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以硝酸铈铵(CAN)、过硫酸钾(KPS)及H2O2/H2A(双氧水/抗坏血酸)为引发体系,采用溶液自由基接枝法制备了具有温敏性的棉纤维N-异丙基丙烯酰胺接枝共聚物(cotton-g-PNIPAAm);在上述3种引发剂作用下的接枝反应可以达到的接枝率(G)排序为G(H2O2/H2A)>G(KPS)>G(CAN);研究了其他因素如引发剂浓度、反应时间、反应温度和单体浓度等对接枝率的影响,得出了优化的接枝反应条件;接枝样品的FTIR分析图谱和SEM观察均表明样品表面已接枝了聚N-异丙基丙烯酰胺;DSC分析显示,棉纤维N-异丙基丙烯酰胺接枝共聚物的低临界溶解温度(LCST)与纯的聚N-异丙基丙烯酰胺凝胶(LCST=32.48℃)相似,约为32~33℃;接枝率的变化对试样LCST的影响很小,但其可逆焓变(ΔH)会随接枝率的提高而增加;采用滴水试验法(AATCC 79)和毛效试验法(FZ/T 01071)检测棉纤维的N-异丙基丙烯酰胺接枝共聚物在不同温度时的吸水性变化,显示试样具有温敏特性,其中接枝率介于25%~45%的试样温敏性较高,过低或过高的接枝率均不利于获得高的温敏性;棉纤维的N-异丙基丙烯酰胺接枝共聚物试样的可逆焓变(ΔH)随试样膨胀/收缩时间变化的研究和分析结果表明,棉纤维的N-异丙基丙烯酰胺接枝共聚物对温度变化的响应比纯聚N-异丙基丙烯酰胺凝胶快.
In this study, the cotton wool with temperature-sensitive cotton N-isopropylacrylamide (AMF) was prepared by free-radical grafting method using cerium ammonium nitrate (CAN), potassium persulfate (KPS) and H2O2 / H2A (hydrogen peroxide / ascorbic acid) (G-PNIPAAm). The grafting degree (G) grafting reaction can reach the order of G (H2O2 / H2A)> G (KPS)> G ); The influence of other factors such as initiator concentration, reaction time, reaction temperature and monomer concentration on the grafting rate was studied, and the optimum grafting reaction conditions were obtained. FTIR analysis and SEM observation of grafted samples showed that Poly (N-isopropylacrylamide) has been grafted on the surface of the sample; DSC analysis shows that the low critical solution temperature (LCST) of cotton N-isopropylacrylamide graft copolymer is almost the same as that of pure N-isopropylacrylamide (LCST = 32.48 ℃) was about 32 ~ 33 ℃. The change of grafting rate had little influence on the LCST of the sample, but the reversible enthalpy change (ΔH) increased with the grafting rate. The drip test method (AATCC 79) and wool effect test (FZ / T 01071) were used to detect the water absorbency of cotton fiber at different temperatures of N-isopropylacrylamide graft copolymer. The results show that the samples have temperature-sensitive properties. The samples with grafting rate of 25% -45% have higher temperature sensitivity, too low or too high graft rates are not conducive to obtaining high temperature sensitivity. N-isopropylacrylamide graft copolymer samples reversible enthalpy change (ΔH) with the sample expansion / contraction time changes in the research and analysis results show that the cotton fiber N-isopropyl acrylamide graft copolymer pairs The response to temperature changes is faster than pure poly-N-isopropylacrylamide gel.