Study of Mechanical and Thermomechanical Properties of Vinyl Ester/Polyurethane Interpenetrating Polymer Network Based Hybrid Composites

Interpenetrating polymer networks of vinyl ester (VE) resin and polyurethane (PU) was synthesized using blend ratio of 93:7 (w/w). Bio-composites with Kenaf fibre reinforcement in VE/PU IPN matrix were prepared by hand-lay-up. Similar bio-composites were prepared with vinyl silane treated kenaf (SKF) and fibre content was varied by 15, 25, 35 and 40 wt. % of the matrix in both the cases. Hybrid composites consisting of both silica nano filler (2 wt. %) and 35 % of kenaf fibre together in VE/PU IPN (93:7 w/w) matrix were prepared. Analysis of these composites showed that 93VESi35SKF hybrid composite possessed improved tensile strength, Young's modulus and Interlaminar Shear Strength by 3.12, 0.24 % and 4.13 % respectively in comparison to that of the 93VESi35KF. Thus silane treatment of natural fibre caused better fibre/matrix adhesion in these hybrid composites. Also the same properties increased by 9.22, 18.53 and 22.07 % respectively for 93VESi35SKF in comparison to that of 93VE35KF showing that the hybrid composite was stronger than the corresponding bio-composite without nanofiller.