field of polylactic acid composite materials, in particular to modified opal soil, a modified opal soil composite material, a preparation method and an application thereof, wherein the modified opal soil is obtained by the following method: and (3) carboxylating and modifying the protein soil, and grafting polylactide on the carboxylated protein soil to obtain the modified protein soil. According to the invention, the polylactic acid-modified opal composite material is prepared by adopting the modified opal, so that the mechanical property and the heat resistance of the polylactic acid-modified opal composite material are obviously improved compared with those of the existing pure polylactic acid material, and the crystallization property and the tensile property of the polylactic acid-modified opal composite material are obviously improved compared with those of the existing pure polylactic acid material, thereby expanding the application field of the polylactic acid composite material.)

1. The preparation method of the modified protein soil is characterized by comprising the following steps: the method comprises the steps of firstly, mixing required amounts of opal, potassium hydroxide and deionized water, stirring to obtain a first mixed material, adding sodium chloroacetate into the first mixed material at a temperature of 70-100 ℃ for reaction to obtain an intermediate product mixed solution, wherein the mass ratio of the opal, the potassium hydroxide and the deionized water is 1: 1-5: 10-30, and the mass ratio of the opal to the sodium chloroacetate is 1:1 to 5; secondly, adjusting the pH of the intermediate product mixed liquor cooled to room temperature to acidity, adding absolute ethyl alcohol, eluting the intermediate product mixed liquor added with the absolute ethyl alcohol, and then evaporating to remove the ethyl alcohol to obtain concentrated liquor; thirdly, adding methanol into the concentrated solution, and then sequentially standing, filtering and drying to obtain carboxylated protein soil; and step four, mixing required amount of stannous octoate, carboxylated proteinous soil and lactide to obtain a second mixed material, and reacting the second mixed material for 20 to 30 hours at the temperature of 140 to 190 ℃ and under the pressure of 0.085 to 0.095MPa to obtain a final reaction product, wherein the mass ratio of the stannous octoate to the carboxylated proteinous soil to the lactide is 1:3 to 10: 50 to 100; and fifthly, adding the final reaction product into an organic solvent for dissolving, then carrying out centrifugal separation to obtain a precipitate, and drying the precipitate to obtain the modified opal.

2. The method for preparing modified egg white soil according to claim 1, wherein the lactide is one of L-lactide, D-lactide and D, L-lactide; or/and the elution is carried out by adopting an alumina column for separation and precipitation, and 30 to 60 percent of ethanol water solution is used as the eluent; or/and, in the first step: the particle size of the opal is 200-400 meshes, the stirring time is 10-30 min, and the reaction time is 3-6 h.

3. The method for preparing a modified opal according to claim 1 or 2, characterized in that in the second step: adding concentrated sulfuric acid into the intermediate product mixed solution to adjust the pH value to 3-6; the addition amount of the absolute ethyl alcohol is that 30mL to 100mL of absolute ethyl alcohol is added into each gram of the opal, and the addition amount of the methanol is that 20mL to 40mL of methanol is added into each gram of the opal.

4. The method for preparing a modified opal according to claim 1, 2 or 3, characterized in that in the third step: standing for 12 to 18 hours, drying at 40 to 70 ℃, at 0.070 to 0.085MPa for 6 to 10 hours; and adding methanol into the concentrated solution, and then sequentially standing, filtering and drying to obtain the carboxylated protein soil.

5. The method for preparing modified opal according to claim 4, wherein in the fourth step, the second mixed material is purged by filling nitrogen before the reaction, and the nitrogen purging rate is 30mL/min to 100 mL/min; or/and in the fifth step: adding an organic solvent into the final reaction product for dissolving, and then carrying out centrifugal separation to obtain a precipitate, wherein the drying time of the precipitate is 24 hours, the drying temperature is 40-70 ℃, and the drying pressure is 0.085-0.095 MPa; the addition amount of the organic solvent is 10mL to 20mL of the organic solvent added into each gram of the opal; the organic solvent adopts dichloromethane or trichloromethane.

6. A modified opal obtained by the method of preparing a modified opal according to claim 1 or 2 or 3 or 4 or 5.

7. A method for preparing a polylactic acid-modified opal composite material by taking the modified opal as the raw material of claim 6, which is characterized in that the raw material comprises 100 parts of polylactic resin, 0.05 to 5 parts of modified opal and 2 to 10 parts of plasticizer by weight, and the preparation method of the polylactic acid-modified opal composite material comprises the following steps: uniformly mixing the polylactic resin, the modified opal and the plasticizer according to the required amount to obtain a mixed material, and extruding the mixed material at the extrusion temperature of 170-190 ℃ to obtain the polylactic acid-modified opal composite material.

8. The method for preparing a polylactic acid-modified opal composite material according to claim 7, wherein the plasticizer is one or more of polyethylene glycol, phosphate ester and acetyl tributyl citrate; or/and the raw material polylactic resin is used after being dried for 20 to 30 hours at the temperature of between 40 and 60 ℃ and under the pressure of between 0.070 and 0.085MPa before being used.

9. A polylactic acid-modified opal composite material obtained by the method for preparing a polylactic acid-modified opal composite material according to claim 7 or 8.

10. Use of the polylactic acid-modified opal composite material according to claim 9 in medical materials or/and food packaging materials or/and agricultural film materials or/and fiber materials.

Technical Field

The invention relates to the technical field of polylactic acid composite materials, in particular to modified opal and a preparation method thereof, and further comprises a polylactic acid-modified opal composite material and a preparation method thereof, and application of the polylactic acid-modified opal composite material in medical materials or/and food packaging materials or/and agricultural film materials or/and fiber materials, wherein in the subject name, the polylactic acid-modified opal composite material is replaced by the modified opal composite material.

Background

Plastics, a class of high molecular materials derived from limited fossil energy synthesis, have been widely used in various aspects of life and industry. However, most plastics are not biodegradable and their accumulation has created a serious environmental hazard. Thus, environmental concerns and shortage of petroleum resources have driven the production of biodegradable materials. Polylactic acid (PLA) is a polymer obtained from renewable resources such as corn starch, tapioca starch, wheat starch and the like through enzymatic decomposition, biological fermentation and chemical polymerization processes, and ester bond breakage in the polylactic acid can ensure that the polylactic acid has complete biodegradability and biocompatibility, so that the polylactic acid can be completely decomposed into CO harmless to the environment under the composting condition₂And H₂And O. However, polylactic acid has the disadvantages of relatively low thermal stability, inherent brittleness, low toughness, low crystallinity and the like due to the inherent chemical components and molecular structure, and further application and development of the polylactic acid are limited. Therefore, modification researches on toughening, thermal stability improvement and the like of the green plastic polylactic acid resin are urgently needed aiming at some defects in the performance of the polylactic acid.

At present, inorganic minerals are added into plastics as fillers to modify the plastics, and the modification is the plastic modification approach with the lowest cost and the widest application at present. Because the compatibility of inorganic nucleating agents and high polymer materials is poor, the production requirements cannot be met. Therefore, the surface modification method has important significance in improving the interfacial compatibility of the nucleating agent and the polylactic acid. The mineral powder is selected as an additive to be blended with the plastic, the problem of agglomeration of the mineral powder needs to be mainly solved, and in order to improve the interface bonding effect of the mineral powder and the plastic and improve the compatibility of the filler and the resin, the most effective way is to perform surface modification treatment on the inorganic filler. After the surface of the inorganic filler is modified, the surface performance of the inorganic filler is changed from polarity to non-polarity, so that the repulsion among filler particles is increased, the inorganic filler is easy to disperse, and the filling and reinforcing effects are improved.

The opal is amorphous or colloidal active silicon dioxide containing deionized water, and the chemical composition of the opal is SiO₂·nH₂O, containing deionized water about 2-13%, and Si0 as main component₂In addition, it also contains a small amount of A1₂0₃、Fe₂0₃、Mg²⁺、Ca²⁺、K⁺、Na⁺、Cu²⁺And organic impurities, wherein the opal is a three-dimensional ordered medium structure with a face-centered cubic structure and is assembled by submicron spheres, has submicron and nanoscale micropores, and is an excellent carrier mineral.

Disclosure of Invention

The invention provides modified opal, a modified opal composite material, a preparation method and application thereof, overcomes the defects of the prior art, can effectively solve the problem of poor compatibility of the existing inorganic nucleating agent and a high polymer material, and can also solve the problem that the application field of a pure polylactic acid material is limited due to low toughness, heat resistance, crystallization property and tensile property.

One of the technical schemes of the invention is realized by the following measures: the modified opal soil is obtained by the following method: the method comprises the steps of firstly, mixing required amounts of opal, potassium hydroxide and deionized water, stirring to obtain a first mixed material, adding sodium chloroacetate into the first mixed material at a temperature of 70-100 ℃ for reaction to obtain an intermediate product mixed solution, wherein the mass ratio of the opal, the potassium hydroxide and the deionized water is 1: 1-5: 10-30, and the mass ratio of the opal to the sodium chloroacetate is 1:1 to 5; secondly, adjusting the pH of the intermediate product mixed liquor cooled to room temperature to acidity, adding absolute ethyl alcohol, eluting the intermediate product mixed liquor added with the absolute ethyl alcohol, and then evaporating to remove the ethyl alcohol to obtain concentrated liquor; thirdly, adding methanol into the concentrated solution, and then sequentially standing, filtering and drying to obtain carboxylated protein soil; and step four, mixing required amount of stannous octoate, carboxylated proteinous soil and lactide to obtain a second mixed material, and reacting the second mixed material for 20 to 30 hours at the temperature of 140 to 190 ℃ and under the pressure of 0.085 to 0.095MPa to obtain a final reaction product, wherein the mass ratio of the stannous octoate to the carboxylated proteinous soil to the lactide is 1:3 to 10: 50 to 100; and fifthly, adding the final reaction product into an organic solvent for dissolving, then carrying out centrifugal separation to obtain a precipitate, and drying the precipitate to obtain the modified opal.

The following is a further optimization or/and improvement of one of the above-mentioned technical solutions of the invention:

the lactide is one of L-lactide, D-lactide and D, L-lactide; the elution is carried out by separating and precipitating with alumina column and using 30-60% ethanol water solution as eluent.

In the first step: the particle size of the opal is 200-400 meshes, the stirring time is 10-30 min, and the reaction time is 3-6 h.

In the second step: adding concentrated sulfuric acid into the intermediate product mixed solution to adjust the pH value to 3-6; the addition amount of the absolute ethyl alcohol is that 30mL to 100mL of absolute ethyl alcohol is added into each gram of the opal, and the addition amount of the methanol is that 20mL to 40mL of methanol is added into each gram of the opal.

In the third step above: standing for 12 to 18 hours, drying at 40 to 70 ℃, at 0.070 to 0.085MPa for 6 to 10 hours; and adding methanol into the concentrated solution, and then sequentially standing, filtering and drying to obtain the carboxylated protein soil.

And in the fourth step, the nitrogen is filled into the mixed material II for purging before the reaction, and the nitrogen purging rate is 30mL/min to 100 mL/min.

In the fifth step: adding an organic solvent into a final reaction product for dissolving, and then carrying out centrifugal separation to obtain a precipitate, repeating the step for 2 to 3 times, wherein the drying time is 24 hours, the drying temperature is 40 to 70 ℃, and the drying pressure is 0.085 to 0.095 MPa; the addition amount of the organic solvent is 10mL to 20mL of the organic solvent added into each gram of the opal; the organic solvent adopts dichloromethane or trichloromethane.

The second technical scheme of the invention is realized by the following measures: the preparation method of the modified protein soil comprises the following steps: the method comprises the steps of firstly, mixing required amounts of opal, potassium hydroxide and deionized water, stirring to obtain a first mixed material, adding sodium chloroacetate into the first mixed material at a temperature of 70-100 ℃ for reaction to obtain an intermediate product mixed solution, wherein the mass ratio of the opal, the potassium hydroxide and the deionized water is 1: 1-5: 10-30, and the mass ratio of the opal to the sodium chloroacetate is 1:1 to 5; secondly, adjusting the pH of the intermediate product mixed liquor cooled to room temperature to acidity, adding absolute ethyl alcohol, eluting the intermediate product mixed liquor added with the absolute ethyl alcohol, and then evaporating to remove the ethyl alcohol to obtain concentrated liquor; thirdly, adding methanol into the concentrated solution, and then sequentially standing, filtering and drying to obtain carboxylated protein soil; and step four, mixing required amount of stannous octoate, carboxylated proteinous soil and lactide to obtain a second mixed material, and reacting the second mixed material for 20 to 30 hours at the temperature of 140 to 190 ℃ and under the pressure of 0.085 to 0.095MPa to obtain a final reaction product, wherein the mass ratio of the stannous octoate to the carboxylated proteinous soil to the lactide is 1:3 to 10: 50 to 100; and fifthly, adding the final reaction product into an organic solvent for dissolving, then carrying out centrifugal separation to obtain a precipitate, and drying the precipitate to obtain the modified opal.

The following is further optimization or/and improvement of the second technical scheme of the invention:

the lactide is one of L-lactide, D-lactide and D, L-lactide; the elution is carried out by separating and precipitating with alumina column and using 30-60% ethanol water solution as eluent.

In the first step: the particle size of the opal is 200-400 meshes, the stirring time is 10-30 min, and the reaction time is 3-6 h.

In the second step: adding concentrated sulfuric acid into the intermediate product mixed solution to adjust the pH value to 3-6; the addition amount of the absolute ethyl alcohol is that 30mL to 100mL of absolute ethyl alcohol is added into each gram of the opal, and the addition amount of the methanol is that 20mL to 40mL of methanol is added into each gram of the opal.

In the third step above: standing for 12 to 18 hours, drying at 40 to 70 ℃, at 0.070 to 0.085MPa for 6 to 10 hours; and adding methanol into the concentrated solution, and then sequentially standing, filtering and drying to obtain the carboxylated protein soil.

And in the fourth step, the nitrogen is filled into the mixed material II for purging before the reaction, and the nitrogen purging rate is 30mL/min to 100 mL/min.

In the fifth step: adding an organic solvent into the final reaction product for dissolving, and then carrying out centrifugal separation to obtain a precipitate, wherein the drying time of the precipitate is 24 hours, the drying temperature is 40-70 ℃, and the drying pressure is 0.085-0.095 MPa; the addition amount of the organic solvent is 10mL to 20mL of the organic solvent added into each gram of the opal; the organic solvent adopts dichloromethane or trichloromethane.

The third technical scheme of the invention is realized by the following measures: the polylactic acid-modified opal composite material comprises 100 parts by weight of polylactic resin, 0.05 to 5 parts by weight of modified opal and 2 to 10 parts by weight of plasticizer, and is prepared by the following steps: uniformly mixing the polylactic resin, the modified opal and the plasticizer according to the required amount to obtain a mixed material, and extruding the mixed material at the extrusion temperature of 170-190 ℃ to obtain the polylactic acid-modified opal composite material.

The third technical scheme of the invention is further optimized or/and improved as follows:

the plasticizer is more than one of polyethylene glycol, phosphate and acetyl tributyl citrate.

Before the polylactic resin is used, the polylactic resin is dried for 20 to 30 hours at the temperature of between 40 and 60 ℃ and under the pressure of between 0.070 and 0.085 MPa.

The fourth technical scheme of the invention is realized by the following measures: the preparation method of the polylactic acid-modified opal composite material comprises the following steps of raw materials, by weight, 100 parts of polylactic resin, 0.05 to 5 parts of modified opal and 2 to 10 parts of plasticizer: uniformly mixing the polylactic resin, the modified opal and the plasticizer according to the required amount to obtain a mixed material, and extruding the mixed material at the extrusion temperature of 170-190 ℃ to obtain the polylactic acid-modified opal composite material.

The following is further optimization or/and improvement of the fourth technical scheme of the invention:

the plasticizer is more than one of polyethylene glycol, phosphate and acetyl tributyl citrate.

Before the polylactic resin is used, the polylactic resin is dried for 20 to 30 hours at the temperature of between 40 and 60 ℃ and under the pressure of between 0.070 and 0.085 MPa.

The fifth technical scheme of the invention is realized by the following measures: the polylactic acid-modified protein soil composite material is applied to medical materials or/and food packaging materials or/and agricultural film materials or/and fiber materials.

According to the invention, the polylactic acid-modified opal composite material is prepared by adopting the modified opal, so that the mechanical property and the heat resistance of the polylactic acid-modified opal composite material are obviously improved compared with those of the existing pure polylactic acid material, and the crystallization property and the tensile property of the polylactic acid-modified opal composite material are obviously improved compared with those of the existing pure polylactic acid material, thereby expanding the application field of the polylactic acid composite material.

Drawings

FIG. 1 is a shape diagram of a polarizing microscope at 200 μm when a conventional pure polylactic acid material and a polylactic acid-modified protein soil composite material of the present invention are crystallized at a constant temperature of 130 ℃ for 10 min.

FIG. 2 is a scanning electron microscope morphology of the existing pure polylactic acid material and the polylactic acid-modified protein soil composite material under 40 μm.

FIG. 3 is a TG curve and a DTG curve of the existing pure polylactic acid material and the polylactic acid-modified protein soil composite material of the invention.

FIG. 4 is a graph showing the elongation at break of the polylactic acid-modified protein soil composite material of the present invention.

In fig. 1 to 4, (a) is a conventional pure polylactic acid material, and (b) is a polylactic acid-modified opal composite material obtained in example 19 of the present invention.

Detailed Description

The present invention is not limited by the following examples, and specific embodiments may be determined according to the technical solutions and practical situations of the present invention. The various chemical reagents and chemical articles mentioned in the invention are all the chemical reagents and chemical articles which are well known and commonly used in the prior art, unless otherwise specified; the percentages in the invention are mass percentages unless otherwise specified; the solution in the present invention is an aqueous solution in which the solvent is water, for example, a hydrochloric acid solution is an aqueous hydrochloric acid solution, unless otherwise specified; the normal temperature and room temperature in the present invention generally mean a temperature of 15 ℃ to 25 ℃, and are generally defined as 25 ℃.

The invention is further described below with reference to the following examples: