RHEOLOGICAL STUDIES ON THE QUASI-QUIESCENT CRYSTALLIZATION OF POLYPROPYLENE NANOCOMPOSITES
Isothermal crystallization behaviors of polypropylene/organoclay (iPP/OMMT) binary nanocomposites and polypropylene/organoclay/poly (ethylene-co-octene) (iPP/OMMT/PEOc) ternary nanocomposites were studied with a combination of ARES rheometer, scanning electron microscope (SEM) and polarized optical microscope (POM) in this work. The crystallization process was mainly divided into three stages: nucleation, crystal growth and shrinkage as shown in the storage modulus (G) vs. time curve in Fig.1. With the growth of spherulites the storage modulus of the sample turned upwards and the corresponding characteristic morphologies of crystallization process at different times during the turning of the G were shown. In the early stage the nucleation was influenced by clay layers and also PEOc component. Clay layers could promote the nucleation to a certain extent, while PEOc could play a role of inhibitor of nucleation because clay layers were mainly distributed around or inside PEOc-rich domains, which has been reported separately 1. In the middle stage when the spherulites grew big enough to have some contact or interaction with each other through the entangled molecules between the spherulites, G started to increase and the increase rate was increased. When the spherulites became crowded and began to huddle together the growth rate of G slowed down. Different contents of OMMT could also affect the growth rate of storage modulus of the bulk material as shown in Fig.2 (a).
Tongchen Sun Fenghua Chen Xia Dong Charles C.Han
Beijing National Laboratory for Molecular Sciences,Joint Laboratory of Polymer Science and Materials,State Key Laboratory of Polymer Physics and Chemistry,Institute of Chemistry,CAS,Beijing,100190,China
国际会议
International Symposium on Polymer Physics(2008年国际高分子物理学术会议PP2008)
厦门
英文
411-412
2008-06-08（万方平台首次上网日期，不代表论文的发表时间）