Browsing by Author "Pastor, Marie-Laetitia"

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    Shear Strength at Sisal Fibre-Polyester Resin Interfaces: Use of Inverse Gas Chromatography to Study Pre-Treatment Effects
    (Composite Interfaces, 2007) Price, G. J.; Pastor, Marie-Laetitia; Towo, Arnold N.; Ansell, Martin P.; Packham, David E.
    Inverse gas chromatography, IGC, has been used to investigate changes to the surface of Sisal fibres on treatment with sodium hydroxide. By determining the retention of a series of alkane probes and of probes with acidic or basic character, it was shown that little change to the chemical nature of the surface occurs as measured by the enthalpy of adsorption of alkane probes or the dispersion component of the surface free energy. This IGC study supports the conclusion of previous work involving S.E.M. which suggested that the major effect of the treatment was the removal of weak or adventitious layers from the substrate surface, thus increasing the interfacial shear strength when incorporated into polyester resin.
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    Weibull Analysis of Microbond Shear Strength at Sisal Fibre-Polyester Resin Interfaces, Composite Interfaces
    (Composite Interfaces, 2005) Towo, Arnold. N.; Ansell, Martin P.; Pastor, Marie-Laetitia; Packham, David E.
    An analysis has been made of the tensile strength of sisal fibres and the interfacial adhesion between fibres and polyester resin droplets. Density and microscopy methods were used to determine the cross-sectional area of the sisal fibres. The average tensile strength of treated sisal fibres decreased by a modest amount following treatment with 0.06 M NaOH. However, this treatment resulted in a substantial increase in the interfacial shear strength at the sisal fibre to polyester resin interface. Weibull analysis has been used successfully to analyse variability in tensile strengths and interfacial shear strength using probability of failure plots. Scanning electron microscopy has revealed the shape of resin droplets on the surface of treated and untreated sisal fibres and contact angles are much lower for droplets on treated fibres. Damage to the surface of fibres has been examined following shear testing. Weibull analysis is an effective tool for characterising highly variable fibre properties and evaluating the level of adhesion between polymer resin and the fibre surface.