Calibration Curve Establishment and Fractionation Temperature Selection of Polyethylene for Preparative Temperature Rising Elution Fractionation  

作　　者：Yan-hu Xue Shu-qin Bo 姬相玲 

机构地区：[1]State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry,Chinese Academy of Sciences [2]University of Chinese Academy of Sciences

出　　处：《Chinese Journal of Polymer Science》2015年第7期1000-1008,共9页高分子科学（英文版）

基　　金：financially supported by the National Natural Science Foundation of China(Nos.20734006 and 50921062)

摘　　要：A series of copolymers of ethylene with 1-hexene synthesized using a metallocene catalyst are selected and mixed. The blend is fractionated via preparative temperature rising elution fractionation（P-TREF）. All fractions are characterized via high-temperature gel permeation chromatography（GPC）, 13 C nuclear magnetic resonance spectroscopy（13C-NMR）, and differential scanning calorimetry（DSC）. The changes in the DSC melting peak temperatures of the fractions from P-TREF as a function of elution temperature are almost linear, thereby providing a reference through which the elution temperature of TREF experiments could be selected. Moreover, the standard calibration curve（ethylene/1-hexene） of P-TREF is established, which relates to the degree of short-chain branching of the fractions. The standard calibration curve of P-TREF is beneficial to study on the complicated branching structure of polyethylene. A convenient method for selecting the fractionation temperature for TREF experiments is elaborated. The polyethylene sample is fractionated via successive self-nucleation and annealing（SSA） thermal fractionation. A multiple-melting endotherm is obtained through the final DSC heating scan for the sample after SSA thermal fractionation. A series of fractionation temperatures are then selected through the relationship between the DSC melting peak temperature and TREF elution temperature.A series of copolymers of ethylene with 1-hexene synthesized using a metallocene catalyst are selected and mixed. The blend is fractionated via preparative temperature rising elution fractionation（P-TREF）. All fractions are characterized via high-temperature gel permeation chromatography（GPC）, 13 C nuclear magnetic resonance spectroscopy（13C-NMR）, and differential scanning calorimetry（DSC）. The changes in the DSC melting peak temperatures of the fractions from P-TREF as a function of elution temperature are almost linear, thereby providing a reference through which the elution temperature of TREF experiments could be selected. Moreover, the standard calibration curve（ethylene/1-hexene） of P-TREF is established, which relates to the degree of short-chain branching of the fractions. The standard calibration curve of P-TREF is beneficial to study on the complicated branching structure of polyethylene. A convenient method for selecting the fractionation temperature for TREF experiments is elaborated. The polyethylene sample is fractionated via successive self-nucleation and annealing（SSA） thermal fractionation. A multiple-melting endotherm is obtained through the final DSC heating scan for the sample after SSA thermal fractionation. A series of fractionation temperatures are then selected through the relationship between the DSC melting peak temperature and TREF elution temperature.

关 键 词：TREF Calibration curve Fractionation temperature SSA Polyethylene 

分 类 号：O632.12[理学—高分子化学]