Elastomeric rubber-plastic blends

Blends and Elastomeric Alloys 5.4.2.1 Elastomeric Rubber-Plastic Blends... 

Rader C.P. and Abdou Sabet S., Two phase elastomeric alloys. Thermoplastic Elastomers from Rubber Plastic Blends (De S.K. and Bhowmick, A.K., eds.), Ellis Horwood, London, 1990, 159. 

Dynamic vulcanization (DV) is also considered. DV is the crosslinking of one polymer in a blend of polymers during its mixing therein, all polymers of the blend being in the molten state. The process is used in the preparation of thermoplastic elastomeric compositions from rubber-plastic blends. 

The lower left qnadrant represents the simple blends. One type of TPE blend is the TPO, which is a simple polymer blend of a rigid thermoplastic polymer with a technologically compatible (not necessarily thermodynamically compatible) elastomeric polymer. Each of the polymeric components exists in its own phase (with its own Tg or The properties of the blend are partly predictable by the properties of the com nents however, the phase morphology is also extremely important. The hard phase must be continuous for the blend to be thermoplastic. Commercial TPO blends include those of EPDM rubber with PP or polyethylene (PE). Another type of simple polymer blend is that of poly(vinyl chloride) and nitrile rubber (NBR). This may have been the first useful rubber-plastic blend. 

Poly(vinyl chloride) (PVC) homopolymer is a stiff, rather brittle plastic with a glass temperature of about 80°C. While somewhat more ductile than polystyrene homopolymer, it is still important to blend PVC with elastomer systems to improve toughness. For example, methyl methacrylate-butadiene-styrene (MBS) elastomers can impart impact resistance and also optical clarity (see Section 3.3). ABS resins (see Section 3.1.2) are also frequently employed for this purpose. Another of the more important mechanical blends of elastomeric with plastic resins is based on poly(vinyl chloride) as the plastic component, and random copolymers of butadiene and acrylonitrile (AN) as the elastomer (Matsuo, 1968). On incorporation of this elastomeric phase, PVC, which is ordinarily a stiff, brittle plastic, can be toughened greatly. A nonpolar homopolymer rubber such as polybutadiene (PB) is incompatible with the polar PVC. Indeed, electron microscopy shows... 

Various depolymerized butyls, butyl rubber solutions or cutbacks, butyl/plasticizer blends, and highly plasticized/partially cured butyls are also available. These products are used by many adhesive companies where equipment limitations prohibit the use of the tougher, regular bale forms of butyl rubber. Principal suppliers of these type materials include Rubber Research Elastomerics, Inc., Minneapolis, Minnesota ADCO Products, Inc., Michigan Center, Michigan and A-Line Products, Detroit, Michigan. 

Note 2 The interfacial interaction between hard and soft phase domains in a thermoplastic elastomer is often the result of covalent bonds between the phases and is sufficient to prevent the flow of the elastomeric phase domains under conditions of use. Note 3 Examples of thermoplastic elastomers include block copolymers and blends of plastics and rubbers. 

This specification covers expanded unicellular elastomeric plastic material in sheet form intended for use in shock-absorbent containers, impermeable extreme-cold-weather jackets, and decorative insulations. The material specified is a blend of vinyl and a butadiene-acrylonitrile rubber or other thermosetting elastomeric material. Recycled material use is encouraged. 

Immiscible blends of polyolefins have been compatibilized by copolymer formation brought about by radical coupling across a melt phase boundary, as shown in the examples listed in Table 5.44. The work of Kim et al. involved simultaneous copolymer formation between immiscible rubber and plastic phases with the dynamic vulcanization of the elastomeric phase. 

Thermoplastic elastomeric materials have many important applications including cable and wire especially in mineral, electronic equipment, and automobile industries. The most commonly used method of obtaining thermoplastic elastomer in materials is to toughen plastics by blending rubbers and plastics. Among the most versatile polymer matrices, polyolefins such as PP are the most widely used thermoplastics because of their well-balanced physical and mechanical properties and their easy processability at a relatively low cost, which makes them a versatile material. PP has the disadvantage of... 

Acrylonitrile-butadiene rubber, NBR, styrene-aciylonitrile rubber, SAN, ethylene-vinyl acetate copolymer, EVA, and acrylic copolymers are helpful modifications of polyvinylchloride that change its processing characteristics and elastomeric properties. Blending with these copolymers helps to reduce the requirement for low molecular weight plasticizers. Ethylene-vinyl acetate copolymer plays a role of high molecular weight plasticizer in production of vinyl hose. This reduces the amount of DOP used in flexible hose applications. Ethylene copolymer is used plasticize PVC that reduces gel. "" Phthalate plasticizers can be eliminated from water based adhesives because of utilization of vinyl acetate ethylene copolymer as a high molecular plasticizer/modifier. " ... 

Plasticizers, such as for example DOP, are required to improve aging resistance of blends of PVC and epoxidized natural rubber." Further addition of NBR helps to retain aging resistance of blend, eliminate a low molecular weight plasticizer, and improve elastomeric properties of compositiom... 

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