Synthesis of high glass transition temperature (meth)acrylic polymers bearing norbornadiene dimer via Lewis pair polymerization

Abstract The introduction of bulky and rigid polycyclic hydrocarbons into the polymer side chains increased the glass transition temperature ( T g ), thereby broadening the application range of the polymer. We synthesized and polymerized new acrylate and methacrylate monomers bearing a norbornadiene dimer, exo-exo -4-pentacyclo[8.2.1.1 5,8 .0 2,9 .0 3,7 ]tetradecanyl acrylate ( 1 ) and its methacrylate analog ( 2 ). The polymerizations of 1 and 2 using Lewis pair catalysts comprising B(C 6 F 5 ) 3 /PPh 3 and methylaluminum bis(2,6-di- tert -butyl-4-methylphenoxide) (MAD)/PCy 3 , respectively, proceeded with full conversion. The T g values of poly 1 and poly 2 were approximately 120 °C and 200 °C, respectively. Considering the T g and tacticity of poly 2 obtained via radical polymerization ( T g = 135 °C; rr triad = 63%), the significantly higher T g value ( T g = 206 °C) can be reasonably assumed to be due to the high syndiotacticity ( rr = 87%), which is likely induced by the steric repulsion between the bulky MAD at the propagating terminal and the penultimate norbornadiene dimer moiety.