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作 者:袁朝圣[1] 王征[1] 王永强[1] 朱祥[1] 杨坤[1] 程学瑞[1] 苏磊[1]
机构地区:[1]郑州轻工业学院高压科学与技术研究中心,河南郑州450002
出 处:《高压物理学报》2014年第5期513-518,共6页Chinese Journal of High Pressure Physics
基 金:国家自然科学基金(21273206;51002144;31201377);河南省教育厅科学技术研究重点项目(12B140018)
摘 要:采用高压技术实现了500 MPa下聚左旋乳酸(PLLA)在稀薄二甲苯溶液中的单晶生长,采用透射电子显微镜、拉曼光谱和红外光谱对样品的结晶形态和结构进行了表征,考察了高压对聚左旋乳酸单晶生长行为的影响。结果表明,在相同的结晶温度和时间下,高压结晶PLLA的单晶仍为α-型晶体,但单晶尺寸明显大于常压样品;高压环境下PLLA分子链在晶核两端的生长扩散速率不同,容易形成非对称的菱晶形态;高压影响PLLA晶体中分子链的构象分布;在单晶生长期,高压诱导有利于PLLA晶体成核,但不利于单晶生长。Lamellar single crystals of poly (L-lactic acid) (PLLA) were prepared from its dilute xylene solutions under 500 MPa by an isothermal crystallization method. Their morphology and structural features were characterized by transmission electron microscopy, raman and infrared spectra. The results show that the single crystals of PLLA grown under high pressure are only a-type crystal struc- ture,and their average size is larger than those obtained under atmospheric conditions. Under high pressure,crystal nucleus on different sides have different growth rates, leading to the formation o{ asymmetric rhombic lozenge. It is found that high pressure has induced conformational distribution change of the PLLA single crystal. Furthermore, during the PLLA crystal growth period, high pressure induction is favorable for promoting the nucleus number and depressing the grown of PLLA crystal.
关 键 词:聚左旋乳酸(PLLA) 等温结晶 高压 单晶
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