Copolymerization of Maleic Anhydride with Styrene and α‐Olefins. Molecular and Thermal Characterization

Abstract

Copolymers of styrene‐maleic anhydride, SMA, and maleic anhydride‐α‐olefins (1‐hexene, 1‐octene, 1‐decene, 1‐dodecene, 1‐tetradecene and 1‐hexadecene) have been synthesized by free radical polymerization, using azobisisobutironitrile and benzoyl peroxide as initiators. Copolymers were characterized by gel permeation chromatography, viscosity measurements, FT‐IR, differential scanning calorimetry (DSC) and thermal gravimetry analysis (TGA). The copolymers of maleic anhydride‐α‐olefins exhibit a monomodal molecular weight distribution. During the TGA analysis, decomposition of maleic anhydride and α‐olefins was observed by FT‐IR. Carboxylic acids and gaseous CO₂ were identified as decomposition products of the copolymers close to 200°C. The SMA copolymer was esterified with 2‐propanol, sec‐butanol and tert‐butanol at 65°C using 4‐dimethylaminopyridine catalyst and tetrahydrofurane solvent. The rate of reaction and limiting ester yields are lower than those obtained in the esterification with primary alcohols.

Keywords:

• copolymerization
• glass transition
• styrene‐maleic anhydride
• styrene‐olefin
• thermal degradation

Acknowledgements

The authors thank the Fondo de Desarrollo Científico y Tecnológico (FONDECYT), Chile (Grant No 1030526) for financial support.