摘要
以2-溴代异丁酸乙酯为引发剂,Cu Br/PMDETA为催化体系,通过原子转移自由基聚合（ATRP）方法,合成了寡聚乙二醇甲基丙烯酸酯与丙烯酸叔丁酯的嵌段共聚物（PMEO2MA-b-Pt BA）;通过水解脱去共聚物中丙烯酸叔丁酯嵌段上的叔丁基,使丙烯酸叔丁酯嵌段转化为丙烯酸嵌段,得到寡聚乙二醇甲基丙烯酸酯与丙烯酸的嵌段共聚物（PMEO2MA-b-PAA）.通过溶液透光率和动态光散射（DLS）等方法,表征了合成得到的嵌段共聚物的温敏性能和p H响应性,发现嵌段共聚物在24~30℃,p H=4~8的范围内发生亲水性性质转变.以二环己基碳二亚胺（DCC）为缩合剂,在4-二甲氨基吡啶（DMAP）的催化下使PMEO2MA-b-PAA上的羧基与蚕丝上的氨基发生缩合反应,从而令共聚物接枝到蚕丝上,通过接触角和回潮率的测试发现改性后的蚕丝在28~42℃具温敏性,较共聚物的转变温度有所升高,其转变温度随p H的增大而上升.
A series of homopolymers and copolymers,based on 2-（ 2-methoxyethoxy） ethyl methacrylate（ MEO2MA） and tertbutyl acrylate（ t BA）,were synthesized by atom transfer radical polymerization（ ATRP）using Cu Br /（ N,N,N’,N″,N″-Pentamethyldiethylenetriamine）（ PMDETA） as a catalyst system and 2-bromo ethyl isobutyrate（ EBi B） as an initiator in a first step. The homopolymer of MEO2 MA exhibited the lower critical solution temperature（ LCST） at around 28 ℃. In a second step,the tert-butyl groups of t BA were hydrolysed with trifluoroacetic acid to form the corresponging block copolymers of MEO2 MA and acrylic acid（ AA）（ PMEO2MA-b-PAA）,which exhibited both temperature and p H responsive behaviour. Transmittance（ 500 nm） measurements were used to obtain the cloud point（ CP） of PMEO2 MA and PMEO2MA-b-PAA. The CP of PMEO2MA-b-PAA aqueous solution（ 1 mg / m L） was raised from 26. 0 ℃ to 31. 1 ℃,when the p H value of solutions was increased from 2 to 12. At 28 ℃,the transformation p H value of PMEO2MA-b-PAA aqueous solutions（ 1 mg / m L） was around 6. When the concentration increased,the CP decreased. Stimulusresponsive polymer modified silk was obtained through condensation reaction between the amino groups on silk surface and the carboxyl groups of PMEO2MA-b-PAA. Contact angle and moisture regain measurements indicated that the modified silk exhibited both temperature and p H-responsive behaviour. When the p H value of modified silk surface is 2,the conformation of modified silk changed at around 28 ℃. When the p H value is 6,the transition temperature increased to about 32 ℃. Smart silk textiles with temperature and p H responsive behaviour could be obtained by a simple and costless process.
出处
《高分子学报》
SCIE
CAS
CSCD
北大核心
2016年第5期637-644,共8页
Acta Polymerica Sinica
基金
国家自然科学基金(基金号21302170)资助项目
