Structural Analyses of Biomaterial Surfaces by X-ray Diffraction

首先，建立了所谓的“薄膜x射线衍射”和/或“x射线衍射的玻璃角度入射角”实验装置。然后，利用该体系对等规聚丙烯和聚丁烯-1等聚α-烯烃进行了表面分析。对不同温度和时间的空气退火薄膜进行了表面结晶度和体部结晶度的比较。无论退火条件如何，表面的结晶度都比体低。在离表面几微米的深度处，结晶度发生了剧烈的变化，靠近表面的结晶度越来越低。表面的表观晶粒尺寸较小。这些结果表明，由于局部缺陷（包括链端）和高链迁移率，晶体生长受到表面附近的限制。高温退火引起表面氧化，使表面结晶度降低。该方法还检测了由于熔体淬火引起的表面残余应力。研究了这些聚α-烯烃的共混物。结果表明，与聚丁烯-1相比，聚丙烯组分的表面自由能较低，在表面占主导地位。然后，将该系统扩展到聚乙烯醇及其层压板的表面和界面结构分析。这些新颖的x射线衍射方法被认为是研究高分子生物材料表面和界面结构的有力手段。

First of all, the experimental apparatus for so-called "Thin Films X-ray Diffraction" and/or "Glazing Angle Incidence of X-ray Diffraction" was set up.After that, by using these system, the surface was analyzed for poly-α-olefins, such as isotactic polypropylene and polybutene-1. The comparison of the crystallinities between the surface and the bulk was done for the films annealed in air at different temperature and times. The crystallinity was lower for the surface compared with the bulk irrespective of annealing conditions. The change in crystallinity drastically occurred up to several micrometers depth from the surface, and the crystallinity was getting low near the surface. The apparent crystallite sizes were smaller for the surface. These showed that crystal growth was restricted near the surface because of localized defects (including chain ends), and high chain mobility. Annealing at higher temperature brought the surface oxidation, which also decreased the surface crystallinity. The residual stress near the surface owing to the quenching from the melt was also detected by this method. The blends of these poly-α-olefins were also investigated. It was found that polypropylene component was predominant at the surface because of its low surface free energy compared with that of polybutene-1.Next, these system were extended for analyses of surface and interface structures of poly (vinyl alcohol) and its laminates. These novel X-ray diffraction methods were found to be quite powerful to investigate the surface and interfacial structures of polymeric biomaterials.