Polymer Morphology and Crystal Structure

首席研究员（P.I.）建议在两个领域进行研究：1)继续开发研究人员的受限薄膜熔体聚合（CTFMP）技术，用于同时聚合/结晶缩合聚合物的单晶，适用于电子衍射（ED）晶体结构的测定；2)重新检查聚合物形态学中的两个“被忽视的问题”。建议将CTFMP技术用于一些感兴趣的聚合物：a)将聚（n-二甲酸乙二醇酯）系列扩展到n值高于2；b)利用基底处理技术生产II相聚（对氧苯甲酸酯）单晶，并尝试“催化”II相晶须生长；C)对称聚(2,6-萘- 2,6-萘二甲酸酯和聚（2,6-萘对苯二甲酸酯）；d)间氧苯甲酸酯和邻氧苯甲酸酯与对氧苯甲酸酯和2,6-氧膦酸酯缔合的均聚物和共聚聚酯。晶体结构，从ED数据辅助建模，形貌通过透射电子显微镜（TEM）和热性能通过DSC将确定所有上述。过渡行为也将适当地用TEM热阶段ED表征。x射线衍射用于与能谱图进行比较，FTIR用于成分、聚合证明和分子量表征，将补充能谱图、透射电镜和DSC研究。对一些系统的兴趣还在于非周期经向间距的起源。此外，P.I.建议重新审视和扩展先前的研究结晶聚合物薄膜的同时双轴变形和熔融结晶聚四氟乙烯（PTFE） （PTFE） （PTFE）的形态的影响。最近的研究表明，单分子单晶（SMSC），折叠和扩展链片和分离的羊肉串都可以从分散的分散颗粒生长在衬底上，并伴有大规模的分子迁移。从纤维中提取的x射线衍射早已被用于聚合物晶体结构的测定。这里提出的研究的一部分继续努力证明用电子衍射补充，有时取代x射线研究的可取性；结合研究者独特的聚合物单晶样品制备技术，电子衍射法往往更简单，（倒）晶格直接可见。研究中选择的聚合物包括刚性（液晶）和柔性骨架，其中许多具有当前和/或潜在的商业利益。这项研究将继续与捷克共和国兹林的新托马斯巴塔大学（前布尔诺技术大学的一部分）的Rybnikar教授合作。在过去的十年中，国际项目基金在帮助大学发展计算机和扫描设备方面发挥了重要作用，共有19篇论文是共同撰写的。另外两个提议的主题涉及发展对许多聚合物薄膜生产中涉及的双轴变形的理解和聚四氟乙烯（即聚四氟乙烯）的纳米结构。后者是与戈尔协会的P. Xu博士合作进行的。在使用聚四氟乙烯作为纳米级涂层和聚合过程方面具有实际意义。除了两名研究生将得到这项资助外，伊利诺伊大学材料科学与工程系聚合物专业的两名本科生也将被纳入研究项目，这将鼓励他们继续攻读更高的学位。所有最近由NSF资助的本科生在P.I.进行研究，他们都是已发表论文的共同作者，并继续攻读高级学位。

The principal investigator (P.I.) proposes research in two areas: 1) continued exploitation of the researcher's confined thin film melt polymerization (CTFMP) technique for the simultaneous polymerization/crystallization of single crystals of condensation polymers suitable for electron diffraction (ED) determination of crystal structures and 2) a re-examination of two "overlooked problems" in polymer morphology. Utilization of the CTFMP technique is proposed for a number of polymers of interest: a) extension of the poly(n-glycol naphthalate) series to n values above 2; b) utilization of a base substrate treatment technique to produce phase II poly(p-oxybenzoate) single crystals complemented by attempts to "catalyze" phase II whisker growth; c) the symmetric poly(2,6-naphthalene 2,6-naphthalate and poly(2,6-naphthalene terephthalate); and d) the kinked homopolymer and copolymer polyesters of m-oxybenzoate and o-oxybenzoate with p-oxybenzoate and 2,6-oxynaphthoate. Crystal structures, from ED data aided by modeling, morphology by transmission electron microscopy (TEM), and thermal properties by DSC will be determined for all of the above. Transition behavior will also be characterized by TEM hot stage ED as appropriate. X-ray diffraction, for comparison with the ED, and FTIR, for composition, proof of polymerization and molecular weight characterization, will complement the ED, TEM and DSC studies. For several of the systems interest also lies in the origin of aperiodic meridional spacings. In addition the P.I. proposes to reexamine and extend prior studies of the effect of simultaneous biaxial deformation of crystalline polymer films and the morphology of melt-crystallized poly(tetrafluoroethylene) (PTFE) Recent studies of PTFE suggest single molecule single crystals (SMSC), folded and extended chain lamellae and isolated shish-kebabs can all be grown from dispersed dispersion particles on substrates, accompanied by large scale molecular mobility.X-ray diffraction from fibers has long been used for polymer crystal structure determination. One portion of the research proposed here continues efforts in demonstrating the desirability of complementing, sometimes replacing, x-ray studies with electron diffraction; combined with the researcher's unique polymer single crystal sample preparation technique, the electron diffraction method is often simpler, with the (reciprocal) lattice being directly visualized. The polymers chosen for the research include those with both rigid (liquid crystalline) and flexible backbones, with many being of current and/or potential commercial interest. This research will continue the collaboration with Prof. Rybnikar of the new University of Tomas Bata (formerly part of Technical University of Brno) in Zlin, Czech Republic. International Program funds in the previous grant were instrumental in aiding in the development of computer and scanning facilities at the University, with 19 papers being co-authored over the last decade. Two additional proposed topics involve developing an understanding of the biaxial deformation involved in the production of many polymer films and the nano-structure of PTFE (i.e., Teflon). The latter is in collaboration with Dr. P. Xu of Gore & Assoc., Inc. and is of practical concern relative to both the use of PTFE as nano-scale coatings and the polymerization process. In addition to the two graduate students to be supported by this grant, the incorporation in the research program of two undergraduates from the Polymer Concentration in the University of Illinois's Materials Science and Engineering Department is expected to encourage their continuation for advanced degrees. All recent NSF supported undergraduates conducting research with the P.I. have both been co-authors of published papers and have continued on for advanced degrees.