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Molecular weight dependency of β phase formation in injection‐molded isotactic polypropylene
Author(s) -
Yang Xiao,
TuineaBobe Cristina,
Whiteside Ben,
Coates Phil,
Lu Ying,
Men Yongfeng
Publication year - 2020
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.48555
Subject(s) - tacticity , nucleation , materials science , phase (matter) , polypropylene , polymer chemistry , composite material , chemical engineering , chemistry , polymer , organic chemistry , polymerization , engineering
The influence of β‐nucleating agents and the molecular weight of isotactic polypropylene (iPP) on the formation of β phase in the injection‐molded iPP were explored using wide‐angle X‐ray diffraction technique. Without the β‐nucleating agents, the molecular weight of iPP was the dominant factor controlling the production of β phase during injection. A higher molecular weight could promote the orientation of molecular chains in the skin layer of injected sample, bringing out a larger content of β phase in the corresponding region. Although the β‐nucleating agents had a profound effect on the formation of β phase, it was only efficient for the iPP with moderate molecular weights. The systems of the lowest and highest molecular weight iPP samples compounded with β‐nucleating agents still performed the same with the corresponding ones without β‐nucleating agents. Such performances can be interpreted as a result of the competition between the β‐nucleating agents and the orientation degree of molecular chains. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137 , 48555.