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《高分子科学(英文版)》 2016-01
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Effects of Molecular Weight on the Crystallization and Melting Behaviors of Poly(L-lactide)

Sheng Xiang;Shao Jun;Gao Li;Xin-chao Bian;Li-dong Feng;Xue-si Chen;Feng-qi Liu;Shao-yong Huang;Key Laboratory of Polymer Ecomaterials, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences;University of Chinese Academy of Sciences;College of Chemistry and Chemical Engineering, Jiangxi Normal University;College of Chemistry, Jilin University;  
In this study, a series of monodispersed poly(L-lactide)(PLLA) were synthesized by the ring-opening polymerization with Schiff base aluminum catalyst, and the effects of the number-average molecular weight(Mn) on the crystallization and melting behaviors of PLLA were investigated by differential scanning calorimetry(DSC) and wide-angle X-ray diffraction(WAXD). The total crystallization rate of PLLA was Mn-dependent, which reached the maximum value for PLLA with Mn of 18.6 kg/mol. In addition, when Mn of PLLA was 18.6 kg/mol, the melting enthalpy(ΔHm) showed a maximum value(87.1 J/g), which was the highest reported value till now. The critical temperature for change of crystal formation from ?-form to ?-form crystals increased in the isothermal crystallization process with Mn increasing. In the reheating procedure, high-Mn PLLA demonstrated a small exothermal peak prior to the dominant melting peak, corresponding to crystal transition from ?- to ?-form, but low-Mn PLLA didn't show the peak of crystal transition. These different crystallization and melting behaviors were attributed to the different chain mobility of PLLA with different Mn.
【Fund】: financially supported by the National Natural Science Foundation of China(Nos.51303176;51373169;51033003;51473166 and 51403089);; Innovative Research Group(No.51321062);; The National High-tech R&D Program of China(863 program)(No.2011AA02A202)
【CateGory Index】: TQ317
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Chinese Journal Full-text Database 2 Hits
1 Yu-kuan An Department of Physics,Binzhou Medical College,Yantai 264003,China Shi-dong Jiang and Shou-ke Yan~(**) State Key Laboratory of Chemical Resource Engineering,Beijing University of Chemical Technology, Beijing 100029,China Jing-ru Sun and Xue-si Chen State Key Laboratory of Polymer Physics and Chemistry,Changchun Institute of Applied Chemistry, Chinese Academy of Sciences,Changchun 130022,China;CRYSTALLIZATION BEHAVIOR OF POLYLACTIDE ON HIGHLY ORIENTED POLYETHYLENE THIN FILMS[J];高分子科学(英文版);2011-04
2 Yuan-ying Liang;Hu Tang;Gan-ji Zhong;Zhong-ming Li;College of Polymer Science and Engineering, State Key Laboratory of Polymer Materials Engineering, Sichuan University;;Formation of Poly(L-lactide) Mesophase and Its Chain Mobility Dependent Kinetics[J];高分子科学(英文版);2014-09
【Secondary Citations】
Chinese Journal Full-text Database 2 Hits
1 ZHAO Yanan,LI Xiaoran,YUAN Xiaoyan(School of Materials Science and Engineering,Tianjin University,Tianjin 300072);SYNTHESIS OF POLY(ETHYLENE GLYCOL)-b-POLY(L-LACTIC ACID) DIBLOCK COPOLYMERS AND FORMATION OF THEIR ELECTROSPUN FIBERS[J];Acta Polymerica Sinica;2008-05
2 YAO Junyan,YANG Qingfang,SHU Xiaojun,Zhang Aijun,DU Jianghua(Department of Applied Chemistry,Northwestern Polytechnical University,Xi'an 710072);PREPARATION AND MISCRIBILITY STUDIES OF POLY(L-LACTIC ACID)/POLY (ASPARTIC ACID-co-LACTIC ACID) BLENDS[J];Acta Polymerica Sinica;2008-10
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