CN106633369A - Preparation method of bi-component modified glass fiber filled composite polypropylene material - Google Patents

Abstract

The invention belongs to the technical field of high-performance engineering plastics, and specifically discloses a preparation method of a two-component modified glass fiber-filled polypropylene composite material, comprising the following steps: S1. Adding glass fiber to an aqueous ethanol solution containing a silane coupling agent Soak in medium to obtain modified glass fiber; S2. Add initiator and monomer to the modified glass fiber in S1 for grafting reaction for a certain period of time, then filter, wash, and dry to obtain ultra-short glass fiber with surface grafted polymer; S3. Blend ultra-short glass fiber in S2, modified glass fiber in S1, antioxidant and polypropylene to make a masterbatch; S4. Extrude the masterbatch in S3, and obtain two-component modified glass fiber after drawing Filling the polypropylene composite material; under the premise of improving the interaction between the glass fiber and the polymer interface, the present invention takes into account the modification characteristics of the polypropylene composite material by glass fibers with different length-to-diameter ratios, and obtains a high Modified glass-filled polypropylene composites that combine strength with good toughness.

Description

Preparation method of a two-component modified glass fiber filled polypropylene composite material

technical field

The invention belongs to the technical field of high-performance engineering plastics, and more specifically relates to a preparation method of a two-component modified glass fiber-filled polypropylene composite material.

Background technique

The rapid development of science and technology and the rapidly growing population in modern society put forward higher requirements for the materials used in life and production. Traditional materials such as wood, stone, and metal can no longer fully meet the needs of production and life in today's society. . Extensive use of wood will cause damage to the ecological environment, and the supply and performance are difficult to meet modern requirements; traditional metal materials have shortcomings such as easy corrosion, high density, and fatigue effects. Since phenolic resin was first prepared by humans in the last century, after more than a hundred years of development, polymer materials have been widely used in many fields of daily life and industrial production, and have even replaced traditional metal materials in some occasions.

Polypropylene (PP) is a general-purpose plastic, which has the advantages of low density, corrosion resistance, good chemical stability, and superior processing performance. It has abundant raw materials, huge output, high cost performance, and reusability, so it has been widely used. Although PP has excellent comprehensive performance, its impact performance and hygroscopicity are poor, its molding shrinkage rate is large, it is prone to melt fracture, its low temperature performance is insufficient, and its mechanical strength is still insufficient compared with engineering plastics. In order to make up for these deficiencies of polypropylene materials and enable them to be applied to more devices, there have been many studies on polypropylene modification. Generally, fillers are added to the polypropylene matrix to enhance its mechanical properties, and a variety of modified polypropylene composite materials are made to meet the needs of various applications. Common fillers include glass fiber (GF), plant fiber/powder, carbon black, carbon nanotubes, etc. Among them, glass fiber reinforced polypropylene composite materials have mechanical properties comparable to engineering plastics, and the production cost is low, so they have been widely used, especially in the automotive and construction industries. In addition to adding fillers, stretch orientation can also be used to increase the strength of the material, and the product can be uniaxially or biaxially stretched and oriented to align the macromolecular chains, which can significantly increase the tensile strength of the material. At the same time, the dispersion of fillers in the stretched product can also be significantly improved.

Contents of the invention

The object of the present invention is to provide a method for preparing a two-component modified glass fiber filled polypropylene composite material according to the deficiencies in the prior art.

The object of the present invention is achieved through the following technical solutions:

The invention provides a method for preparing a two-component modified glass fiber filled polypropylene composite material, comprising the following steps:

S1. Adding the glass fiber to an aqueous ethanol solution containing a silane coupling agent and soaking it to obtain a modified glass fiber;

S2. Add initiator and monomer to the modified glass fiber in S1 for grafting reaction for a certain period of time, then filter, wash, and dry to obtain ultra-short glass fiber with surface grafted polymer;

S3. blending ultra-short glass fiber in S2, modified glass fiber in S1, antioxidant and polypropylene to make a masterbatch;

S4. Extrude the masterbatch in S3, and obtain a two-component modified glass fiber filled polypropylene composite material after drawing;

In step S2, the mixing mass ratio of initiator, monomer and modified glass fiber is (0.001-0.1):(0.05-0.2):1;

In step S3, the mixing mass ratio of ultra-short glass fiber, modified glass fiber in S1, antioxidant and polypropylene is (1-30):(1-30):(1-5):100.

In the invention, two kinds of glass fiber materials with different surface modification and different length-to-diameter ratios are simultaneously filled in polypropylene, and the two-component modified glass fiber filled polypropylene composite material is obtained after blending and post-drawing orientation. Wherein, in the method step S2, it is an ultra-short glass fiber with a surface grafted polymer, and the polymerized monomer is grafted to the glass fiber modified by a silane coupling agent in step S1 by using a grafting method (such as a ball milling grafting method). The surface is obtained, and the purpose of adding it is to toughen the polypropylene material; and the modified glass fiber in step S1 is only the glass fiber modified by the silane coupling agent, and the high aspect ratio of the original glass fiber is retained. Can play a reinforcing role in polypropylene materials. The present invention aims at improving the interface interaction between glass fiber and polymer, and at the same time taking into account the modification characteristics of glass fibers with different aspect ratios to polypropylene composite materials, and obtains high strength and good toughness through the means of post-drawing orientation. fiberglass polypropylene composites.

In step S2 of the present invention, the modified glass fiber is used to add an initiator and a monomer for grafting reaction, and the aspect ratio of the glass fiber is greatly reduced at this time. After reacting for a certain period of time, filter and wash to remove impurities such as solvents and unreacted polymer monomers, and dry to obtain ultra-short glass fibers with surface-grafted polymers.

Preferably, in step S3, the mixing ratio of the ultra-short glass fiber and the modified glass fiber in S1 is 1: (1-3). In step S3, the mixing amount of ultra-short glass fiber and modified glass fiber in S1 accounts for 10% of the masterbatch. In this ratio, the best polypropylene composite material with high strength and good toughness can be obtained.

Preferably, the blending temperature in step S3 is 190-220° C., the rotor speed of the internal mixer is 60-80 rpm, and the blending time is 6-15 min.

Preferably, the extrusion molding temperature in step S4 is 200-220° C., and the extrusion speed is 40-80 rpm.

Preferably, in step S1, the concentration of ethanol in the ethanol aqueous solution is 50-95%.

Preferably, in step S1, the mass concentration of the silane coupling agent is 0.5-2%.

Preferably, in step S1, the mixing ratio of the glass fiber to the aqueous ethanol solution containing the silane coupling agent is 1: (1-5). Wherein the amount of glass fiber is in g, and the amount of ethanol aqueous solution is in ml.

Preferably, in step S1, the silane coupling agent is isobutyltriethoxysilane, γ-aminopropyltriethoxysilane, vinyltrimethoxysilane, vinyltrichlorosilane, 3-mercapto One or more of propyltriethoxysilane and 3-(methacryloyloxy)propyltrimethoxysilane.

Preferably, in step S3, the polypropylene includes isotactic polypropylene, syndiotactic polypropylene or atactic polypropylene.

Preferably, the aspect ratio of the glass fiber used in step S1 is >100.

Preferably, in step S2, the initiator is azobisisobutyronitrile, azobisisoheptanonitrile, benzoyl peroxide, di(2,4-dichlorobenzoyl), diacetyl peroxide, peroxide Dicaprylyl oxide or dilauroyl peroxide, the monomers are methyl acrylate, butyl acrylate, trifluoroethyl acrylate, ethyl acrylate or 2-ethylhexyl acrylate.

Compared with the prior art, the present invention has the following advantages and beneficial effects:

The present invention mixes ultra-short glass fibers and coupling-modified conventional glass fibers to prepare a masterbatch, which is beneficial to give full play to the advantages of the orientation process and the filling of long glass fiber reinforced polypropylene materials; Short glass fibers modify the brittleness of polypropylene materials and refine the crystal form, which is beneficial to make up for the decrease in toughness caused by the process of reinforcing polypropylene materials; a polypropylene composite material with high strength and good toughness is obtained, which is expected to be applied In high-strength polypropylene pipes and polymer composite structural parts.

Description of drawings

Fig. 1 is a polarizing microscope picture of the modified glass fiber prepared in the method provided by the present invention.

Fig. 2 is a polarizing microscope image of the two-component modified glass fiber filled polypropylene composite material prepared by the method provided by the present invention.

detailed description

The present invention will be further described below in conjunction with specific embodiments and drawings, but the embodiments do not limit the present invention in any form. Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the technical field.

Unless otherwise specified, the reagents and materials used in the present invention are commercially available.

Example 1

Weigh 100g of glass fiber into a glass bottle, use absolute ethanol and ultrapure water to prepare 95% ethanol aqueous solution, weigh 1g (1wt%) silane coupling agent (KH-570) and add it to 300mL ethanol aqueous solution, mix well After that, it was added to the glass fiber and stirred for 24 hours with a mechanical stirrer to obtain the modified glass fiber. Weigh 1g (5wt%) AIBN initiator and 20g (20wt%) butyl acrylate (BA), add them into a glass bottle and mix them evenly with the modified glass fiber. The glass fiber and the solution in the glass bottle are divided into 4 ball milling jars, and an equal amount of ball milling beads (5 large beads, 30 medium beads, and 60 small beads) are added in each ball milling jar, and the ball milling jar ( or roller ball mill for production) and put into planetary ball mill after sealing. Turn on the ball mill, and react for 72 hours at a rotational speed of 290r/min. Take out the ball mill tank, put the ball mill tank in a fume hood for 12 hours, take out the glass fiber in the tank, wash it three times with ultrapure water, and then wash it once with acetone to remove other impurities such as polymerized monomers, and put the glass fiber in a vacuum to dry Dry in the box for 24h. A glass fiber (BA-g-GF) grafted with butyl acrylate on the surface was obtained.

Put the polypropylene (PP) pellets and glass fibers (KH570-g-GF, BA-g-GF) into an electric constant temperature blast oven, and dry them at 110°C for 24 hours to remove the moisture in the raw materials. Weigh and mix equal parts of KH570-g-GF and BA-g-GF respectively, the total mass content is 2%, 5%, 10%, 20%, 30% respectively, and then weigh 1wt% antioxidant 1010, after After mixing, the glass fiber, PP pellets and antioxidant are preliminarily mixed, and then added to an internal mixer for internal mixing for 10 minutes to obtain a masterbatch. Use a plastic crushing granulator to crush the obtained block masterbatch into masterbatches. Use the single-screw extruder head of the torque rheometer for extrusion molding. The die size of the extruder is 10mm×2mm. The die is connected with a drafting machine to draw the sheet to a thickness of about 0.3mm-0.5 mm sheet, the modified glass fiber polypropylene composite sheet can be obtained after winding, and the draft ratio is about 4:1. The specific conditions of each step are shown in the table below.

Table 1 Processing parameters of banburying and extrusion process

Note: 2% means the percentage content of KH570-g-GF and BA-g-GF in masterbatch raw materials, where the mixing ratio of KH570-g-GF and BA-g-GF is 1:1, and other ratios can be deduced accordingly.

Cut the extruded and stretched sheet into dumbbell-shaped specimens, the tensile speed of the testing machine is 10 mm/min, and the ambient temperature is room temperature. Using the composite material with grafted modified glass fiber, the properties of elongation at break and tensile strength are better than those of modified glass fiber, which can be increased by 23.9% and 2.3% respectively.

Table 2 shows the elongation at break increase rate and tensile strength increase rate of materials obtained with different doping percentages of KH570-g-GF and BA-g-GF.

Table 2

Example 2

Similar to the operation of Example 1, the polymerized monomer is trifluoroethyl acrylate to prepare graft-modified glass fiber, which is mixed with KH570-g-GF at a mixing mass ratio of 3:2, and other preparation conditions remain unchanged. The processing conditions for preparing composite materials from two-component glass fiber-filled polypropylene are the same as those in Table 1. Cut the extruded and stretched sheet into dumbbell-shaped specimens, the tensile speed of the testing machine is 10 mm/min, and the ambient temperature is room temperature. The measured elongation at break and tensile strength properties of the composite material are better than those of the modified glass fiber, which can be increased by 30.1% and 5.0%, respectively.

Claims (10)

1. a preparation method of two-component modified glass fiber filled polypropylene composite material, is characterized in that, comprises the steps: S1. Adding the glass fiber to an aqueous ethanol solution containing a silane coupling agent and soaking it to obtain a modified glass fiber; S2. Add initiator and monomer to the modified glass fiber in S1 for grafting reaction for a certain period of time, then filter, wash, and dry to obtain ultra-short glass fiber with surface grafted polymer; S3. blending ultra-short glass fiber in S2, modified glass fiber in S1, antioxidant and polypropylene to make a masterbatch; S4. Extrude the masterbatch in S3, and obtain a two-component modified glass fiber filled polypropylene composite material after drawing; In step S2, the mixing mass ratio of initiator, monomer and modified glass fiber is (0.001~0.1):(0.05~0.2):1; In step S3, the mixing mass ratio of ultra-short glass fiber, modified glass fiber in S1, antioxidant and polypropylene is (1-30):(1-30):(1-5):100. 2. The preparation method according to claim 1, characterized in that, in step S3, the mixing ratio of the ultra-short glass fiber to the modified glass fiber in S1 is 1: (1~3), and in step S3, the ultra-short glass fiber The mixed amount of modified glass fiber in fiber and S1 accounted for 10% of the masterbatch. 3. The preparation method according to claim 1, wherein the blending temperature in step S3 is 190~220°C, the rotor speed of the internal mixer is 60~80 rpm, and the blending time is 6~15 min; in step S4 The extrusion molding temperature is 200-220°C, and the extrusion speed is 40-80 rpm. 4. The preparation method according to claim 1, characterized in that, in step S1, the concentration of ethanol in the ethanol aqueous solution is 50-95%. 5. The preparation method according to claim 1, characterized in that, in step S1, the mass concentration of the silane coupling agent is 0.5-2%. 6. The preparation method according to claim 1, characterized in that, in step S1, the mixing ratio of glass fiber and ethanol aqueous solution containing silane coupling agent is 1:(1~5). 7. The preparation method according to claim 1, characterized in that, in step S1, the silane coupling agent is isobutyltriethoxysilane, γ-aminopropyltriethoxysilane, vinyl trimethyl One or more of oxysilane, vinyltrichlorosilane, 3-mercaptopropyltriethoxysilane, and 3-(methacryloyloxy)propyltrimethoxysilane. 8. The preparation method according to claim 1, characterized in that, in step S3, the polypropylene comprises isotactic polypropylene, syndiotactic polypropylene or atactic polypropylene. 9. The preparation method according to claim 1, characterized in that, the aspect ratio of the glass fibers adopted in step S1 is >100. 10. preparation method according to claim 1 is characterized in that, initiator is azobisisobutyronitrile, azobisisoheptanonitrile, benzoyl peroxide, di(2,4- Dichlorobenzoyl), diacetyl peroxide, dioctanoyl peroxide or dilauroyl peroxide, the monomers are methyl acrylate, butyl acrylate, trifluoroethyl acrylate, ethyl acrylate or 2-ethyl acrylate Hexyl ester.