CN109666219B - Polypropylene/shear thickening gel composite material and application thereof in bumper - Google Patents
Polypropylene/shear thickening gel composite material and application thereof in bumper Download PDFInfo
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- CN109666219B CN109666219B CN201811536888.5A CN201811536888A CN109666219B CN 109666219 B CN109666219 B CN 109666219B CN 201811536888 A CN201811536888 A CN 201811536888A CN 109666219 B CN109666219 B CN 109666219B
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- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L23/00—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers
- C08L23/02—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers not modified by chemical after-treatment
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- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L23/00—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers
- C08L23/02—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers not modified by chemical after-treatment
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- C08L2205/00—Polymer mixtures characterised by other features
- C08L2205/03—Polymer mixtures characterised by other features containing three or more polymers in a blend
- C08L2205/035—Polymer mixtures characterised by other features containing three or more polymers in a blend containing four or more polymers in a blend
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- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L2205/00—Polymer mixtures characterised by other features
- C08L2205/06—Polymer mixtures characterised by other features having improved processability or containing aids for moulding methods
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- C—CHEMISTRY; METALLURGY
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- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
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- C08L2205/08—Polymer mixtures characterised by other features containing additives to improve the compatibility between two polymers
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- C08L2207/00—Properties characterising the ingredient of the composition
- C08L2207/04—Thermoplastic elastomer
Abstract
The invention provides a polypropylene/shear thickening gel composite material and application thereof in bumpers, the provided polypropylene/shear thickening gel composite material is particularly suitable for being used as an impact resistant material of bumpers, the composite material has good impact resistance, the composite material also has good processing fluidity, and the compatibility of polypropylene and shear thickening gel in the composite material is good. The polypropylene/shear thickening gel composite material provided by the invention mainly comprises the following components in percentage by mass based on the total mass of the composite material: 42-95% of polypropylene, 5-25% of shear thickening gel, preferably 15-25%, and further preferably 15-20%; the shear thickening gel is polymethyl methacrylate modified polyborosiloxane microgel.
Description
Technical Field
The invention relates to a polypropylene/shear thickening gel composite material, and further relates to a polypropylene/shear thickening gel composite material particularly suitable for impact resistance of bumpers and a preparation method thereof.
Background
When the automobile is accidentally collided in the front and rear directions, the bumper can buffer the impact force, absorb the energy of collision, reduce the damage of the automobile and ensure the safety of pedestrians and passengers. Therefore, the bumper material needs to have good rigidity and toughness balance, and on one hand, the good impact resistance enables the bumper to keep good elasticity during collision so as to provide protection for passengers; on the other hand, the material can resist deformation during collision due to enough rigidity, and damage to the material during collision is reduced.
At present, the automobile bumper material is a multi-purpose polypropylene/elastomer/talcum powder blending system, talcum powder is used as a material for reinforcing, and the elastomer is used for improving the toughness and enhancing the impact resistance effect. Among elastomers, ethylene octene copolymer (POE) is most widely used, has good impact toughness, and can be molded on general processing equipment like general thermoplastics. Although the addition of POE can enhance the impact resistance of the polypropylene material, the rigidity and melt flowability of the material are obviously reduced, which causes inconvenience to the application.
Shear thickening materials are smart impact materials that become rigid and absorb external forces upon encountering high speed impacts or extrusions. When the force is removed, the material returns to its original state. The shear thickening material has strong impact absorption capacity, can keep enough rigidity after being hardened when being impacted, does not reduce the processing fluidity of the polypropylene material, and is very suitable for being applied to bumper materials.
The shear thickening fluid is one of shear thickening materials, and generally, silicon dioxide micro-nano particles are dispersed in a liquid polymer matrix (such as polyethylene glycol, polyvinyl alcohol and the like) dispersion medium. Shear thickening fluids have been reported for toughening polypropylene. Patent documents CN104817770A, CN104817771A, CN105037921A and CN105037921A disclose a series of shear thickening fluids applied to high impact resistance modified polypropylene bumper materials, but the addition amount of the shear thickening fluid is only 4-10 parts, and the impact resistance effect is difficult to achieve.
Patent document CN102702622A also provides a method for preparing a high toughness material of polypropylene/shear thickening fluid, which comprises dispersing dispersed phase particles in a liquid dispersion medium by using one or more of a high shear emulsifier, an emulsification pump or an ultra-speed stirrer, removing air bubbles in the liquid by using an ultrasonic generator to obtain the shear thickening fluid, and then melt blending the polypropylene and the shear thickening fluid in one or more of an open mill, an internal mixer or an extruder to obtain the high toughness material of polypropylene/shear thickening fluid. The material can be used in the fields of automobiles, machinery, household appliances, packaging and the like, and compared with the common toughened polypropylene material, the impact property of the polypropylene can be improved, and the processing fluidity of the polypropylene can be improved at the same time.
However, in the above inventions, the shear thickening fluid is in a liquid form, has strong fluidity, is difficult to be uniformly mixed with solid substances in the forming process, brings inconvenience to the application, and the product has the disadvantages of easy loss of a dispersion medium in the using process, short service life, poor aging resistance and the like.
Patent CN103506057A provides a method for preparing high-toughness material of polypropylene/shear thickening fluid microcapsule, the method comprises the steps of firstly dispersing nano silicon dioxide in polypropylene glycol through the high-speed stirring action of a high-speed shearing emulsifying machine to prepare a shearing thickening fluid, then preparing a uniform solution from the prepared shearing thickening fluid and water according to a certain proportion, then adding an emulsifier and an organic solvent into the uniform solution, stirring by a stirrer to obtain a uniform water-in-oil emulsion, transferring the water-in-oil emulsion into a three-neck flask, adding isonitrile acid ester for reaction to prepare the shear thickening fluid microcapsule, then the polypropylene and the shear thickening fluid microcapsule are subjected to melt blending in one or more of an open mill, an internal mixer or an extruder to prepare the high-toughness material of the polypropylene/shear thickening fluid microcapsule. Compared with the common toughened polypropylene material, the polypropylene/shear thickening fluid microcapsule can improve the toughness of polypropylene without reducing the rigidity of the polypropylene, improve the heat resistance and the processing fluidity of the polypropylene, and simultaneously, microencapsulate the shear thickening fluid into solid powder which is more convenient for molding processing compared with liquid. However, the preparation process of the shear thickening fluid microcapsule relates to toxic substances such as toluene, xylene and MDI, which is not beneficial to industrial popularization and application, and in addition, once the high-toughness material of the polypropylene/shear thickening fluid microcapsule is impacted, the microcapsule does not have self-repairing capability after being broken, and the problem that a dispersion medium is easy to run off still exists.
Shear thickening gel generally refers to boride-modified polysiloxane or hydroxyl-terminated polysiloxane, which can be kneaded into any shape at will in a normal state, the molecules of the gel are separated from each other, and upon high-speed impact, the molecules are interlaced and locked together, and become firm. After the external force disappears, the gel automatically recovers to be soft. Few shear thickening gels have been reported for use in bumper materials. Patent CN103772794A discloses a high-density polyethylene/modified silicon shear thickening gel composite material, which is prepared by directly carrying out melt blending on 5-40% (mass percent) of modified silicon shear thickening gel and 60-95% (mass percent) of high-density polyethylene in a high-molecular blending device, and has excellent impact resistance and processability. However, the composite material uses polyethylene as a base material, has insufficient rigidity, and is not suitable for preparing a bumper material, and in addition, the proposal provided by the document cannot lead the modified silicon shear thickening gel to be uniformly dispersed and is difficult to be compatible with PE.
Disclosure of Invention
In view of the above, the present invention provides a polypropylene/shear thickening gel composite material, particularly suitable for use as an impact resistant material for bumpers, the composite material has good impact resistance, the composite material also has good processing flowability, and the polypropylene and the shear thickening gel in the composite material have good compatibility.
In order to achieve the purpose, the invention adopts the following technical scheme:
the invention provides a polypropylene/shear thickening gel composite material, which mainly comprises the following components in percentage by mass based on the total mass of the composite material:
polypropylene 42-95%, e.g., 45%, 60%, 75%, 90%, etc.;
shear thickening gels 5-25%, preferably 15-25%, further preferably 15-20%, e.g. 5%, 10%, 15%, 17%, 20%, etc.;
0 to 25% of an inorganic filler, for example, 0.5%, 5%, 10%, 15%, 20%, etc.;
optionally, the composite material further comprises an additive;
the shear thickening gel is polymethyl methacrylate modified polyborosiloxane microgel.
Wherein "optional" means that may or may not be added.
According to the composite material provided by the invention, the polymethyl methacrylate modified polyborosiloxane microgel is used as the shear thickening gel to replace the traditional POE elastomer as the toughening agent of the bumper material, the shear thickening gel can be kneaded into any shape at will under the normal state, molecules of the gel are separated from each other, and once the composite material is impacted at a high speed, the molecules are staggered and locked together to become firm; and after the external force disappears, the gel can automatically recover to be soft, and compared with the traditional bumper impact-resistant material using POE elastomer, the composite material provided by the invention has good impact resistance and good rigidity. Moreover, the shear thickening gel and the polypropylene in the composite material have good compatibility, and the shear thickening gel and the polypropylene are easy to disperse and blend and have good processing fluidity. In a preferred embodiment, the shear thickening gel is preferably 15 to 25%, more preferably 15 to 20%, and a composite material having good compatibility and melt flowability and excellent impact resistance can be obtained. In addition, compared with the existing shear thickening liquid, the shear thickening gel used in the composite material has the advantages that the semi-solid property enables the shear thickening gel to be convenient to transport and store, easy to compound or blend with other materials, stable in the using process, free of dispersion medium loss in the using process and long in service life; and the main chain is firmer, is not easy to break, and has better ageing resistance and heat resistance because the main chain contains the B-0 bond with high bond energy.
In a preferred embodiment, the additive comprises a compatibiliser and/or a modified heterophasic polyolefin composition. The compatilizer is selected from PP-g-MMA (polypropylene grafted polar monomer methyl methacrylate), and is preferably added to increase the compatibility between polypropylene and the shear thickening gel. The modified heterophasic polyolefin composition is preferably a Deltamax modifier from Milliken & company comprising a propylene polymer phase, an ethylene polymer phase and a compatibilizer to increase the melt flow of the material while improving the impact strength of the polypropylene resin by optimizing the rubber dispersion and domain size. In a preferred embodiment, the composite material is added with the compatilizer (PP-g-MMA) and the modified heterogeneous polyolefin composition at the same time, so that the comprehensive performance of the obtained material is remarkably improved, and the obtained material has good compatibility between the shear thickening gel and the polypropylene, good melt flowability and better impact strength.
Further, the additive preferably further comprises one or a combination of two or more of an antioxidant, a lubricant and an antistatic agent.
In some preferred embodiments, the PP-g-MMA is prepared by a process comprising the steps of: under the protection of nitrogen, PP (polypropylene), BPO (benzoyl peroxide), MMA (methyl methacrylate) and toluene are mixed and subjected to ultrasonic treatment for 40-90min, the ultrasonic treatment can be carried out at room temperature, then standing and swelling are carried out, the preferable swelling time is 12-36h (such as 12h, 20h, 25h, 30h, 36h and the like), then grafting reaction is carried out under the condition of water bath at the temperature of 70-85 ℃, the preferable reaction is carried out for 3-6h, and the obtained mixture is filtered and dried; specifically, the filtration may be performed by pouring the mixture into acetone and performing suction filtration. Preferably, the mass ratio of the BPO to the PP is 0.6-1.2%, preferably 0.8-1.0%, and a high grafting rate of MMA can be obtained; the mass ratio of MMA to PP is 0.1:1.0-0.25:1.0, preferably 0.2:1.0-0.25: 1.0; the mass ratio of toluene to PP is 0.02:1.0-0.2:1.0, preferably 0.05:1.0-0.15: 1.0.
The shear thickening gel is formed by polymerizing the polymethyl methacrylate on the surface of the polyborosiloxane microgel, and the mass ratio of the polymethyl methacrylate to the polyborosiloxane microgel is preferably 0.1:1.0-0.5:1.0, and more preferably 0.3:1.0-0.5: 1.0.
In some preferred embodiments, the shear thickening gel is prepared according to a method comprising the steps of:
1) the polyborosiloxane microgel is in contact reaction with a silane coupling agent, in a specific embodiment, isopropanol serving as a solvent is also added into a reaction system, the reaction time is 1h for example, and the polyborosiloxane microgel modified by the silane coupling agent is obtained through reaction; the silane coupling agent is preferably KH 570; the mass ratio of the silane coupling agent to the polyborosiloxane microgel is preferably 0.01:1.0-0.05: 1.0;
2) reacting the polyborosiloxane microgel modified by the silane coupling agent obtained in the step 1) with an isopropanol solution of methyl methacrylate containing a catalyst at 70-90 ℃ for 4-10 h; drying the reaction product to obtain the shear thickening gel; the catalyst is preferably ammonium persulfate; in a specific embodiment, the catalyst-containing isopropyl alcohol solution of methyl methacrylate is preferably added dropwise; preferably the catalyst is present in the isopropanol solution in an amount of from 0.2 to 1 wt%;
preferably, in the step 1), the preparation of the polyborosiloxane microgel comprises the following steps: mixing and stirring double-end hydroxyl polydimethylsiloxane (PDMS-OH) and trimethoxy boroxine (TMOB) at the temperature of 120-150 ℃, reacting for 4-8h, then adding a chain extender isophorone diisocyanate to continue reacting for 4h, and obtaining the polyboroxine microgel (PBDMS); wherein, the mass ratio of Si to B is preferably 13: 1-18: 1; the chain extender is preferably used in an amount of 1 to 3% based on the total mass of the hydroxy-terminated polydimethylsiloxane and the trimethoxyboroxine.
In the polypropylene/shear thickening gel composite, the polypropylene to be used is not particularly limited, and for example, polypropylene having a melt flow rate of 0.01 to 150g/10min (test conditions: 230 ℃ C., 2.16kg) is selected; the polypropylene may be selected from homo polypropylene, random co-polypropylene and/or block co-polypropylene.
The polypropylene/shear thickening gel composite material specifically comprises the following components in percentage by mass:
42-95% of polypropylene,
5 to 25 percent of shear thickening gel,
0 to 25% of inorganic filler, preferably 8 to 20%;
0-5% of compatilizer, preferably 3-5%;
modified heterophasic polyolefin compositions 0 to 1%, preferably 0.5 to 1%;
0 to 1 percent of antioxidant, preferably 0.2 to 0.6 percent;
0 to 0.5%, preferably 0.2 to 0.4% of a lubricant;
0 to 0.5%, preferably 0.2 to 0.4%, of an antistatic agent.
The inorganic filler is preferably selected from one or a combination of more than two of talcum powder, calcium carbonate and barium sulfate; the particle size of the inorganic filler is preferably 1250-;
the antioxidant is preferably selected from one or a mixture of more than two of complex of acryloyl functional group and thioester, phenols, amines, phosphites and hindered phenols, and is preferably combined by the following two: tetrakis [ beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate ] pentaerythritol ester and tris [2, 4-di-tert-butylphenyl ] phosphite;
the lubricant is preferably selected from one or a mixture of more than two of stearic acid complex esters, metal soaps and low molecular esters;
the antistatic agent is preferably selected from one or a mixture of more than two of sulfuric acid derivatives, phosphoric acid derivatives, imidazoles and amides.
The second aspect of the present invention also provides a method for preparing the above-mentioned polypropylene/shear thickening gel composite material, which has the advantages of simple process and low requirement for production equipment, and the shear thickening gel and the polypropylene can be very simply and conveniently dispersed and fused by the preparation method, and the preparation method is easy for large-scale production, and comprises the following steps:
1) dispersing the shear thickening gel by using a solvent to obtain a dispersion liquid, wherein the mass fraction of the shear thickening gel in the dispersion liquid is preferably 40-80%, more preferably 60-80%, and the solvent is preferably isopropanol; the invention can be prepared under the condition of small amount of solvent such as isopropanol, thereby being more beneficial to completely volatilizing the isopropanol in the mixing process of the step 2;
2) mixing the dispersion with polypropylene, preferably at a mixing temperature of 80-90 ℃ for a mixing time of, for example, 10-30 minutes, to form a shear thickening gel coating on the surface of the polypropylene particles by mixing; then adding additives such as an antioxidant, a compatilizer and other processing aids and the like for continuous mixing; the mixing is preferably carried out at the rotating speed of 200-400r/min, and particularly, the mixing can be carried out in a high-speed heating mixer; through the step, the isopropanol is fully volatilized while the polyborosiloxane is uniformly coated on the polypropylene particles;
3) adding the mixture obtained in the step 2) and the inorganic filler into an extruder, and performing melt extrusion in the extruder such as a double-screw extruder, wherein the mixture is added into a main feeding cylinder of the extruder, and the side feed of the inorganic filler is fed; shearing and granulating, controlling the temperature of each temperature zone of the extruder at 220 ℃ and controlling the rotating speed of the screw at 800r/min at 400 ℃.
The polypropylene/shear thickening gel composite material provided by the invention is particularly suitable for being used as an impact-resistant material of a bumper, and therefore, the invention also provides an application of the polypropylene/shear thickening gel composite material or the polypropylene/shear thickening gel composite material prepared by the preparation method as described above as the impact-resistant material of the bumper.
The technical scheme provided by the invention has the following beneficial effects:
1. according to the invention, the shear thickening gel is used for replacing the traditional POE elastomer as a toughening agent of the bumper material, and is matched with polypropylene according to a specific proportion, so that the shear thickening gel and the polypropylene have good compatibility, the shear thickening gel and the polypropylene can be effectively mixed, the composite material formed by combining the shear thickening gel and the polypropylene has more excellent impact resistance, the processing flowability and the ageing resistance are excellent, and enough rigidity can be kept when the composite material is impacted;
2. according to the shear thickening gel used in the composite material, in a preferable scheme, the surface of Polyborosiloxane (PBDMS) microgel particles is modified by introducing KH570, and methyl methacrylate is polymerized on the surface of polyborosiloxane microspheres, so that the obtained shear thickening gel has good compatibility with a polypropylene system and is easy to disperse and mix, and particularly, a compatilizer PP-g-MMA is added into the shear thickening gel, so that the polyborosiloxane microspheres and the polypropylene system are better in mutual solubility, and the melt flowability is better.
3. The composite material system of the invention is preferably added with a small amount of the modified heterogeneous polyolefin composition, and the impact strength and the melt flowability of the material can be further improved under the condition of not influencing the rigidity.
4. When the composite material is prepared, the shear thickening gel is pre-dispersed by using isopropanol, and the obtained dispersion liquid is mixed with the polypropylene at a high speed, so that the polyborosiloxane can be uniformly coated on polypropylene particles, and simultaneously, a solvent such as the isopropanol can be fully volatilized, and the problem of non-uniform dispersion when the shear thickening gel is blended with the polypropylene is solved.
Drawings
FIG. 1 is a Scanning Electron Microscope (SEM) photograph of a sample of Experimental example 1.
FIG. 2 is a Scanning Electron Microscope (SEM) photograph of a sample of Experimental example 2.
Detailed Description
In order to better understand the technical solution of the present invention, the following examples are further provided to illustrate the present invention, but the present invention is not limited to the following examples.
Unless otherwise indicated, all formulations and tests in the following examples occurred in an environment of 23 ℃.
The use of "including," "comprising," "containing," "having," or other variations thereof herein, is meant to encompass the non-exclusive inclusion, as such terms are not to be construed. The term "comprising" means that other steps and ingredients can be added that do not affect the end result. The term "comprising" also includes the terms "consisting of …" and "consisting essentially of …". The compositions and methods/processes of the present invention can comprise, consist of, and consist essentially of the essential elements and limitations described herein, as well as any of the additional or optional ingredients, components, steps, or limitations described herein.
Methods of formulation and use
The following examples further illustrate preferred embodiments within the scope of the present invention. These examples are merely illustrative and not intended to limit the scope of the invention, as many variations of the invention are possible without departing from the spirit and scope thereof.
The preparation of a shear thickening gel for use in the following experiments, comprising the steps of: firstly, putting hydroxyl-terminated polydimethylsiloxane (PDMS-OH) and trimethoxy boroxine (TMOB) in a mass ratio of (m), (Si)/m (B) of 15:1) into a three-neck flask, and reacting for 4 hours at 150 ℃ under stirring; then adding 2 percent (based on the total mass of PDMS-OH and TMOB) of chain extender isophorone diisocyanate (IPDI) to continue reacting for 4 hours to obtain Polyborosiloxane (PBDMS) microgel; after cooling at room temperature, adding an Isopropanol (IPA) solution of a silane coupling agent (KH570), wherein the concentration of the solution is 5 wt%, and the mass ratio of the silane coupling agent to the polyborosiloxane microgel is 0.03: 1.0. after the reaction is carried out for 1h, dropwise adding an isopropanol solution of Methyl Methacrylate (MMA) containing 0.5 wt% of catalyst (ammonium persulfate), wherein the concentration of MMA in the solution is 20 wt%, and reacting for 8h at 75 ℃; the resulting mixture was finally dried at 70 ℃ for 72 h. The ratio of PMMA to PBDMS is 0.3: 1.0.
The preparation of the compatibilizer PP-g-MMA used in the following experiments included the following steps: firstly, adding PP, Benzoyl Peroxide (BPO), MMA and toluene into a round-bottom flask in sequence, introducing nitrogen for 10min at room temperature, quickly plugging a bottle mouth, putting into ultrasonic waves for 60min, standing and swelling for 24h, then transferring into a water bath at 80 ℃, carrying out grafting reaction for 5h, finally, carrying out suction filtration on the mixture through acetone, and drying for 48h at 80 ℃. The mass usage ratio of BPO to PP is 1.0 percent; the mass ratio of MMA to PP was 0.2:1.0, and the mass ratio of toluene to PP was 0.1: 1.0.
In the following examples, the preparation of a bumper-specific polypropylene/shear thickening gel composite comprises the following steps:
1) dispersing the shear thickening gel by using isopropanol, wherein the mass fraction of the shear thickening gel is 60%;
2) placing the dispersion liquid obtained in the step 1) and polypropylene into a high-speed heating mixer for mixing for 15 minutes, wherein the temperature of the mixer is 90 ℃, and the rotating speed is 400r/min, so that the polypropylene particles are uniformly coated with the polyborosiloxane and the isopropanol can be fully volatilized, the surface of the polypropylene particles can observe a uniform shear thickening gel coating, and then adding an antioxidant, a compatilizer and/or other processing aids (additives) into the high-speed mixer for continuously mixing for 3 minutes according to the specific conditions of the formula, and the rotating speed of the mixer is 200 r/min;
3) adding the mixture obtained in the step 2) into a main feeding cylinder of a double-screw extruder, feeding the inorganic filler from a side feed according to the specific conditions of the formula, and performing melt extrusion, shearing and granulation; the temperature of each temperature zone is controlled between 180 ℃ and 220 ℃, and the rotating speed of the screw is 600 r/min.
The method for measuring the melt index of the polypropylene/shear thickening gel composite material comprises the following steps: the melt index of the polypropylene/shear thickening gel composite was measured using a melt index meter at 230 ℃ and 2.16Kg according to test standard ASTM D1238. The higher the melt index, the lower the sample melt viscosity and the better the flowability.
The method for measuring the notched impact strength of the cantilever beam comprises the following steps: the notched izod impact strength of the polypropylene/shear thickening gel composite was tested using a pendulum impact tester according to test standard ISO 180. The splines are 80 × 10 × 4mm, V-shaped notches.
Polypropylene
Copolypropylene EP548RQ, melt flow rate 28g/10min, Astro-Seikari Co., Ltd
Homopolypropylene HA5029, melt flow rate 65g/10min, available from PolyMerle Korea
Thermoplastic elastomer (POE)
Engage7467 (Dow), melt index 1.2g/10min (190 ℃, 2.16kg), density 0.862g/cm3
Modified heterophasic polyolefin compositions
DeltaMax modifier, Milliken & company
Antioxidant agent
Antioxidant Inganox 1010, tetrakis [ beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propanoic acid ] pentaerythritol ester, basf Corp
Antioxidant Inganox 168, tris [2, 4-di-tert-butylphenyl ] phosphite, BASF corporation
Lubricant agent
Magnesium stearate as lubricant, Wuhan far-reaching Co-creation science and technology Limited
Antistatic agent
Antistatic agent Atmer 129, a chemical plant
Bumper-specific Polypropylene/shear thickening gel composite examples 1-3 and comparative example 1
The polypropylene/shear thickening gel composite was prepared according to the preparation method described above according to the respective component compositions of examples 1 to 3 and comparative example 1 in table 1.
Table 1 materials formulation (% by mass)
Table 2 shows the results of the melt index and notched Izod impact strength tests for the samples of examples 1-3 and comparative example 1. The significantly higher melt index and significantly better impact resistance of examples 1-3 compared to comparative example 1 indicates that the shear thickening gel used in the present invention does not reduce the processing flowability of the polypropylene material compared to POE and that an equivalent fraction of shear thickening gel absorbs more energy when impacted. The melt index is higher and the impact resistance is better for example 3 compared to example 2, so the addition of the modified heterophasic polyolefin composition further improves the impact strength and melt flow of the material. The impact resistance of example 2 is better than that of example 1, and therefore, the addition of the compatibilizer PP-g-MMA improves the compatibility of the shear-thickening gel with polypropylene, thereby allowing the polypropylene/shear-thickening gel composite to obtain better impact resistance.
TABLE 2 melt index and notched Izod impact Strength test results
FIGS. 1-2 are scanning electron micrographs of samples from example 1 and example 2, respectively, showing a shear thickening gel phase as the ellipsoidal phase and a polypropylene phase as the matrix. It can be seen that the shear thickening gel of the sample of example 2 is more uniform in phase size and more tightly bound to the polypropylene matrix, and the addition of the compatibilizer PP-g-MMA improves the compatibility of the shear thickening gel with the polypropylene.
Examples 4 to 8
Bumper polypropylene/shear thickening gel composites were prepared according to the above preparation method based on the composition of the components of examples 4-8 in Table 3, and the results of the tests for melt index and notched Izod impact strength for the polypropylene/shear thickening gel composites prepared in examples 4-8 are also included in Table 3. It can be seen that within the range of the components of the present invention, the prepared polypropylene/shear thickening gel composite material has good processing fluidity and excellent impact resistance, and is very suitable for being applied to bumper materials. In addition, because the composite material of the invention has good compatibility between the shear thickening gel and the polypropylene, the dosage of the shear thickening gel can be adjusted in a larger range according to the requirement, the effect is better when the dosage is 15-20%, the composite material has better melt fluidity and excellent impact resistance.
Table 3 example 4-8 material formulation (% by mass)
In conclusion, the shear thickening gel is adopted to replace the traditional POE elastomer to be used as the toughening agent of the bumper material, and particularly, a proper compatilizer and a heterogeneous polyolefin composition are added, so that the prepared special bumper polypropylene/shear thickening gel composite material has more excellent impact resistance and more excellent processing flow property. In addition, the preparation method of the polypropylene/shear thickening gel composite material special for bumpers effectively solves the problem of uneven dispersion when the shear thickening gel and the polypropylene are blended, and has the advantages of simple process, low requirement on production equipment and good application prospect.
It will be appreciated by those skilled in the art that modifications or adaptations to the invention may be made in light of the teachings of the present specification. Such modifications or adaptations are intended to be within the scope of the present invention as defined in the claims.
Claims (20)
1. The polypropylene/shear thickening gel composite material is characterized by mainly comprising the following components in percentage by mass based on the total mass of the composite material:
42-79% of polypropylene;
15-25% of shear thickening gel;
0-25% of inorganic filler;
the composite further comprises an additive comprising a compatibilizer and a modified heterophasic polyolefin composition, the compatibilizer being PP-g-MMA and the modified heterophasic polyolefin composition being a DeltaMax modifier;
the shear thickening gel is polymethyl methacrylate modified polyborosiloxane microgel.
2. The polypropylene/shear thickening gel composite of claim 1, wherein the composite comprises essentially the following components in mass percent, based on the total mass of the composite:
42-79% of polypropylene;
15-20% of shear thickening gel;
0 to 25 percent of inorganic filler.
3. The polypropylene/shear thickening gel composite of claim 1, wherein the additive further comprises one or a combination of two or more of an antioxidant, a lubricant and an antistatic agent.
4. The polypropylene/shear thickening gel composite of claim 1, wherein the PP-g-MMA is prepared by a process comprising: under the protection of nitrogen, PP, BPO, MMA and toluene are mixed and ultrasonically treated for 40-90min, then the mixture is stood for swelling, then grafting reaction is carried out under the condition of water bath at the temperature of 70-85 ℃, and the obtained mixture is filtered and dried.
5. The polypropylene/shear thickening gel composite of claim 4, wherein in the preparation method of PP-g-MMA, the swelling time is 12-36h and the grafting reaction is 3-6 h.
6. The polypropylene/shear thickening gel composite of claim 4, wherein in the preparation method of PP-g-MMA, the mass ratio of BPO to PP is 0.6-1.2%; the mass ratio of MMA to PP is 0.1:1.0-0.25: 1.0; the mass ratio of the toluene to the PP is 0.02:1.0-0.2: 1.0.
7. The polypropylene/shear thickening gel composite of claim 6, wherein in the preparation method of PP-g-MMA, the mass ratio of BPO to PP is 0.8-1.0%; the mass ratio of MMA to PP is 0.2:1.0-0.25: 1.0.
8. The polypropylene/shear thickening gel composite according to any one of claims 1 to 7, wherein the shear thickening gel is a substance polymerized on the surface of the polyborosiloxane microgel to form the polymethylmethacrylate, and the mass ratio of the polymethylmethacrylate to the polyborosiloxane microgel is 0.1:1.0-0.5: 1.0.
9. The polypropylene/shear thickening gel composite of claim 8, wherein the mass ratio of the polymethylmethacrylate to the polyborosiloxane microgel is 0.3:1.0-0.5: 1.0.
10. The polypropylene/shear thickening gel composite of claim 8, wherein the shear thickening gel is prepared according to a process comprising the steps of:
1) the polyborosiloxane microgel is in contact reaction with a silane coupling agent to obtain polyborosiloxane microgel modified by the silane coupling agent;
2) reacting the polyborosiloxane microgel modified by the silane coupling agent obtained in the step 1) with an isopropanol solution of methyl methacrylate containing a catalyst at 70-90 ℃ for 4-10 h; drying the reaction product to obtain the shear thickening gel.
11. The polypropylene/shear thickening gel composite of claim 10, wherein in the method of preparing the shear thickening gel, the mass ratio of the silane coupling agent to the polyborosiloxane microgel of step 1) is 0.01:1.0-0.05: 1.0; the silane coupling agent is KH 570;
the catalyst in the step 2) is ammonium persulfate, and the content of the catalyst in the isopropanol solution is 0.2-1 wt%.
12. The polypropylene/shear thickening gel composite of claim 10, wherein in the method of preparing the shear thickening gel, the step 1) of preparing the polyborosiloxane microgel comprises the steps of: mixing and reacting double-end hydroxyl polydimethylsiloxane and trimethoxy boroxine at the temperature of 120-150 ℃ for 4-8h, and then adding a chain extender isophorone diisocyanate for continuous reaction to obtain the polyboroxine microgel; wherein, the mass ratio of Si to B is 13: 1-18: 1; the amount of the chain extender is 1-3% based on the total mass of the double-end hydroxyl polydimethylsiloxane and the trimethoxyboroxine.
13. The polypropylene/shear thickening gel composite of any one of claims 1 to 7, 9 to 12, wherein the polypropylene has a melt flow rate of 0.01 to 150g/10min measured at 230 degrees celsius at 2.16 kg; the polypropylene is selected from homo-polypropylene, random co-polypropylene and/or block co-polypropylene.
14. The polypropylene/shear thickening gel composite according to any one of claims 3 to 7 and 9 to 12, wherein the polypropylene/shear thickening gel composite comprises the following components in percentage by mass:
42-79% of polypropylene;
15-25% of shear thickening gel;
0-25% of inorganic filler;
3-5% of a compatilizer;
0.3-1% of a modified heterophasic polyolefin composition;
0-1% of antioxidant;
0-0.5% of lubricant;
0 to 0.5 percent of antistatic agent.
15. The polypropylene/shear thickening gel composite of claim 14, wherein the polypropylene/shear thickening gel composite comprises the following components in mass percent:
42-79% of polypropylene;
15-25% of shear thickening gel;
8-20% of inorganic filler;
3-5% of a compatilizer;
0.5-1% of a modified heterophasic polyolefin composition;
0.2 to 0.6 percent of antioxidant;
0.2 to 0.4 percent of lubricant;
0.2 to 0.4 percent of antistatic agent.
16. The polypropylene/shear thickening gel composite of claim 3,
the inorganic filler is selected from one or the combination of more than two of talcum powder, calcium carbonate and barium sulfate; the particle size of the inorganic filler is 1250-;
the antioxidant is selected from one or a mixture of more than two of compounds of acryloyl functional groups and thioesters, phenols, amines and phosphites;
the lubricant is selected from one or a mixture of more than two of stearic acid composite esters and metal soaps;
the antistatic agent is selected from one or a mixture of more than two of sulfuric acid derivatives, phosphoric acid derivatives, imidazoles and amides.
17. The polypropylene/shear thickening gel composite of claim 16, wherein the inorganic filler particle size is 5000-8000 mesh;
the antioxidant is a combination of the following two: tetrakis [ beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate ] pentaerythritol ester and tris [2, 4-di-tert-butylphenyl ] phosphite.
18. A process for the preparation of a polypropylene/shear thickening gel composite according to any one of claims 1 to 17, comprising the steps of:
1) dispersing the shear thickening gel by using a solvent to obtain a dispersion liquid, wherein the mass fraction of the shear thickening gel in the dispersion liquid is 40-80%; the solvent is isopropanol;
2) mixing the dispersion liquid with polypropylene to form a shear thickening gel coating on the surface of polypropylene particles; then adding the additive and continuously mixing;
3) adding the mixture obtained in the step 2) and the inorganic filler into an extruder, carrying out melt extrusion in the extruder, and carrying out shearing granulation.
19. The method for preparing a polypropylene/shear thickening gel composite according to claim 18, wherein the mass fraction of the shear thickening gel in the dispersion of step 1) is 60-80%;
the mixing temperature of the mixing in the step 2) is 80-90 ℃; the mixing is carried out at the rotating speed of 200-400 r/min;
the temperature of each temperature zone of the extruder in the step 3) is controlled to be 220 ℃ and the rotating speed of the screw is controlled to be 800r/min in 400-.
20. Use of a polypropylene/shear thickening gel composite according to any one of claims 1 to 17 or a polypropylene/shear thickening gel composite produced by the process according to any one of claims 18 to 19 as impact resistant material for bumpers.
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| CN113072810B (en) * | 2021-03-30 | 2022-01-11 | 江南大学 | Crosslinked starch reinforced composite shear thickening elastomer |
| CN114106554A (en) * | 2021-11-25 | 2022-03-01 | 重庆长安汽车股份有限公司 | Polyurethane/shear thickening gel composite material and application thereof in automobile seat |
| CN115584064B (en) * | 2022-12-12 | 2023-06-06 | 中裕铁信交通科技股份有限公司 | Variable modulus damping rubber material and preparation method and application thereof |
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