Study On Structure And Properties Of Blends Of Isotactic Polypropylene With Poly (Cis-butadiene) Rubber

In this paper, the blends of Isotactic polypropylene and material poly (cis-butadiene) rubber (iPP/PcBR) blends were prepared by melt blending. The stucture and properties of the blends were investigated.The phase structure of iPP/PcBR blends was analysised by small-angle x-ray scattering (SAXS). The sesults showed that this system followed the deviation of law of Porod, which indicated that this blends belond to the incompatible system. In scanning electron microscope (SEM) results, the boundary of iPP and PcBR was clear, proving the above results. The long period of iPP increased with the addition of PcBR, but the changes of the content had limited effect on it.The crystal structure of iPP was investigated by Wide Angle X-ray scattering (WAXS). The results indicated that the addition of PcBR limited the growth of iPP spherulite, refined the microcrystalline size, and raised crystallization degree of iPP.The SEM images showed that the dispersed phase with irregular particle shape distributed in the continuous phase, the distribution of particle size became widely with the content of the dispersed phase increasing, and the average particle size increased accordingly. When the contents of PcBR were 40% and 50%, co-continuous structure could be observed, and the phase reversion occured when the contents exceed 50%.The crystal morphology of iPP/PcBR blends was analysised by polarized optical microscopy (POM). With the increase of the content of PcBR, the spherulite integrity of iPP fell and spherulite size reduced. With the PcBR adding, the radial growth rate of spherulite have a significantly reduce, but the changes of contents of PcBR showed little influence on it, suggesting that the addition of PcBR limited the space of spherulite growth. The POM results also showed that the difference of iPP distribution the crystallization rate had great effect on the growth of spherulite.The viscosity mutation time and Normal Stress mutations time were used to characterize the crystallization inducted time of iPP. It was showed that the temperature and shearing rate had significantly effect on it. In the blend system, the crystallization inducted time decreased, indicating that PcBR acted as nucleation agent, and different molecular weight of iPP showed little effect on it.