Syndiotactic polystyrene applications

Syndiotactic polymerization, 76 99-102 Syndiotactic polymethacrylate esters, glass transition temperatures of, 76 273t Syndiotactic polypropylene, 20 524 Syndiotactic polystyrenes (SPS), 23 365 Syndiotactic polystyrene, 70 180-183 applications for, 70 183 properties of, 70 182... 

Syndiotactic Polystyrene. Syndiotactic polystyrene is an interesting material because it has a Tg of 95 °C and a Tm of 260 °C [38], Polystyrene made via radical polymerisation may show some syndiotacticity, but its heat distortion temperature is too low to allow its use in important applications requiring temperatures around 120 °C or higher, such as medical equipment which requires sterilization or hot water storage containers. Idemitsu and Dow have reported titanium-based catalysts such as the one shown in Figure 10.23. We presume that the mechanism is a chain-end controlled "2,1" insertion. 

Ishihara et al. reported in 1986 that syndiotactic polystyrene can be prepared with the aid of organic or inorganic titanium compounds activated with methylaluminoxane [177]. There is much greater incentive to commercialize syndiotactic polystyrene than the isotactic one. This is because isotactic polystyrene crystallizes at a slow rate. That makes it impractical for many industrial applications. Syndiotactic polystyrene, on the other hand, crystallizes at a fast rate, has a melting point of 275°C, compared to 240°C for the isotactic one, and is suitable for use as a strong structural material. 

In the present text we attempt to do justice to the different topics of polymers and their uses. This text is generally suitable for researchers rather than students. The first chapter of this book discussed sorption mechanism of organic compound in the nanopore of syndiotactic polystyrene crystal. In the second chapter, a discussion was done to illustrate a physico-chemical characterization and processing of pulse seeds. The chemo-enzymatic polymerization for peptide polymers were illustrated in the third chapter. In the fourth chapter, an electrokinetic potential method was used to characterize the surface properties of polymer foils and their modifications. Also, an emulsion polymerizations was discussed in the fifth chapter. Nonconventional methods of polymer surface patterning, polymer characterization using atomic force microscope, biopolymers in the environment, and carbon nanostructure and their properties and applications were discussed in the sixth, seventh, eighth and ninth chapters respectively. Finally, let us point that although many books in the field of pol)nner science appear, none of them are complementary. 

An example of the latter is Dow s development of syndiotactic polystyrene, which has the properties of an engineering plastic. Also important is the incorporation of comonomers in a highly uniform manner. Again, Dow has produced an 80% ethylene/20% octane elastomer (89). Metallocene polymers have mainly been used in higher priced specialty applications (). 

Syndiotactic polystyrene (sPS) is a relatively new material discovery in semicrystalline pol5nners with a high melting point and rapid crystallization rate, which makes it possible to injection mold the material. The stereospecific polymerization was made possible by the combination of a transition metal catalyst with weakly coordinating cocatalysts, such as methylaluminoxane. The excellent balance of mechanical, electrical, solvent resistance, and dimensional stability properties combined with a relatively low price (based on styrene monomer) have made this material a competitor to existing engineering plastics. The products also have excellent heat performance and are finding application in antomotive (under the hood), electrical, and electronic connector systems. 

The physical and mechanical properties of a polymeric material critically depend on many factors, one of which is stereochemistry. Polymers that have chiral centers in the repeated unit can exhibit two structures of maximum order, isotactic and syndiotactic [27]. Sequential stereocenters of isotactic polymers are of same relative stereochemistry whereas those of syndiotactic polymers are of opposite relative configuration. Due to their stereoregularity, isotactic and syndiotactic polymers are typically crystalline, which is an important feature for many applications. Isotactic polymers are used in a wide range of applications. Typical examples include isotactic polyolefins and almost all natural polymers. In contrast, syndiotactic polymers have limited applications mainly due to their hard productivity and inherently alternating stereochemistry. The properties of syndiotactic polymers are usually similar to or in some cases better than isotactic counterparts according to the studies on syndiotactic polystyrene and other syndiotactic polyolefins [28]. Syndiotactic PLA is expected to be a versatile polymer with controllable stereochemistry. 

Other applications of FTIR in microstructural analysis of homopolymers include 1,4-diazophenylene - bridged Cu-phthalocyanine [63], isobornyl methacrylate [64], polypropylene [65, 66], polyaniline [67, 68], polycaprolactone [69], viscose fibres [70], Kevlar [71], polystyrene sulfonic acid [66, 72], syndiotactic polystyrene [73], isotactic polypropylene [66,74,75], polyurethane [76], PMMA [75, 77], poljmrethane ether [78], PE [79-80], fluorinated acrylates [81], rigid PU [82], N-(2-biphenyl)4-(2 phenylethynyljphthalamide [83], polyacrylic acid [84], polysodium styrene sulfonate [84], and polyacrylic acid [85]. 

Aliphatic polyketones offer toughness, chemical resistance, and wear resistance and was targeted to compete with polyamides, thermoplastic polyesters, and syndiotactic polystyrene in the electrical connector market and POM in gear and barring applications. 

The purpose of providing a brief overview on recent reviews of nanocomposite materials that discuss synthesis, structure properties, and applications is to bring to the reader s attention the nascence of this field and justify the rare availability of degradation studies of these materials when we have only recently embarked on our journey to understanding the fundamentals about them. Nevertheless, a few examples of degradation studies of nanocomposite materials are provided with the hope of advances towards mechanistic aspects of degradation with nanomaterials components. Chrisaffis et al [56, 57] report studies on the decomposition mechanisms of syndiotactic polystyrene (sPS) nanocomposites with two different types of nano fillers multi-walled carbon nanotubes (MWCNTs) and carbon nanodiamonds (NDs). sPS is a semicrystalline polymer considered to be a... 

Syndiotactic polystyrene, once commercially available from Dow as Questra , continues to be available from Idemitsu Kosan (Japan)(Xarec ) and is available in fiberglass filled versions as well as impact modified versions for electrical, automotive and appliance applications. Blends with polystyrene are noted and presumably include impact polystyrene to achieve toughened versions. 

Preparation, Structure, Properties, and Applications of Co-Crystals and Nanoporous Crystalline Phases of Syndiotactic Polystyrene... 

Structure, preparation, properties, and applications of the nanoporous crystalline phases of syndiotactic polystyrene are described in section 3 of this chapter. 

The field of co-crystalline and nanoporous polymer materials is expected to be widely expanded. In fact, until now, only materials based on syndiotactic polystyrene have been considered for possible applications. Relevant new cocrystalline and nanoporous materials are expected in the future for other stereoregular polymers. 

Schellenberg, I, Leder, H.-J. Syndiotactic polystyrene Process and applications. Adv. Polym. TechnoL, 25,141-151 (2006). 

Because of its semicrystalline nature, syndiotactic polystyrene (SPS) exhibits performance attributes that are significantly different from amorphous sty-renic materials. These properties include a high melting point, excellent hydrocarbon resistance, a high degree of dimensional stabUity, and excellent electrical performance. This combination of properties opens a wide array of potential applications. These applications are arrived at through a combination of formulation science and melt processing to enable maximum benefit from the crystalline structure of the material [1]. 

Bank, D., Wessel, T., Kolb, I J. Syndiotactic polystyrene A new polymer for high performance automotive applications. Proceedings from the SEE International Congress and Exposition, Detroit, MI, March 1993. 

Yamasaki, K., Tomotsu, N., Malanga, M. Characterization, properties and applications of syndiotactic polystyrene. In Modern Styrenic Polymers Polystyrenes and Styrenic Copolymers, Scheirs, J., Priddy, D. B. (eds.), John Wiley Sons, New York, 2003, pp. 389-409. 

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