Water absorption effects on hydrophilic polymer matrix of carboxyl functionalized glucose resin and epoxy resin

The effects of water absorption on hydrophilic polymer matrices based on carboxylic functionalized glucose (glucose maleic acid ester vinyl resin) and epoxy resins were studied as a function of curing temperature. The matrix cured at higher temperature shows compact crosslinks due to the higher concentration of ether bonds comparing to the matrix cured at the lower temperature. The polymer matrices cured at different temperatures were immersed in water at room temperature for 1000 h and the thermomechanical properties of the cured polymers were characterized using DMA and TGA. Two types of sorbed water were identified. Type I sorbed water contributed mainly to increasing the weight and to the decrease in T_g due to a plasticizer effect. Type II sorbed water was not removed after heating the polymer to 110 °C for an hour. Type II sorbed water causes changes in the mechanical properties of the polymers cured at different temperatures depending on the crosslinks of the matrix. The cured matrix at the higher temperature has the comparatively tight crosslinks in the network structure and the sorbed water molecule disturbed the polymer network resulting in the degradation of the matrix such as microcracks.