Preparation and properties of adjacency crosslinked polyurethane-urea elastomers

Adjacency crosslinked polyurethane-urea（PUU）elastomers with different crosslinking density were prepared by using hydroxyl-terminated liquid butadiene-nitrile （HTBN）,toluene diisocyanate （TDI）and chain extender 3.5-dimethyl thio-toluene diamine（DMTDA）as raw materiats,dicumyl peroxide （DCP）as initiator,and N,N＇-m-phenylene dimaleimide（HVA-2）as the crosslinking agent,The influences of the crosslinking density and temperature on the structure and properties of such elastomers were investigated.The crosslinking desity of PUU elastomer was tested by the NMR method.it is found that when the content of HVA-2 is 1.5%,the mechanical properties of polyurethane elastomer achieve optimal performance.By testing thermal performance of PUU,compared with linear PUU,the thermal stability of the elastomars has a marked improvement. With the additlon of HVA-2 ,the loss factor tano decreases, FT-IR spectral studies of PUU elastomer at various temperatures were performed .From this study,heat-resistance polyurethane could be prepared,and the propertes of PUU at high temperrature could be improved obviously.