Elastomer alloys thermoplastic vulcanizates

EA-TPV Elastomer alloy thermoplastic vulcanizate EP Epoxide or epoxy (cured)... 

Vulcanized elastomeric alloys (EA) are TPEs composed of mixtures of two or more polymers that have received a proprietary treatment. Elastomeric alloy-thermoplastic vulcanizates (EA-TPVs) are a category of TPEs made of a rubber and plastic polymer mixture in which the rubber phase is highly vulcanized. The plastic phase of an EA-TPV is a polypropylene, and the rubber phase is an ethylene-propylene elastomer. 

Considerable improvements in properties result, compared to RRPP, if cross-linking/curing is introduced into the rubber particles. PR modified, rubber compounds. Such materials may be known as dynamically crosslinked polyolefin elastomer or TPO-XL or, as a d5mamically vulcanized material or, as an elastomeric alloy (EA) or, as an elastomeric alloy thermoplastic vulcanizate (EA-TPV). If enough plastic is present (say 50%), the compound can still be easily processed by thermoplastic techniques. 

Keywords Dynamic vulcanization Polymer blends and alloys Reactive processing Thermoplastic elastomers Thermoplastic vulcanizates... 

The structure and physical properties of the thermoplastic vulcanizates (TPE-V) produced in the process of the reactive processing of pol5rpropyl-ene (PP) and ethylene-octene elastomer (EOE) in the form of alloy, using the cross-linking system was analyzed. With the DMTA, SEM and DSC it has been demonstrated that the d5mamically produced vulcanizates constitute a typical dispersoid, where semicrystal PP produces a continuous phase, and the dispersed phase consists of molecules of the cross-linked ethylene-octene elastomer, which play a role of a modifier of the properties and a stabilizer of the two-phase structure. It has been found that the mechanical as well as the thermal properties depend on the content of the elastomer in the blends, exposed to mechanical strain and temperature. The best results have been achieved for grafted/cross-linked blends with the contents of iPP/EOE-55/45%. 

In contrast to the rigid TPOs described above, low-modulus/flexible grades of TPO blends are also produced commercially. In flexible TPOs, the rubber content can be as high as 60 %, and in some cases, the dispersed rubber may also be partially cross-linked during the mixing without losing the thermoplastic character of the matrix. However, the latter type of dynamically vulcanized elastomeric alloys or thermoplastic vulcanizate rubbers (TPVs) are considered as a separate class of elastomeric materials and hence will be discussed under elastomer blends. On the other hand, the soft TPO blends discussed here contain a low-modulus olefln copolymer elastomer as the major component with some polypropylene added to impart melt processability. 

Dynamically vulcanized, elastomeric thermoplastic alloys or TPVs display properties as good as or even better than the block copolymers, viz., a high degree of rubber elasticity yet good melt processability. The main advantages of the thermoplastic vulcanizate elastomer blends over the uncured thermoplastic/elasto-mer blends are... 

The structure and physical properties of the thermoplastic vulcanizates produced in the process of the reactive processing of polypropylene and ethylene-octane elastomer in the form of alloy, using the cross-linking system was analyzed. 

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