Probing Chain Proximity and Interpenetration in Polymer Glasses
报告人：
南京大学高分子科学与工程系主任
薛奇教授、博导
时间：2006年12月8日（周五） 下午2:00
地点：材料大楼522学术报告厅
欢迎研究生、教师积极参加
本报告同时作为博士生系列专题讲座
纤维材料改性国家重点实验室
材料科学与工程学院
2006.12.5
附薛奇教授简介：南京大学高分子科学与工程系主任、教授、博士生导师。1945年1月出生任。1983年获美国Case Western Reserve University高分子博士学位，1984年在美国Case Western Reserve University从事博士后研究。先后担任国家教委理科教学指导委员会材料化学组组长，国际杂志《复合材料界面》、《粘接科学与技术》编委。已连续两届当选为国际复合材料界面结构会议学术委员会成员。
主研方向： 主要研究方向为功能导电聚合物和高分子的构象及相行为。包括导电聚合物的电化学合成；纳米层状导电功能性聚合物复合材料；高分子在溶液中熵致链的构象转变；相分离；凝胶化；结晶和玻璃化转变。
报告摘要：Chain-chain proximity related to chain interpenetration and local structural relaxation in polymer glasses were investigated on a scale of 0.5 nm by a new strategy of 1H solid state NMR experiment using fast magic angle spinning (MAS). The fast MAS at 25 kHz induces crucial changes in spin dynamic and selectively enhances the signal of 1H of a hydrogenous polystyrene (PS-H)) chain which is sufficiently close to 2H of a deuterated PS (PS-D) chain in an isotopic blend. Chain interpenetration and the intimacy of segment mixing in polymer blends were successfully characterized. Poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) and PS blend prepared from the melt is not intimately mixed at sub-segmental scale, although this blend has been considered as homogenous at multi-segment level. The rate of enthalpy relaxation of freeze-dried polymer with reduced interchain contact was increased relative to that of the solution cast film. This sensitive NMR method should be applicable to many synthetic or natural organic systems containing copious amount of hydrogen.
报告人：
南京大学高分子科学与工程系主任
薛奇教授、博导
时间：2006年12月8日（周五） 下午2:00
地点：材料大楼522学术报告厅
欢迎研究生、教师积极参加
本报告同时作为博士生系列专题讲座
纤维材料改性国家重点实验室
材料科学与工程学院
2006.12.5
附薛奇教授简介：南京大学高分子科学与工程系主任、教授、博士生导师。1945年1月出生任。1983年获美国Case Western Reserve University高分子博士学位，1984年在美国Case Western Reserve University从事博士后研究。先后担任国家教委理科教学指导委员会材料化学组组长，国际杂志《复合材料界面》、《粘接科学与技术》编委。已连续两届当选为国际复合材料界面结构会议学术委员会成员。
主研方向： 主要研究方向为功能导电聚合物和高分子的构象及相行为。包括导电聚合物的电化学合成；纳米层状导电功能性聚合物复合材料；高分子在溶液中熵致链的构象转变；相分离；凝胶化；结晶和玻璃化转变。
报告摘要：Chain-chain proximity related to chain interpenetration and local structural relaxation in polymer glasses were investigated on a scale of 0.5 nm by a new strategy of 1H solid state NMR experiment using fast magic angle spinning (MAS). The fast MAS at 25 kHz induces crucial changes in spin dynamic and selectively enhances the signal of 1H of a hydrogenous polystyrene (PS-H)) chain which is sufficiently close to 2H of a deuterated PS (PS-D) chain in an isotopic blend. Chain interpenetration and the intimacy of segment mixing in polymer blends were successfully characterized. Poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) and PS blend prepared from the melt is not intimately mixed at sub-segmental scale, although this blend has been considered as homogenous at multi-segment level. The rate of enthalpy relaxation of freeze-dried polymer with reduced interchain contact was increased relative to that of the solution cast film. This sensitive NMR method should be applicable to many synthetic or natural organic systems containing copious amount of hydrogen.