N-异丙基丙烯酰胺-甲基丙烯酸酯类共聚物温敏性能及应用的研究

Study on the characteristics and application of the temperature-sensitive N-isopropylacrylamide copolymer with methacrylate segments

利用溶液聚合法合成了一系列不同质量配比的N-异丙基丙烯酰胺（NIPA）／甲基丙烯酸甲酯（MMA）、甲基丙烯酸乙酯（MEA）或甲基丙烯酸丁酯（MBA）线型共聚物，用傅立叶红外光谱（FT～IR）和热重分析（TG）对共聚物进行了表征。采用紫外可见分光光度计（UV）测定了共聚物水溶液的低临界溶解温度（LCST），研究表明，通过改变共聚单体的配比LCST可在18～32℃范围内调节。对聚合物水溶液进行UV测试发现，共聚物水溶液在LCST附近光透过率变化显著，共聚物水溶液在LCST温度之上为白浊状态而在该温度下为清澈透明状，在LCST以下，溶液的透光率受到浓度、单体投料比等因素影响。该变化过程呈现可逆性，且变化迅速，灵敏性高，重复性好，在智能调光材料领域有广泛的应用前景。

A series of linear copolymers p （N-isopropylacrylamide-co-methyl methaerylate）, p （N-isopropylacrylamide-co-ethyl methacrylate） and p （N-isopropylacrylamide-co-butyl methacrylate） with different mass ratio were synthesized by solution free radical polymerization method. The structures of these copolymers were characterized by infrared spectrum and TG analysis. The low critical solution temperature （LCST） of aqueous copolymers solution was measured by UV-Vis. The aqueous solution of copolymers change from transparent to opaque when the temperature is above LCST. This change was reversible and exhibited celerity,marked sensitivity and good reproducibility. The results showed that different ratio of comonomer influenced temperature sensitive properties significantly. The range of LCST can be regulated from 18-32℃ based on the mass ratio of comonomer. The transmittance of the aqueous solution nearby the LCST was tested by UV-Vis spectrophotometer and the transmittance showed significant change nearby LCST. The transmittance of aqueous solution was influenced by concentration,the quantity and sorts of comonomer when the temperature was lower than LCST. The aqueous solution is expected to be applied as a kind of intelligent light-control material.