Microstructure, Basic Characteristics Of Domestic Rare Earth Isoprene Rubber And Its Application On Tyre Tread

Isoprene rubber is the best replacement of NR. With the expand of thedemand of rubber and the rising of the NR, as well as the C5resources aresufficient, it is likely to industrialize the production of isoprene rubber. Somedomestic enterprises use rare earth catalyst to produce isoprene rubber, thecatalysts for isoprene rubber imported usually are titanium. We have donesome application studies on domestic isoprene rubber and provided data andreferences for the industrial application and promotion. The main work is asfollowed：1、Through the GPC, DSC and IR spectra of SMR20, IR70and SKI-3analysis,found that compared with the SMR20，the number average molecular weight（Mn）,Weight average molecular weight （MW）and Molecular weightdistribution （MW/Mn）of IR70and SKI-3are smaller。In the nitrogenatmosphere, the heat resistance of the two isoprene rubber is higher thannatural rubber. The glass transition temperature of the two isoprene rubber isalso higher than natural rubber. In the IR, for the SMR20a weak absorption band at1538cm-1, and no absorption band at the IR70’s and SKI-3’s. Theband is the key factor difference between Nature Rubber and isoprene rubber.2、Basic performances of domestic isoprene rubber were tested by the ASTMD3403-isoprene rubber (IR) evaluation method. The results showed that, in thecompound of domestic IR and NR, with the increasing of the IR content, T90of the rubber compound increased, the scorch time become longer, processingperformance become poorer, carbon black dispersion unchanged. Shore Ahardness, the modulus at300%, elasticity and Tearing Properties of thevulcanized rubber compound is reduced. When the content of IR is more than50phr, the reduce speed is obvious, but the compression heat resistantperformance and flexibility become better with the use of IR. In considerationof performance and cost saving, Using IR less than50%instead of NR has theactual application prospect.3、The all steel truck tread is investigated in this study, the result showed that,when compound is processed with internal mixer, energy consumptiongradually reduced along with the increase of the content of IR. The energyconsumption reduced13%and the layout temperature decreased when usingIR only. As a result, it affects significantly on Energy saving and emissionreduction for the factory and it ensures the safety during compound mixingprocess. With the increasing of the IR content, processing performance of therubber become poorer, processing safety become better, embouchure inflationof the rubber is close. The optimum cure time of rubber compound gradually extended along with the increasing of IR content. The optimum cure time ofrubber compound became less and was close to the cure time of pure NRformula when the amount of accelerator increased(20%more). Along with theincreasing of IR content, the hardness，tensile strength，the modulus at300%and permanent set of the rubber decreased, while the elongation at breakincreased. When20%more accelerator is added into the pure IR formula, thehardness and the modulus at300%of the rubber increased, and theperformance is close to the pure NR formula. With the increasing of IR,resilience and wear durability are close to NR formula, but tearing strengthand resistance to cut performance decreased. Compared with NR, resistance tostab firm performance of IR fell by37%.With more accelerator, resistance tostab firm performance fell by49%, while other mechanical properties, such ascompression heat, scratch cracked and resistance to rolling became better.Through the analysis and prediction of vulcanized rubber tyres by DMA, wecan know that NR formula is better than IR formula in traction performance,but it turns around to resistance to rolling. Other dynamic properties aresimilar.NR formula is better than IR formula after hot air ageing.