Study of photopolymers. XXXIV. Etherification and esterification reactions of polymers with (<i>o</i>, <i>m</i>, or <i>p</i>)‐bromomethylnitrobenzene using the DBU method and the photochemical properties of the resulting polymers

Abstract

Abstract Poly[4‐(4‐nitrobenzyloxy)styrene] was synthesized with a high degree of etherification by the reaction of poly(4‐hydroxystyrene) (PHST) with p ‐bromomethylnitrobenzene ( p ‐BMNB) using 1,8‐diazabicyclo‐[5,4,0]‐7‐undecene (DBU) in hexamethylphosphoramide (HMPA). Poly[4‐(3‐nitrobenzyloxy)styrene] and poly[4‐(2‐nitrobenzyloxy)styrene] were also prepared with a high degree of etherification by the corresponding reaction with m ‐ or o ‐BMNBs. However, the degrees of etherification of PHST with these BMNBs were relatively low when the reactions were carried out in other aprotic polar solvents such as DMF, DMSO, and N ‐methyl‐2‐pyrrolidone. On the other hand, poly(4‐introbenzyl methacrylate) (PPNBMA), poly(3‐nitrobenzyl methacrylate) (PMNBMA), and poly(2‐nitrobenzyl methacrylate) (PONBMA) were synthesized with a high degree of esterification by the reaction of poly(methacrylic acid) with the corresponding BMNBs using DBU in DMSO at 30°C. The photochemical properties of the resulting poly(nitrobenzyl methacrylate)s were examined, and it was found that the rates of photodecomposition of PPNBMA and PMNBMA were promoted by the addition of tributylamine and trifluoromethanesulfonic acid, respectively. However, the rate of photodecomposition of PONBMA was not affected by addition of the base or the acid.