CN103113730A - Polylactic acid composite material and preparation method thereof - Google Patents

Abstract

The invention provides a polylactic acid composite material made of polylactic acid, polycaprolactone, nano silicon dioxide, antioxidant and compatibilizer and a preparation method thereof. The toughness of polylactic acid is improved by adding biodegradable polycaprolactone, and nano-silica with high strength, toughness and high stability is dispersed in the material and combined with polymer chains to form a three-dimensional network structure, thereby improving polylactic acid. The impact strength, elasticity and other basic properties meet the needs of biological environmental protection.

Description

A kind of polylactic acid composite material and preparation method thereof

the

technical field

The invention relates to the technical field of polymer materials, in particular to a high-strength and high-toughness polylactic acid composite material and a preparation method thereof. the

Background technique

Polylactic acid can be completely derived from renewable resources and completely get rid of the dependence on petroleum resources. Its mechanical and physical properties are relatively better than polyester, and it also has high gloss and transparency, good resilience and curl durability, Good oil resistance and dyeing performance, low flammability, non-toxic to human body and so on. the

At present, polylactic acid has not been widely used because it is limited by some shortcomings of the material, mainly manifested in low crystallinity, resulting in low strength; easy to degrade during melt processing, difficult to control molecular weight and molecular weight distribution; brittle Hard, poor toughness, lack of flexibility and elasticity, low impact strength, etc. Although some methods have been taken to improve the shortcomings of polylactic acid, such as polylactic acid and other materials such as acrylonitrile-butadiene-styrene copolymerization, chain extension and branching of polylactic acid, and polylactic acid with other materials Reactive blending, etc., among which the method of blending polylactic acid with other materials to improve the performance of polylactic acid is the simplest and feasible method, but usually the modified polylactic acid still cannot meet the requirements of engineering parts in the market . The invention uses the biodegradable material polycaprolactone to modify polylactic acid, so that the mechanical properties of the prepared composite material are improved, and the nano-silica is uniformly dispersed in the composite material, so that the prepared material has excellent and stable performance . the

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Contents of the invention

The purpose of the present invention is to provide a high-strength and high-toughness polylactic acid composite material and a preparation method thereof. The preparation method of the biodegradable polyester toughened polylactic acid composite material is simple and easy, and makes the obtained composite The material has good mechanical properties and biodegradable properties. the

The purpose of the present invention can be achieved through the following technical solutions, a polylactic acid composite material is prepared by the following components by weight:

                              60-85 parts

Polycaprolactone 10-33 parts

Nano silica 3-8 parts

Antioxidant 0.1-5 parts

Compatibilizer 0.1-5 parts.

The polylactic acid is a composition of L-type lactic acid and D-type lactic acid, wherein the content of L-type lactic acid is 70%-96%, and the weight average molecular weight is 10000-200000g/mol. the

The polycaprolactone is a linear polycaprolactone with a weight average molecular weight of 10000-100000 g/mol. the

The nano-silica is amphiphilic nano-silica produced by chemical vapor deposition. the

The antioxidants are tris(2,4-di-tert-butyl)phenyl phosphite (Irganox168 for short), tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid]pentaerythritol At least one of ester (Irganox1010 for short) and 1,3,5-trimethyl-2,4,6-(3,5-di-tert-butyl-4-hydroxybenzyl)benzene (Irganox1330 for short). the

The compatibilizer is N , N , N ', N '-tetraglycidyl-4, 4' diaminodiphenylmethane (Ag80), bisphenol A liquid epoxy resin (E44), isocyanuric acid At least one of triglycidyl esters (TGIC). the

A method for preparing the above-mentioned polylactic acid composite material, comprising the following steps:

(1) Dry the polylactic acid and polycaprolactone first, dry the polylactic acid at 80°C for 8 hours, and dry the polycaprolactone at 60°C for 6 hours;

(2) Stir the dried polylactic acid, polycaprolactone, antioxidant, and compatibilizer through a high-speed mixer for 10 to 12 minutes according to the proportion to form a mixed material;

(3) Put the mixed material in (2) into the hopper of the twin-screw extruder, and after melting reaction, add nano-silica in the third zone, the fourth zone or the fifth zone by side feeding, Then extrude and granulate to obtain polylactic acid composite material.

The temperature of each zone of the twin-screw extruder is 70-100°C in the first zone, 190-210°C in the second zone, 190-210°C in the third zone, 180-200°C in the fourth zone, and 180-200°C in the fifth zone , the temperature in the six zones is 180-200°C, the head temperature is 170-190°C; the speed of the extruder screw is 150-200r/min. the

The present invention has the following beneficial effects:

1. The present invention improves the toughness of polylactic acid and improves the impact strength of polylactic acid by adding biodegradable polycaprolactone.

2. Since nano-silica still has the characteristics of high strength, toughness and high stability at high temperature, it is dispersed in the material and combined with polymer chains to form a three-dimensional network structure, thereby improving the strength and elasticity of the composite material. basic performance. the

3. The addition of compatibilizer and other additives improves the adhesion between polylactic acid and biodegradable polycaprolactone components, further improves the performance of polylactic acid, and keeps the prepared polylactic acid composite material at a high level. The impact strength was improved under the condition of tensile strength. the

4. Biodegradable polycaprolactone is used to modify polylactic acid, which ensures that the biodegradable performance of polylactic acid is not damaged, so that the prepared composite material has high strength and high toughness while meeting the needs of biological environmental protection. the

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Detailed ways

The present invention will be described in detail below in conjunction with specific embodiments. the

A composite material of polylactic acid with high strength and high toughness according to the present invention comprises the following components according to weight percentage: 60-90 parts of polylactic acid; 10-40 parts of polycaprolactone; 3-8 parts of nano silicon dioxide; Oxygen agent 0.1-5 parts; compatibilizer 0.1-5 parts. the

In each of the following comparative examples and examples, polylactic acid (PLA) is a composition of L-type lactic acid and D-type lactic acid, wherein the content of L-type lactic acid is 70%-96%, and the weight average molecular weight is 10000-200000g/mol. the

Polycaprolactone (PCL) is a linear polycaprolactone with a weight average molecular weight of 10000-100000 g/mol. the

Nano-silica is a kind of silicon dioxide produced by chemical vapor deposition, also known as pyrolysis, dry method, or combustion method. the

The antioxidants are BASF’s tris(2,4-di-tert-butyl)phenyl phosphite (Irganox168 for short), tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid] At least one of pentaerythritol ester (Irganox1010 for short) and 1,3,5-trimethyl-2,4,6-(3,5-di-tert-butyl-4-hydroxybenzyl)benzene (Irganox1330 for short) . the

The compatibilizer is N , N , N ', N '-tetraglycidyl-4, 4' diaminodiphenylmethane (Ag80), bisphenol A liquid epoxy resin 6101 (E44), triisocyanurate At least one of glycidyl esters (TGIC). the

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Example 1

Dry polylactic acid at 80°C for 8 hours, polycaprolactone at 60°C for 6 hours; then take 85 parts of polylactic acid, 10 parts of polycaprolactone, 0.3 parts of Irganox168, and 0.4 parts of Irganox1010 part, Ag80 is 0.3 part and stirred together for 11 minutes by a high-speed mixer to form a mixed material; finally, the mixed material is put into the hopper of a twin-screw extruder, and after melting reaction, 5 parts are added in the third zone by side feeding Parts of nano-silica, then extruded, granulated to obtain polylactic acid composites. The temperature and screw speed of each zone of the twin-screw extruder are as follows: the temperature of the first zone is 80°C, the temperature of the second zone is 200°C, the temperature of the third zone is 200°C, the temperature of the fourth zone is 195°C, the temperature of the fifth zone is 190°C, and the temperature of the sixth zone is 190°C , head temperature 180°C; screw speed 170r/min.

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Example 2

First dry polylactic acid at 80°C for 8 hours, and polycaprolactone at 60°C for 6 hours; then take 60 parts of polylactic acid, 33 parts of polycaprolactone, 3.2 parts of Irganox1330, and 1.8 parts of Irganox1010 part, 0.2 part of Ag80, and 0.3 part of E44 are stirred together by a high-speed mixer for 10 minutes to form a mixed material; finally, the mixed material is put into the hopper of the twin-screw extruder, melted and reacted, and passed through the side position in the fourth zone Add 7 parts of nano silicon dioxide in the way of feeding, then extrude and granulate to obtain polylactic acid composite material. The temperature and screw speed of each zone of the twin-screw extruder are: the temperature of the first zone is 70°C, the temperature of the second zone is 190°C, the temperature of the third zone is 190°C, the temperature of the fourth zone is 180°C, the temperature of the fifth zone is 180°C, and the temperature of the sixth zone is 180°C , head temperature 170°C; screw speed 150r/min.

the

Example 3

First dry polylactic acid at 80°C for 8 hours, polycaprolactone at 60°C for 6 hours; then take 80 parts of polylactic acid, 10 parts of polycaprolactone, 0.3 parts of Irganox168, and 0.3 parts of Irganox1330 2.5 parts of E44 and 2.5 parts of TGIC are stirred together by a high-speed mixer for 11 minutes to form a mixed material; put the mixed polylactic acid, polycaprolactone and additives into the hopper of the twin-screw extruder, and For melting reaction, add 5 parts of nano silicon dioxide in the third zone by side feeding, then extrude and granulate to obtain polylactic acid composite material. Among them, the temperature and screw speed of each zone of the twin-screw extruder are: the temperature of the first zone is 80°C, the temperature of the second zone is 200°C, the temperature of the third zone is 200°C, the temperature of the fourth zone is 195°C, the temperature of the fifth zone is 190°C, and the temperature of the sixth zone is 190°C. ℃, head temperature 180 ℃; screw speed 170r/min.

the

Example 4

First dry polylactic acid at 80°C for 8 hours, and polycaprolactone at 60°C for 6 hours; then take 77 parts of polylactic acid, 25 parts of polycaprolactone, 0.5 parts of Irganox1010, and 0.4 parts of Ag80 The parts are stirred together by a high-speed mixer for 12 minutes to form a mixed material; the mixed polylactic acid, polycaprolactone and additives are put into the hopper of the twin-screw extruder, and after melting reaction, they pass through the side position in the fifth zone. Add 8 parts of nano silicon dioxide in the way of feeding, then extrude and granulate to obtain polylactic acid composite material. Among them, the temperature and screw speed of each zone of the twin-screw extruder are: the temperature of the first zone is 100°C, the temperature of the second zone is 210°C, the temperature of the third zone is 210°C, the temperature of the fourth zone is 200°C, the temperature of the fifth zone is 200°C, and the temperature of the sixth zone is 200°C , head temperature 190°C; screw speed 200r/min.

the

Example 5

First dry polylactic acid at 80°C for 8 hours, and polycaprolactone at 60°C for 6 hours; then take 67 parts of polylactic acid, 30 parts of polycaprolactone, 0.3 parts of Irganox1330, and 0.3 parts of Irganox168 part, Ag80 is 0.1 part and stirred together by a high-speed mixer for 11 minutes to form a mixed material; put the mixed polylactic acid, polycaprolactone and additives into the hopper of the twin-screw extruder, and undergo melting reaction. In the third zone, 3 parts of nano-silicon dioxide is added by side feeding, and then extruded and granulated to obtain a polylactic acid composite material. The temperature and screw speed of each zone of the twin-screw extruder are as follows: the temperature of the first zone is 80°C, the temperature of the second zone is 200°C, the temperature of the third zone is 200°C, the temperature of the fourth zone is 195°C, the temperature of the fifth zone is 190°C, and the temperature of the sixth zone is 190°C , head temperature 180°C; screw speed 170r/min.

the

In order to better reflect the superior performance of the polylactic acid composite material of the present invention, the existing polylactic acid composite material is made into a sample by the same method as a comparative example for performance comparison with the material of the present invention, and the result data are shown in Table 1.

Comparative example 1

First, 75 parts of polylactic acid, 20 parts of acrylonitrile-butadiene-styrene, 0.6 parts of Irganox1010, 0.3 parts of Irganox168, and 0.2 parts of TGIC were stirred together by a high-speed mixer for 11 minutes to form a mixed material; Polylactic acid, acrylonitrile-butadiene-styrene and additives are put into the hopper of a twin-screw extruder, melted and reacted, then extruded and pelletized to obtain a polylactic acid composite material. Among them, the temperature and screw speed of each zone of the twin-screw extruder are: the temperature of the first zone is 80°C, the temperature of the second zone is 200°C, the temperature of the third zone is 200°C, the temperature of the fourth zone is 195°C, the temperature of the fifth zone is 190°C, and the temperature of the sixth zone is 190°C. ℃, head temperature 180 ℃; screw speed 170r/min.

Performance Testing:

 The polylactic acid composite materials prepared in the above-mentioned implementations 1-5 and comparative example 1 were made into test strips with an injection molding machine.

Tensile strength is tested according to ASTM D 638 standard, elongation at break is tested according to ASTM D 638 standard, flexural strength and flexural modulus are tested according to ASTM D790 standard, notched impact strength is tested according to ASTM D256 standard, heat distortion temperature is tested according to ASTM D648 standard . The test data is shown in Table 1:

Table 1 Product performance test of each embodiment Test items unit Example 1 Example 2 Example 3 Example 4 Example 5 Comparative example 1 Tensile Strength MPa 50 52 53 50 55 39 elongation at break % 200 205 215 210 220 250 Bending strength MPa 50 51 55 57 60 39 Flexural modulus MPa 1750 1700 1690 1790 1800 1450 Izod notched impact strength KJ/ ^m2 50 60 70 65 55 35

As can be seen from Table 1, compared with Comparative Example 1, the polylactic acid composite material prepared by using the present invention has good tensile strength while the impact strength is improved, and its flexural modulus is also improved to a certain extent , improving the mechanical properties of the material, thus expanding the application field of the material. In addition, this method uses biodegradable polycaprolactone to modify polylactic acid through reaction processing, so that the prepared composite material has high strength and high toughness while meeting the needs of bio-environmental protection. It overcomes the application limitations of polylactic acid and ensures the wide application of the material in the medical field.

The above description of the embodiments is for those of ordinary skill in the art to understand and apply the present invention. It is obvious that those skilled in the art can easily make various modifications to these embodiments, and apply the general principles described here to other embodiments without creative efforts. Therefore, the present invention is not limited to the embodiments herein. Improvements and modifications made by those skilled in the art according to the disclosure of the present invention without departing from the scope of the present invention should fall within the protection scope of the present invention. the

Claims (8)

1. lactic acid composite material is characterized in that: be prepared from by weight by following component:

Poly(lactic acid) 60-85 part

Polycaprolactone 10-33 part

Nano silicon 3-8 part

Oxidation inhibitor 0.1-5 part

Compatilizer 0.1-5 part.

2. a kind of lactic acid composite material according to claim 1, it is characterized in that: described poly(lactic acid) is the composition of L-type lactic acid and D type lactic acid, and wherein the L-type lactic acid content is 70%-96%, and weight-average molecular weight is 10000-200000g/mol.

3. a kind of lactic acid composite material according to claim 1, it is characterized in that: described polycaprolactone is linear polycaprolactone, weight-average molecular weight is 10000-100000g/mol.

4. a kind of lactic acid composite material according to claim 1, it is characterized in that: described nano silicon is the parental type nano silicon of producing by chemical Vapor deposition process.

5. a kind of lactic acid composite material according to claim 1, it is characterized in that: described oxidation inhibitor is three (2, the 4-di-t-butyl) phenyl-phosphite, four [β-(3, the 5-di-tert-butyl-hydroxy phenyl) propionic acid] pentaerythritol ester and 1,3,5-trimethylammonium-2,4,6-(3,5-di-t-butyl-4-hydroxybenzene methyl) at least a in benzene.

6. a kind of lactic acid composite material according to claim 1, it is characterized in that: described compatilizer is N, N, N ', N '-four glycidyl group-4, at least a in 4 ' diaminodiphenyl-methane, bisphenol A-type liquid-state epoxy resin, isocyanuric acid three-glycidyl ester.

7. method for preparing lactic acid composite material as claimed in claim 1 is characterized in that: comprise the following steps:

(1) first poly(lactic acid) and polycaprolactone are carried out drying treatment, poly(lactic acid) was in 80 ℃ of dry oven dry 8 hours, and polycaprolactone was in 60 ℃ of dry oven dry 6 hours;

(2) by proportioning, poly(lactic acid), polycaprolactone and oxidation inhibitor, the compatilizer of drying stirred 10～12 minutes the formation mixture by high-speed mixer;

(3) mixture in (2) is put in the hopper of twin screw extruder, through frit reaction, in the 3rd district, the 4th district or place, the 5th district add nano silicon by the reinforced mode in side position, then extruded, granulation gets lactic acid composite material.

8. preparation method according to claim 7, it is characterized in that: the temperature of respectively distinguishing of described twin screw extruder is 70～100 ℃ of district's temperature, two 190～210 ℃ of district's temperature, three 190～210 ℃ of district's temperature, four 180～200 ℃ of district's temperature, five 180～200 ℃ of district's temperature, six 180～200 ℃ of district's temperature, 170～190 ℃ of head temperatures; The rotating speed of extruder screw is 150～200r/min.