**10. Morphology**

The disperse hard-phase in TPE self-agglomerates after processing to form reinforcing domains within the elastomeric matrix. The morphology contribution to elastomeric properties has been investigated using a semi- phenomenological approach (Baeurle et al., 2005). The authors describe an extended domain model for the size and distribution of hard phase within the elastomer and the contribution to stress relaxation times. Relaxation was modelled using a stretched exponential function to correlate stress decay due to multiple length-scales and time-scales. Behaviour under stress for long times resulted from plastic flow, chain pull-out from hard domains and finally disruption of the hard domains.

Transmission electron microscopy (TEM) is one of the most powerful equipment to characterize the structure and morphology of thermoplastic elastomers. It is often used to interpenetrate polymer networks (IPNs), morphology and crystallinity of hard blocks, structural evolution of segmented copolymers under strain and blends. The morphology of the IPNs transformed from SBS by using γ-radiation as shown by TEM is a homogeneous and sponge-like network (Robert et al., 2003). Sometimes, TEM is associated with other techniques, particularly small-angle X-ray scattering (SAXS), wide-angle X-ray scattering (WAXS), small-angle neutron scattering (SANS), and atomic force microscopy (AFM) to provide more information on the microstructure of TPEs. TEM and SANS have been used to examine the morphology of tough-semi– and full– IPNs with SIS crosslinkings and PS at different content (Bhavna & Robert, 2001). TEM showed similar structure for both samples which are different in total of PS content, while for SANS, the plot of intensity against the scattering vector *q* showed that both structures are significantly different with the tough

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

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

The disperse hard-phase in TPE self-agglomerates after processing to form reinforcing domains within the elastomeric matrix. The morphology contribution to elastomeric properties has been investigated using a semi- phenomenological approach (Baeurle et al., 2005). The authors describe an extended domain model for the size and distribution of hard phase within the elastomer and the contribution to stress relaxation times. Relaxation was modelled using a stretched exponential function to correlate stress decay due to multiple length-scales and time-scales. Behaviour under stress for long times resulted from plastic

Transmission electron microscopy (TEM) is one of the most powerful equipment to characterize the structure and morphology of thermoplastic elastomers. It is often used to interpenetrate polymer networks (IPNs), morphology and crystallinity of hard blocks, structural evolution of segmented copolymers under strain and blends. The morphology of the IPNs transformed from SBS by using γ-radiation as shown by TEM is a homogeneous and sponge-like network (Robert et al., 2003). Sometimes, TEM is associated with other techniques, particularly small-angle X-ray scattering (SAXS), wide-angle X-ray scattering (WAXS), small-angle neutron scattering (SANS), and atomic force microscopy (AFM) to provide more information on the microstructure of TPEs. TEM and SANS have been used to examine the morphology of tough-semi– and full– IPNs with SIS crosslinkings and PS at different content (Bhavna & Robert, 2001). TEM showed similar structure for both samples which are different in total of PS content, while for SANS, the plot of intensity against the scattering vector *q* showed that both structures are significantly different with the tough

flow, chain pull-out from hard domains and finally disruption of the hard domains.

and mechanical properties of the composites.

& Zuraida, 2011).

**10. Morphology** 

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 surface of carbon blacks which chemically absorb olefin well.
