Investigation Of Influence Factors For Rheological Properties In SBR/BR Blends

The SBR/BR blends were the research object in this work and the effects of SBR molecular structure,CNT structure,storage condition,remilling times and filling system on the extrusion rheology properties were investigated.The results showed that the SBR2636 modified by alkoxyl silicon substrate in the chain,had much lower number-average molecular weight and weight-average molecular weight,wider molecular weight distribution,higher glass transition temperature and smaller mean square radius ratation and intrinsic viscosity number,compared with SBR4526.The Payne effect was not obvious,and the storage modulus,apparent viscosity,entrance pressure drop and the die swell ratio of SBR2636-BR were smaller compared with those of SBR4526-BR.The appearance of extrudate was rougher than that of SBR4526-BR.In addition,the temperature sensitivity of extrusion viscosity in SBR2636-BR was lower than that in SBR4526-BR.Compared with CNT GT3000,CNT FT7000 had much larger diameter and draw ratio.The CNT aggregation formed by FT7000 had one dimensional orientation structure.The entanglement structure between rubber molecular chains and CNT was much easier formed in the FT7000 filled system.The filler network formed by entanglement structure was more orderly.The compound filled with FT7000 had the higher storage modulus and apparent shear viscosity,entrance pressure drop and the die swell ratio,and the lower loss factor and smoother extrudate appearance.For Silica/CNT filled compound,the storage modulus,Payne effect,apparent shear viscosity increased firstly and then decreased,and the entrance pressure drop increased with increase of storage temperature and storage time.The storage modulus,Payne effect,apparent shear viscosity decreased and the entrance pressure drop increased with incerase of remilling times.Compared CB/CNT,Silica,Silica/CNT and Silica/CB/CNT,the CB/CNT filled system had the highest mooney viscosity,storage modulus,Payne effect,complex viscosity,and the smallest entrance pressure drop and die swell ratio.The CB/CNT network supported the extrusion appearance.It made the extrudate appearance smooth.The temperature sensitivity of entrance pressure drop and die swell ratio was the smallest in the CB/CNT filled system.For the Silica filled system,the mooney viscosity,storage modulus,Payne effect,complex viscosity were the smallest,and entrance pressure drop and die swell ratio were the highest.The extrudate appearance distortion was the most serious.For Silica/CNT filled system,the mooney viscosity,storage modulus,Payne effect,and the complex viscosity were higher,and the entrance pressure drop and die swell ratio were lower,ompared with the Silica filled system,the extrudate appearance improved.For Silica/CB/CNT filled system,the mooney viscosity,storage modulus,Payne effect and the complex viscosity were smaller.The entrance pressure drop and die swell ratio were higher.Compared with Silica/CNT filled system,the extrudate appearance distortion was much more serious.