| The curing reaction mechanism of epoxide group and C/C double band was investigated by using sulfur (S) as curing agent, and liquid nitrile butadiene rubber (NBR), phenyl glycidyl glycerol ether (GPE) and allyl phenyl glycidyl ether (APE) as model compounds. Differential scanning Calorimetry (DSC), FTIR, XPS and dynamic mechanical thermal analysis (DMA) were used to detect the variations of curing enthalpy, double bond and the epoxy groups with reaction time.The experimental results showed that the chemical reactions between the nitrile rubber and epoxy model compounds were verified, and the curing reaction in NBR/sulfur system is one step reaction, and in rubber /epoxy compounds/sulfur system is the two step reaction. Comparatively, the cured NBR/S shows the lowest glass transition temperature and the highest energy storage modulus and crosslinking density, while, NBR/APE/S presents the highest glass transition temperature and the lowest energy storage modulus and crosslinking density. Furthermore, the curing mechanism of the liquid rubber and epoxy compound is suggested as:sulfur can cleavage into sulfur radicals, which initiate addition reaction of rubber double bonds to form mercapto groups. Finally, resultant mercapto groups react further with epoxy groups through ring-opening reaction. Meanwhile, coupling reactions between different radicals occur.The diallyl bisphenol epoxy resin have bothepoxy groupsand allyl.When adding sulfur, allyl epoxy resin with liquid nitrile rubber chemical reaction will occur at high temperature.This paper developed the allyl epoxy/liquid nitrile butadiene rubber/sulfur adhesive.It can be used for bonding rubber to metal.The adhesive used for bonding rubber and aluminum can obtain good bonding strength. |
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