温敏性非对称偶氮聚合物的合成及性质

Synthesis and characterization of thermo-sensitive and asymmetric azo polymers

偶氮苯类化合物是良好的光敏变色材料,利用重氮法合成一种新型含不饱和键的非对称偶氮单体6-(4′-甲氧基-4-氧基偶氮苯)-甲基丙烯酸己酯(AzoMA),然后与N-异丙基丙烯酰胺(NIPAM)经可逆加成-断裂链转移聚合(RAFT)形成末端羧基化非对称温敏性偶氮聚合物,并运用FT-IR、~1HNMR、紫外可见光谱等进行表征。结果表明:聚合物具有良好的温敏性;随着紫外光照射时间的延长,聚合物在450 nm处的吸收峰逐渐变强,显示AzoMA中的偶氮苯基团顺式构型比例逐渐增大;当紫外光照射时间足够长时,偶氮苯顺式-反式构型达到平衡,紫外可见光谱不再发生变化。

Azobenzene compounds were good photochromic materials.The novel asymmetric azo mono⁃mer 6-(4′-methoxy-4-oxyazobenzene)-hexyl methacrylate(AzoMA)which contained unsaturated bond was synthesized by diazo method,then it was polymerized with N-isopropylacrylamide(NIPAM)by reversible addi⁃tion-fragmentation chain transfer(RAFT)to form carboxyl-terminated asymmetric thermo-sensitive azo poly⁃mer.The synthesized polymers were characterized by FT-IR,1HNMR and UV-Vis spectrum.The results showed that the polymer had good thermal sensitivity.With the prolongation of UV irradiation time,the absorp⁃tion peak at 450 nm of the polymer was gradually strengthened,which indicated that the cis configuration ra⁃tio of azo group in AzoMA was increased gradually.When the UV irradiation time was long enough,the cistrans configuration of azobenzene reached equilibrium,and the UV-Vis spectrum did not change.