Effect of cashew nut shell liquid on gelation, cure kinetics, and thermomechanical properties of benzoxazine resin

Effects of cashew nut shell liquid (CNSL) on properties of a bifunctional benzoxazine resin (BA-a) have been investigated. The CNSL remarkably decreases the liquefying temperature, gel time and curing temperature of the neat benzoxazine resin. The Kissinger and Ozawa methods are used to calculate the curing kinetic parameters of BA-a/CNSL systems. The activation energy values obtained from both models show fairly consistent results i.e. the activation energy values decrease with increasing the CNSL content. It was found that optimal CNSL content from solvent extraction experiment should not exceed 20 wt% to avoid the presence of unreacted CNSL in the alloy network. Properties of bamboo fiber-reinforced BA-a/CNSL alloys are also investigated in this work. The filled BA-a/CNSL at 65 wt% of bamboo fiber shows a substantial increase in storage modulus and Tg of the composites. BA-a/CNSL alloy shows great potential as high performance lignocellulosic adhesive for wood composite applications.

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► Gel point of benzoxazine resin is lowered by cashew nut shell liquid (CNSL).
► Activation energy of benxozazine alloy decreases with increasing the CNSL content.
► Benzoxazine-CNSL mixture provides novel matrix for highly filled wood composites.