Thermoplastic rubber Terms Links

However some non-rubber compounds are also called elastomers if they exhibit a nondeforming elastic property similar to rubber at room temperature, even if the compound is relatively hard. The two main groups of non-rubber elastomers are thermoplastics, e.g., polyvinyl chloride, polypropylene and thermosets, e.g., ethylene propylene rubber, cross-linked polyethylene. These two groups are also covered by the term plastic . 

Rheometer re- a-m9-t9r [ISV] (ca. 1859) (plastometer) n. An instrument for measuring the flow behavior of high-viscosity materials such as molten thermoplastics, rubbers, pastes, and cements. The most widely used principle is that of the capillary rheometer of which a variety of makes and models are in daily use. Instruments for measuring the flow properties of less viscous fluids, e.g., dilute polymer solutions, are called viscometers but the terms rheometer and viscometer are often used interchangeably. Currently, computerized, on-hne capillary rheometers linked to a single control station can simultaneously monitor melt viscosity in ten or more extruders in a resin-finishing plant. 

If the rubber content of a PP blend is less than 50%, then the material may be referred to as rubber reinforced polypropylene (RRPP) or, as rubber modified polypropylene ( PP) or, as an elastomer modified thermoplastic MT) or, as an olefin thermoplastic elastomer (OTE) or, as impact modified polypropylene (IMPP). The material may also be known as a thermoplastic elastomer (TFE) or, as a thermoplastic rubber (TPR). The rubber/elastomer in such a mbcture is not crosslinked, or cured, or vulcanized). The term rubber reinforced PP (RMPP) will be used for those systems in which the rubber is present in relatively low concentations (<30%) and is not cross-linked/cured. 

The dynamic cross-linking process is used to produce thermoplastic elastomers from mixtures of crystallizable polyolefins and various rubbers. Variations of basically the same method are employed to produce novel, stable polymer alloys by performing chemical reactions during extrusion of such mixtures. In that case, the cunent industrial term is reactive extrusion. Such processes are used, for example, to improve processability of LLDPE s into tubular film (by introducing long chain branches during extrusion with low levels of peroxides) or to... 

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