Abstract:
In the first part of this work, three phosphonate containing (meth)acrylamides (1-3) were synthesized. Monomers 1 and 3 were synthesized by amidation reaction of acryloyl chloride with diethyl amino(phenyl)methylphosphonate and diethyl 1-aminoheptylphosphonate. Monomer 2 was synthesized via the reaction of methacryloyl chloride with diethyl amino(phenyl)methylphosphonate. Monomers 1 and 2 were white solids with melting points of 154 oC and 114 oC but monomer 3 was a yellow viscous liquid. Thermal homopolymerizations of monomers 1 and 2 in methanol and monomer 3 in bulk using 2 mol% of 2,2’-azobis(isobutyronitrile) (AIBN) at 65 oC gave polymers with Mn values of 8700, 9600 and 81494. Addition of these monomers (5 mol%) to 2-hydroxyethyl methacrylate (HEMA) did not change its photopolymerization kinetics. In the second part of this work, one reference urea monomer (4) and two new phosphonate-containing urea methacrylates (5 and 6) were synthesized from the reaction of of 2-isocyanatoethyl methacrylate (IEM) and benzyl amine (4), diethyl 1-aminomethylphosphonate (5) and diethyl amino(phenyl)methylphosphonate (6). Monomers 4 and 6 were obtained as white solids with melting points of 70 oC and 72 oC, whereas monomer 5 was a colorless viscous liquid. Monomers were homo and copolymerized with HEMA, triethylene glycol dimethacrylate (TEGDMA) and bisphenol A-glycolate methacrylate (BISGMA) using photo-DSC with 2,2’-dimethoxy-2-phenyl acetophenone (DMPA) as photoinitiator. These monomers were found to have significantly high polymerization rate and degree of conversion despite having one double bond and gave crosslinked polymers. Their photopolymerization reactivities were found to be higher or comparable to commercial dental crosslinkers such as Bis-GMA and TEGDMA, indicating their potential as reactive diluents or crosslinkers in dental systems.
