Fiber Reinforced Silicone

Abstract

This thesis revolves around reinforcement of silicone, fibers and rule of mixtures. Rule of mixture serves as a mean to anticipate properties of a composite made up of continuous or unidirectional fibers. However, it doesn’t tell anything about short or particle fibers. The main objective of this thesis project is to investigate if the rule of mixtures is valid for short/particle fibers. Mold silicone 1540A and mold silicone 1540B mixed in the ratio of 1:1 and the mix were used as the matrix. Carbon fiber, glass fiber and cellulose fibers were used as reinforcements. Moulds for tensile test specimen and tear test specimen were designed using inkscape software according to standards ASTM D3039 and ASTM D624-C respectively. Five specimens of each fiber for tensile test and two specimens of each fiber for tear test were made of different fiber volume fractions of each silicone-fiber mix. Silicone-carbon specimens had fiber volume fraction ranging from 0%-17.8%, silicone-glass specimen had fiber volume fraction ranging from 0%-20.6% and silicone-cellulose specimen had fiber volume fraction ranging from 0%-27%. A general equation was derived from rule of mixtures combining upper and lower limit with a reinforcement factor ‘p’ . The equation was then used to find the p-value of each type of fiber. Carbon fiber was found to have the highest p-value of 0.3, glass fiber of 0.075 and cellulose fiber with the lowest of -0.5. Microscopic analysis of each fibers was done to examine what factors affected the p-value and it was observed carbon fiber had very less fibers in the range of 20-40 microns, most in the range of 100-120 microns and some in the range of 180 microns and above. Glass fiber was observed to have most fibers in the range of 20-40 microns while some in 100 microns-above. Cellulose fiber whereas had most fibers in the range of 60-80 microns and very less fibers of higher length.