A method for modifying rubber using waste plastic track powder

Abstract

The application discloses a method for modifying rubber by using waste plastic track powder, first, the waste plastic track powder is modified to obtain polystyrene modified plastic track powder; then the polystyrene modified plastic track powder, a styrene butadiene rubber matrix and 4,4'-bismaleimide diphenylmethane are added into a banbury mixer in a specific order, and mixing is carried out to obtain waste plastic track powder modified rubber. The modified rubber prepared by the application has self-repairing capability, and the tensile modulus is also improved compared with the original rubber. Meanwhile, the technology modifies the rubber by using the waste plastic track powder, so that the waste plastic track is fully utilized, resources are saved, and pollution to the environment caused by discarding the waste plastic track is avoided.

Description

Technical Field

[0001] This invention belongs to the field of self-healing rubber technology, specifically relating to a method for modifying rubber using waste plastic track powder. Background Technology

[0002] Currently, with rapid economic development, synthetic running tracks are widely used in the construction of athletic fields due to their good elasticity and ease of maintenance. However, with increasing use, their wear resistance and elasticity gradually decrease, requiring repair or replacement. Traditional methods for disposing of used synthetic running tracks involve incineration or landfill, but these methods do not meet environmental protection requirements. Firstly, incineration produces toxic fumes, and landfilling can cause plasticizers to leach into soil and water, polluting the environment. Secondly, used synthetic running tracks are typically made of polyurethane rubber, ethylene propylene rubber, and neoprene rubber; failure to recycle them represents a significant waste. Therefore, for environmental protection and the recycling of waste resources, it is essential to properly recycle used synthetic running tracks. Summary of the Invention

[0003] This invention addresses the shortcomings of existing technologies by providing a method for modifying rubber using waste plastic running track powder. This method enhances the mechanical properties of rubber and imparts self-healing capabilities while enabling the recycling and reuse of waste plastic running tracks. This invention aligns with the concept of green and sustainable development and opens up new avenues for the recycling and reuse of waste plastic running tracks.

[0004] This invention relates to a method for modifying rubber using waste plastic track powder, comprising the following steps:

[0005] Step 1: Modify the waste plastic track powder to obtain polystyrene modified plastic track powder;

[0006] Step 2: Add polystyrene-modified plastic track powder, styrene-butadiene rubber matrix, and 4,4'-bismaleimide diphenylmethane into a mixer in a specific order and mix to obtain waste plastic track powder modified rubber.

[0007] In step 1, the polystyrene-modified plastic running track powder is prepared by dispersing waste plastic running track powder in styrene, divinylbenzene, and 2-vinylfuran, followed by swelling and polymerization. Specifically, it is prepared through the following steps:

[0008] 1a. Crush the waste plastic running track and screen it to obtain powder with a diameter ≤0.5mm;

[0009] 1b. Add the waste plastic track powder obtained in 1a into the reactor, then add styrene (SM), divinylbenzene (DVB) and 2-vinylfuran, and then add azobisisobutyronitrile (AIBN). After completely submerging the powder, place it at room temperature for 4-6 hours to allow the waste rubber track powder to fully swell.

[0010] 1c. Take out the waste plastic track powder after swelling in step 1b, disperse it in water, add sodium dodecylbenzene sulfonate (SDBS), react at 80°C for 3-4 hours, cool to room temperature and filter to obtain polystyrene modified plastic track powder.

[0011] Further, the amount of each raw material added in step 1 by mass parts is as follows: 100 parts waste plastic track powder, 100 parts styrene, 5-20 parts divinylbenzene, 5-10 parts 2-vinylfuran, 0.5-2 parts azobisisobutyronitrile, 1-5 parts sodium dodecylbenzenesulfonate, and 500 parts water.

[0012] To ensure uniform mixing of all components in the composite material, the feeding sequence in step 2 is as follows: First, add the rubber matrix and polystyrene-modified plastic track powder to the internal mixer and mix for a period of time. Then, add 4,4'-bismaleimide diphenylmethane and 2-vinylfuran to the internal mixer and mix for a period of time. Finally, add the crosslinking agent DCP and antioxidant D and continue mixing until the mixture is uniform.

[0013] First, the rubber matrix and polystyrene-modified plastic track powder are mixed to ensure uniform physical mixing. Second, bismaleimide and vinyl furan small molecules are added to ensure uniform physical mixing with the rubber and track powder. Finally, DCP is added to initiate the reaction between the double bonds of vinyl furan and the double bonds of rubber.

[0014] In step 2, the amount of each raw material added by mass parts is as follows: 100 parts of polystyrene modified plastic track powder, 100-200 parts of styrene-butadiene rubber, 5-15 parts of 4,4'-bismaleimide diphenylmethane, 5 parts of 2-vinylfuran, 1 part of crosslinking agent DCP, and 1 part of antioxidant D.

[0015] Furthermore, the internal mixer temperature is set to 80-100℃, the mixing time of the styrene-butadiene rubber matrix and the polystyrene modified plastic track powder is 2-6 minutes, the mixing time of the mixture after adding 4,4'-bismaleimide diphenylmethane is 2-6 minutes, and the mixing time after adding DCP and antioxidant D is 2-6 minutes.

[0016] Finally, the mixed rubber is placed in a mold with a suitable inner cavity, heated to 140°C, and molded for 15 minutes under a pressure of 10 MPa (during this process, furan and bismaleimide will react to form reversible crosslinks).

[0017] The modified rubber prepared by this invention has a self-healing function. At the interface between waste plastic track powder and rubber, it can form a reversible interaction through furan and bismaleimide. Figure 1 ).

[0018] Compared with the prior art, the beneficial effects of the present invention are reflected in:

[0019] This invention utilizes waste plastic running track powder as a rubber modifier, avoiding environmental pollution caused by incinerating or landfilling waste plastic running tracks while ensuring their full utilization and conserving resources. Simultaneously, the polystyrene-modified plastic running track powder effectively strengthens the rubber composite material and improves its tensile strength. By introducing furan and bismaleimide at the interface between the waste plastic running track powder and rubber, a reversible interaction can be formed, giving the modified rubber composite material self-healing capabilities. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the reversible interaction between modified plastic track powder and the rubber matrix in modified rubber.

[0021] Figure 2 This is a flowchart of the process of modifying rubber using waste plastic track powder. Detailed Implementation

[0022] The technical solution of the present invention will be further described below with reference to specific embodiments. However, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] Example 1:

[0024] This embodiment prepares a rubber composite material modified with waste plastic track powder according to the following steps:

[0025] 1. The waste rubber track is crushed using a crusher to obtain rubber raw material particles; the crushed rubber particles are then sieved through a 0.5mm diameter screen to obtain waste rubber powder.

[0026] 2. Under the protection of inert gas N2, add 20g of waste rubber powder, 0.3g of initiator azobisisobutyronitrile, 20g of styrene solvent, 3g of divinylbenzene and 2g of 2-vinylfuran into a container and let it stand at room temperature for 4-6 hours to allow the waste rubber track powder to fully swell.

[0027] 3. Take out the swollen waste plastic track powder, disperse it in 100g of water, and add 0.6g of sodium dodecylbenzenesulfonate. React at 80℃ for 3-4 hours. After the reaction is complete, cool to room temperature and filter. Then place it in a vacuum drying oven at 100℃ for 6 hours to obtain polystyrene modified plastic track powder.

[0028] 4. Add 16g of styrene-butadiene rubber to a mixer at 100rpm and 90℃ for 6min. Add 20g of the modified waste plastic track powder obtained in step 3, and add 4g of 4,4'-bismaleimide diphenylmethane, 4g of 2-vinylfuran, 0.2g of DCP, and 0.2g of antioxidant D premixed powder to the mixer in sequence, and continue mixing for 15min.

[0029] 5. The product obtained from the internal mixing process is vulcanized on a flat vulcanizing apparatus and then cut into standard test strips. The heating temperature is 180℃, the pressure is 10MPa, and the vulcanization time is 15min, to obtain a rubber composite material modified from waste plastic track powder.

[0030] Example 2:

[0031] This embodiment uses the same method as Example 1 to prepare a rubber composite material modified from waste plastic track powder. The difference is that the 16g of styrene-butadiene rubber in Example 1 is replaced with 20g of styrene-butadiene rubber.

[0032] Example 3:

[0033] This embodiment uses the same method as Example 1 to prepare a rubber composite material modified from waste plastic track powder. The difference is that the 3g of 4,4'-bismaleimide diphenylmethane in Example 1 is replaced with 6g of 4,4'-bismaleimide diphenylmethane.

[0034] Example 4:

[0035] This embodiment uses the same method as Example 1 to prepare a rubber composite material modified from waste plastic track powder. The difference is that the 16g of styrene-butadiene rubber in Example 1 is replaced with 40g of styrene-butadiene rubber.

[0036] The above description is merely a preferred embodiment of the present invention and is not intended to limit the patent scope of the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention. Comparative Example 1:

[0037] This comparative example uses the same method as Example 1 to prepare a rubber composite material modified from waste plastic track powder. The difference is that the 3g of 4,4'-bismaleimide diphenylmethane in Example 1 is replaced with 0g of 4,4'-bismaleimide diphenylmethane, that is, the system does not contain 4,4'-bismaleimide diphenylmethane.

[0038] Comparative Example 2:

[0039] This comparative example uses the same method as Example 1 to prepare a rubber composite material modified from waste plastic track powder. The difference is that the 0.2g DCP in Example 1 is replaced with 0g DCP, that is, the system does not contain DCP.

[0040] Table 1. Powder ratio for polystyrene-modified plastic running track

[0041]

[0042] Table 2. Proportioning of Waste Plastic Track Powder Modified Rubber Composite Material

[0043]

[0044] Table 3 Mechanical properties and self-healing properties of the embodiments and comparative examples

[0045] Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 2 Tensile strength / MPa 1.63 1.35 1.96 1.03 1.47 0.99 Elongation at break / % 470 552 510 625 595 637 Self-healing tensile strength (MPa) 1.59 1.25 1.87 0.96 / 0.85 Elongation at break after self-repair / % 450 537 416 595 / 610

[0046] As can be seen from the data in the table above, the mass fraction of the modified plastic track powder decreased continuously in Examples 1, 2, and 4, and the tensile strength of the material also gradually decreased. This indicates that the modified plastic track powder is beneficial to improving the mechanical properties of styrene-butadiene rubber. Compared with Example 3, the amount of 4,4'-bismaleimide diphenylmethane in Example 3 was doubled, which improved the strength of the material and also improved the tensile strength after self-healing.

[0047] Compared to Example 1, Comparative Example 1 did not contain 4,4'-bismaleimide diphenylmethane, therefore its tensile strength was only 1.47 MPa and it had no self-healing effect.

[0048] Compared to Example 1, Comparative Example 2 did not include the vulcanizing agent DCP, and the resulting composite material had poor tensile strength but exhibited self-healing properties.

[0049] The self-healing conditions for all the above materials are 80℃ for 24 hours.

Claims

1. A method for modifying rubber using waste plastic track powder, characterized in that... Includes the following steps: Step 1: Modify the waste plastic track powder to obtain polystyrene modified plastic track powder; Step 2: Add polystyrene-modified plastic track powder, styrene-butadiene rubber matrix, and 4,4'-bismaleimide diphenylmethane into a mixer in a specific order and mix to obtain waste plastic track powder modified rubber. In step 1, the polystyrene-modified plastic running track powder is prepared by dispersing waste plastic running track powder in styrene, divinylbenzene, and 2-vinylfuran, followed by swelling and polymerization. Specifically, it is prepared through the following steps: 1a. Crush the waste plastic running track and screen it to obtain powder with a diameter ≤0.5 mm; 1b. Add the waste plastic track powder obtained in 1a into the reactor, then add styrene, divinylbenzene and 2-vinylfuran, and then add azobisisobutyronitrile. After completely submerging the powder, place it at room temperature for 4-6 hours to allow the waste rubber track powder to fully swell. 1c. Take out the waste plastic track powder after swelling in step 1b, disperse it in water, add sodium dodecylbenzene sulfonate, react at 80 ℃ for 3-4 h, cool to room temperature and filter to obtain polystyrene modified plastic track powder. The feeding sequence in step 2 is as follows: First, add the rubber matrix and polystyrene modified plastic track powder into the internal mixer and mix for a period of time. Then, add 4,4'-bismaleimide diphenylmethane and 2-vinylfuran into the internal mixer and mix for a period of time. Finally, add the crosslinking agent DCP and antioxidant D and continue mixing until the mixture is uniform.

2. The method according to claim 1, characterized in that: The amount of each raw material added in step 1 by mass parts is as follows: 100 parts waste plastic track powder, 100 parts styrene, 5-20 parts divinylbenzene, 5-10 parts 2-vinylfuran, 0.5-2 parts azobisisobutyronitrile, 1-5 parts sodium dodecylbenzenesulfonate, and 500 parts water.

3. The method according to claim 1, characterized in that: In step 2, the amount of each raw material added by mass parts is as follows: 100 parts of polystyrene modified plastic track powder, 100-200 parts of styrene-butadiene rubber, 5-15 parts of 4,4'-bismaleimide diphenylmethane, 5 parts of 2-vinylfuran, 1 part of crosslinking agent DCP, and 1 part of antioxidant D.

4. The method according to claim 1, characterized in that: The internal mixer temperature is set to 80-100℃. The mixing time of the styrene-butadiene rubber matrix and the polystyrene modified plastic track powder is 2-6 min. The mixing time of the mixture after adding 4,4'-bismaleimide diphenylmethane is 2-6 min. The mixing time of the mixture after adding DCP and antioxidant D is 2-6 min.

5. The method according to claim 1, characterized in that: The mixed rubber is placed in a mold and heated to 140°C. It is then molded for 15 minutes under a pressure of 10 MPa. During this process, furan and bismaleimide react to form reversible crosslinks.

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