Polystyrene alloy and preparation method thereof

Abstract

The invention discloses a polystyrene alloy and a preparation method thereof, the polystyrene alloy is formed by respective polymerization reaction of at least one styrene monomer and thermosetting resin, the polymerization reaction of the styrene monomer is free radical polymerization, and the polymerization reaction of the thermosetting resin is thermosetting polymerization. According to the characteristics of curing reaction of thermosetting resin and polymerization reaction of polar free radical monomers, a step-by-step polymerization process is adopted, and the thermoplastic polystyrene alloy with excellent performance is prepared through a preferred thermosetting resin curing system, a preferred polar free radical monomer bulk polymerization catalytic system and a preferred reaction condition. The alloy has excellent thermodynamic compatibility and excellent mechanical properties, can be used for preparing injection molded parts or molded parts with high dimensional precision requirements, and has very wide application prospects.

Description

Technical Field

[0001] The present invention belongs to the technical field of polymer composites, and particularly relates to a polystyrene alloy and a preparation method thereof. Background Art

[0002] Polystyrene (PS) refers to a polymer synthesized by free radical addition polymerization of styrene monomers. As a kind of thermoplastic plastic, it is currently widely used in industries such as household appliances, automobiles, packaging, and electronics. However, polystyrene has defects such as poor impact resistance, environmental stress cracking resistance, and heat resistance.

[0003] Currently, in order to improve the above defects, the alloying method of polymers is usually used to concentrate the advantages of two (or more) polymer materials in one material. More common commercial polystyrene alloys include PPO / PS alloys, polyolefin / PS alloys, PC / PS alloys, PA / PS alloys, etc.

[0004] The primary factor affecting the performance of polymer alloys is the compatibility between polymers. Since polymers usually have a high molecular weight, the mixing entropy of polymers is low, resulting in a generally high free energy of blending between polymers. Therefore, most polymers do not have thermodynamic compatibility, which leads to relatively serious phase separation between polymers and has a great impact on the mechanical properties of polymers. Therefore, when preparing alloys, generally, a strong blending shear force is applied to provide sufficient dispersion kinetically, and a polymer alloy with better dispersibility can also be obtained through the relatively high viscosity of the material itself. However, microscopically, there are always relatively obvious phase separation morphologies in polymer alloys. Summary of the Invention

[0005] In view of this, it is necessary for the present invention to provide a polystyrene alloy in order to overcome the problems existing in the above-mentioned prior art.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] The present invention provides a polystyrene alloy formed by at least one styrene monomer and a thermosetting resin through their respective polymerization reactions. Among them, the polymerization reaction of the styrene monomer is free radical polymerization, and the polymerization reaction of the thermosetting resin is thermosetting polymerization.

[0008] The styrene monomers described in this text refer to monomers with a benzene ring in their molecular structure and a vinyl group attached to the benzene ring. The styrene monomers may be at least one of styrene, methylstyrene, ethylstyrene, methoxystyrene, dimethoxystyrene, ethoxystyrene, dimethylstyrene, acetoxystyrene, tert-butylstyrene, divinylbenzene, or their homologues or halogenated compounds, but are not limited thereto.

[0009] From the perspective of reducing the steric hindrance of the polymerizable monomers, in some typical embodiments of the present invention, the styrene monomer is styrene.

[0010] In a further aspect, the thermosetting resin is selected from various epoxy resins, various high-temperature vulcanized silicone rubbers, various melamine resins, various thermosetting phenolic resins, or various unsaturated polyester resins. When selecting a thermosetting resin, it is necessary to consider matching it with an appropriate curing agent. The specific type of the curing agent can be selected according to the type of the thermosetting resin, and will not be elaborated here in detail.

[0011] From the perspective of resin operation convenience and reducing side reactions, in a typical embodiment of the present invention, the thermosetting resin is an epoxy resin.

[0012] In a further aspect, the antioxidant is a compound of a hindered phenol antioxidant, a phosphite antioxidant, and a thioester antioxidant.

[0013] Among them, the hindered phenol antioxidant can be at least one of antioxidant 1010, antioxidant 1076, antioxidant 1098, or antioxidant 1024; the phosphite antioxidant can be at least one of antioxidant V76-P or antioxidant 168; the thioester antioxidant can be at least one of antioxidant DSTDP or antioxidant DLTDP. However, it is not limited thereto, and the specific type can be selected according to performance requirements or in combination with the resin type and production process. In some specific embodiments of the present invention, the antioxidant is a mixture of antioxidant 1076, antioxidant V76-P, antioxidant 168, and antioxidant DSTDP in a mass ratio of 1:1:1:1.

[0014] Further, the radical initiator can be a conventional radical initiator in the art, such as any one of organic peroxide initiators, azo initiators, inorganic peroxide initiators, and redox system initiators. Among them, the organic peroxide initiators specifically include but are not limited to at least one of benzoyl peroxide, lauroyl peroxide, tert-butyl perpivalate, diisopropyl peroxydicarbonate, dicyclohexyl peroxydicarbonate, tert-butyl hydroperoxide, cumene hydroperoxide, and acetylcyclohexanesulfonyl peroxide. The azo initiators specifically include but are not limited to at least one of azobisisobutyronitrile, azobisisoheptonitrile, dimethyl azobisisobutyrate, azobis(2-methylpropionamidine) dihydrochloride, azobis(2-methylpropionamidine) hydrochloride, and azoisobutyronitrile formamide. The inorganic peroxide initiators specifically include but are not limited to at least one of potassium persulfate and ammonium persulfate. In some specific embodiments of the present invention, the initiator is azobisisobutyronitrile.

[0015] Further, in some specific embodiments of the present invention, by weight, the polystyrene alloy is prepared from 30-70 parts of styrene monomers, 15-35 parts of thermosetting resin, 15-35 parts of curing agent, 0.8 part of antioxidant, and 0.2-0.5 part of radical initiator.

[0016] The present invention further provides a method for preparing the polystyrene alloy. The preparation of the polystyrene alloy uses one of solution polymerization, bulk polymerization, emulsion polymerization, suspension polymerization, and reactive extrusion polymerization; preferably, the preparation of the polystyrene alloy uses reactive extrusion polymerization.

[0017] Further, the method for preparing the polystyrene alloy includes the following steps:

[0018] After mixing 30-70 parts of styrene monomers, 15-35 parts of thermosetting resin, 15-35 parts of curing agent, 0.8 part of antioxidant, and 0.2-0.5 part of radical initiator, stir and reflux in a protective gas at 90-110°C for 15-20 min. When the viscosity of the system is visually observed to increase significantly, quickly transfer it to a kneader and knead at 220-240°C for 10-20 min. After the viscosity of the system is stable, extrude and pelletize. The particles are placed in a vacuum drying oven at 80-100°C and vacuum-heated for 20-26 h to obtain the polystyrene alloy. This preparation method has few side reactions and high yield. The polystyrene alloy prepared by this preparation method has significant mechanical advantages.

[0019] Among them, it can be understood that the protective gas in the above preparation method refers to at least one of nitrogen or noble gases.

[0020] The beneficial effects of the present invention:

[0021] The polystyrene alloy provided by the present invention, by virtue of the characteristics of the curing reaction of thermosetting resin and the polymerization reaction of polar radical monomers, adopts a stepwise polymerization process. Through an optimized thermosetting resin curing system, a bulk polymerization catalytic system for polar radical monomers, and reaction conditions, a thermoplastic polystyrene alloy with excellent properties is prepared. This alloy has excellent thermodynamic compatibility and mechanical properties, and can be used to prepare injection-molded parts or compression-molded parts with high dimensional accuracy requirements, and has a very broad application prospect. Detailed Embodiments

[0022] The embodiments of the present invention will be described in detail below. The following described embodiments are exemplary and are only used to explain the present invention, and should not be construed as a limitation to the present invention.

[0023] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which the present invention belongs. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention. Additionally, unless otherwise specified, the methods without specific conditions or steps recorded are conventional methods, and the reagents and materials used can be obtained from commercial channels. The "parts", "number of parts", etc. mentioned in the following embodiments and comparative examples all refer to parts by weight.

[0024] The raw material information used in the following embodiments and comparative examples is specifically as follows:

[0025] Styrene monomer, α-methylstyrene, p-methoxystyrene, commercially available styrene products purchased from Aladdin Biochemical Technology, and used after dehydration and re-distillation;

[0026] Epoxy resin, grade 5313A, purchased from Shanghai Huayi Resin;

[0027] Epoxy curing agent, grade 5313B, purchased from Shanghai Huayi Resin;

[0028] Free radical initiator AIBN, a commercially available product purchased from Aladdin Biochemical Technology, recrystallized with absolute ethanol and fully dried before use.

[0029] The compound antioxidant is a mixture of antioxidant 1076, antioxidant V76-P, antioxidant 168, and antioxidant DSTDP in a mass ratio of 1:1:1:1.

[0030] Example 1

[0031] After mixing 30 parts of styrene monomer, 35 parts of epoxy resin, 35 parts of epoxy curing agent, 0.8 parts of compound antioxidant and 0.2 parts of free radical initiator, it was protected by nitrogen in a three-necked flask and stirred and refluxed at 90 °C for 10 min. When the viscosity of the visual system increased significantly, it was quickly transferred to a mixer and processed by mixing at 240 °C for 20 min. After the viscosity of the system was stable, it was extruded and pelletized; the particles were placed in a vacuum drying oven at 90 °C and vacuum-heated for 24 h to obtain a polystyrene alloy.

[0032] Example 2

[0033] After mixing 40 parts of styrene monomer, 30 parts of epoxy resin, 30 parts of epoxy curing agent, 0.8 parts of compound antioxidant and 0.3 parts of free radical initiator, it was protected by nitrogen in a three-necked flask and stirred and refluxed at 90 °C for 18 min. When the viscosity of the visual system increased significantly, it was quickly transferred to a mixer and processed by mixing at 230 °C for 15 min. After the viscosity of the system was stable, it was extruded and pelletized; the particles were placed in a vacuum drying oven at 90 °C and vacuum-heated for 24 h to obtain a polystyrene alloy.

[0034] Example 3

[0035] After mixing 50 parts of styrene monomer, 25 parts of epoxy resin, 25 parts of epoxy curing agent, 0.8 parts of compound antioxidant and 0.4 parts of free radical initiator, it was protected by nitrogen in a three-necked flask and stirred and refluxed at 100 °C for 18 min. When the viscosity of the visual system increased significantly, it was quickly transferred to a mixer and processed by mixing at 220 °C for 15 min. After the viscosity of the system was stable, it was extruded and pelletized; the particles were placed in a vacuum drying oven at 90 °C and vacuum-heated for 24 h to obtain a polystyrene alloy.

[0036] Example 4

[0037] After mixing 70 parts of styrene monomer, 15 parts of epoxy resin, 15 parts of epoxy curing agent, 0.8 parts of compound antioxidant and 0.5 parts of free radical initiator, it was protected by nitrogen in a three-necked flask and stirred and refluxed at 110 °C for 20 min. When the viscosity of the visual system increased significantly, it was quickly transferred to a mixer and processed by mixing at 220 °C for 10 min. After the viscosity of the system was stable, it was extruded and pelletized; the particles were placed in a vacuum drying oven at 90 °C and vacuum-heated for 24 h to obtain a polystyrene alloy.

[0038] Example 5

[0039] After mixing 70 parts of α-methylstyrene, 15 parts of epoxy resin, 15 parts of epoxy curing agent, 0.8 parts of compound antioxidant and 0.5 parts of free radical initiator, it was protected by nitrogen in a three-necked flask and stirred and refluxed at 110 °C for 20 min. When the viscosity of the system was visually observed to increase significantly, it was quickly transferred to a mixer and processed by mixing at 220 °C for 10 min. After the viscosity of the system was stable, it was extruded and pelletized; the pellets were placed in a vacuum drying oven at 90 °C and vacuum-heated for 24 h to obtain a polystyrene alloy.

[0040] Example 6

[0041] After mixing 70 parts of p-methoxystyrene, 15 parts of epoxy resin, 15 parts of epoxy curing agent, 0.8 parts of compound antioxidant and 0.5 parts of free radical initiator, it was protected by nitrogen in a three-necked flask and stirred and refluxed at 110 °C for 20 min. When the viscosity of the system was visually observed to increase significantly, it was quickly transferred to a mixer and processed by mixing at 220 °C for 10 min. After the viscosity of the system was stable, it was extruded and pelletized; the pellets were placed in a vacuum drying oven at 90 °C and vacuum-heated for 24 h to obtain a polystyrene alloy.

[0042] Comparative Example 1

[0043] After mixing 100 parts of styrene monomer, 0.8 parts of compound antioxidant and 0.4 parts of free radical initiator, it was protected by nitrogen in a three-necked flask and stirred and refluxed at 110 °C for 20 min. When the viscosity of the system was visually observed to increase significantly, it was quickly transferred to a mixer and processed by mixing at 220 °C for 15 min. After the viscosity of the system was stable, it was extruded and pelletized. The pellets were placed in a vacuum drying oven at 90 °C and vacuum-heated for 24 h to obtain a polystyrene product.

[0044] Comparative Example 2

[0045] After mixing 50 parts of styrene monomer, 25 parts of epoxy resin, 25 parts of epoxy curing agent, 0.8 parts of compound antioxidant and 0.4 parts of free radical initiator, it was protected by nitrogen in a three-necked flask and stirred and refluxed at 100 °C for 18 min. When the viscosity of the system was visually observed to increase significantly, it was directly poured into the mold of a standard spline and cured at 140 °C for 120 min to obtain a spline.

[0046] Comparative Example 3

[0047] After mixing 50 parts of epoxy resin, 50 parts of epoxy curing agent and 0.8 parts of compound antioxidant, it was poured into the mold of a standard spline and cured at 140 °C for 120 min to obtain a spline.

[0048] Performance Test

[0049] The materials prepared in Examples 1-4 and Comparative Example 1 were injection molded into a mold for a standard specimen to obtain the corresponding standard specimens (in Comparative Examples 2 and 3, since the specimens were directly obtained, they could be directly tested). The above specimens were subjected to standardized tests, and the test results are shown in Table 1.

[0050] Table 1

[0051]

[0052] Among them, the specific conditions for each test item in Table 1 are as follows:

[0053] 1. Tensile test conditions: Type A1 specimen, tensile speed: 50 mm / min;

[0054] 2. Izod notched impact strength test conditions: Machined V-notch, temperature: 23 °C;

[0055] 3. Glass transition temperature test: Heating rate: 20 °C / min;

[0056] 4. Hot pressing temperature: 210 °C, pressure: 4 MPa.

[0057] It can be seen from the test data in Table 1 that the polystyrene-based alloy prepared by the present invention has both the good rigidity of thermosetting plastics and the recyclability of thermoplastic materials, and the toughness of its alloy materials has been improved to a certain extent, solving a series of deficiencies such as the notch brittleness of raw materials, overcoming the problem of thermodynamic incompatibility of polymer alloys, and obtaining a polymer alloy with excellent mechanical properties.

[0058] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0059] The above-described embodiments only represent several implementation manners of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention patent shall be subject to the appended claims.

Claims

1. A polystyrene alloy, characterized in that, It is formed by at least one styrenic monomer and a thermosetting resin through their respective polymerization reactions. Among them, the polymerization reaction of the styrenic monomer is free radical polymerization, and the polymerization reaction of the thermosetting resin is thermosetting polymerization.

2. The polystyrene alloy according to claim 1, characterized in that, The styrenic monomer is selected from at least one of styrene, methylstyrene, ethylstyrene, methoxystyrene, dimethoxystyrene, ethoxystyrene, dimethylstyrene, acetoxystyrene, tert-butylstyrene, divinylbenzene, or its homologues or halogenated compounds.

3. The polystyrene alloy according to claim 2, wherein The styrenic monomer is styrene.

4. The polystyrene alloy according to claim 1, characterized in that, The thermosetting resin is selected from epoxy resin, high temperature vulcanized silicone rubber, melamine resin, thermosetting phenolic resin or unsaturated polyester resin; Preferably, the thermosetting resin is epoxy resin.

5. The polystyrene alloy according to claim 1, wherein The antioxidant is a compound of a hindered phenol antioxidant, a phosphite antioxidant and a thioester antioxidant; Preferably, the antioxidant is a mixture of antioxidant 1076, antioxidant V76-P, antioxidant 168, and antioxidant DSTDP in a mass ratio of 1:1:1:

1.

6. The polystyrene alloy according to claim 1, wherein The free radical initiator is selected from any one of organic peroxide initiators, azo initiators, inorganic peroxide initiators, and redox system initiators.

7. The polystyrene alloy according to claim 6, characterized in that, The initiator is azobisisobutyronitrile.

8. The polystyrene alloy according to claim 1, wherein By weight, the polystyrene alloy is prepared from 30-70 parts of styrenic monomer, 15-35 parts of thermosetting resin, 15-35 parts of curing agent, 0.8 part of antioxidant, and 0.2-0.5 part of free radical initiator.

9. A method for preparing a polystyrene alloy as described in any one of claims 1-8, characterized in that, The preparation of the polystyrene alloy adopts one of solution polymerization, bulk polymerization, emulsion polymerization, suspension polymerization, and reactive extrusion polymerization; Preferably, the preparation of the polystyrene alloy adopts reactive extrusion polymerization.

10. The preparation method of the polystyrene alloy according to claim 9, characterized in that, It includes the following steps: After mixing 30-70 parts of styrenic monomer, 15-35 parts of thermosetting resin, 15-35 parts of curing agent, 0.8 part of antioxidant, and 0.2-0.5 part of free radical initiator, stir and reflux in a protective gas at 90-110 °C for 15-20 min. When the viscosity of the visual system increases significantly, quickly transfer it to an internal mixer and carry out internal mixing at 220-240 °C for 10-20 min. After the viscosity of the system is stable, extrude and pelletize. Place the pellets in a vacuum drying oven at 80-100 °C and heat them in vacuum for 20-26 h to obtain the polystyrene alloy.

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