Post-cure effect of long-chain alkylene dimethacrylates

A series of six long-chain alkylene dimethacrylates, namely tetra-, penta-, hexa-, octa-, deca- and dodecamethylene dimethacrylate, have been prepared and polymerized. Post-cure behavior was studied by means of non-isothermal differential scanning calorimetry. It has been found that in the temperature range of ca. 165-185 degrees C a post-cure effect occurs. The enthalpy of post-curing decreases with increase of spacer length in the main methacrylate chain. This suggests that if a fully crosslinked system should be obtained the curing reaction is to be carried out at elevated temperature. The thermal behavior of the networks has been investigated by thermogravimetric analysis alone and in combination with Fourier transform infrared spectroscopy. A typical degradation scheme leading to low-molecular weight volatiles (carbon dioxide, olefins) was confirmed.