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首页> 外文期刊>Journal of Applied Polymer Science >Atomic Force Microscopy (AFM) Study of Poly(ethylene terephthalate-co-4,4'-bibenzoate): A Polymer of Intermediate Structure
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Atomic Force Microscopy (AFM) Study of Poly(ethylene terephthalate-co-4,4'-bibenzoate): A Polymer of Intermediate Structure

机译：聚对苯二甲酸乙二醇酯-co-4,4'-联苯甲酸酯的原子力显微镜（AFM）研究：一种中间结构的聚合物

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摘要

An atomic force microscope (AFM) operating in both tapping and contact modes was used to study the surface topography and the molecular organization of a molded flexural test bar prrepared form a poly(ethylene terephthalate-co-4,4'-bibenzoate) copolymer contaiing a terephthalate:4,4'-bibenzoate molar ratio of 45:55 (PETBB-55). Micrometer-scale (15 X 15 #mu#m) contact-mode AFM images revealed that the PETBB surface contains a deep indetation that forms trenches that extend over the entire surface examined. In addition, the surface may appear as an overlay of fibrils having different orientation. At greater magnification (1 x 1 #mu#m), it is possible to observe the existence of micropores. These results wee also observe din images obtained while operating the AFM in the taopping mode. The side of the part is more homogeneous and ordered than is its top surface. It has the appearance of a stacked lamellar structure in which missing fibrils can originate cracks approx 0.5-#mu#m wide. Fine surface details were observed in which they are almost parallel to each other and have a preferred orientation: this structural organization was generated without any orientation other than that produced during a mold flow. Alternatively, chain lengths are interrupted and while spots form, distorted by easily recognizable hexagonal arrangements. The degree of lamellar order observed in the side of the bar, the area of greatest flow orientation in the part, was not been observed for the PET homopolymer in the past and bears some resemblance ot previously imaged liquid crystalline polyester (LCP) structures. Combined with some previously reported LCP-like mechanical properties, we propose that this PETBB copolymer is, in fact, a "frustrated LCP," one that with some driving force could be convered to liquid crystallinity.
机译：使用在敲击和接触两种模式下运行的原子力显微镜（AFM）研究了由聚对苯二甲酸乙二酯-co-4,4'-联苯甲酸酯共聚物构成的模制挠曲测试棒的表面形貌和分子结构对苯二甲酸酯：4,4'-联苯甲酸酯的摩尔比为45:55（PETBB-55）。微米级（15 X 15＃mu＃m）接触模式AFM图像显示，PETBB表面含有深厚的内含物，形成了在整个被检表面上延伸的沟槽。另外，该表面可以表现为具有不同取向的原纤维的覆盖物。在更大的放大倍率下（1 x 1＃mu＃m），可以观察到微孔的存在。这些结果还观察到在倒模模式下运行AFM时获得的din图像。零件的侧面比其顶面更均匀且有序。它具有堆叠的层状结构的外观，其中缺失的原纤维会产生大约0.5-＃μ＃m的裂纹。观察到精细的表面细节，其中它们几乎彼此平行并具有优选的方向：生成这种结构组织时，除了在模具流动过程中产生的取向外，没有任何其他取向。可替代地，链长被中断并且在形成斑点的同时由于易于识别的六边形布置而变形。过去从未在PET均聚物上观察到在棒的侧面观察到的层状有序度，即该部分中最大的流动取向，并且与先前成像的液晶聚酯（LCP）结构有些相似。结合一些先前报道的类似LCP的机械性能，我们认为，这种PETBB共聚物实际上是一种“受挫的LCP”，可以通过某种驱动力将其转化为液晶性。

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