**9. Composites**

Various fillers and reinforcements have been introduced into thermoplastic elastomers to enhance their processability and mechanical properties, as well as to reduce material costs.

IPNs (lower PS content) having two types of domains. The morphology of natural rubber (NR)/high density polyethylene (HDPE) reinforced with carbon black composite was examined using TEM, SAXS and SANS (Kazuhiro et al., 2005). TEM image showed that NR and HDPE were phase-separated in the blends and carbon black nanoparticles were located in the NR domains. This phenomenon can be explained by the chemical groups on the

Elastomers are often used in blends with other polymers. When the elastomer is the minor component it will constitute a disperse phase. A disperse phase elastomer will be a toughening

When the elastomer is the major component it will be a matrix phase and the overall blend will be an elastomer. The disperse phase blended polymer will contribute to physical cross-

When tested under a tensile stress-strain condition, TPE behave as elastomers until the yield stress after which they can undergo plastic flow, part of which may be viscoelastic (timedependant recovery) and part will be permanent set. The pre-yield region represents an elastomeric response where the physical cross-links are not deformed. The stress-strain

additive for the matrix phase that could be a thermoplastic or a thermoset polymer.

links that will prevent creep and assist with reversibility of elastomer deformation.

surface of carbon blacks which chemically absorb olefin well.

**11. Elastomer polymer blends** 

**12. Mechanical properties** 

curve of SBS is shown in Figure 4.

Fig. 4. The stress-strain curve of SBS

**12.1 Stress-strain** 

Most common fillers used in TPEs include cubic and spheroidal fillers (calcium carbonate, silica, carbon black), fibrous fillers (glass fibers, aramid fibers), platy fillers (kaolin, mica, talc) and nanofillers (carbon nanotubes, nanoclays, nanosilica). Reinforcing TPEs with fillers such as silica, clay, carbon black, carbon nanotubes, natural fiber results in better thermal and mechanical properties of the composites.

Carbon black composites with polyether polyurethane exhibited a percolation threshold of 1.25 %·v/v and significant conductivity at 2 %·v/v carbon black content (Wongtimnoi et al., 2011). Electric field induced strain was observed due to an increase in dielectric constant. Polyester thermoplastic elastomers reinforced by mica showed significant increment in the flexural, thermal and electrical properties with an increase in the filler concentration. The improved thermal properties are attributed to the small and uniform crystallite size distribution with the addition of mica (Sreekanth et al., 2009). Composites containing silica and poly(styrene-b-ethylene-co-butylene-b-styrene) (SEBS) block copolymer-based thermoplastic elastomer showed an improvement in the mechanical properties such as tear strength due to the strong interaction between the fillers and polymer matrices where the silica particles are wetted by the polymer (Veli et al., 2009) . Polypropylene/natural rubber (PP/NR) and poly(propylene-ethylene-propylene-diene-monomer) (PP/EPDM) reinforced by kenaf natural fibre with maleic anhydride polypropylene (MAPP) as a compatibilizer agent has significantly increased the tensile strength, flexural properties and impact strength as compared to unreinforced thermoplastic elastomer. The improvement achieved in mechanical properties was due to the interaction both matrix system and kenaf fibre (Anuar & Zuraida, 2011).
