Research And Application Of Crumb Rubber-based Thermoplastic Elastomer

Preparation and research Crumb Rubber/Polyolefin ThermoplasticElastomer (RTPE) has important theoretical signififcance and practicalvalue for promote utilization waste rubber, protect ecologicalenvironment and creation social and economic value. At home andabroad RTPE research are mostly concentrated in using rubber moldingequipment, such as mill and mixer, combined with interface modificationtechnology to prepare such materials. For using the most strong shearstress plastic molding equipment, such as twin-screw extruder andinjection molding machine, to preparate RTPE is not very much. Thisstudy will use rubber chemicals and traditional compatibilizer to improveinterfacial adhension between plastic and rubber powder. Using hightemperature-high shear flow which twin-screw extruder established andhigh temperature-high pressure-high shear flow which injection moldingmachines established to forming RTPE.Contrast different types of polyolefin, using LLDPE prepared RTPEhas suitable hardness and higher packing bearing endurance. Selectgrades DNDA7144of LLDPE as a substrate, prepared RTPE haveappropriate flowability and elongation at break. By FT-IR and TGanalysis, tire rubber powder has a higher gel content and more activegroups, such asC=C and-OH. A further study found that crumb rubberparticle size is60mesh and crumb rubber fill capacity is60weightpercent can prepared cost-effective RTPE.Compare different types compatibilizer, EVA can effectively promoteinterfacial adhesion between powder and LLDPE and has a goodperformance for RTPE, tensile strength is6.9MPa, elongation at break is408, density is0.993g/cm~3, hardness is83A and MI is2.48g/10min.RTPE melt is a typical pseudoplastic fluid. EVA can effectively reducemelt viscosity of RTPE. The higher of EVA content, the more favorableviscosity can reduce. SEM study found that EVA can effectively reducegaps and holes between LLDPE and rubber powder, reducing particlesize of rubber powder. The higher EVA content, the more improve ofinterface. Compare different types of rubber chemicals, naphthenic oil and pine tar can improve liquidity, lower hardness, reduce density andimprove the elongation of RTPE; Coumarone and petroleum resin wasable to effectively improve tensile strength and elongation at break. Whenoumarone and naphthenic oils is1:1, RTPE has better overallperformance, tensile strength is7.2MPa, elongation at break is493,density is0.988g/cm~3, hardness is75A and MI is3.13g/10min. Rubberchemicals can effectively reduce melt viscosity of RTPE. The highercontent of rubber chemicals, the more favorable viscosity reduce. SEMstudy found that rubber additives can further improve interface adhesionbetween LLDPE and rubber powder, further reduce rubber powderparticle size and two-phase interface is more ambiguous.Compared four kinds of mixing mode, C process can effectivelypromote disperse powder and LLDPE. The high temperature-high shearfield which two-screw extruder established can effectively improveperformance of RTPE, when extrusion temperature is190/200/200℃andscrew speed is10, RTPE materials has the best performance. Secondextrusion can better improve surface agglutinate, further reduce theparticle size of crumb rubber power. The high temperature-highpressure-high shear field which injection molding machine establishedcan effectively improve performance of RTPE, when injectiontemperature is190/200/195℃, injection pressure is110MPa and injectionspeed is12can overall performance of RTPE.EVA can improve wear resistance of RTPE, folding properties andheat resistance, but adverse crystallization of RTPE. Rubber chemicalsare beneficial on folding properties of RTPE, adverse and unfavorable forcrystallization, wear resistance and heat resistance.By choice of resin and crumb rubber powder, established ofcompatibilizer system and optimize process prepared a betterperformance RTPE, tensile strength is7.4MPa, elongation at break is535,density is0.997g/cm~3, hardness is74A and MI is3.13g/10min, wearresistance of RTPE can up to0.28cm~3/1.61km, crystallinity degree canup to34.6%and folding properties would not rupture under40000times.