Crosslink network evolution of nature rubber/zinc dimethacrylate composite during peroxide vulcanization

In this article, we investigated the evolution of the crosslink networks in nature rubber (NR) which is filled with in situ zinc dimethacrylate (ZDMA) during vulcanization. The results revealed that a primary network dominated by the ionic bond could be formed in the first 1 min, while the backbone of the covalent crosslink network was not formed. The ionic crosslinks, cooperating with some other physical crosslinks and some primary covalent crosslink points, play an important role in supporting the crosslink backbone of the composite in this period. This primary network was strong enough to bear the force exerted by the moving die of the Rheometer and to enable the composite that do not dissolve in toluene. After that, both the covalent crosslinking of NR molecules and polymerization of ZDMA react rapidly to give a birth to the fundamental network of the composites. Fourier transform infrared spectroscopy and differential scanning calorimeter were also used to investigate the curing reaction of the NR/ZDMA compounds. After ZDMA reaching a considerable conversion, the substantial covalent crosslinking reaction starts to be initiated. These results support the primary network dominated by the ionic bond formed in the first 1 min. POLYM. COMPOS., 2011.