Abstract
Abstract This study focuses on the synthesis of polymers possessing Meldrum’s acid (MA) groups at the main chains and the studies on their crosslinking reactions and the properties of the corresponding crosslinked polymers. In the first part, MA is used as a monomer to directly polymerize with 1,4-bis(chloromethyl)benzene or 2,5-bis(chloromethyl)-p-xylene through the dehydrochlorination condensation reaction. The resulting polymers contain MA groups which could perform thermally-induced dimerization, so as to make the polymers thermally crosslinkable. The thermally crosslinking reactions were monitored with a Fourier transform infrared spectroscopy to demonstrate the MA decomposition, formation of active ketene groups, and dimerization of ketene groups take place in the crosslinking process. As a result, crosslinked polymers could be obtained at 270 oC for 1 h. Nevertheless, the solubility of the obtained polymers was poor so as to limit their molecular weights and processing properties. Although 2,5-bis(chloromethyl)-p-xylene was used as a monomer instead, the solubility of the polymer was not therefore improved. It could be referred that intermolecular structure was too rigid and intermolecular forces was so strong to cause such a polymer of poor solubility. In the second section, a MA monomer possessing two furan groups (MA-FBCB) was synthesized and used as a monomer to polymerize with a bismaleimide compound through Diels-Alder (DA) reaction. The polymer also possessed MA groups at the main chains and was thermally crosslinkable. After being cured at 230 oC for 15 minutes, the corresponding crosslinked polymer was obtained to show good thermal properties.