【作者】 张继川； 张天鑫； 董梦洁； 刘根实；

【Author】 Jichuan Zhang;Tianxin Zhang;Mengjie Dong;Genshi Liu;Center of Advanced Elastomer Materials, Beijing University of Chemical Technology;Engineering Research Center of Elastomer Materials Energy Conservation and Resources,Ministry of Education;

【机构】 Center of Advanced Elastomer Materials, Beijing University of Chemical Technology； Engineering Research Center of Elastomer Materials Energy Conservation and Resources,Ministry of Education；

【摘要】 The number of free chain segments of the amorphous zone in a crystalline polymer can be characterized by the enveloped area under the tans-T curve at the Tg zone measured by DMTA,which can be used to calculate the degree of crystallinity of the crystalline polymer.The results indicated that the degree of crystallinity determined by DMTA was much larger than that of DSC.This is because the degree of crystallinity determined by DMTA involves not only the ratio of the crystalline zone,but also the ratio of the mesomorphic zone,while the degree of crystallinity tested by DSC only include the ratio of crystalline zone.So the degree of crystallinity,degree of mesomorphic zone and degree of amorphous zone of NR and EU gums with different degrees of crosslinking can be quantitatively determined by DMTA and DSC.The results show that the degree of crystallinity,the degree of mesomorphic zone and the degree of amorphous zone of NR(crystallized at-25℃ for 12 h)and EU gum are 33%,53%,14% and 34%,54%,13%,respectively.For NR,increasing the induced time or decreasing the crosslink density will increase the degree of crystallinity and the degree of mesomorphic zone simultaneously,but will decrease the degree of amorphous zones.For EU gum,increasing the crosslink density will decrease the degree of crystallinity and increase the degree of amorphous zone,but keep the degree of mesomorphic zone consistent invariably within the critical crystallization point,which is about 55% or so.更多还原

【Abstract】 The number of free chain segments of the amorphous zone in a crystalline polymer can be characterized by the enveloped area under the tans-T curve at the Tg zone measured by DMTA,which can be used to calculate the degree of crystallinity of the crystalline polymer.The results indicated that the degree of crystallinity determined by DMTA was much larger than that of DSC.This is because the degree of crystallinity determined by DMTA involves not only the ratio of the crystalline zone,but also the ratio of the mesomorphic zone,while the degree of crystallinity tested by DSC only include the ratio of crystalline zone.So the degree of crystallinity,degree of mesomorphic zone and degree of amorphous zone of NR and EU gums with different degrees of crosslinking can be quantitatively determined by DMTA and DSC.The results show that the degree of crystallinity,the degree of mesomorphic zone and the degree of amorphous zone of NR(crystallized at-25℃ for 12 h)and EU gum are 33%,53%,14% and 34%,54%,13%,respectively.For NR,increasing the induced time or decreasing the crosslink density will increase the degree of crystallinity and the degree of mesomorphic zone simultaneously,but will decrease the degree of amorphous zones.For EU gum,increasing the crosslink density will decrease the degree of crystallinity and increase the degree of amorphous zone,but keep the degree of mesomorphic zone consistent invariably within the critical crystallization point,which is about 55% or so.更多还原