VPS / RPS / CaCO3 composite material based on recycled polystyrene and preparation method thereof

Abstract

The invention belongs to the technical field of high polymer materials, and particularly relates to a VPS / RPS / CaCO3 composite material based on recycled polystyrene and a preparation method of the VPS / RPS / CaCO3 composite material. The VPS / RPS / CaCO3 composite material is obtained by extruding the following raw materials in parts by mass through a screw rod; the polystyrene composite material is prepared from 100 parts of pure polystyrene, 10-25 parts of recycled polystyrene, 1-5 parts of calcium carbonate and 0.01-0.05 part of coupling agent. According to the invention, the pure polystyrene and the recycled polystyrene are used as matrixes, then the coupling agent and the CaCO3 are added for compounding, and the CaCO3 is activated by using the coupling agent, so that the CaCO3 is well dispersed in the matrixes under the condition of a small dosage, the mechanical property of the composite material is improved, and the problems of complex treatment and pollution of the recycled polystyrene are solved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of high polymer materials, and particularly relates to a VPS / RPS / CaCO3 composite material based on recycled polystyrene and a preparation method thereof. BACKGROUND

[0002] Polystyrene (PS) foam plastics are widely used in packaging, building, electronics, home furnishing and other fields due to their lightness, durability, heat insulation and other characteristics. However, the overuse of these materials and their difficult degradation characteristics have caused serious environmental problems, namely the so-called "white pollution". Due to the non-degradability of polystyrene, it exists in the environment for a long time, forming a serious ecological problem. The treatment methods for waste polystyrene include incineration method, but harmful gases are generated, causing air pollution.

[0003] In recent years, by compounding waste polystyrene with other materials (such as mineral fillers, fibers, etc.) to form new materials, the physical and mechanical properties can be effectively improved, and the application value of the material can be improved. However, the existing composite material adopts chemical recycling, specifically converting waste polystyrene into raw materials through thermal cracking, catalytic cracking and other chemical methods. However, there are the following problems: the existing treatment process is complex and will cause serious pollution; and the high temperature of thermal cracking and catalytic cracking treatment further damages the performance of recycled polystyrene, resulting in a decrease in the mechanical properties of the final composite material. SUMMARY

[0004] In view of the technical problems in the prior art that the treatment process of recycled polystyrene is complex, serious pollution is caused, and the high temperature of the treatment further damages the performance of the recycled polystyrene, resulting in a decrease in the mechanical properties of the final composite material, the application provides a VPS / RPS / CaCO3 composite material based on recycled polystyrene and a preparation method thereof.

[0005] The application adopts a mixture of pure polystyrene and recycled polystyrene as a matrix, and then forms a VPS / RPS / CaCO3 composite material by screw extrusion with a coupling agent and CaCO3. The coupling agent is used to activate CaCO3, so that CaCO3 is well dispersed in the matrix at a small amount, thereby improving the mechanical properties of the composite material.

[0006] To achieve the above object, the technical scheme adopted by the application is as follows:

[0007] A VPS / RPS / CaCO3 composite material based on recycled polystyrene, the VPS / RPS / CaCO3 composite material is obtained by screw extrusion of the following raw materials in mass fraction;

[0008] Pure polystyrene 100 parts, recycled polystyrene 10-25 parts, calcium carbonate 1-5 parts and coupling agent 0.01-0.05 parts.

[0009] Further limit, the number average molecular weight of the pure polystyrene is 50000-80000.

[0010] Further limit, the number average molecular weight of the recycled polystyrene is 30000-40000.

[0011] Further limit, the recycled polystyrene is prepared by washing, drying, crushing, melting, extruding and cutting granulation of waste polystyrene products.

[0012] Further limit, the average particle size of the calcium carbonate is 400-1250 mesh.

[0013] Further limit, the coupling agent is a titanate coupling agent and / or a silane coupling agent.

[0014] A preparation method of the VPS / RPS / CaCO3 composite material based on recycled polystyrene, comprising the following steps:

[0015] Step 1: calcium carbonate and coupling agent are added to a high-speed mixer, and stirred and mixed uniformly to obtain an activated mixture;

[0016] Step 2: pure polystyrene, recycled polystyrene and the activated mixture in step 1 are added to a double-stage screw extruder, and VPS / RPS / CaCO3 composite material is obtained by mixing, extruding and shearing granulation.

[0017] Further limit, in step 1, the stirring temperature is controlled at 100-120 DEG C.

[0018] Further limit, in step 2, the temperature during extrusion is controlled at 190-200 DEG C.

[0019] Compared with the prior art, the beneficial effects of the present application are embodied in:

[0020] 1, the present application adopts pure polystyrene and recycled polystyrene mixed as a matrix, and then forms VPS / RPS / CaCO3 composite material with coupling agent and CaCO3 through screw extrusion; the coupling agent is used to activate CaCO3, so that CaCO3 is well dispersed in the matrix at a smaller amount, thereby improving the mechanical properties of the composite material.

[0021] 2, in the preparation of VPS / RPS / CaCO3 composite material, the screw extrusion method is adopted, which is not only simple in operation, but also does not produce carbon dioxide waste gas, solving the problems of complex process and pollution existing in the chemical treatment of recycled polystyrene.

[0022] 3、The VPS / RPS / CaCO3 composite material based on recycled polystyrene has the highest tensile strength of 37.563 MPa, the highest elongation at break of 56.60%, the highest flexural modulus of 3130 MPa, and the highest flexural strength of 54.21 MPa through tests, and has significant advantages in tensile and bending properties, and has great application prospects in the fields of packaging, household appliance shells, or billboards.

[0023] 4、In the present application, the pure polystyrene and the recycled polystyrene are mixed in a specific ratio, so that the mechanical properties of the composite material are improved; at the same time, the recycled polystyrene is used as a substrate, the waste polystyrene products are recycled, energy saving and environmental protection, and it is in line with the green development concept, which is conducive to market promotion.

[0024] 5、The preparation method of the present application utilizes activation and physical extrusion, and the process is simple, only simple blending is needed, no additional compatibilizers and plasticizers are needed, and the method is not only low in energy consumption and cost, but also easy to realize industrialization. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 is a tensile stress-strain curve;

[0026] Figure 2 is a bending stress-strain curve;

[0027] Figure 3 is a morphology diagram of the VPS / RPS / CaCO3 composite material and the RPS / CaCO3 composite material. DETAILED DESCRIPTION

[0028] The present application will be further described in conjunction with the accompanying drawings and examples, but the embodiments of the present application are not limited thereto. Other methods for preparing the compounds of the present application are considered to be within the scope of the present application, with some conventional modifications of the reaction conditions according to the present application.

[0029] Unless otherwise defined, the technical terms or scientific terms used in the present application shall have the usual meanings understood by those skilled in the art to which the present application belongs.

[0030] It should also be understood that the specific examples described above are intended to be illustrative only and not limiting of the scope of the present application, which is set forth in the claims below, and any modifications of the present application that come within the scope of the technical range disclosed by the present application and the inventive concept thereof, according to the technical solution and inventive concept of the present application, are encompassed within the scope of protection of the present application.

[0031] The application discloses a VPS / RPS / CaCO3 composite material based on recycled polystyrene, which is prepared from the following raw materials in parts by mass: pure polystyrene 100 parts, recycled polystyrene 10-25 parts, calcium carbonate 1-5 parts and coupling agent 0.01-0.05 parts by means of screw extrusion.

[0032] In the application, the recycled polystyrene is 10 parts, 15 parts, 20 parts or 25 parts, the calcium carbonate is 1 part, 2 parts, 3 parts, 4 parts or 5 parts, and the coupling agent is 0.01 part, 0.02 part, 0.03 part, 0.04 part or 0.05 part.

[0033] In the application, the pure polystyrene refers to new polystyrene directly purchased from the market.

[0034] Preferably, the number-average molecular weight of the pure polystyrene is 50000-80000.

[0035] Preferably, the number-average molecular weight of the recycled polystyrene is 30000-40000.

[0036] Preferably, the recycled polystyrene is prepared by cleaning, drying, crushing, melting, extruding and cutting and granulating the waste polystyrene products. In the implementation, the waste polystyrene products are wastes generated in the fields of packaging, household appliances and automobiles, for example, common waste polystyrene products such as foam packaging bags / boxes, disposable tableware and household appliance packaging boxes. The operation modes and operation parameters of the recycled polystyrene drying, crushing, melting and extruding are all prior art, and will not be described here.

[0037] In the application, the average particle size of the calcium carbonate is 400-1250 mesh. Preferably, the average particle size of the calcium carbonate is 400 mesh, 500 mesh, 600 mesh, 700 mesh, 800 mesh, 900 mesh, 1000 mesh, 1100 mesh or 1250 mesh.

[0038] In the application, the coupling agent is a titanate coupling agent and / or a silane coupling agent. Preferably, the coupling agent is a titanate coupling agent, a silane coupling agent or a mixture of the titanate coupling agent and the silane coupling agent. When the titanate coupling agent and the silane coupling agent are mixed, they are mixed according to equal mass.

[0039] A preparation method of the VPS / RPS / CaCO3 composite material based on recycled polystyrene, comprising the following steps:

[0040] Step 1: calcium carbonate and a coupling agent are added into a high-speed mixer, and are stirred and mixed uniformly to obtain an activated mixture; the stirring temperature is controlled to be 100-120 DEG C;

[0041] Step 2: The pure polystyrene, the recycled polystyrene and the activated mixture in Step 1 are all added into a double-stage screw extruder, and a VPS / RPS / CaCO3 composite material based on recycled polystyrene is obtained by mixing extrusion and shear granulation.

[0042] In Step 2, the temperature is controlled at 190-200°C during extrusion. For example, the temperature is controlled at 190°C, 195°C or 200°C.

[0043] In the present application, the VPS / RPS / CaCO3 composite material based on recycled polystyrene obtained by extrusion and shear granulation is further injected by an injection molding machine to obtain a sample for performance test.

[0044] In the present application, the melt temperature is controlled at 190-210°C during injection molding. For example, the temperature is controlled at 190°C, 195°C, 200°C, 205°C or 210°C.

[0045] In the present application, the mold temperature is controlled at 90-110°C during injection molding. For example, the temperature is controlled at 90°C, 95°C, 100°C, 105°C or 110°C.

[0046] The technical solutions of the present application are described in detail below with several groups of examples.

[0047] It should be noted that, in the following examples, the chemicals and reagents used are all commercially available products in the art unless otherwise specified.

[0048] It should be noted that, in the following examples, the operations used are all conventional operations unless otherwise specified. The test methods are all standard test methods in the art unless otherwise specified.

[0049] In the following examples, the recycled polystyrene is prepared by cleaning, drying, crushing, melting, extruding and shear granulation of waste polystyrene products. The prepared recycled polystyrene is denoted as RPS matrix (abbreviated as RPS), and dumbbell-shaped and long strip-shaped samples are prepared by micro-injection molding instrument with an injection melt temperature of 210°C, a mold temperature of 105°C, an injection pressure of 35 MPa and an injection time of 10 s.

[0050] Example 1

[0051] In this example, a VPS / RPS / CaCO3 composite material based on recycled polystyrene is prepared by screw extrusion of the following raw materials in mass fraction: pure polystyrene 100 parts, recycled polystyrene 10 parts, calcium carbonate 2 parts and coupling agent 0.02 parts.

[0052] The number average molecular weight of pure polystyrene is 50,000 to 80,000, and the number average molecular weight of recycled polystyrene is 30,000 to 40,000; the average particle size of calcium carbonate is 1250 mesh; and the coupling agent is a titanate coupling agent and a silane coupling agent mixed in equal parts by weight.

[0053] In this embodiment, a method for preparing a VPS / RPS / CaCO3 composite material based on recycled polystyrene includes the following steps:

[0054] Step 1: Add calcium carbonate and coupling agent into a high-speed mixer, stir and mix evenly to obtain an activated mixture;

[0055] Specifically, 2 parts of calcium carbonate were dried in a vacuum drying oven at 100° C. for 12 hours, and after drying, 0.01 parts of silane coupling agent and 0.01 parts of titanate coupling agent were added to a high-speed mixer and reacted at 100° C. for 20 minutes to obtain an activated mixture, i.e., activated calcium carbonate.

[0056] Step 2: First, pure polystyrene and 10 parts of recycled polystyrene were dried in a vacuum drying oven at 80°C for 12 hours, and then 100 parts of pure polystyrene, 10 parts of recycled polystyrene and the activated mixture of step S1 were added to a twin-stage screw extruder at an extrusion temperature of 190°C. VPS / RPS / CaCO3 composite materials based on recycled polystyrene were obtained by mixed extrusion and shear granulation.

[0057] The VPS / RPS / CaCO3 composite material based on recycled polystyrene prepared above was then molded into dumbbell-shaped splines and long strip splines using a microinjection molding instrument with an injection melt temperature of 210°C, a mold temperature of 105°C, an injection pressure of 35 MPa, and an injection time of 10 s.

[0058] The tensile properties were tested according to national standards. The tensile results showed that the tensile strength was 36.80±0.97MPa and the elongation at break was 50.96±3.67%.

[0059] According to the national standard test of bending performance, the three-point bending results showed: bending modulus 3130±42MPa, bending strength 53.31±0.49MPa.

[0060] Example 2

[0061] In this embodiment, a VPS / RPS / CaCO3 composite material based on recycled polystyrene is obtained by screw extrusion of the following raw materials in parts by weight:

[0062] 100 parts of pure polystyrene, 10 parts of recycled polystyrene, 3 parts of calcium carbonate and 0.03 parts of coupling agent.

[0063] The number average molecular weight of the pure polystyrene is 50000-80000, the number average molecular weight of the recycled polystyrene is 30000-40000, and the average particle size of the calcium carbonate is 1250 mesh. The coupling agent is a mixture of equal mass portions of a titanate coupling agent and a silane coupling agent.

[0064] In this embodiment, a preparation method of a VPS / RPS / CaCO3 composite material based on recycled polystyrene is referred to Example 1.

[0065] The VPS / RPS / CaCO3 composite material based on recycled polystyrene prepared above is used to prepare dumbbell-shaped samples and long strip-shaped samples by micro-injection molding, the injection melt temperature is 210℃, the mold temperature is 105℃, the injection pressure is 35MPa, and the injection time is 10s.

[0066] According to the national standard test of tensile properties, the tensile strength is 36.59±0.65MPa, and the elongation at break is 50.37±7.98%.

[0067] According to the national standard test of bending properties, the three-point bending results show that the bending modulus is 3124±78MPa, and the bending strength is 53.74±1.04MPa.

[0068] Example 3

[0069] In this embodiment, a VPS / RPS / CaCO3 composite material based on recycled polystyrene is obtained by screw extrusion from the following mass portions of raw materials:

[0070] The pure polystyrene is 100 parts, the recycled polystyrene is 25 parts, the calcium carbonate is 2 parts, and the coupling agent is 0.02 parts.

[0071] The number average molecular weight of the pure polystyrene is 50000-80000, the number average molecular weight of the recycled polystyrene is 30000-40000, and the average particle size of the calcium carbonate is 1250 mesh. The coupling agent is a mixture of equal mass portions of a titanate coupling agent and a silane coupling agent.

[0072] In this embodiment, a preparation method of a VPS / RPS / CaCO3 composite material based on recycled polystyrene is referred to Example 1.

[0073] The VPS / RPS / CaCO3 composite material based on recycled polystyrene prepared above is used to prepare dumbbell-shaped samples and long strip-shaped samples by micro-injection molding, the injection melt temperature is 210℃, the mold temperature is 105℃, the injection pressure is 35MPa, and the injection time is 10s.

[0074] According to the national standard test of tensile properties, the tensile strength is 37.56±0.25MPa, and the elongation at break is 46.98±3.36%.

[0075] According to the national standard test of bending performance, the three-point bending results show that the bending modulus is 2929±50 MPa, and the bending strength is 53.31±0.19 MPa.

[0076] Example 4

[0077] In this embodiment, a VPS / RPS / CaCO3 composite material based on recycled polystyrene is obtained by screw extrusion of the following raw materials in mass fraction:

[0078] Pure polystyrene 100 parts, recycled polystyrene 25 parts, calcium carbonate 3 parts, and coupling agent 0.03 parts.

[0079] The number average molecular weight of pure polystyrene is 50000-80000, and the number average molecular weight of recycled polystyrene is 30000-40000; the average particle size of calcium carbonate is 1250 mesh. The coupling agent is equal mass fraction of titanate coupling agent and silane coupling agent.

[0080] In this embodiment, the preparation method of the VPS / RPS / CaCO3 composite material based on recycled polystyrene refers to Example 1.

[0081] The VPS / RPS / CaCO3 composite material based on recycled polystyrene prepared above is then used to prepare dumbbell-shaped and long strip-shaped samples by micro-injection molding instrument. The injection melt temperature is 210℃, the mold temperature is 105℃, the injection pressure is 35MPa, and the injection time is 10s.

[0082] According to the national standard test of tensile properties, the tensile results show that the tensile strength is 36.86±0.99 MPa, and the elongation at break is 52.60±4.30%.

[0083] According to the national standard test of bending performance, the three-point bending results show that the bending modulus is 2960±47 MPa, and the bending strength is 54.21±0.18 MPa.

[0084] In the test, the tensile stress and bending stress of the VPS / RPS / CaCO3 composite material based on recycled polystyrene prepared in Example 1-Example 4 are shown in Figure 1 and Figure 2 .

[0085] Meanwhile, using the proportioning of Reference Example 1, a composite material prepared by using pure polystyrene, i.e. polystyrene new material, has the following properties.

[0086] Table 1 Properties of composite material prepared by polystyrene new material

[0087] Polystyrene virgin material Properties Tensile strength / MPa 34.88±0.88 Elongation at break / % 48.72±2.92 Flexural modulus / MPa 2232±39 Flexural strength / MPa 48.87±0.55

[0088] FromFigure 1 , Figure 2 and Table 1 can be seen: the present application will recycle polystyrene and pure polystyrene blending, the performance of VPS / RPS / CaCO3 composite material prepared is superior to polystyrene new material composite. It shows that calcium carbonate can be uniformly dispersed in the matrix, improve the performance of the composite material; at the same time, using part of the recycled polystyrene as the matrix, the waste polystyrene products are recycled, energy saving and environmental protection.

[0089] Further, the appearance of the VPS / RPS / CaCO3 composite material based on recycled polystyrene prepared in Example 1 was observed, and in order to show the advantages of the technical scheme of the present application, a control sample was designed: that is, the RPS / CaCO3 composite material was prepared by the method of Example 1 without adding pure polystyrene. The results are shown in Figure 3 .

[0090] Referring to Figure 3 , the left side is the VPS / RPS / CaCO3 composite material based on recycled polystyrene, and the right side is the RPS / CaCO3 composite material, from which it can be seen that compared with the RPS / CaCO3 composite material, the VPS / RPS / CaCO3 composite material of the present application with VPS as the main matrix and supplemented by a specific proportion of recycled polystyrene is more white and has more advantages, which can be used in more packaging environments.

[0091] The above are several preferred embodiments of the preparation method of the present application, but they cannot be regarded as a limitation on the technical scheme protected by the present application. Any alternative scheme based on the technical idea of the present application and obtained by ordinary skilled personnel in the art without creative labor shall fall within the protection scope of the present application.

Claims

1. A VPS / RPS / CaCO3 composite material based on recycled polystyrene, characterized in that: VPS / RPS / CaCO3 composite material is obtained by screw extrusion of the following raw materials in parts by mass: 100 parts of pure polystyrene, 10-25 parts of recycled polystyrene, 1-5 parts of calcium carbonate and 0.01-0.05 parts of coupling agent.

2. The VPS / RPS / CaCO3 composite material based on recycled polystyrene according to claim 1, characterized in that The number average molecular weight of the pure polystyrene is 50,000 to 80,000.

3. The VPS / RPS / CaCO3 composite material based on recycled polystyrene according to claim 1, characterized in that The number average molecular weight of the recycled polystyrene is 30,000 to 40,000.

4. The VPS / RPS / CaCO3 composite material based on recycled polystyrene according to claim 1, characterized in that The recycled polystyrene is obtained by washing, drying, crushing, melting, extruding and cutting and granulating waste polystyrene products.

5. The VPS / RPS / CaCO3 composite material based on recycled polystyrene according to claim 1, characterized in that The average particle size of the calcium carbonate is 400 mesh to 1250 mesh.

6. The VPS / RPS / CaCO3 composite material based on recycled polystyrene according to claim 1, characterized in that The coupling agent is a titanate coupling agent and / or a silane coupling agent.

7. A method for preparing the VPS / RPS / CaCO3 composite material based on recycled polystyrene according to claim 1, characterized in that: The steps include: Step 1: Add calcium carbonate and coupling agent into a high-speed mixer, stir and mix evenly to obtain an activated mixture; Step 2: Pure polystyrene, recycled polystyrene and the activated mixture in step 1 are added into a twin-stage screw extruder, and a VPS / RPS / CaCO3 composite material is obtained by mixing, extruding and shearing granulation.

8. The preparation method according to claim 7, characterized in that In the step 1, the stirring temperature is controlled at 100° C. to 120° C.

9. The preparation method according to claim 7, characterized in that In the step 2, the temperature during extrusion is controlled at 190° C. to 200° C.

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