Glass Fiber Reinforced Epoxy Nanocomposites: Influence of Postcuring and Nanoclay Content on Mechanical Properties

Abstract

Nanocomposites are as a multiphase solid material where one of the phases has one, two or three dimensions of less than 100 nanometer (nm). These differ from conventional composites due to the exceptionally high surface to volume ratio of the reinforcing phase and/or its exceptionally high aspect ratio. In the present work epoxy modified with Closite 30B® nanoclay added at different concentrations (0.5wt%, 2wt%, 3wt% and 4wt %) is used as matrix with unidirectional glass fibers to manufacture laminates having [00, 900 ,00] stacking sequence . The samples were then cured under different conditions (I) Normal temperature and ambient conditions for 12 hrs (II) At 1000C in Vaccum oven for 4 hours (III) A combination of I &II. X-Ray Diffraction of Epoxy/Clay nanocomposites indicates exfoliation of nanoclay at all loadings .The mechanical tests shows an increase in the tensile strength, flexural strength and micro hardness of nanocomposites with addition of nanoclay at small quantities. Significant improvement in properties was seen in all specimens as an effect of post curing at high temperatures. Further durability studies on nanocomposites have been performed in water and NaOH baths under accelerated hygrothermal loading. During exposure it is observed that the properties degradation in NaOH environment was more severe as compared to simple water. Results show that with postcuring of the samples under condition (III), the degradation of the specimen significantly reduced in comparison to samples cured under conditions I or II. This is probably due to more efficient crosslinking of the polymer .