Elastomer blends applications

Maier, T. R., Jamieson, A. M., and Simha, R., Phase equilibria in SBR/polybutadiene elastomer blends application of Flory-Huggins theory, J. Appl. Polym. Sci., 51 (6), 1053-1062 (1994). 

Blends of NR and ethylene-vinyl acetate copolymer (EVA) (physical blends and statically vulcanized) combine the good elastomeric and mechanical properties of NR with the excellent ageing and flex crack resistance of EVA. Blends of NR/EVA copolymer are becoming an important rubber/thermoplastic elastomer blend. Applications of these materials can be found in fields where... 

Research concerning nylon-elastomer blends has mostly focused on the improvement of mechanical and thermal properties. Their dynamic mechanical properties are quite important both for processing and engineering applications. Wang and Zheng have smdied the influence of grafting on the dynamic mechanical properties of a blend based on nylon 1212 and a graft... 

Aijunan, P. Technological Compatibilization of Dissimilar Elastomer Blends Part 1. Neoprene and Ethylene o-Propylene Rubber Blends for Power Transmission Belt Application. Rubber Division, Proceedings of the American Chemical Society, Nashville, TN, Sept. 29-Oct. 2, 1998, Paper No. 52, 1-28. 

Silicones are frequently used in transdermal drug delivery. Recently, the use of loosely cross-linked silicone elastomer blends for this application was surveyed.537 The mechanisms of controlled drug release in the silicone-based systems have been studied,538 as silicones are evaluated for relatively new protein drug-delivery systems.5... 

Other reported TG-MS applications concern polybutadiene [153], styrene-butadiene rubbers [153], gums [14], polyisoprenes [52], polyurethanes [144, 146, 147, 166], ABS [144], chlorosulphonated polyethylene elastomer [169, 170] and elastomer blends (NBR/SBR/ BR) [13]. Table 1.5 summarises the use of advanced TG-MS systems in elastomer analysis. 

Guo, Z., Fang, Z., and Tong, L. 2007. Application of percolation model on the brittle to ductile transition for polystyrene and polyolefin elastomer blends. eXPRESS Polymer Letters 1 37-43. http //www. expresspolymlett.com/... 

Immiscible Blends. Rubber. Elastomer/elastomer blends are used extensively for commercial applications, particularly in the construction of automobile tires. There is an extensive patent and technological literature on this subject. A recent review (see chapter 19 of Ref. 19 by McDonel, Baranwal, and Andries) summarizes a great deal of this... 

Other Nuclei. - 6.2.1 Application to Materials and Plants. Techniques of C-NMR imaging and its apphcations to plants and elastomer blend systems were reviewed. " In this review, the authors focused on the imaging of C nuclei as a means to deal with the spatial distribution of molecules of interest other than water. 

Commercial impact modified (elastomer blended) polycarbonates are used for the production of protective headgear, sporting goods, bobbins for textile industry and automotive components requiring high toughness. Impact modified PC has to compete with the more solvent resistant impact modified PBT/PC, PET/PC blends and polyamides in some of the applications. 

PBT/copoly(ether-ester) elastomer blend molded parts exhibit excellent surface finish and good paint adhesion without the need for primers. About 3 kton/y of this blend is being used for painted, flexible bumper fascias in selected luxury model cars in the USA. Because of the excellent surface esthetics of the blend, molded-in colors are also being evaluated to reduce the painting costs. Lower levels (< 20%) of copoly(ether-ester) elastomers have also been blended with PBT for high impact strength molding resin applications (Celanex , Hoechst-Celanese). 

Blends of the commodity polymers with more specialty polymers are limited although many specific examples exist in the patent/open literature. In the design of polymer blends for specific application needs, countless opportunities can be envisioned. Examples may include PE/poly(s-caprolactone) (PCL) blends for biodegradable applications (proposed), polyolefin (PO)/poly(vinyl alcohol) (PVAL) blends for antistatic films, PO/silicone rubber blends for biomedical applications, PO/thermoplastic polyurethane TPU (or other thermoplastic elastomers) for applications similar to plasticized PVC, functionalized PO/thermoset blends. 

Because of low cost, high heat deflection temperature (HDT (104°C)), notched impact resistance, improved low temperature impact and flexibility, weather resistance, flame retardancy, and impact resistance, the PP/EPDM blend has got a widespread applications. These unique characteristics of this thermoplastic elastomer blend make it an attractive alternative to conventional elastomer in a variety of markets such as automobile industries, wire, cable insulator, automobile bumpers and fascia, hose, gaskets, seals, weather stripping, among others. 

The major use of SBR is in the production of tires, particularly passenger-car and light-truck tires, and in other automotive applications where SBR is blended with other elastomers. These applications include belts, hoses, seals, and various extruded and molded items. Nontire and nonautomotive uses of SBR are in industries that require hoses, belts, gaskets, or seals. Others include footwear (shoe soles) various kinds of solid wheels roll covers coated fabrics and electrical (wire and cable) insulation. 

Plastics find extensive use in several areas of fiber optic cables. Buffer tubes, usually extruded from high-performance plastics such as fluoropolymers, nylon, acetal resins, or polybutylene terephthalate (PBT) are used for sheathing optical fibers. A blend o PVC and ethylene vinyl acetate (EVA) polymer, such as Pantalast 1162 of Pantasote Incorporated, does not require a plasticizer, which helps the material maintain stability when in contact with water-proofing materials. PVC and elastomer blends, Carloy 6190 and 6178, of Cary Chemicals are also used for fiber optic applications (Stiffening rods for fiber optics are either pultruded epoxy and glass or steel. Around these is the outer jacketing, which is similar to conventional cable.)... 

Multiple notable reviews of elastomer blends exist. The first general treatment of the subject by Hess et al. (1993) reviews the applications, analysis, and the properties of the immiscible elastomer blends. Two related treatments by Roland (1989) and Ngai and Roland (2004) exist and describe the physics of mixing immiscible polymer blends and a more recent account of the analytical methods. Mangaraj (2002) has a more detailed review of elastomer blends. Other reviews by Corish (1978) and McDonel et al. (1978) deal with specific aspects of elastomer blends. A publication by Zhang (2009) on specific EPDM blends with NR/BR for tire sidewall approaches this area from the view of a specific application. Less comprehensive accounts of this area are also described for polyolefin elastomer blends by Slusarski et al. (2003) and Feldman (2005). 

The most common blends of unsaturated elastomers are those used in various sections of automotive tires. Table 12.9 lists the important component of tires and the typical blends used for them. Much of the literature of elastomer blends reflects this important application. It is outside the scope of this chapter to discuss each of the applications. We have outlined most of the important principles used in the generation of the blends. 

The transport properties of polymer blends are of interest both for the practical application of blends and for providing insight into the morphology of the blend. Measurement of the effect of blend composition on permeability in various rubbers has been described [49i].The permeability of elastomer blends depends on the concentration of the continuous phase and the morphology of the dispersed phase. Extended disperse phase structures, particularly lying in a stacked or lamellar configuration, can lead to a reduced permeability because of the more tortuous path that must be taken by penetrants [49]]. 

The application of new, novel approaches to raw materials development and their use in elastomer blends could offer potential for the next breakthrough in polymer science. To conclude, a wide range of subjects in the field of elastomer blends offer opportunities for further research. These include ... 

To fulfil this demand, immiscible blend components have traditionally found their synergistic properties utilized in macroscopic blend applications. As an example, for over fifty years polyamides have been blended with a multitude of partners to produce materials with a wide range of highly desirable properties these include improved mechanical properties (with poly(vinyl acetate)), increased hardness and molding stability (with ABS), excellent processability, low permeability and good printability (with polyolefins), and improved toughness (with alkenes or elastomers) [1]. 

Today, TPOs are used increasingly in special automotive applications because of their lower specific gravity, injection moldability, economics, recyclability, and noise performance. Some variations of these essential ingredients either are compounded in extruders (other mixers) or are prepared in some combination of reactors (often referred to as reactor TPO) that can make both PP and the rubber followed by some post-reactor addition of other chemicals. Toyota Super Olefin Polymer (TSOP) is a special type of TPO offered primarily in Japan.7 It is highly differentiated in its flow characteristics, modulus, and balance of low-temperature properties due to some unusual shared continuous morphology achieved through a unique fabrication route of PP and elastomer blend. The ratio of elastomer to PP in this blend can be adjusted to control the modulus and elastic recovery of a TPO. ... 

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