Thermoplastic elastomeric propertie

Random copolymers of e-CL with l,5-dioxepan-2-one (DXO) have been investigated [52,138,139]. The copolymers were crystalline up to a DXO content of 40%, and it was concluded that the DXO units were incorporated into the po-ly(e-CL) crystals. The block copolymerization has also been investigated and the resulting material was shown to exhibit thermoplastic elastomeric properties [63]. 

By this procedure it is possible to synthesize [150] block copolymers, having thermoplastic elastomeric properties, with a micro-domain morphology and glass transition temperatures of -120 and 105 °C, corresponding to polysiloxane and poly(MMA) blocks, respectively. 

Very recently, Coates et al. used a vinyl-substituted Upy-unit to be part of an olefin polymerization using the Brookhart catalyst. With small amounts of Upy-units incorporated, the polyolefins showed thermoplastic elastomeric properties.120... 

The microstructure and stereoblock distribution peculiar of polypropenes produced with this class of catalysts imparts thermoplastic elastomeric properties to the polymers. Thermoplastic elastomers or elastoplasts (TPEs) owe their elastomeric properties of resiliency and high tensile strength to physical cross-linking (formation of hard domains in a soft matrix) due to the presence of short, crystallizable... 

Chien, J. C. W. Iwamoto, Y. Rausch, M. D. Wedler, W. Winter, H. H. Homogeneous binary zircono-cenium catalyst systems for propylene polymerization. 1. Isotactic/atactic interfacial compatibilized polymers having thermoplastic elastomeric properties. Macromolecules 1997, 30, 3447-3458. 

Novel arborescent block copolymers comprised of mbbery PIB and glassy PSt blocks (arb-PIB-b-PSt) are described by Puskas et The synthesis was accomplished with the use of arb-PIB maaoinitiators, prepared by the use of 4-(2-meth-oxyisopropyl)styrene inimer, in conjunction with TiCU. Samples with 11.7-33.8 wt.% PSt exhibited thermoplastic elastomeric properties with 3.6-8.7MPa tensile strength and 950-1830% elongation. 

In conclusion, viologen elastomers derived from the reaction of telechelic liquid rubber with viologen moiety have high tensile properties and thermoplastic elastomeric properties. Further exj)crime 11 ts on functionalizations of NBV are being carried out. 

Fig. 10.11 The concept of self-healing sujnamolecular block copolymer design, a Conventional PS-b-PBA-b-PS triblock copolymers form a microphase-separated thermoplastic elastomer, b Supramolecular triblock copolymers combine the advantageous thermoplastic elastomeric properties of microphase-separated block copolymer systems with the reversible H-bonding interactions at the junction of the soft PBA block to afford dynamic, self-healing properties. Reproduced from Ref. [31] by permission of John Wiley Sons Ltd...

Polyuretha.ne, A type of spunbonded stmcture has been commercialized in Japan based on thermoplastic polyurethanes (15). This represents the first commercial production of such fabrics, although spunbonded urethane fabrics have been previously discussed (16). The elastomeric properties claimed are unique for spunbonded products and appear to be weU suited for use in apparel and other appHcations requiring stretch and recovery. Polyurethanes are also candidates for processing by the meltblown process. 

Because of increased production and the lower cost of raw material, thermoplastic elastomeric materials are a significant and growing part of the total polymers market. World consumption in 1995 is estimated to approach 1,000,000 metric tons (3). However, because the melt to soHd transition is reversible, some properties of thermoplastic elastomers, eg, compression set, solvent resistance, and resistance to deformation at high temperatures, are usually not as good as those of the conventional vulcanized mbbers. AppHcations of thermoplastic elastomers are, therefore, in areas where these properties are less important, eg, footwear, wine insulation, adhesives, polymer blending, and not in areas such as automobile tires. 

Over the past 40 years there have been a number of developments that have resulted in the availability of rubbery materials that are thermoplastic in nature and which do not need chemical cross-linking (vulcanisation or setting) to generate elastomeric properties (see also Section 11.8 and 31.2). This approach has been extended to the fluoroelastomers. 

Commercial thermoplastics are the engineering materials containing two or more compatibilized polymers that are chemically bounded in a way that creates a controlled and stable morphology with a unified thermodynamic profile. In view of multiplicity and contradictory requirements of various properties for most of the applications, almost all the commercial PBAs are made of two or more thermoplastics, elastomeric modifiers along with a series of compatibilizers with modifiers compounded together. A considerable number of blends have been appearing in the market regularly, some of which are listed in Table 9. 

Jha and Bhowmick [51] have reported the development and properties of thermoplastic elastomeric blends from poly(ethylene terephthalate) and ACM by solution-blending technique. For the preparation of the blend the two components, i.e., poly(ethylene terephthalate) and ACM, were dried first in vacuum oven. The ACM was dissolved in nitrobenzene solvent at room temperature with occasional stirring for about three days to obtain homogeneous solution. PET was dissolved in nitrobenzene at 160°C for 30 min and the rubber solution was then added to it with constant stirring. The mixture was stirred continuously at 160°C for about 30 min. The blend was then drip precipitated from cold petroleum ether with stirring. The ratio of the petroleum ether/nitrobenzene was kept at 7 1. The precipitated polymer was then filtered, washed with petroleum ether to remove nitrobenzene, and then dried at 100°C in vacuum. 

Properties of Thermoplastic Elastomeric Composition Based on Hydrogenated Styrene-Butadiene Rubber and Low-Density Polyethelene... 

Chattopadhyay S., Chaki T.K., and Bhowmick A.K., New thermoplastic elastomers from poly(ethyle-neoctene) (engage), poly(ethylene-vinyl acetate) and low-density polyethylene by electron beam technology structural characterization and mechanical properties. Rubber Chem. TechnoL, 74, 815, 2001. Roy Choudhury N. and Dutta N.K., Thermoplastic elastomeric natural rubber-polypropylene blends with reference to interaction between the components. Advances in Polymer Blends and Alloys Technology, Vol. 5 (K. Finlayson, ed.), Technomic Publishers, Pensylvania, 1994, 161. 

Jha A. and Bhowmick A.K., Thermoplastic elastomeric blends of nylon 6/acrylate rubber Influence of interaction of mechanical and dynamic mechanical thermal properties. Rubber Chem. TechnoL, 70, 798, 1997. 

Puskas J.E., Antony P., ElFray M., and Altstadt V. The effect of hard and soft segment composition and molecular architecture on the morphology and mechanical properties of polystyrene-polyisobutylene thermoplastic elastomeric block copolymers, Eur. Polym. J., 39, 2041, 2003. 

Choudhury N.R., Chaki T.K., Dutta A., and Bhowmick A.K. Thermal, x-ray and d3mamic mechanical properties of thermoplastic elastomeric natural rubber-polyethylene blends. Polymer, 30, 2047, 1989. Marasch M.J., TPU s Growth from versatility, 53rd Annual Tech. Conference, Antech 95 4088, Boston, May 7-11, 1995. 

Roy Choudhury N. and Bhowmick A.K., Adhesion between individual components and mechanical properties of natural rubber-polypropylene thermoplastic elastomeric blends, J. Adhes. Sci. Technol., 2(3), 167, 1988. 

El Fray, M., Prowans, P., Puskas, J.E., and Altstadt, V. Biocompatibility and fatigue properties of polystyrene-polyisobutylene-polystyrene, an emerging thermoplastic elastomeric biomaterial. Biomacromolecules, 7, 844-850, 2006. 

---