阅读说明：本技术 一种聚丙烯/碳纳米管纤维复合材料的制备方法 (Preparation method of polypropylene/carbon nanotube fiber composite material ) 是由 姜昊 郑骏驰 苏昱 赵亚风 郭新利 安峻莹 陈婧 吴超 孙兆懿 钱晶 于 2019-12-10 设计创作，主要内容包括：本发明涉及一种聚丙烯/碳纳米管纤维复合材料制备方法,具体为：将PP、硅烷偶联剂改性碳纳米管及一系列添加剂在双螺杆挤出机中熔融共混并通过熔融纺丝的手段得到碳纳米管改性聚丙烯纤维,并将这些纤维相互交错排列编制成一种网状结构,得到碳纳米管改性聚丙烯纤维交错束网,将它和热压得到的聚丙烯薄片交替叠压,每两片聚丙烯纤维束网之间相差30°,通过热压机在190℃热压制得聚丙烯/碳纳米管纤维复合材料。本发明所制得的复合材料具有高强度、低收缩率、各方向受力稳定均一、性价比高的特点,可在汽车外饰中作为增强材料,也满足交通、建筑等领域的使用要求。(The invention relates to a preparation method of a polypropylene/carbon nanotube fiber composite material, which comprises the following steps: the PP, the silane coupling agent modified carbon nano tube and a series of additives are melted and blended in a double screw extruder, carbon nano tube modified polypropylene fibers are obtained through a melt spinning method, the fibers are mutually staggered and woven into a net structure, a carbon nano tube modified polypropylene fiber staggered bundle net is obtained, the carbon nano tube modified polypropylene fiber staggered bundle net and a polypropylene sheet obtained through hot pressing are alternately laminated, the difference between every two polypropylene fiber bundle nets is 30 degrees, and the polypropylene/carbon nano tube fiber composite material is prepared through hot pressing at 190 ℃ through a hot press. The composite material prepared by the invention has the characteristics of high strength, low shrinkage, stable and uniform stress in each direction and high cost performance, can be used as a reinforcing material in automobile exterior trim, and also meets the use requirements in the fields of traffic, buildings and the like.)

1. A preparation method of a polypropylene/carbon nanotube fiber composite material is characterized by comprising the following steps:

(1) preparing a polypropylene/carbon nano tube fiber staggered bundle net:

PP granules, a thermoplastic elastomer, a lubricant, a silane coupling agent modified carbon nanotube and a compound antioxidant are mixed according to the mass ratio of (60-90%); (10% -20%); (0.1% -1%); (0.1% -1%); (0.1% -1%) mixing, uniformly mixing the raw materials and the auxiliary agent for 3-5 minutes by using a high-speed mixer, adding the obtained mixture into a co-rotating double-screw extruder through a main feeding port, carrying out melt blending, wherein the extrusion temperature is 180-. 500 composite fiber yarns are integrated into one bundle every 100-500, one bundle of composite fiber yarns is placed every 1-2cm in two mutually perpendicular directions, and a fiber staggered bundle net with a latticed structure is manufactured by mutually staggered weaving of fiber tows;

(2) preparation of Polypropylene sheets

PP granules, thermoplastic elastomer, talcum powder, lubricant and compound antioxidant are mixed according to the mass ratio (60-90%); (10% -20%); (10% -20%); (0.1% -1%); (0.1% -1%) mixing, mixing the raw materials at the temperature of 170-190 ℃ for 10 minutes by using a mixing roll, hot-pressing the obtained melt for 30 minutes at the temperature of 170-190 ℃ under the pressure of 10MPa by a hot press, and fully cooling to obtain a polypropylene sheet;

(3) preparation of the end product

The polypropylene sheet and the polypropylene/carbon nano tube composite fiber staggered bundle nets with the latticed structure are sequentially stacked at intervals, wherein the angle difference between every two staggered bundle nets at intervals is 30 degrees, the composite material sheets stacked by the structure are hot-pressed for 30min at 190 ℃ and 10MPa by a hot press, and then the final product, namely the polypropylene carbon nano tube modified polypropylene fiber composite material, is obtained after cooling to room temperature.

2. The method as claimed in claim 1, wherein the PP pellets are homopolymeric PP or copolymeric PP or a mixture of both, having a molecular weight of more than 8 ten thousand and a melting point of 150-170 ℃.

3. The method according to claim 1, wherein the thermoplastic elastomer is an elastomer which can be processed by a thermoplastic equipment, such as styrene-based, polyurethane-based, polyolefin-based elastomers, etc.

4. The preparation method of claim 1, wherein the silane coupling agent modified carbon nanotube is prepared by immersing carbon nanotube in 4% silane coupling agent solution, reacting at 80 deg.C for 1.5h, taking out, placing in a forced air drying oven, and reacting at 100 deg.C for 2 h. The selected silane coupling agent is one of or a mixture of KH550, KH560 and other silane coupling agents with amino groups or epoxy groups. The carbon nano tube modified by the silane coupling agent can greatly improve the surface polarity of the carbon nano tube and improve the dispersing capacity in subsequent PP.

5. The preparation method according to claim 1, wherein the compound antioxidant is a compound of antioxidant 168 and antioxidant 1010, and the mass ratio is 1-4: 1, preferably 1-3: 1, and more preferably 2: 1.

6. The process according to claim 1, wherein the co-rotating twin-screw extruder has a diameter of 20 to 45mm and an aspect ratio of 25 to 60: 1.

7. The method according to claim 1, wherein the fiber diameter of the carbon nanotube-modified polypropylene fiber prepared by the melt spinning process is 5 to 20 μm.

Technical Field

The invention relates to the technical field of polymer composite materials, in particular to a preparation method of a polypropylene/carbon nanotube fiber composite material.

Background

Polypropylene (PP) is a general plastic with excellent comprehensive performance, and is widely used for manufacturing automotive interior and exterior plastic parts due to the advantages of strong chemical stability, good electrical insulation, low density, low price and the like. However, polypropylene itself has some disadvantages, such as low impact strength, low use temperature, and large shrinkage, which limit the application of polypropylene plastics.

At present, the living standard of people is higher and higher, the application of plastics in life is wider and wider, and the requirements on the performance of plastics are improved. The technology of replacing steel with plastic is continuously developed, the use scene of the plastic is continuously expanded to all corners of life, the application of the plastic, especially polypropylene materials, on automobiles is very wide, most of interior door panels, instrument panels, exterior bumpers, bottom guard plates and the like of the automobiles are all made of polypropylene plastics, if the automobiles are impacted in the moving process, the interior and exterior materials are required to have certain mechanical strength to better resist deformation and protect drivers, the damage is reduced to the minimum, meanwhile, because the environmental temperature difference of the automobiles is large, the interior and exterior materials are required to have certain capacity of resisting shrinkage, the deformation under extreme environments can be prevented, and the conventional polypropylene materials cannot directly meet the requirements and must be modified.

The carbon nano tube is a typical one-dimensional nano material, has the diameter of 1 nm-100 nm, the length-diameter ratio of more than 1000, and has very good mechanical property, electrical property and thermal property; if the carbon nano tube modified polypropylene material is adopted, the mechanical properties and the like of the polypropylene can be effectively improved, and the mechanical properties such as tensile strength and the like can be greatly improved by preparing the polypropylene fiber from the carbon nano tube modified polypropylene material by a melt spinning method.

The polypropylene-carbon nanotube modified polypropylene fiber composite material is prepared by adopting a simpler method and through spinning, weaving, laminating and hot pressing, has simple process, very excellent mechanical property and high tensile and impact strength, the thickness of the material can be determined by controlling the number of hot pressing layers, the material can be used as an interlayer material and filled in automotive interior and exterior trims, the mechanical strength of plastic parts such as bumpers and the like is greatly enhanced, the problem of after-shrinkage of the material in an extreme environment can be reduced, the material is prevented from deforming, the production process is green and environment-friendly, the requirements of a great number of applications can be met, and the polypropylene-carbon nanotube modified polypropylene fiber composite material has a good application prospect.

Disclosure of Invention

The technical problem solved by the invention is as follows: the preparation method of the polypropylene/carbon nanotube fiber composite material is simple and environment-friendly, and the composite material plate prepared by the method has excellent mechanical properties.

In order to realize the purpose of the invention, the invention adopts the following technical scheme:

the preparation method of the polypropylene/carbon nanotube fiber composite material sheet provided by the invention comprises the following steps:

(1) preparing a polypropylene/carbon nano tube fiber staggered bundle net:

PP granules, a thermoplastic elastomer, a lubricant, a silane coupling agent modified carbon nanotube and a compound antioxidant are mixed according to the mass ratio of (60-90%); (10% -20%); (0.1% -1%); (0.1% -1%); (0.1% -1%) mixing, uniformly mixing the raw materials and the auxiliary agent for 3-5 minutes by using a high-speed mixer, adding the obtained mixture into a co-rotating double-screw extruder through a main feeding port, carrying out melt blending, wherein the extrusion temperature is 180-. 500 composite fiber yarns are integrated into one bundle every 100-500, one bundle of composite fiber yarns is placed every 1-2cm in two mutually perpendicular directions, and a fiber staggered bundle net with a latticed structure is manufactured by mutually staggered weaving of fiber tows;

(2) preparation of Polypropylene sheets

PP granules, thermoplastic elastomer, talcum powder, lubricant and compound antioxidant are mixed according to the mass ratio (60-90%); (10% -20%); (10% -20%); (0.1% -1%); (0.1% -1%) mixing, mixing the raw materials at the temperature of 170-190 ℃ for 10 minutes by using a mixing roll, hot-pressing the obtained melt for 30 minutes at the temperature of 170-190 ℃ under the pressure of 10MPa by a hot press, and fully cooling to obtain a polypropylene sheet;

(3) preparation of the end product

The polypropylene sheet and the polypropylene/carbon nano tube composite fiber staggered bundle nets with the latticed structure are sequentially stacked at intervals, wherein the angle difference between every two staggered bundle nets at intervals is 30 degrees, the composite material sheets stacked by the structure are hot-pressed for 30min at 190 ℃ and 10MPa by a hot press, and then the final product, namely the polypropylene carbon nano tube modified polypropylene fiber composite material, is obtained after cooling to room temperature.

The PP granules can be homopolymerized PP or copolymerized PP or a mixture of the homopolymerized PP and the copolymerized PP, the molecular weight is more than 8 ten thousand, and the melting point is 150-170 ℃.

The thermoplastic elastomer refers to a type of elastomer which can be processed by thermoplastic equipment, such as styrene-based, polyurethane-based, polyolefin-based elastomers, and the like.

The silane coupling agent modified carbon nano tube is prepared by immersing the carbon nano tube in 4% silane coupling agent solution, reacting for 1.5h at 80 ℃, then taking out the carbon nano tube, putting the carbon nano tube into a forced air drying oven, and continuing to react for 2h at 100 ℃. The selected silane coupling agent is one of or a mixture of KH550, KH560 and other silane coupling agents with amino groups or epoxy groups. The carbon nano tube modified by the silane coupling agent can greatly improve the surface polarity of the carbon nano tube and improve the dispersing capacity in subsequent PP.

The compound antioxidant is a compound of antioxidant 168 and antioxidant 1010, and the mass ratio is 1-4: 1, preferably 1-3: 1, and more preferably 2: 1.

The diameter of the co-rotating twin-screw extruder is 20-45mm, and the length-diameter ratio is 25-60: 1.

The diameter of the carbon nano tube modified polypropylene fiber prepared by the melt spinning process is 5-20 μm.

When the product is finally shaped by hot pressing, a method of laminating polypropylene sheets and carbon nanotube modified polypropylene fiber staggered bundle nets in sequence is adopted, two separated carbon nanotube modified fibers are staggered and bundled, the fiber angle difference is 30 degrees, and the like, so that the prepared composite material product is ensured to have uniform mechanical properties in all directions.

Compared with the prior art, the invention has the following advantages

1. The polypropylene-carbon nanotube modified polypropylene fiber composite material is sequentially laminated and hot-pressed with polypropylene sheets through fiber staggered bundles, the thickness of the material is controllable, the equipment and the operation process are simple, the production process is green and pollution-free, the cost is low, and the prepared composite material is good in mechanical property, low in shrinkage rate, light in density and high in cost performance.

2. The base material and the fiber are the same material, the interface compatibility is good, the performance of the final product obtained after hot pressing is stable, and the combination of the base material and the fiber is more dense.

3. The carbon nano tube used in the invention is treated by the silane coupling agent, has good interface compatibility with polypropylene, and better achieves the enhancement effect.

4. The invention adopts a special overlapping mode, and the staggered fiber bundle nets at intervals are arranged at intervals of 30 degrees in sequence, so that the prepared composite material sheet is more uniform in stress in all directions and more uniform in mechanical property.

Detailed Description

The present invention will be further illustrated by the following examples and comparative examples. The following embodiments are merely exemplary of the present invention, and the scope of the present invention is not limited thereto. Tensile resistance was measured according to ASTM D638 (tensile speed 20mm/min), and Izod impact was measured according to ASTM D256.