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学科主题: 高分子化学
题名: Preparation and crystallization kinetics of new structurally well-defined star-shaped biodegradable poly(L-lactide)s initiated with diverse natural sugar alcohols
其他题名: 新型结构规整型星状生物降解性聚乳酸的合成与结晶动力学研究
作者: Hao QH(郝庆辉) ; Li FX(李发学) ; Li QB(李巧波) ; Li Y(李洋) ; Jia L(贾林) ; Yang J(杨晶) ; Fang Q(房强) ; Cao AM(曹阿民)
通讯作者: 曹阿民
刊名: Biomacromolecules
发表日期: 2005
卷: 6, 期:4, 页:2236-2247
收录类别: SCI
部门归属: 上海有机所; 东华大学; 西北大学
英文摘要: This study presents syntheses, structural characterization, and crystallization kinetic investigation of new structurally well-defined star-shaped poly(L-lactide)s (PLLAs). First, a series of new 3- to 6-arm star-shaped PLLAs were synthesized through SnOct(2) catalyzed ring-opening polymerization of (L)-lactide with natural sugar alcohols of glycerol, erythritol, xylitol, and sorbitol as the favorable initiators. Subsequently, their chemical structures were characterized by means of GPC, NMR, and viscometer with respect to the star-shaped structures, demonstrating the well-defined arm structures as evidenced on the g(1/2)/g' values, where g and g' denote the ratios of mean-square radius of gyration and intrinsic viscosity of a star-shaped polymer to those of a linear structural reference with similar absolute molecular weight. Furthermore, spherulite morphologies and growth rates were studied by a polarized microscopy (POM) for the synthesized starshaped PLLAs with different molecular weights, and it was found that the more arms of a star-shaped PLLA finally resulted in a lower spherulite growth rate. With regard to the crystallization kinetics of these star-shaped PLLAs, isothermal and nonisothermal crystallization were examined by differential scanning calorimeter DSC. It was found that Avrami exponent n values of isothermal crystallization were almost independent of the isothermal crystallization temperature T, for different series of star-shaped PLLAs. In contrast, the values of Avrami exponent n were observed to strongly depend on the star-shaped structures with different arms, implying their distinct nucleation mechanisms, and the more arms of a star-shaped PLLA led to a slower isothermal crystallization rate. On the basis of a modified Avrami equation, new light was shed on the nonisothermal crystallization kinetics for the star-shaped PLLAs, and the activation energies were found to vary from 146.86 kJ/mol for the linear PLLA EG-3 to 221.23 kJ/mol of the star-shaped S-3, demonstrating much decreased crystallizabilities of star-shaped PLLAs with more arms.
语种: 英语
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WOS记录号: WOS:000230498400056
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内容类型: 期刊论文
URI标识: http://ir.sioc.ac.cn/handle/331003/22894
Appears in Collections:高分子材料研究室_期刊论文

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Recommended Citation:
Hao QH,Li FX,Li QB,et al. Preparation and crystallization kinetics of new structurally well-defined star-shaped biodegradable poly(L-lactide)s initiated with diverse natural sugar alcohols[J]. Biomacromolecules,2005,6(4):2236-2247.
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