EFFECTS OF FABRIC ARCHITECTURE AND ALKALI TREATMENT ON THE MECHANICAL PROPERTIES OF COTTON FABRIC-REINFORCED UNSATURATED POLYESTER COMPOSITES

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dc.contributor.authorACHUKWU, Okechukwu,
dc.contributor.authorEmmanuel.
dc.date.accessioned2015-09-30T10:39:42Z
dc.date.available2015-09-30T10:39:42Z
dc.date.issued2014-07
dc.descriptionA THESIS SUBMITTED TO THE SCHOOL OF POSTGRADUATE STUDIES, AHMADU BELLO UNIVERSITY, ZARIAen_US
dc.description.abstractThe effects of fabric architectures and alkali treatment on the properties of cotton fabricreinforced unsaturated polyester composites have been studied. The problems of low mechanical properties of textile composites from natural origin have been a source of concern for researchers; insufficient utilization of cotton fibres has further reduced the economic returns of cotton growers. In this work, four different yarns of known count were twisted (plied) to obtain a single strand which was woven and knitted into fabrics of different architectures. The cotton fabrics were subjected to chemical modifications using 20% sodium hydroxide for 1 and 2 minutes and its influence on some mechanical properties were analyzed. The fabrics were used to reinforce unsaturated polyester resin as matrix, applying both single layer and two layers of fabrics to form different 2-ply laminate configurations. The tensile and flexural strength, tensile and flexural modulus, impact strength and hardness of the textile composites were compared. Alkali treatment improved the tensile strength and breaking extension of the fabrics by 10-30% and 31-56% respectively requiring a certain percentage concentration and duration of treatment, going by the fact that the close treatment times of 1 and 2 minutes with 20% concentration of sodium hydroxide gave inconsistent tensile strength and breaking extension. Fabric architecture was found to have great influence on the breaking strength of the fabrics. The tensile strength of the fabrics was found to decrease in this order: Plain woven fabric > twill fabric > knitted fabric when untreated, but when treated, twill fabric > plain fabric > knitted fabric. Composites reinforced with twill fabrics generally had better tensile strength and modulus as well as flexural strength and modulus than those reinforced with plain and knitted fabrics either when the reinforcing fabrics were untreated or treated with sodium hydroxide with an increase of 72–119%. The flexural strength of composite with twill, plain and knitted fabrics are 62.32%, 56.75% and 52.68% respectively and increased by 65%, 60% and 37% when treated with 20% NaOH. Results also showed that increase in the volume of reinforcement (increase in fabric layer) gave a corresponding increase in the mechanical properties of the composites; however, the increase was not proportional with respect to those composites reinforced with single fabric samples. The mechanical properties tested were optimized by the plying effect carried out on the yarns. The impact strength of the unsaturated polyester was improved by about 105% when reinforced with the fabrics. Composites reinforced with knitted fabrics showed better resistance to impact forces than other fabrics with good energy absorbing characteristics. There was an increase in the Rockwell hardness of polyester resin composite for both single and double layer reinforced laminates. Composites with twill fabrics gave highest hardness number (25.9) than those of other fabrics (plain, 24.4 and knitted, 22.2) for the single ply and same for 2- ply (twill-twill, 30.6; plain-plain, 29.9 and knitted-knitted, 25.6). Much variation in hardness numbers were not recorded for the various reinforcements. The behaviour of other hybrid composites reinforced with two layers of fabrics was seen to follow the properties of the fabrics reinforcing them.en_US
dc.identifier.urihttp://hdl.handle.net/123456789/6849
dc.language.isoenen_US
dc.subjectFABRIC ARCHITECTURE ,en_US
dc.subjectALKALI,en_US
dc.subjectTREATMENT,en_US
dc.subjectTHE MECHANICAL,en_US
dc.subjectPROPERTIES,en_US
dc.subjectCOTTON FABRIC-REINFORCED,en_US
dc.subjectUNSATURATED ,en_US
dc.subjectPOLYESTER COMPOSITES.en_US
dc.titleEFFECTS OF FABRIC ARCHITECTURE AND ALKALI TREATMENT ON THE MECHANICAL PROPERTIES OF COTTON FABRIC-REINFORCED UNSATURATED POLYESTER COMPOSITESen_US
dc.typeThesisen_US
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