The temperature dependence of the specific refractive index increment d n /d c of aqueous poly( N isopropylacrylamide) solution in the range of 20 ℃ to 35 ℃ were determined by a differential refractometer. The measu...The temperature dependence of the specific refractive index increment d n /d c of aqueous poly( N isopropylacrylamide) solution in the range of 20 ℃ to 35 ℃ were determined by a differential refractometer. The measured d n /d c of the solution decreases regularly and smoothly with increasing temperature until to the specific coil globule transition temperature of PNIPAM (around 32 ℃) and afterwards it increases with increasing temperature on the contrary. This extraordinary phenomenon is successfully explained and treated by a quantitative theory in terms of accompanying solvation desolvation process in the course of coil globule transition of the polymer chain in solution.展开更多
A poly(N-isopropylacrylamide)/β-Cyclodextr in (PNIPAM/β-CD) ionic polymer was synthesized by the reaction of poly( N-isopropylacrylamide-co-acryl acid) (poly(NIPAM-co-AA) with mo no-6-ethanolamine-β-cyclodextrin (E...A poly(N-isopropylacrylamide)/β-Cyclodextr in (PNIPAM/β-CD) ionic polymer was synthesized by the reaction of poly( N-isopropylacrylamide-co-acryl acid) (poly(NIPAM-co-AA) with mo no-6-ethanolamine-β-cyclodextrin (EAA-β-CD).EAA-β-CD was synthesized via the reaction of mono-6-OTs-β-CD(Ts= p-toluensulfo nyl) with E.The ionic polymer was characterized by means of FT-IR and UV-V isi ble spectroscopes,and DSC.The result shows that the formation of ionic interacti on between poly(NIPAM-co-) and E-β-CD leads to an increase of t he glass transition temperature (T g) of poly(NIPAM-co-).In additio n,not only the ionic polymer exhibits a well-defined lower critical solution te mperature (LCST),but also β-CD on the polymer backbone can be modulated by changing the pH values,as compared with β-CD-conjugated polymers with co valent bonds.Also,β-CD can easily be bound to the polymer backbone in form of free,or inclusion complex.It is expected that the polymer may find some usef ul applications such as drug delivery system.展开更多
用前端聚合法制备了聚(N-异丙基丙烯酰胺)/多壁碳纳米管(PNIPAM/MWCNTS)复合水凝胶,对产物的微观形貌、温敏性、力学性能和释药性能进行了研究。结果表明,PNIPAM/MWCNTS复合水凝胶具有温度敏感性,MWCNTS的加入不影响水凝胶的低临界转变...用前端聚合法制备了聚(N-异丙基丙烯酰胺)/多壁碳纳米管(PNIPAM/MWCNTS)复合水凝胶,对产物的微观形貌、温敏性、力学性能和释药性能进行了研究。结果表明,PNIPAM/MWCNTS复合水凝胶具有温度敏感性,MWCNTS的加入不影响水凝胶的低临界转变温度,随MWCNTS含量增加,水凝胶吸水能力降低,力学强度显著提高,当MWCNTS的含量由0%增至10%时,水凝胶的压缩强度从88 k Pa增加到666 k Pa。复合水凝胶具有良好的药物缓释性能。展开更多
文摘The temperature dependence of the specific refractive index increment d n /d c of aqueous poly( N isopropylacrylamide) solution in the range of 20 ℃ to 35 ℃ were determined by a differential refractometer. The measured d n /d c of the solution decreases regularly and smoothly with increasing temperature until to the specific coil globule transition temperature of PNIPAM (around 32 ℃) and afterwards it increases with increasing temperature on the contrary. This extraordinary phenomenon is successfully explained and treated by a quantitative theory in terms of accompanying solvation desolvation process in the course of coil globule transition of the polymer chain in solution.
文摘A poly(N-isopropylacrylamide)/β-Cyclodextr in (PNIPAM/β-CD) ionic polymer was synthesized by the reaction of poly( N-isopropylacrylamide-co-acryl acid) (poly(NIPAM-co-AA) with mo no-6-ethanolamine-β-cyclodextrin (EAA-β-CD).EAA-β-CD was synthesized via the reaction of mono-6-OTs-β-CD(Ts= p-toluensulfo nyl) with E.The ionic polymer was characterized by means of FT-IR and UV-V isi ble spectroscopes,and DSC.The result shows that the formation of ionic interacti on between poly(NIPAM-co-) and E-β-CD leads to an increase of t he glass transition temperature (T g) of poly(NIPAM-co-).In additio n,not only the ionic polymer exhibits a well-defined lower critical solution te mperature (LCST),but also β-CD on the polymer backbone can be modulated by changing the pH values,as compared with β-CD-conjugated polymers with co valent bonds.Also,β-CD can easily be bound to the polymer backbone in form of free,or inclusion complex.It is expected that the polymer may find some usef ul applications such as drug delivery system.
文摘用前端聚合法制备了聚(N-异丙基丙烯酰胺)/多壁碳纳米管(PNIPAM/MWCNTS)复合水凝胶,对产物的微观形貌、温敏性、力学性能和释药性能进行了研究。结果表明,PNIPAM/MWCNTS复合水凝胶具有温度敏感性,MWCNTS的加入不影响水凝胶的低临界转变温度,随MWCNTS含量增加,水凝胶吸水能力降低,力学强度显著提高,当MWCNTS的含量由0%增至10%时,水凝胶的压缩强度从88 k Pa增加到666 k Pa。复合水凝胶具有良好的药物缓释性能。
