Phase transitions of lignin-based polycaprolactones and their polyurethane derivatives

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• 作者：Hatakeyama ; T. ; Izuta ; Y. ; Hirose ; S. ; Hatakeyama ; H.
• 关键词：Alcoholysis lignin ; Kraft lignin ; Caprolactone
• 刊名：Polymer
• 出版年：2002
• 期刊代码：83_00323861
• 类别：ms
• 出版时间：February, 2002
• 卷：43
• 期：4
• 页码：1177-1182
• 文件大小：141 K

摘要

Alcoholysis and kraft lignin-based polycaprolactones (LigPCL) were synthesized by the polymerization of ?-caprolactone which was initiated by the hydroxyl (OH) group in lignin. LigPCL-based polyurethanes were also prepared from LigPCL. The caprolactone (CL)/OH ratio of the CAPCLs was changed from 1 to 25molmol⁻¹. Thermal properties of the LigPCL and LigPCL-based polyurethane (PU) sheets were studied by differential scanning calorimetry (DSC). Glass transition temperature (T_g), heat capacity difference at T_g (ΔC_p) cold crystallization temperature (T_cc) and melting temperature (T_m), were determined by DSC. The main chain motion of lignin is observed in the whole CL/OH ratio. When CL/OH ratio exceeds 5molmol⁻¹ in the LigPCL samples and 10molmol⁻¹ in the LigPCL-based PU samples, the crystalline region which is organized by the PCL chain association is observed. It was found that PCL chain association is controlled by both chain length and chemical cross linking.