Morphology-property investigation

An ongoing example of correlating morphology and properties is that of the mechanical behavior of engineering polymers. In the case of tensile deformation, one ideally follows changes in 

Optical microscopy [24,25] and light scattering [26] studies in the 1960s showed clearly that spherulites underwent large-scale deformation as entities. In this earlier work, a specimen was extended a certain amount and then held there until a measurement was made (over several minutes) and then extended to the next level stretch-hold investigation). But polymer spherulites are composed of ribbonlike crystals, with intervening layers of uncrystallized material. How does this finer structure deform so as to allow spherulites to change 

Fairly recently, IR measurements have been combined with mechanical testing and synchrotron X-rays, providing additional information on changes within the chain [35]. Finally, microbeam synchrotron X-ray investigation has permitted the study of structural variations at different positions within a specimen, for instance, skin versus core in fibers [36]. 

It should be mentioned that the spherulite size itself can be important in the failure behavior of spherulitic polymers. Some early literature in this area can be found in Refs [37] and [38]. 

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Literature search shows that epoxy-based nanocomposites have been prepared by many researchers [34-38]. Becker et al. have prepared nanocomposites based on various high-functionahty epoxies. The mechanical, thermal, and morphological properties were also investigated thoroughly [39 3]. The cure characteristics, effects of various compatibilizers, thermodynamic properties, and preparation methods [16,17,44 9] have also been reported. ENR contains a reactive epoxy group. ENR-organoclay nanocomposites were investigated by Teh et al. [50-52]. 

The term star-block copolymer is used for a star architecture in which each arm is a diblock. The influence of chain topology on mechanical and morphological properties was investigated for copolymers composed of PS and PB with a constant styrene content of = 0.74 by Michler s group (Fig. 32) [101,102], While hexagonally packed cylinders of PB in a PS matrix were observed in a symmetric PS-fo-PB-fr-PS triblock copolymer, an L phase... 

Foams were prepared from blends of EVA and ethylene-styrene interpolymers having styrene contents ranging from 30 to 73 wt.% and Tgs ranging from -2 to 33C, in the presence of various amounts of dicumyl peroxide and their viscoelastic and mechanical properties investigated. The effects of styrene content and peroxide concentration on the morphology, degree of crosslinking and expansion ratio of the foams were assessed as was the influence of the type of ethylene-styrene interpolymer on the Tg of the foams. It was found that the Tg of the blends could be tailored by selection of the appropriate interpolymer. 19 refs. 

PP-structural foam mouldings were produced on an injection moulding machine in a pre-pressurised mould cavity by the classical low-pressure process and an alternative low-pressure process. Melt temperature, injection direction and sprae diameter were varied. Cross-sections cut from the middle of the small cylinder in longitudenal orientation were investigated by site-resolved X-ray scattering. Morphological properties were investigated. 4 refs. 

The structural and morphological properties of monoclinic Zr02 samples calcined at increasing temperatures were investigated by XRD, HRTEM, and IR techniques (603, 604). The data show that the (111) face is predominant, and the (001) and (011) faces were observed only for samples sintered at low temperatures. Two types of surface OH groups and undissociated, strongly coordinated H20 molecules were detected by IR spectroscopy. Computer simulations of the (111), (001), and (011) faces were used to explain the experimental results. 

N.K. Dutta, N.D. Tran, and N.R. Choudhury, Perfluoro(methylcyclohexane) plasma pol3fmer thin film Growth, surface morphology, and properties investigated hy scanning thermal microscopy, J. Polym. Sci. B., 43, 1392-1400 (2005). 

Cellulose has been dissolved in A-methylmorpholine iV-oxide at high temperature and the recrystallization of the polysaccharide upon cooling investigated." The crystallization system is analogous to the solidification of binary mixtures of polymer and diluent, which present unusual thermodynamic and morphological properties. The system provides a new method of texturing cellulose. 

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