Investigating the Nucleation Effect of DMDBS on Syndiotactic Polypropylene from the Perspective of Chain Conformation  

作　　者：Xin-Xin Wang Jian-Jun Yi Li Wang Yuan Yuan Jia Chun Feng 

机构地区：[1]State Key Laboratory of Molecular Engineering of Polymers,Department of Macromolecular Science,Fudan University,Shanghai 200433,China [2]Laboratory for Synthetic Resin Research,Petrochina Petrochemical Research Institute Beijing 102200,China

出　　处：《Chinese Journal of Polymer Science》2020年第12期1355-1364,共10页高分子科学（英文版）

基　　金：supported by the National Natural Science Foundation of China(Nos.51973037 and 51773040)and PetroChina Company Limited,China.

摘　　要：The mechanism of nucleating agents(NAs)accelerating the crystallization of semi-crystlline polymers has received continuous attention due to the extreme importance in academic research and industry application.In this work,the nucleation effect and probable mechanism of 1,3.2,4 bis(3,4-dimethylbenzylidene)sorbitol(DMDBS)on promoting the crystallization of syndiotactic polypropylene(sPP)was systematically investigated.Our results showed that DMDBS could significantly accelerate the crystallization process and did not change the crystalline form of sPP.The in situ infrred spectra recorded in the crystallization process showed that in pristine sPP the tttt conformers decreased and the tgg conformers increased subsequently.In sPP/DMDBS system,DMDBS could promote the increase of tgg conformers rather than the decrease of tttt conformers.The further analysis by 2D-IR spectra revealed that ttgg conformers increased prior to the decrease of tttt conformers in the sPP/DMDBS system comparing with pristine sPP.Considering that ttgg conformers were basic elements of helical conformation of Form I crystal for sPP,we proposed a probable nucleation mechanism of DMDBS for sPP:DMDBS could stabilize the ttgg conformers which induced these ttgg conformers to pre-orientate and aggregate into helical conformation sequences as initial nuclei quickly and early to promote the sPP crystallization.Our work provides some new insights into the nucleation mechanism of NAs for sPP.

关 键 词：Syndiotactic polypropylene Nucleating agent Crsallization CONFORMATION 

分 类 号：TQ325.14[化学工程—合成树脂塑料工业]