Applications of Syndiotactic Polystyrene

TOM FIOLA, AKIHIKO OKADAMASAMI MIHARA, and KEVIN NICHOLS  

The principal performance limitations of GPPS are brittleness limited heat resistance and poor chemical resistance to oils, aromatic and chlorinated hydrocarbons, esters, ketones, and aliphatic hydrocarbons. Riled grades of GPPS are available but offer limited improvements in mechanical properties and sacrifice transparency and clarity. The blending, alloying, and copolymerization of polystyrene is frequently employed to improve toughness, offering some improvement in chemical resistance but little to improve heat resistance [2]. 

Improvements in the performance of homopolymer GPPS through polymerization with traditional Ziegler-Natta catalysts are primarily limited to flow and glass transition temperatures. Polymerization into an isotactic backbone configuration results in a semicrystalUne structure that improves both heat and chemical resistance however, isotactic polystyrene (IPS) is slow to crystallize and therefore of little practical use with modem injection molding production techniques [3]. 

Syndiotactic Polystyrene, Edited by Jurgen Schellenberg Copyright 2010 John Wiley Sons, Inc. 

In contrast to atactic GPPS, the SPS configuration results in a dramatic improvement in the heat and chemical resistance of polystyrene due to the semicrystalhne structure of SPS. With a melting point of 210°C and improvements in the chemical resistance to oils, aliphatic hydrocarbons, esters, and ketones, SPS extends the performance envelope of polystyrene and offers designers another option to capture the inherent benefits of the polystyrene structure. 

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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. 

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 (). 

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... 

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. 

Blends of two immiscible polymers are created to yield a material with properties that could not be obtained otherwise. Each component of the blend overcomes the property deficiencies of the other component of the blend. In the case of syndiotactic polystyrene (SPS)/polyamide (PA nylon) blends, the blends have improved strength, ductility, and creep versus SPS formulations, and the blends have improved dimensional stability and flow versus nylon compounds. Other attributes of the SPS/nylon blends are low specific gravity (lower weight parts), high thermal diffusivity (low cycle time), excellent electrical properties, good chemical resistance, and excellent United States Council for Automotive Research (USCAR) electric wiring components test performance. In this chapter, the composition, properties, and applications for SPS/ nylon blends will be reviewed. 

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. 

A number of halogenated polystyrenes are used in practice, either for specific applications as thermoplastics or in copolymers. Among the halogenated polystyrenes, the most common are the poly(chlorostyrenes). Poly(4-chlorostyrene) can be obtained in isotactic form (CAS 24991-47-7) or in syndiotactic form (CAS 62319-29-3) and is represented by the formula [-CH2CH(p-C6H4CI)-]n. Other poly(chlorostyrenes) include poly(2-chlorostyrene) with CAS 26125-41-7, and poly(3-chlorostyrene) with CAS 26100-04-9, CAS 116002-24-5 (isotactic), and CAS 107830-48-8 (syndiotactic). 

Figure 9.36 Raman spectra of polybutadiene-polystyrene copolymer in the C=Cstretching region showing three distinct bands of polybutadiene isomers cis-1,4 at 1650 cm-1, trans-1,4 at 1665 cm-1 and syndiotactic-1,2 at 1655 cm-1 (a) spectrum from the center of sample and (b) spectrum from the edge of sample. (Reproduced with permission from G. Turrell and J. Corset, Raman Microscopy, Developments and Applications, Academic Press, Harcourt Brace Company, London. 1996 Elsevier B.V.)...

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. 

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]. 

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