Modification Of Rubber Powder And Its Application In Rubber

The development of the car industry becomes not only the arch-criminal of Eastern haze, but also cause serious "black pollution", so the recycling of waste tires has become pressing. At present, rubber powder is the dominant direction of waste rubber recycling. Rubber powder with crosslinking network structure, inert surfactivity and poor compatibility with polymer, results in a decline in the performance of the composites. Therefore, surface modification of rubber powder is essential to improve interface combination between rubber powder and polymer matrix. At present, the modified methods mainly have mechano-chemical modification, polymer coating, desulphurization, graft and so on. In this paper, we studied the application of unsaturated carboxylic acid/Zn O in SBR/RP composites and the mechano-chemical modified rubber powder in ENR and NR.Using both Sorbic acid/Zn O(SA/Zn O) and methacrylic acid/Zn O(MAA/Zn O) to modify SBR/RP composites, SA/Zn O or MAA/Zn O can react in situ to form unsaturated carboxylates, homopolymerize or graft to the rubber chain. So the interface between rubber powder and SBR improved. When the content of SA was 9phr, the tensile strength of material increased by 25%, significantly improved tear strength, hardness and so on, volume loss reduced by 8%, the swelling index increased by 23%. When the MAA was 12 phr., SBR tensile strength increased by 30%, tear strength increased by 42%, swelling index fell by 47%, the fatigue heat build-up decreased by 26%; When the MAA was 20 phr, the volume loss decreased by 32%. The DMA test results showed that when the SA was 9phr the tan δ fell by 20% at 60 ℃. RPA test results show an improvement of the processing properties of the material. TGA results shown that the addition of SA/Zn O or MAA/Zn O had little effect on the thermal stability of the material. In addition, SEM showed a significant improvement bonding between the unsaturated carboxylic acid salt powder interfacial and the rubber matrix.In the mechano-chemical modification of rubber powder, using mechanical forces and plasticizer M to improve rubber powder activity, then add the silane coupling agent KH550 to obtain modified powder, the modified powder used in ENR and NR. Due to the reaction of the Amino group of KH550 and the epoxy group, the GRP can be applied to the ENR/RP composites. Compared with RP vulcanizates, the tensile strength of SRP vulcaniz improved significantly, swelling index lower by 7%, the thermal stability decreased, surface crack brittle fracture specimens were very subtle and combination between powder particles were more closely. Compared with the RP, GRP made ENR and NR maximum torque MH increased, scorch time reduced, curing rate increased. When the amount of KH550 was 1.2 phr, the tensile strength of ENR had increased by 10%; KH550 for 2.0 phr., abrasion volume fell by 13%, a 17% dropped in heating. The DMA results show that the modified rubber powder make ENR has G’ lower under low temperature and normal temperature, tan δ reduced by 9% at 60 ℃. Compared with the RP, added 1.6 phr KH550, tensile strength increases by about 10% and tear strength increased by 18%; with 2.0 phr. KH550, wear volume fell by 30%, with 1 phr. KH550, NR heat production fell by 22%, DMA test results show that the loss peak also reduced by 8%, tan δ reduced by 17% at 60 ℃, SEM test showed that rubber powder after modification dispersed in matrix is relatively uniform, more closely combined with the matrix.