Correlation of chemical shrinkage of polyacrylonitrile fibres with kinetics of cyclization

Simitzis, J; Soulis, S

dc.contributor.author	Simitzis, J	en
dc.contributor.author	Soulis, S	en
dc.date.accessioned	2014-03-01T01:28:05Z
dc.date.available	2014-03-01T01:28:05Z
dc.date.issued	2008	en
dc.identifier.issn	0959-8103	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/18703
dc.subject	Chemical shrinkage	en
dc.subject	Fibres	en
dc.subject	Nitrile cyclization reactions	en
dc.subject	Oxidative thermal treatment	en
dc.subject	Polyacrylonitrile	en
dc.subject.classification	Polymer Science	en
dc.subject.other	Chemical reactions	en
dc.subject.other	Heat treatment	en
dc.subject.other	Oxidation	en
dc.subject.other	Shrinkage	en
dc.subject.other	Synthetic fibers	en
dc.subject.other	Chemical shrinkage	en
dc.subject.other	Cyclization reaction	en
dc.subject.other	Oxidative thermal treatment	en
dc.subject.other	Polyacrylonitriles	en
dc.subject.other	Chemical reactions	en
dc.subject.other	Heat treatment	en
dc.subject.other	Oxidation	en
dc.subject.other	Polyacrylonitriles	en
dc.subject.other	Shrinkage	en
dc.subject.other	Synthetic fibers	en
dc.subject.other	carbon fiber	en
dc.subject.other	chemical reaction	en
dc.subject.other	fiber property	en
dc.subject.other	kinetics	en
dc.subject.other	polyacrylonitrile	en
dc.subject.other	shrinkage	en
dc.subject.other	temperature effect	en
dc.subject.other	thermal treatment	en
dc.title	Correlation of chemical shrinkage of polyacrylonitrile fibres with kinetics of cyclization	en
heal.type	journalArticle	en
heal.identifier.primary	10.1002/pi.2322	en
heal.identifier.secondary	http://dx.doi.org/10.1002/pi.2322	en
heal.language	English	en
heal.publicationDate	2008	en
heal.abstract	It has been established that the most important step in the production of carbon fibres from polyacrylonitrile (PAN) precursor fibres is the oxidative thermal treatment applied. During this treatment, physical phenomena and chemical reactions take place accompanied by the shrinkage of the fibres, which has a physical or chemical origin, depending on the nitrile cyclization reactions. The aim of the present study is to establish a correlation between the chemical shrinkage of PAN fibres and the kinetics of cyclization reactions. Based on the isothermal treatment of PAN fibres, we developed a method in order to distinguish between physical and chemical shrinkages. The onset time for the chemical shrinkage follows a relationship with temperature. Chemical shrinkage versus cyclization time data were fitted with the exponential rise to the maximum of the curves. Furthermore, the cyclization kinetics was studied using differential scanning calorimetry and the kinetic parameters determined were identical to those calculated from the chemical shrinkage, demonstrating that the latter is directly related to the kinetics of the cyclization reactions. It was therefore concluded that according to the method developed to distinguish the physical from the chemical shrinkages: (1) there exists a certain onset time for a given treatment temperature to trigger the chemical shrinkage; (2) cyclization reactions do not start below a limiting temperature of 168 degrees C; (3) at 340 degrees C, the temperature where the cyclization reactions are completed, the maximum shrinkage is 24%; and (4) the oxidized PAN fibres contain mainly ladder polymer structures with approximately symmetrical sequences connected in angled positions. (c) 2007 Society of Chemical Industry.	en
heal.publisher	JOHN WILEY & SONS LTD	en
heal.journalName	Polymer International	en
dc.identifier.doi	10.1002/pi.2322	en
dc.identifier.isi	ISI:000252413800015	en
dc.identifier.volume	57	en
dc.identifier.issue	1	en
dc.identifier.spage	99	en
dc.identifier.epage	105	en