Preparation, Structure and Properties of Natural Rubber/CB-nSiO2Composite
|School||South China University of Technology|
|Keywords||NR Latex Carbon Black Silica Sol In-situ Formation-Coprecipitation NanoSilica Structure and Properties|
Carbon Black （CB） and Silica （SiO2） were filled into rubber to reduce tire rollingresistance and improve its wet-skid resistance. Because of both CB and SiO2are highsurface energy nanoparticles, they are generally existed as aggregates when using traditionalmechanical mixing method（Dry Mixing） to prepare gross rubber, so they are difficultto achieve nano-dispersion in rubber, therefore increasing the hysteresis loss of vulcaniatesand result in poor dynamic properties. The interaction between rubber and aggregatesparticles is very weak, not good for the reinforcement of rubber. So it’s not help toreduce tire rolling resistance and improve wet-skid resistance.As silica sol will become SiO2particles after being heat, this thesis used natural rubber（NR） latex, carbon black （N330） and silica sol as the main raw material, preparingC（NR/CB-nSiO2） composite in the way of in-situ formation-coprecipitation method（WetMixing）. Effect of CB and SiO2content and concentration, silica sol type and concentration,surfactant type and content, reaction temperature, reaction time, flocculent agent type, Si69content, and sulfur content on mechanical properties of C（NR/CB-nSiO2） vulcanizates arestudied systematically. Dynamic properties, filler dispersion, compound rubber morphologyand vulcanizate microstructure were analyzed, and the reinforcing effect of the CB-nSiO2particles on NR was also discussed in this thesis. The results show that, compared with thesamples prepared by traditional mechanical mixing method, the in-situ formation-coprecipitation C（NR/CB-nSiO2） composite have more excellent mechanical properties,abrasion resistance, compression fatigue properties, rebound performance and agingresistance. The bound rubber content and crosslinking degree increase with the increase offiller content. FTIR spectra show that the number of surface Si-OH is greatly reduced, andSiO2have combine with rubber or Si69. RPA show that C（NR/CB-nSiO2） Payne effect isrelatively small, proving C（NR/CB-nSiO2） have lower filler network, better good dispersion,and stronger interactions with rubber matrix. DMA show that C（NR/CB-nSiO2） have higherwet skid resistance and lower rolling resistance. DSC show that these two method compositehave similar Tg, and TG show that compared with pure NR vulcanizate, the thermal stabilityof C（NR/CB-nSiO2） vulcanizate have been significantly improve. SEM show that there are a lot of valve-like structure in C（NR/CB-nSiO2） vulcanizate tensile fracture, the formation ofthese structure need additional stretching energy, so the composite have better mechanicalproperties, filler particles have better dispersion in NR matrix.Wet Mixing technology combine the process of solid rubber made from rubber latex andthe process of solid rubber mixed with filler into one integrated process, so it has thesignificant advantages of energy saving and environmentally friendly, and it will be animportant change in the field of rubber processing industry. C（NR/CB-nSiO2） vulcanizateshave a excellent comprehensive performance, especially high wet-skid resistance and lowrolling resistance, therefore, it’s a high-quality radial truck tire tread rubber and havingindustrial development value.