Functional Groups,Wettability of Wheat Straw and Its Hot-reaction Characters with MDI

Relationships between functional groups,wettability of wheat straw,leaf,and spike-stalk and the hot-reaction characters with methylene diphenyl diisocyanate(MDI) were examined.FTIR analysis showed that the inner surface of wheat straw was rich in hydroxyl group,favorable to the infiltration of MDI.However,surfaces of wheat leaf and spike-stalk were poor in hydroxyl group,which was not favorable to the infiltration of adhesive.Contact angle experiment results showed that MDI had smallest contact angle and best wettability on the inner surface of the straw,compared to the outer surface of the straw and wheat leaf.DSC results showed that MDI was able to conduct exothermic reaction with hydroxyl group in the wheat straw.The amounts of heat released from the reaction of MDI and wheat straw were higher than those with wheat leaf and spike-stalk.