Higher-order crystalline structures of poly(oxyethylene) in poly(d,l-lactide)/poly(oxyethylene) blends
Higher-order crystalline structures of poly(oxyethylene) in poly(d,l-lactide)/poly(oxyethylene) blends
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聚(d,l-丙交酯)/聚(氧乙烯)共混物中聚(氧乙烯)的高阶晶体结构
DOI：
10.1016/j.polymer.2013.06.028
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发表时间：
2013
期刊：
影响因子：
4.6
通讯作者：
S. Sakurai
中科院分区：
文献类型：
--
作者：
N. Tien;T. Hoa;M. Mochizuki;K. Saijo;H. Hasegawa;S. Sasaki;S. Sakurai
用小角X射线散射（SAXS）研究了聚乳酸/聚乙二醇（PLA/PEG）共混物的高阶结晶结构。为了这个目的，两种聚合物都是结晶的这一事实使得情况变得更加复杂。为了简化，我们使用非结晶PLA：聚（d，l-丙交酯）（DLPLA），这是一种包含d-和l-丙交酯部分的外消旋共聚物。在各种共混物样品以及PEG 100%样品中观察到由PEG的有序层状堆叠产生的高阶峰（即晶格峰），所有这些样品均由其二氯甲烷溶液浇铸而成。令人惊讶的是，我们发现在DLPLA的组成为5-20重量%的DLPLA/PEG的共混物中的结构比在PEG 100%样品中的结构或多或少规则。我们进一步研究了这种规则结构随温度的变化，发现了非常特殊的SAXS曲线，仅低于熔化温度1 °C，这可以归因于层状颗粒散射。据我们所知，这种定义明确的颗粒散射既没有报道的聚合物共混物，也没有晶体层状结构。此外，对于PEG 100%样品和具有5-20重量%DLPLA的共混物样品，在室温至64 °C的温度范围内观察到从晶格散射到颗粒散射的交叉。
Higher-order crystalline structures in blends of poly(lactide)/poly(oxyethylene) (PLA/PEG) were investigated using small-angle X-ray scattering (SAXS). For this purpose, the fact that two polymers are both crystalline makes situation much complicated. To simplify, we used non-crystalline PLA: poly(d,l-lactide) (DLPLA), which is a racemic copolymer comprisingd- andl-lactide moieties. Higher-order peaks arising from the ordered lamellar stacking of PEG (i.e. the lattice peaks) were observed in the various blend samples, as well as in the PEG 100% sample, all of which were cast from their solutions in dichloromethane. Surprisingly, we found that the structure is more or less regular in the blend of DLPLA/PEG at compositions of 5–20 wt% of DLPLA than that in the PEG 100% sample. We further examined changes in such regular structures with temperature and found very peculiar SAXS profiles just 1 °C below melting temperature, which can be ascribed to a lamellar particle scattering. To our best knowledge, such a well-defined particle scattering has neither been reported for polymer blends, nor for the crystalline lamellar structure. Moreover, crossover from the lattice scattering to the particle scattering was observed in the temperature range from room temperature to 64 °C for the PEG 100% sample and blend samples with 5–20 wt% of DLPLA.
影响因子：
5.5
作者：
Fukushima, Kazuki;Hirata, Masayuki;Kimura, Yoshiharu
通讯作者：
Kimura, Yoshiharu
影响因子：
5.5
作者：
Shiomi, T;Takeshita, H;Miya, M
通讯作者：
Miya, M