Molecular Characterization of Poly (2-methyl-1,3-pentadiene) and Its Hydrogenated Derivative, Atactic Polypropylene

Xu Zhongde, Jimmy Mays, Chen Xuexin, Nikolaos Hadjichristidis, F. C. Schilling, H. E. Bair, Dale S. Pearson, Lewis J. Fetters*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

30 Scopus citations

Abstract

The anionic polymerization of (E)-2-methyl-1,3-pentadiene leads to near-monodisperse poly(1,3-dimethyl-1-butenylene) (PDMB). The hydrogenation of PDMB yields atactic polypropylene (PP). We report the complete characterization of the microstructure and thermal properties of these two polymers. The carbon-13 NMR spectral analysis reveals that PP is a head-to-tail, ideal-Bernoullian (Pm= 0.502) material. The characteristic ratios for the two polymers were determined under θ conditions, and, for the case of PP, good agreement is found with the value calculated by Suter and Flory using the five-state rotational isomeric state (RIS) model. The glass transition temperature for the ideal-Bernoullian PP was found to be -2.5 °C, which is about 10 °C higher than values previously reported for non-Bernoullian atactic PP. The conversion of PDMB to atactic PP results in an increase in flexible bonds from three to four along the backbone and in a 28% increase (0.100-0.128 cal g-1°C-1) in the change of heat capacity at Tgbetween the glassy and liquid states of the respective polymers. Comparisons with previous studies on the thermal properties of PP are discussed.

Original languageEnglish (US)
Pages (from-to)2560-2566
Number of pages7
JournalMacromolecules
Volume18
Issue number12
DOIs
StatePublished - Jan 1 1985

ASJC Scopus subject areas

  • Organic Chemistry
  • Polymers and Plastics
  • Inorganic Chemistry
  • Materials Chemistry

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