Isothermal and non-isothermal crystallization kinetics of hydroxyl-functionalized polypropylene

Sahil Gupta, Xuepei Yuan, T. C.Mike Chung, M. Cakmak, R. A. Weiss

Research output: Contribution to journalArticle

23 Scopus citations

Abstract

Hydroxyl-modified polypropylenes (PPOH) with side chains containing OH groups were synthesized by copolymerization of the propylene and undecenyloxytrimethylsilane monomers. The isothermal and non-isothermal crystallization behavior of the modified polypropylenes (PPOH) with side chains containing up to 6.8 mol% OH groups were compared with that of polypropylene (PP). The introduction of the OH-comonomer decreased the overall rate of isothermal crystallization compared with PP due to steric effects of the hydroxyl-containing side-chains that hindered packing of the PP backbone chains into a lamellar structure. However, a maximum reduction in the rate of crystallization occurred at an intermediate hydroxyl concentration as a consequence of a competition between the effects of the comonomer on the nuclei density and the thermodynamic barrier to crystallization. Steric hindrance by the comonomer side-chains also reduced the radial growth rate of the crystals in PPOH and produced a coarser crystal morphology than that for PP. PP and PPOH exhibited an identical α-monoclinic crystal structure, but the introduction of only ∼6.8 mol% comonomer reduced the fold-surface free energy of the crystals by 42%. For non-isothermal crystallization, the crystallization peak temperature (Tp) decreased for low concentrations of OH, but above a critical OH concentration, Tp increased, a result similar to the isothermal crystallization rate.

Original languageEnglish (US)
Pages (from-to)924-935
Number of pages12
JournalPolymer
Volume55
Issue number3
DOIs
StatePublished - Feb 12 2014

All Science Journal Classification (ASJC) codes

  • Organic Chemistry
  • Polymers and Plastics
  • Materials Chemistry

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