Sequence determination of acrylonitrile-(ethyl acrylate) copolymers by 13C-NMR spectroscopy and correlation with glass transition temperature

✍ Scribed by A.S. Brar; Sunita

• Publisher: Elsevier Science
• Year: 1992
• Tongue: English
• Weight: 486 KB
• Volume: 28
• Category: Article
• ISSN: 0014-3057
• DOI: 10.1016/0014-3057(92)90087-i

✦ Synopsis

Abstraet--Acrylonitrile-(ethyl acrylate) copolymers of various compositions were prepared by bulk polymerization using benzoyl peroxide as initiator. Copolymer compositions were determined by elemental analyses; monomer reactivity ratios were determined using a nonlinear least square errors in variables model which gave more reliable value of r~ and r 2. Terminal and penultimate reactivity ratios have been calculated using the observed monomer triad sequence distribution determined from ~3C{tH}-NMR spectra. The triad sequence distribution was used to calculate diad concentrations, conditional probability parameters and number--average sequence lengths in the copolymers. The observed triad sequence concentrations determined from 13C{IH}-NMR spectra agreed well with those calculated from reactivity ratios. Glass transition temperatures of various copolymers determined from DSC agreed well with those obtained from diad concentrations.