Comparative studies on the crosslinking reaction of bis-maleimides and bis-citraconimides in squalene and natural rubber

A study has been made to differentiate between the crosslinking reaction of bis-maleimides and bis-citraconimides in squalene as well as in natural ru bber. Bis-maleimides are found to participate in the crosslinking reaction in the absence of curatives such as accelerators and sulfur. Bis-citraconim ides take part in the crosslinking reaction when polysulfidic crosslinks ar e under the process of degradation. Sulfur and accelerator are required for the formation of polysulfidic crosslinks and hence the presence of sulfur and accelerator are essential for bis-citraconimide crosslinking. The diffe rences in the reactivity and the chemistry of crosslinking are studied and discussed. Some application data are provided in order to elaborate the dif ferences.