降温速率对高密度聚乙烯在全同立构聚丙烯上附生结晶的影响

用欠焦电子显微术和电子衍射技术研究了降温速率对高密度聚乙烯（ＨＤＰＥ）在全同立构聚丙烯（ｉＰＰ）上附生结晶的影响．ＨＤＰＥ在高取向ｉＰＰ基质膜上的附生生长仅发生在ＨＤＰＥ与ｉＰＰ的直接接触面上，存在一临界附生层厚度，超出这一厚度的ＨＤＰＥ与ｉＰＰ无取向附生关系．降温速率不影响附生层内的ＨＤＰＥ与ｉＰＰ的附生结构关系，但对ｉＰＰ基质膜上附生生长的ＨＤＰＥ的厚度，即ＨＤＰＥ的临界附生层厚度有明显影响．在缓慢降温（０．５℃／ｍｉｎ）条件下，ＨＤＰＥ在ｉＰＰ上的附生层厚度约为１００ｎｍ．而室温空气降温条件下，ＨＤＰＥ在ｉＰＰ上的附生层厚度则为２５０ｎｍ．

EFFECTS OF COOLING RATES ON THE EPITAXY OF HIQH-DENSITY POLYETHYLENE ON ORIENTED ISOTACTIC POLYPROPYLENE SUBSTRATE FILMS

ffects of cooling rates on the epitaxy of high-density polyethylene(HDPE) on isotactic polypropylene(iPP)substrate film have been studied by TEM and electron diffraction. The results of electron microscopy and electron diffraction indicate that epitaxial nucleation and growth of HDPE on oriented iPP substrate take place only on the direct contact plane of HDPE with iPP.There exists a critical epitaxial thickness of HDPE on iPP film.The thickness of epitaxial interface layer is strongly affected by the cooling rate of HDPE after heat treatment.During slow cooling process, three layers of crystalline structure of HDPE are formed.The thickness of critical epitaxial layer is about 100urn.Fast cooling rate results in the formation of two layer crystalline structure.The thickness of critical epitaxial layer is about 250nm.