TWI421275B - Pla composite material and a method of manufacturing the same - Google Patents

Description

Polylactic acid composite material and manufacturing method thereof

The invention relates to a plastic composite material, in particular to a polylactic acid composite material and a manufacturing method thereof.

Since the plastic material has flexibility and viscoelasticity and is biased toward a soft material, the plastic material is often provided with a desired physical property by adding a filler material, such as improving material properties such as rigidity or hardness, or increasing functionality such as electrical conductivity or heat resistance. Clay, fiberglass, metal, mica, calcium carbonate, etc. are common filling materials.

Montmorillonite is mainly composed of a piece of aluminoxy octahedron sandwiched between two xenon tetrahedrons, a layered structural clay formed by sharing oxygen atoms. Organic montmorillonite is a product of organic modification of montmorillonite via an organic cationic surfactant. Because montmorillonite itself has polarity and hydrophilicity, it has poor compatibility with plastic materials, and organically modified organic montmorillonite transforms hydrophilic surface into lipophilic surface, so it is in plastic materials. It can have better dispersibility.

When added to plastic materials, organic montmorillonite can improve the impact resistance, dimensional stability and gas barrier properties of plastic materials without causing pollution to the environment. However, since the adhesive force of organic montmorillonite and polylactic acid (PLA) plastic materials is still insufficient, how to improve the combination of organic montmorillonite and polylactic acid materials to form a polylactic acid composite material with good properties, Still a research and development player in the industry.

Since the combination of organic montmorillonite and polylactic acid is still improved, the object of the present invention is to provide a polylactic acid composite material and a method for producing the same, wherein the organic montmorillonite can form a good combination with the polylactic acid material. And effectively improve the mechanical properties and thermal properties of the polylactic acid material.

The present invention provides a polylactic acid composite material comprising a polylactic acid material and an organic montmorillonite modified by a coupling agent, the organic montmorillonite system being grafted on the main chain of the polylactic acid material.

The polylactic acid composite may further comprise a transparent nucleating agent such as sorbitol or a toughening agent such as polybutylene succinate.

The coupling agent can be a decane type coupling agent such as triethoxyvinyl decane.

The present invention further provides a method for producing a polylactic acid composite material, comprising the steps of: providing a polylactic acid material; providing an organic montmorillonite; modifying the organic montmorillonite with a coupling agent; and modifying the coupling agent The organic montmorillonite is grafted onto the main chain of the polylactic acid material to form the polylactic acid composite.

In the grafting step, a transparent nucleating agent such as sorbitol or a toughening agent such as polybutylene succinate may be further added.

The coupling agent can be a decane type coupling agent such as triethoxyvinyl decane.

The grafting step can graft the organic montmorillonite onto the backbone of the polylactic acid material by initiating a chemical reaction via dicumyl peroxide.

The polylactic acid composite material of the present invention may comprise a polylactic acid material and an organic montmorillonite modified by a coupling agent, and the organic montmorillonite is grafted on the main chain of the polylactic acid material.

Referring to the first figure, the preparation method of the polylactic acid composite material of the present invention may comprise the steps of: providing a polylactic acid material; providing an organic montmorillonite; modifying the organic montmorillonite with a coupling agent, coupling agent and organic The schematic diagram of the reaction of montmorillonite is shown in the second figure. The present invention treats organic montmorillonite by a coupling agent to reduce its water absorption, and improves the compatibility of organic montmorillonite and polylactic acid. The coupling agent can be decane. a coupling agent such as triethoxyvinylsilane; and grafting the organic montmorillonite modified by the coupling agent onto the main chain of the polylactic acid material to form the polylactic acid composite material, the grafting step The organic montmorillonite can be grafted onto the main chain of the polylactic acid material by starting a chemical reaction through Dicumyl peroxide (DCP) to promote the adhesion of the organic montmorillonite to the polylactic acid material, so that the organic The montmorillonite can be stably dispersed in the polylactic acid material. For the schematic diagram of the chemical reaction, as shown in the third figure, the grafting step can be carried out by melt-kneading the above materials in a spectrometer.

In the grafting step of the preparation method, a toughening agent such as polybutylene succinate (PBS) may be further added to improve the impact strength of the material, and a transparent nucleating agent such as sorbitol (D) may be added. -sorbitol) so that the material not only maintains crystallinity but also exhibits a light transmissive appearance.

Example 1: Preparation of Polylactic Acid Composite Material

The properties and sources of the materials used in this example are as follows:

1. Polylactic acid raw material granules, source: Wei Meng Industrial Co., Ltd. Nature Gerrn ^TM 2002D type, molecular weight: >100000.

2. Dicumyl peroxide, source: Aldrich Co., molecular formula: C18H22O2, relative molecular weight: 270.37 g/mole, white crystal, melting point: 41 to 42 ° C, relative density: 1.082, specific gravity: 0.97.

3. decane coupling agent, reagent grade, source: Aldrich Co. Z-6060, molecular formula: C8H18O3Si, molecular weight: 190.32 g/mole, purity: 97%, boiling point: 123 ° C, specific gravity: 0.97 (coupling agent).

4. Organic montmorillonite powder, source: Huanqi International Trading Co., Ltd., model: Cloiste 20A, density: 1.77 g/cm3, with a unique layered shape and nano structure characteristics (nucleating agent).

5. Polybutylene succinate raw material granules, source: Mingan Technology Co., Ltd., GP-9001N (toughening agent).

6. Sorbitol, source: Jingming Chemical Co., Ltd., molecular weight: 182.17 g / mole, molecular formula: C6H14O6, good nucleation effect, easy to disperse, can improve material transparency, surface gloss and physical and mechanical properties.

Modification of organic montmorillonite coupling agent:

First, add organic montmorillonite to a 500 mL round bottom flask, add appropriate amount of acetone and 3% decane coupling agent, adjust to pH=4 with acetic acid and alkali indicator, and place it on the heater. Stir (4 hours, 70 °C). Then, it was filtered with suction and rinsed with n-propanol. The organic montmorillonite modified by the coupling agent was placed in a suction cabinet for 24 hours, and then placed in an oven and dried at 50 ° C for 48 hours. It is the organic montmorillonite modified by the coupling agent.

Preparation process of polylactic acid composite sample:

First, the organic montmorillonite modified by the coupling agent is mixed with polylactic acid, and then poured into a plastic spectrometer. According to the composition ratio of each sample in Table 1, the mixing temperature is 175 °C at a rotation speed of 60 rpm for 6 minutes, and then through hot pressing. The molding mechanism obtained a test piece sample.

Example 2: Thermogravimetric analysis test

The results of thermogravimetric analysis of organic montmorillonite and organic montmorillonite modified by coupling agent are shown in the fourth figure. The test results show that the general organic montmorillonite is 311.23 °C at Td ₅ , and the coupling agent is changed. The organic montmorillonite was 339.61 °C at Td ₅ , and its TGA test data is summarized in Table 2.

The above test data shows that the surface of the organic montmorillonite modified by the coupling agent has been connected to the antimony component with excellent heat resistance. Therefore, the organic montmorillonite modified by the coupling agent will be more than the organic montmorillonite. The cracking temperature is still high. The organic montmorillonite modified by the coupling agent has higher coke content than the general organic montmorillonite, indicating that the addition of polylactic acid reduces the burning of polylactic acid at high temperature, and improves the flame resistance of the polylactic acid composite material.

Example 3: Impact resistance test of polylactic acid composite material

The samples prepared in Example 1 were subjected to an impact resistance test, and the test results are summarized in Table 3. The impact resistance test results show that the impact strength of the polylactic acid composite material is higher than that of the pure polylactic acid material, and the highest lifting rate can reach more than 80%.

Example 4: Thermal Deformation Temperature Test of Polylactic Acid Composites

The sample prepared in the first embodiment is subjected to a heat distortion temperature test, and the heat distortion temperature can evaluate the resistance of the polylactic acid composite material to shape and dimensional deformation at a relatively high temperature, and is one of the important detection methods for determining the heat resistance property of the composite material. . The prepared samples were subjected to a heat distortion temperature test, and the test results are summarized in Table 4. The heat distortion temperature test results show that the heat distortion temperature of the polylactic acid composite material is higher than that of the pure polylactic acid material, and the highest lifting rate can reach more than 55%. According to the results, the composite material with the addition of Dicumyl peroxide (DCP) has a higher heat distortion temperature than the composite material without adding Dicumyl peroxide (DCP). This indicates that there is a bond between the polylactic acid polymer and the organic montmorillonite modified by the coupling agent.

Example 5: Analysis of light transmission properties

The samples prepared in Example 1 were subjected to penetration analysis, and the results of the analysis are shown in Table 5. The analysis results show that as the content of organic montmorillonite increases, the transmittance decreases, because organic montmorillonite itself is an opaque filler, and the addition of polylactic acid reduces the transmittance of polylactic acid composite. With the increase of sorbitol content, the transparency of polylactic acid composites is also improved, because sorbitol itself is a transparent nucleating agent which will make the crystal shape of the material smaller, which will increase the transparency of polylactic acid composites. degree.

The invention firstly modifies the organic montmorillonite with a coupling agent to improve the compatibility with the polylactic acid material, and then grafts the organic montmorillonite modified by the coupling agent onto the main chain of the polylactic acid material to Further enhancing the adhesion between the organic montmorillonite and the polylactic acid material, the organic montmorillonite and the polylactic acid can form a well-bonded polylactic acid composite material, and the polylactic acid composite material of the present invention can further add a toughening agent or transparent nucleation. Agent to enhance the properties of polylactic acid composites.

The first figure is a schematic flow chart of a preferred embodiment of a method for preparing a polylactic acid composite material of the present invention.

The second figure is a schematic diagram of the reaction of a preferred embodiment of the coupling agent of the present invention and organic montmorillonite.

The third figure is a schematic diagram of the reaction of the preferred embodiment of the grafting step of the present invention.

The fourth figure is the thermogravimetric analysis test result of the organic montmorillonite of the invention and the organic montmorillonite modified by the coupling agent.

Claims (8)

A polylactic acid composite material comprising a polylactic acid material, an organic montmorillonite modified with a decane coupling agent, a transparent nucleating agent and a toughening agent, and the organic montmorillonite is grafted to the polylactic acid material On the main chain. The polylactic acid composite material according to claim 1, wherein the transparent nucleating agent is sorbitol. The polylactic acid composite material according to claim 1 or 2, wherein the toughening agent is polybutylene succinate. A method for producing a polylactic acid composite material, comprising the steps of: providing a polylactic acid material; providing an organic montmorillonite; modifying the organic montmorillonite with a coupling agent; and removing the organic montmorillonite modified by the coupling agent The soil is grafted on the main chain of the polylactic acid material to form the polylactic acid composite material, wherein a transparent nucleating agent and a toughening agent are further added in the grafting step. The manufacturing method according to claim 4, wherein the coupling agent is a decane coupling agent. The manufacturing method according to claim 5, wherein the decane coupling agent is triethoxyvinyl decane. The manufacturing method according to claim 6, wherein the transparent nucleating agent is sorbitol, and the toughening agent is polybutylene succinate. The manufacturing method according to any one of claims 4 to 7, wherein the grafting step grafts the organic montmorillonite onto the main chain of the polylactic acid material by initiating a chemical reaction via dicumyl peroxide.