ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

The influences of polymerization conditions on thermal and structural properties of carbon fiber precursor polymers

G. Santhana Krishnan, P. Thomas, and S. Naveen

Materials Science Division, CSIR-National Aerospace Laboratories, Bangalore, India

E-mail: santhana@nal.res.in

Received: 19 June 2021  Accepted: 2 November 2021

Abstract:

The influences of polymerization conditions, viz. the kind of catalyst, solvent medium and temperature, on thermal, molecular and structural characteristics of carbon fiber precursor polymer were investigated. The dependence of the exothermic peak temperature (T_pk) and heat release rate on the kind of polymerization process was established. An aqueous redox slurry polymer had narrow exothermic peaks (T_pk = 294–297 °C) and relatively high heat release rates (∆H/∆T = 0.96–3.3 J g⁻¹ s⁻¹), and polymers prepared in solid state, solution and bulk had a broader exotherms with T_pk in the range 264–318 °C and low heat release rates in the range 1.15–3.9 J g⁻¹ s⁻¹. Dynamic and thermomechanical analyses indicate three glass transition temperature ranges, i.e., 42–54 °C, 80–98 °C, and 140–142 °C, which are similar irrespective of catalysts. Branching tendency in aqueous redox slurry polymer was notable beyond the intrinsic viscosity of 250 cm³/g. Bulk densities of the polymers were found to be in the range 0.25–0.45 g cm⁻³.

Keywords: Process parameters; Exothermic peak temperature; Heat release rate; Glass transition temperature; Branching

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-021-01966-4

Chemical Papers 76 (3) 1607–1620 (2022)