nunna-formationofskincore-2019.pdf (568.72 kB)
Download file

Formation of skin-core in carbon fibre processing: A defect or an effect?

Download (568.72 kB)
journal contribution
posted on 2019-02-01, 00:00 authored by Srinivas NunnaSrinivas Nunna, Mohan Setty, Minoo NaebeMinoo Naebe
The influence of stabilized fibre structure and skin-core formation induced by rapid thermal stabilization of polyacrylonitrile (PAN) on the tensile properties of carbon fibres was investigated. Three sets of samples were prepared by stabilizing PAN fibres under three temperature profiles using a continuous carbon fibre processing line. Initially, the chemical structure and density variations in stabilized fibres were examined with respect to process conditions using Fourier Transform Infrared Spectroscopy (FTIR) and density column methods. Interestingly, while the cyclization and dehydrogenation indices are similar for all the stabilized fibres irrespective of temperature profiles used, the densities of these fibres varied from 1.34 to 1.366 g/cc. Micro-Raman studies showed the existence of structural heterogeneity in the fibres from low temperature
(LT) carbonization (I(D)/I(G) ratio of core was ~5.6% higher than the skin) that eventually reduced with high temperature (HT) carbonization because of uniform sp3 to sp2 hybridization of carbons. However, modulus mapping revealed heterogeneous storage modulus distribution in the HT carbon fibre cross-section from Trial-2 (storage modulus of core was ~23 GPa less than the skin). Interestingly, this heterogeneity did not show a significant effect on the bulk properties of carbon fibres suggesting skin-core formation is an effect rather than a defect.

History

Journal

Express Polymer Letters

Volume

13

Issue

2

Pagination

146 - 158

Publisher

Budapest University of Technology

Location

Budapest, Hungary

ISSN

1788-618X

Language

eng

Publication classification

C1 Refereed article in a scholarly journal

Copyright notice

2019, BME-PT