Syndiotactic polystyrene morphology

Since the last edition several new materials have been aimounced. Many of these are based on metallocene catalyst technology. Besides the more obvious materials such as metallocene-catalysed polyethylene and polypropylene these also include syndiotactic polystyrenes, ethylene-styrene copolymers and cycloolefin polymers. Developments also continue with condensation polymers with several new polyester-type materials of interest for bottle-blowing and/or degradable plastics. New phenolic-type resins have also been announced. As with previous editions I have tried to explain the properties of these new materials in terms of their structure and morphology involving the principles laid down in the earlier chapters. 

Hong, B. K. and Jo, W. H. (2000) Effects of molecular weight of SEBS triblock copolymer on the morphology, impact strength, and rheological property of syndiotactic polystyrene/ ethylene-propylene rubber blends. Polymer, 41, 2069-2079. 

Liao X, Nawaby AV, Handa YP (2007) Layered and cellular morphologies in atac-tic/syndiotactic polystyrene blends. Cell Polym 26 69-81... 

Thus, also in this case an increase in the quantity and quaUty of the available experimental data can help to remove ambiguity and aid to understand the polymer solidification in more detail. Interesting examples of the complex morphology that can be achieved in a transformation process come from the structural analysis of injection molded samples in Syndiotactic Polystyrene [22-25]. 

Syndiotactic polystyrene will strain-induce crystalhze, as well as quiescently crystallize as discussed previously. Furthermore, imder certain conditions, it may also be quenched to the amorphous state. In injection molded parts, these processes may lead to skin/core differences in morphology that can be observed (111,112). With higher temperature molds (>150°C) the parts are generally fully... 

Wang, C., C. L. Huang, Y. C. Chen, G. L. Hwang, and S. J. Tsai. 2008. Carbon nanocapsules-reinforced syndiotactic polystyrene nanocomposites Crystallization and morphological features. Polymer A9 (25) (November) 5564—5574. doi 10.1016/j.polymer.2008.09.057. http //hnkinghub.elsevier.eom/retrieve/pii/S0032386108008409. 

FAN Fang, J. and Kiran, E., Gelation, crystallization and morphological transformations of syndiotactic polystyrene in acetophenone and acetophenone -i- carbon dioxide mixtures at high pressures, J. Supercrit. Fluids, 49, 93, 2009. 

Han, J. J., Yoon, W. J., Lee, H. W., Choi, K. Y. Nascent morphology of syndiotactic polystyrene synthesized over silica-supported metallocene catalyst. Polymer, 49, 4141 149 (2008). 

Structure, Morphology, and Crystallization Behavior of Syndiotactic Polystyrene... 

Cai, J., Han, Y. Morphology, structure, and kinetic analysis of nonisothermal cold- and melt-crystallization of syndiotactic polystyrene. J. Appl. Polym. Sci, 103,1311-1324 (2007). 

Wang, C., Lin, C-C., Chu, C-P. Crystallization and morphological features of syndiotactic polystyrene induced from glassy state. Polymer, 46, 12595-12606 (2005). 

Sun, Y. S., Woo, E. M. Correlation between thermal behavior and crystalhne morphology in P-form syndiotactic polystyrene. Macromol. Chem. Phys., 202(9), 1557-1568 (2001). 

Wang, C., Cheng, Y-W., Hsn, Y-C., Lin, T-L. Lamellar morphology and equilibrium melting temperature of syndiotactic polystyrene in P crystaUine form. J. Polym. Sci. Part B Polym. Phys., 40,1626—1636 (2002). 

Pantani, R., Sorrentino, A., Speranza, V., Titomanlio, G. Morphology distribution in injection moldings of syndiotactic polystyrene. PPS-Polymer Processing Society, 18th Annual Meeting, Taipei, Taiwan, November 4-8,2002. 

Wang, C., Chen, C-C., Hung, C-H., Lin, K-S. Lamellar morphologies and crystal stability of syndiotactic polystyrene in a-crystalline form. Polymer, 45,6681-6689 (2004). 

Guadagno, L., Raimondo, M., Silvestre, C, Immediata, I., Rizzo, R, Guerra, G. Processing, thermal stability and morphology of chiral sensing syndiotactic polystyrene films. J. Mater. Chem., 18, 567-572 (2008). 

Zhang, X. Q., Son, Y. Effects of maleated syndiotactic polystyrene on the morphology, mechanical properties, and crystallization behavior of syndiotactic polystyrene/polyamide 6 blends. Journal of Applied Polymer Science, 89(9), 2502-2506 (2003). 

The smaller the arc, the higher the orientation. If/is 1, then the fiber is completely oriented if/is 0, then it is randomly oriented and if/is -0.5, then orientation is perpendicular to the fiber direction. Orientation may also be present because a polymer has liquid crystalline properties and an orientation parameter may be similarly calculated. A combination of FTIR and XRD has been recently used in the analysis of the complex morphology of biaxially oriented syndiotactic polystyrene films [14]. 

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