Curing kinetic, thermal and adhesive properties of epoxy resin cured with cashew nut shell liquid

摘要

The curing kinetic, thermal and adhesive properties of epoxy resin cured with cashew nut shell liquid (CNSL) were investigated. The CNSL was used as a curing agent for epoxy resin. The epoxy resin cured with 10, 20 30, 40 and 50 wt% of CNSL showed two-stages curing process between 165-170 degrees C and 230-235 degrees C. The solvent extraction experiment indicated that the CNSL content should not exceed 40 wt% to avoid the presence of unreacted CNSL. The apparent activation energy (E-a) of 60/40 epoxy resin/CNSL copolymer was obtained from Friedman's model-free method for both stages of curing process. The kinetic model and kinetic parameters were determined by Malek's method and the reaction processes was simulated favorably by Sestak-Berggren (SB (m, n)) model. In addition, silica powder was used to improve the adhesion and thermal properties of copolymer. The epoxy resin/CNSL copolymer with 0.5 wt% silica showed a substantial increase in the lap shear strength and thermal stability tended to increase with increasing silica content. The epoxy resin/CNSL composite showed a great potential for use as a high performance adhesive with good thermal stability. (C) 2014 Elsevier B.V. All rights reserved.