CN102241827B - Adjusting method of natural vegetable fiber and polylactic acid interface - Google Patents

Abstract

A method for regulating the interface between natural plant fibers and polylactic acid, using hexamethyldisiloxane hot volatile gas as the gas medium, using a low-temperature plasma processor to treat the natural plant fibers under normal pressure, and depositing ultra- The thin silicon-oxygen-carbon compound nonpolar layer changes the surface properties of natural plant fibers, thereby achieving the purpose of regulating the interfacial compatibility between natural plant fibers and polylactic acid. The invention gets rid of the defects of very clear interface and poor cohesive force in the composition phase, so that the stress can be effectively transmitted at the interface, and the compatibility between natural plant fiber and polylactic acid can be improved, thereby improving the comprehensive performance of the composite material.

Description

A method for regulating the interface between natural plant fiber and polylactic acid

technical field

The invention relates to a method for regulating the interface of composite materials, belonging to the field of composite material manufacturing, in particular to a method for regulating the interface between natural plant fibers and polylactic acid.

Background technique

Natural plant fibers such as wood fiber, bamboo fiber and hemp fiber have the advantages of large aspect ratio, high specific strength, large specific surface area, low density, low price, renewability and biodegradability. Composite preparation of high-quality raw materials for biodegradable composite materials. However, natural plant fiber is composed of cellulose, hemicellulose, lignin and various extracts. It is an inhomogeneous anisotropic material with complex interfacial properties. Its main components, cellulose, hemicellulose, and lignin, contain a large number of polar hydroxyl and phenolic hydroxyl functional groups, making its surface exhibit strong chemical polarity, resulting in the interface between plant fibers, polylactic acid, and other biodegradable plastic substrates. Poor compatibility, microscopically inhomogeneous system, two phases have a very clear interface, poor cohesion, so that the stress cannot be effectively transmitted at the interface, the physical and mechanical properties of the prepared biodegradable composite material are significantly reduced, thus affecting Comprehensive properties of composite materials.

Therefore, when preparing natural plant fiber-reinforced polylactic acid biodegradable composites, it is necessary to regulate the interface between natural plant fibers and polylactic acid, so that there is a positive interaction between the hydrophilic polar natural plant fiber surface and the hydrophobic non-polar polylactic acid interface. Good compatibility enables intermolecular fusion between the surface layer of natural plant fibers and the surface layer of polylactic acid.

Contents of the invention

The technical problem to be solved by the present invention is to provide a method for regulating the interface between natural plant fibers and polylactic acid to improve the interfacial compatibility between natural plant fibers and polylactic acid, so as to solve the above-mentioned shortcomings in the background technology.

The technical problem solved by the present invention adopts following technical scheme to realize:

A method for regulating the interface between natural plant fibers and polylactic acid, which is different from other regulating methods in that it uses hot volatile gas of hexamethyldisiloxane as a modification medium, and uses a low-temperature plasma processor to treat natural plants under normal pressure. The surface of the fiber is modified, and an ultra-thin silicon-oxygen-carbon compound non-polar layer is deposited on the surface of the natural plant fiber to change the surface properties of the natural plant fiber, so as to achieve the purpose of regulating the interfacial compatibility between the natural plant fiber and polylactic acid.

The specific method is as follows:

(1) Pour 500ml of hexamethyldisiloxane into a round-bottom flask with three times the volume, and use a high-temperature-resistant hose with a valve and a flow meter to react with the low-temperature plasma processor at the mouth of the flask Chamber connections (closed prior to processing).

(2) Place the round bottom flask filled with hexamethyldisiloxane on a water bath, and set the temperature of the water bath at 100°C.

(3) Weigh a certain amount of natural plant fiber and put it into the stage in the reaction chamber of the low-temperature plasma processing apparatus.

(4) Turn on the vacuum pump of the low-temperature plasma processor to pump out the air in the reaction chamber, open the valve on the high-temperature-resistant hose while pumping air, fill the gaseous hexamethyldisiloxane into the reaction chamber, and adjust the flow meter to control the inlet The flow rate of the gaseous hexamethyldisiloxane in the reaction chamber reaches a dynamic equilibrium after a period of time, maintaining an atmospheric pressure in the reaction chamber.

(5) Press the RF power source switch of the low-temperature plasma processor, adjust the RF power, and perform plasma treatment on natural plant fibers. After 3 minutes or 4 minutes, turn off the RF power source switch of the instrument and the valve on the high-temperature-resistant hose, and the natural plant fibers After being taken out, it can be directly used to prepare reinforcement materials of biodegradable composite materials.

Beneficial effects: the surface of the natural plant fiber treated by the method of the present invention will deposit a non-polar layer of silicon-oxygen-carbon compound, which can improve the compatibility between the natural plant fiber and polylactic acid, thereby realizing the utilization of natural plant fiber and Interfacial regulation of biodegradable composites prepared by polylactic acid compounding.

Detailed ways

The present invention is described in detail with examples below.

Example 1

1. Pour 500ml of hexamethyldisiloxane into a round bottom flask with a volume of 1500ml, and connect the mouth of the flask to the reaction chamber of the low temperature plasma processor with a high temperature resistant hose with a valve and a flow meter ( closed before processing).

2. Place the round bottom flask filled with hexamethyldisiloxane on the water bath, and set the temperature of the water bath at 100°C.

3. Weigh a certain amount of natural plant fiber and put it into the stage in the reaction chamber of the low-temperature plasma processing apparatus.

4. Turn on the vacuum pump of the low-temperature plasma processor to pump out the air in the reaction chamber, open the valve on the high-temperature resistant hose while pumping air, fill the gaseous hexamethyldisiloxane into the reaction chamber, and adjust the flow meter to control the reaction. The gaseous hexamethyldisiloxane flow rate in the chamber will reach a dynamic equilibrium after a period of time to maintain an atmospheric pressure in the reaction chamber.

5. Press the RF power source switch of the low-temperature plasma processor, adjust the RF power to 30W, and conduct plasma treatment on the natural plant fibers for 4 minutes. After the natural plant fibers are taken out, they can be directly used to prepare reinforcement materials for biodegradable composite materials.

Example 1 is mainly used for regulating the interface between natural plant fibers with enamel layer on the surface of rice straw and wheat straw and polylactic acid.

Example 2

1. Pour 500ml of hexamethyldisiloxane into a round bottom flask with a volume of 1500ml, and connect the mouth of the flask to the reaction chamber of the low temperature plasma processor with a high temperature resistant hose with a valve and a flow meter ( closed before processing).

2. Place the round bottom flask filled with hexamethyldisiloxane on the water bath, and set the temperature of the water bath at 100°C.

3. Weigh a certain amount of natural plant fiber and put it into the stage in the reaction chamber of the low-temperature plasma processing apparatus.

4. Turn on the vacuum pump of the low-temperature plasma processor to pump out the air in the reaction chamber, open the valve on the high-temperature resistant hose while pumping air, fill the gaseous hexamethyldisiloxane into the reaction chamber, and adjust the flow meter to control the reaction. The gaseous hexamethyldisiloxane flow rate in the chamber will reach a dynamic equilibrium after a period of time to maintain an atmospheric pressure in the reaction chamber.

5. Press the RF power source switch of the low-temperature plasma processor, adjust the RF power to 20W, and conduct plasma treatment on the natural plant fibers for 3 minutes. After the natural plant fibers are taken out, they can be directly used to prepare reinforcement materials for biodegradable composite materials.

Embodiment 2 is mainly used for regulating the interface between natural plant fibers such as wood fibers and bamboo fibers that do not contain an enamel layer and polylactic acid.

。 The basic principles and main features of the present invention and the advantages of the present invention have been shown and described above. Those skilled in the industry should understand that the present invention is not limited by the above-mentioned embodiments. What are described in the above-mentioned embodiments and the description only illustrate the principle of the present invention. Without departing from the spirit and scope of the present invention, the present invention will also have Variations and improvements all fall within the scope of the claimed invention. The protection scope of the present invention is defined by the appended claims and their equivalents

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Claims (1)

1. a natural plant fibre and poly(lactic acid) interface regulate and control method as gaseous media, adopt the low-temperature plasma processing instrument under normal pressure natural plant fibre to be processed with the hot volatilization gas of hexamethyldisiloxane, it is characterized in that concrete operation method is as follows:

(1) hexamethyldisiloxane of 500ml is poured in the round-bottomed flask that volume is three times of volumes, the flask mouth is used with valve, the Thermostable flexible hose that is connected under meter be connected with Low Temperature Plasma Treating instrument reaction chamber;

The round-bottomed flask that (2) hexamethyldisiloxane will be housed is placed on water-bath, and the water-bath temperature is set up at 100 ℃;

(3) take by weighing the Stage microscope that a certain amount of natural plant fibre is put into Low Temperature Plasma Treating instrument reaction chamber;

(4) vacuum pump of opening the Low Temperature Plasma Treating instrument is taken out the indoor air of dereaction, open valve on the Thermostable flexible hose when bleeding, the hexamethyldisiloxane of gaseous state is filled with reaction chamber, the control of adjust flux meter enters the hexamethyldisiloxane flow of reaction chamber gaseous state, after after a while, reach running balance, keep normal atmosphere in the reaction chamber;

(5) press Low Temperature Plasma Treating instrument radio frequency power source switch, regulate radio frequency power, natural plant fibre is carried out Cement Composite Treated by Plasma, close valve on instrument radio frequency power source switch and the Thermostable flexible hose after processing 3min or 4min, natural plant fibre takes out the strongthener that can be directly used in the preparation biodegradable composite.