Effects of Nucleating Agents On TPO Performance

摘要

Effects of nucleation agents on a talc filled and compounded TPO were investigated. The purpose is to determine whether the nucleating agents can improve the TPO's physical properties and/or processing performance, although they have been shown to improve the performance of neat polypropylene resins such as increase of flexural modulus and reduction of cycle time due to increased crystallization temperature and rate. The bulk isothermal and non-isothermal crystallization kinetics of the TPOs with different nucleating agents (A, B, C, and none) were studied and compared through means of DSC and model calculations. Isothermal crystallization study showed that nucleating agent "A" significantly reduces the crystallization half time (rate) of polypropylene (PP) component in the TPO and increased its crystallization temperature (Tc), while nucleating agents B and C do not offer any crystallization advantage of the PP component against the non-nucleated TPO in regards of its Tc and half-time. However, the non-isothermal data by analysis using both Avrami and Tobin models indicated that none of three nucleating agents showed any improvement over the non-nucleated TPO in regards of PP crystallization rate and activation energy. This implies that addition of nucleation agents to the TPOs studied offers little advantage kinetically for PP crystallizatioa Physical properties testing results showed that both the nucleating agents A and B slightly improve TPO's flex modulus and HDT, and that the nucleating agent A also improves the melt flow property. The molding performance of nucleated and non-nucleated TPOs is in process of evaluation.