DEVELOPMENT OF PITCH BASED CARBON FIBRES THROUGH POLYMER BLEND TECHNIQUE

摘要

Pitch based carbon fibres are strategicrnmaterial due to their unique properties and low cost. Arngood technology base is available on the pitch basedrncarbon fibres, whereas very little literature is availablernon their developmental aspects. It is also known thatrnthe processing of carbon fibres from pitch suffers fromrnthe disadvantage of leading to low strength greenrnfibres (Tensile Strength ～3 Mpa), which wererndifficult to handle for further processing to carbonrnfibres. To overcome this problem polymer additivesrnhave been added to the pitch before spinning. Thernpresent authors adopted the method of blending thernpitch with polystyrene (PS), which possesses reactivernmethylene group and good melt strength andrndeveloped the carbon fibres from the polymer blendrnpitch. A suitable high softening point pitch with zerornquinoline insoluble content was prepared and mixedrnwith different amounts of PS (10, 20 and 30% byrnweight) dissolved in suitable solvent and finally spunrnto green fibres after the removal of the solvent. Therngreen fibres were stabilised in air and carbonised inrninert atmosphere to get carbon fibres. The polymericrnfibres, green fibres and the carbon fibres developedrnfrom the polymer blend were characterised for theirrnpyrolysis behaviour, mechanical properties and forrntheir surface morphology. The weight and therndimensional changes occurring during the heatrntreatment of the green fibres to carbon fibres were alsornstudied and reported. The mechanical properties of therngreen and carbonised fibres showed an improvementrnby the polymer blend technique employed in thernpresent investigation.