U.S.-Bulgarian Research on Microfibrillar-Reinforced Polycondensate Blends

小行星9307812 这笔赠款支持美国-保加利亚联合合作研究“微纤维增强缩聚物共混物”博士。Schultz和保加利亚索菲亚大学聚合物结构和性质实验室的Stoyko Fakirov博士。 此前，研究人员表明，具有异常高的单轴机械性能的不相容缩聚物共混物可以通过三阶段工艺生产：（1）单轴冷拉伸;（2）高于不连续相的熔融或软化温度的热处理;和（3）在与固态交换反应一致的温度范围内持续热处理。 表明纤维状晶体或玻璃在第一阶段形成，而“基质”在第二阶段松弛。 最不寻常的阶段是第三阶段，其中原纤维/基质界面似乎是通过交换反应增容。 有了这笔赠款，将进一步研究上述过程，以表征和测试建议结构开发的所有阶段。 模型不相容体系中界面交换反应的动力学研究将采用光谱和其他方法。 研究人员将使用他们实验室最近开发的透射电子显微镜方法和小角度x射线散射来检查微纤维微观结构假设。 他们将遵循链取向的变化与处理时间和温度，使用红外线电子学。 他们将测量选定材料的机械性能，并将其与他们使用微观结构表征开发的模型相匹配。 这项材料科学研究通过使美国和保加利亚的领先专家能够联合收割机互补人才并在共同感兴趣和能力强的领域汇集研究资源来实现推进科学的计划目标。

9307812 Schultz This grant supports U.S.-Bulgaria joint cooperative research on "Microfibrillar-Reinforce Polycondensate Blends" between Dr. Jerold M. Schultz of the University of Delaware and Dr. Stoyko Fakirov of the Laboratory on Structure and Properties of Polymers, Sofia University, Bulgaria. Previously, the researchers showed that incompatible polycondensate blends of unusually high uniaxial mechanical properties can be produced through a three- stage process: (1) uniaxial cold-drawing; (2) heat-treatment above the melting or softening temperature of the discontinuous phase; and (3) continued heat-treatment in a temperature range consistent with solid-state exchange reaction. Indications are that fibrillar crystals or glass are formed in the first stage, and the "matrix" is relaxed in the second. The most unusual stage is the third, where the fibril/matrix interface appears to be compatibilized through an exchange reaction. With this grant, the preceding process will be further studied, to characterize and test all phases of the suggested structure development. Kinetic studies of interfacial exchange reactions in model incompatible systems will be followed by spectroscopic and other means. The researchers will examine the microfibrillar microstructural hypothesis using transmission electron microscope methods developed recently in their laboratory and also by small-angle x-ray scattering. They will follow changes in chain orientations with processing time and temperature, using infrared dichronism. They will measure mechanical properties of selected materials and fit them to models they developed using microstructural characterizations. This research in materials science fulfills the program objectives of advancing science by enabling leading experts in the U.S. and Bulgaria to combine complementary talents and pool research resources in areas of strong mutual interest and competence.