High-Pressure Crystallization of iPP Nucleated with 1,3:2,4-bis(3,4-dimethylbenzylidene)sorbitol

Polymers

卷:13

SeverineA. E. Boyer¹  Jean-Marc Haudin¹  Przemyslaw Sowinski²  Ewa Piorkowska² 

[1] Centre for Material Forming, MINES ParisTech, PSL-Research University, UMR CNRS 7635, 1 Rue Claude Daunesse, 06904 Sophia Antipolis, France;

[2] Centre of Molecular and Macromolecular Studies, Polish Academy of Sciences, Sienkiewicza 112, 90 363 Lodz, Poland;

关键词: polypropylene;    1,3:2,4-bis(3,4-dimethylbenzylidene)sorbitol;    nucleation;    crystallization;    high pressure;    γ-form;   

DOI  :  10.3390/polym13010145

来源: DOAJ

【 摘 要 】

1,3:2,4-bis(3,4-dimethylbenzylidene)sorbitol (DMDBS) is highly effective in nucleation of the α- form of isotactic polypropylene (iPP). However, its role in high-pressure crystallization of iPP, facilitating the formation of the γ- polymorph, has not been explored. The present paper focuses on the influence of DMDBS on nucleation of high-pressure crystallization of iPP. iPP with 0.2–1.0 wt.% of the DMDBS was crystallized under elevated pressure, up to 300 MPa, in various thermal conditions, and then analyzed by PLM, WAXD, SEM, and DSC. During cooling, crystallization temperatures (T_c) were determined. It was found that under high-pressure DMDBS nucleated crystallization of iPP in the orthorhombic γ- form. As a consequence, T_c and the γ- form content increased for the nucleated iPP, while the size of polycrystalline aggregates decreased, although the effects depended on DMDBS content. The significant increase of T_c and the decrease of grain size under high pressure of 200–300 MPa required higher content of DMDBS than the nucleation of the α-form under lower pressure, possibly due to the effect of pressure on crystallization of DMDBS itself, which is a prerequisite for its nucleating activity.

【 授权许可】

Unknown