摘要
在含偶氮苯的三硫酯链转移剂(CTA-AZO)存在下,将甲基丙烯酸二甲氨基乙酯(DMAEMA)通过可逆加成断裂链转移(RAFT)聚合,制备了pH、温度和光三重敏感的含偶氮苯端基的聚甲基丙烯酸二甲氨基乙酯聚合物(PDMAEMA-AZO)。采用UV、FTIR、^(1)HNMR和GPC对PDMAEMA-AZO的结构进行了表征,并考察了聚合物的光敏性、温敏性和pH敏感性。结果表明,PDMAEMA-AZO的相对分子质量可控,且相对分子质量分布(PDI)≤1.78。PDMAEMA-AZO在氯仿、乙醇和水中均能够快速进行可逆光致顺反异构反应,在紫外与可见光的交替照射下,快速达到光稳态。与聚甲基丙烯酸二甲氨基乙酯(PDMAEMA)相比,PDMAEMA-AZO的低临界溶解温度(LCST)更低。随着聚合物浓度的增加,PDMAEMA-AZO的LCST降低,且相变窗口变窄。当pH≥9.44时,PDMAEMA-AZO的LCST保持不变,pH由9.44下降到7.34时,LCST升高,pH<7.34时不再具有温敏性,说明PDMAEMA-AZO是一种pH控制的具备LCST的温敏性聚合物。在紫外与可见光交替照射下,PDMAEMA-AZO的LCST表现为可逆的升高和降低,表明聚合物PDMAEMA-AZO具备光控温敏性。
Azobenzene-terminated poly(dimethylaminoethylmethacrylate)(PDMAEMA-AZO)with pH,temperature and light triple-sensitivity was synthesized by reversible addition fragmentation chain transfer(RAFT)polymerization of dimethylaminoethylmethacrylate(DMAEMA)in the presence of azobenzene-containing trithiocarbonate chain transfer agent(CTA-AZO).The structure of PDMAEMA-AZO obtained was characterized by UV,FTIR,^(1)HNMR and GPC,followed by investigation on its photo-thermal-pH triple response.The results indicated that PDMAEMA-AZO,with controllable relative molecular mass and a polymer dispersity index(PDI)≤1.78,could undergo reversible light-induced cis-trans isomerization rapidly in water,ethanol and chloroform,while achieve quick photostability under the alternating irradiation of ultraviolet and visible light.Meanwhile,in comparison to PDMAEMA,PDMAEMA-AZO exhibited a reduced lower critical solution temperature(LCST),which decreased along with the increase of polymer concentration,and narrower phase transition temperature range.The LCST of PDMAEMA-AZO remained unchanged when pH≥9.44,increased when pH dropped from 9.44 to 7.34,and the polymer no longer showed thermo-sensitivity when the pH<7.34.Moreover,The LCST of the polymer reversibly increased and decreased under the alternating irradiation of UV and visible light,indicating that PDMAEMA-AZO had pH and light-controlled thermos-sensitivity.
作者
侯玉梅
杨栋
黄如霞
罗春华
董秋静
HOU Yumei;YANG Dong;HUANG Ruxia;LUO Chunhua;DONG Qiujing(School of Chemistry and Materials Engineering,Fuyang Normal University,Fuyang 236037,Anhui,China;Anhui Provincial Key Laboratory for Degradation and Monitoring of the Pollution of the Environment,Fuyang 236037,Anhui,China)
出处
《精细化工》
EI
CAS
CSCD
北大核心
2022年第11期2282-2289,共8页
Fine Chemicals
基金
安徽高校优秀青年人才支持计划项目(gxyq2020027)
省级大学生创新训练项目(S202010371054,S202010371070)。
关键词
聚甲基丙烯酸二甲氨基乙酯
RAFT聚合
光敏性
温敏性
偶氮苯
功能材料
poly(dimethylaminoethylmethacrylate)
RAFT polymerization
light sensitivity
thermosensitivity
azobenzene
functional materials
