成核剂对等规聚丙烯透明度及结晶形态的影响

研究了二(对甲氧基苯亚甲基)山梨糖醇和二苯亚甲基山梨糖醇两种成核剂的结晶形态,以及前者对等规聚丙烯结晶形态的影响.结果表明,后者消光环是由于晶片间相互搭接的边界而形成;二者都能形成类似等规聚丙烯的负球晶;少量前者的加入使等规聚丙烯中形成比纯等规聚丙烯“辐条”状球晶小得多的粒状结晶,从而显著提高了等规聚丙烯制品的透明度.

EFFECT OF NUCLEATING AGENT ON TRANSPARENCY AND CRYSTALLINE MORPHOLOGY OF ISOTACTIC POLYPROPYLENE

The crystalline morphology of two kinds of nucleating agent- 1.3,2.4-di (p-methoxybenzylidene) sorbitol (DOS) and 1.3,2.4-dibenzylidene sorbitol (DBS) was studied. The new-synthesised nucleator-DOS' effect on Isotactic polypropylene(IPP)crystaline morphology was also investigated. The SEM micrograph of DBS showed that the formation of DBS dulling rings was due to the connected cracks of DBS lamellae. Both DOS and DBS formed negative spherulites similar to those of IPP/DOS had a notable effect on the IPP surface crystals. There were spherulites formed on pure IPP film and the pebbled crystals were formed on IPP surface with the addition of a small amount of DOS. Compared with DBS, less amount of DOS was used and better transparency could be obtained.