PVC/EVA共混物的研究

本文研究了混炼温度和时间对PVC/EVA共混物抗冲性能的影响,发现加入聚乙烯,共混体系的抗冲击强度能进一步提高.用TEM观察了PVC/EVA的形态结构,采用Brabender塑化仪和毛细管流变仪研究了共混物的塑化和熔体流变行为.通过计算机对实验结果进行二元线性回归,建立了共混物的熔体粘度与剪切应力和温度相关联的数学模型.

A Study on Poly (vinyl chloride) Blends with Poly (ethylene-CO-vinyl acetate)

The experimental results show that the impact strength of PVC/EVA blend strongly depends on EVA content, blending temperature and blending time. It reaches a maximum at 10 parts of EVA per 100 parts of PVC, and will be further increased when PE is added in. TEM observation confirms that the formation of EVA continuous network in PVC/EVA is responsible tor the high impact strength of the blend. EVA could promote the gelation of PVC, while PE could reduce the apparent viscosity of the Mend and has a delayed action on the gelation of PVC. A series of mathematic models are established by means of binary linear regression to correlate the melt viscosity of the blend with both shear stress and temperature. The flow activation energy of PVC/EVA decreases with increasing EVA content. The addition of EVA re-duces the non-Newtonian flow index, indicating the increased dependence of the melt viscosity of the blend on the shear stress.