Multivariate analysis of DSC-XRD simultaneous measurement data: a study of multistage crystalline structure changes in a linear poly(ethylene imine) thin film
Multivariate analysis of DSC-XRD simultaneous measurement data: a study of multistage crystalline structure changes in a linear poly(ethylene imine) thin film
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DOI：
10.1007/s00216-008-2341-0
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发表时间：
2009-01-01
影响因子：
4.3
通讯作者：
Hasegawa, Takeshi
中科院分区：
文献类型：
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作者：
Kakuda, Hiroyuki;Okada, Tetsuo;Hasegawa, Takeshi
为了研究线性聚乙烯亚胺（LPEI）薄膜的结晶结构的热变化，采用多元分析技术对差示扫描量热法（DSC）和X射线衍射法（XRD）的同时测量数据进行了分析。大量的XRD图案产生的同时测量进行了增广的替代最小二乘（ALS）回归分析，和XRD图案很容易分解成化学独立的XRD图案和它们的热分布也得到了在同一时间。分解的XRD图谱和轮廓有助于讨论DSC中的微小峰。分析结果揭示了以下变化的多态性详细：通过流延水溶液制备的LPEI膜由倍半水合物和半水合物晶体。在加热的早期阶段，倍半水合物的损失，和膜变成无定形状态。一旦倍半水合物因加热而损失，即使将其冷却回室温也不能回收。当样品再次加热时，发现半水合物和无定形组分之间的结构变化。以这种方式，同时DSC-XRD测量结合ALS分析被证明是强大的，以获得更好的理解的热诱导的聚合物膜中的晶体结构的变化。
A multivariate analytical technique has been applied to the analysis of simultaneous measurement data from differential scanning calorimetry (DSC) and X-ray diffraction (XRD) in order to study thermal changes in crystalline structure of a linear poly(ethylene imine) (LPEI) film. A large number of XRD patterns generated from the simultaneous measurements were subjected to an augmented alternative least-squares (ALS) regression analysis, and the XRD patterns were readily decomposed into chemically independent XRD patterns and their thermal profiles were also obtained at the same time. The decomposed XRD patterns and the profiles were useful in discussing the minute peaks in the DSC. The analytical results revealed the following changes of polymorphisms in detail: An LPEI film prepared by casting an aqueous solution was composed of sesquihydrate and hemihydrate crystals. The sesquihydrate one was lost at an early stage of heating, and the film changed into an amorphous state. Once the sesquihydrate was lost by heating, it was not recovered even when it was cooled back to room temperature. When the sample was heated again, structural changes were found between the hemihydrate and the amorphous components. In this manner, the simultaneous DSC-XRD measurements combined with ALS analysis proved to be powerful for obtaining a better understanding of the thermally induced changes of the crystalline structure in a polymer film.