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The ethylene vinyl acetate (EVA), high-density polyethylene (HDPE), compatibilizer (maleic anhydride-grafted polyethylene (MA-g-PE)) and organophilic montmorillonite (OMMT) clays were added in different sequences in a corotating twin screw extruder followed by injection molding. Montmorillonite clay was modified by octadecylamine and aminopropyltriethoxysilane to make it organophilic. The thermal behavior was characterized by thermogravimetric analysis and differential scanning calorimetry (DSC). The influence of blending HDPE with EVA on the thermal properties of EVA/HDPE blends was investigated. The effect of MA-g-PE and nanoclay on the thermal properties of EVA/HDPE blend and modified EVA/HDPE blends, respectively, were also investigated. The blends show two distinct unchanged melting peaks corresponding to the individual components of the blend. The addition of nanoclay improves the thermal properties of nanocomposites. The results of DSC behavior of the nanocomposites indicate that melting temperature (T m ) and melting enthalpy (ÁH m ) of the HDPE phase of the nanocomposites are lower than those of the neat EVA/HDPE blend. Although crystallization temperature (T c ) of the nanocomposites is higher than the neat EVA/HDPE blend, it is

Conventional ceramic piezoelectric materials have been used in hydrophones for sonar applications since 1940's. In the last few years since the discovery of polymeric piezoelectric hydrophones, the technology has matured, applications have emerged in extraordinary number of cases such as underwater navigation, biomedical applications, biomimetics, etc. Hydrophones are used underwater at high hydrostatic pressures. In the presence of hydrostatic pressures, the anisotropic piezoelectric response of ceramic materials is such that it has poor hydrophone performance characteristics whereas polymeric piezoelectric materials show enough hydrostatic piezoelectric coefficients. Moreover, piezoelectric polymers have low acoustic impedance, which is only 2-6 time that of water, whereas in piezoelectric ceramics, it is typically 11-time greater than that of water. A close impedance match permits efficient transduction of acoustic signals in water and tissues. Newly developed hydrostatic-mode polyvinylidene flouride (PVDF) hydrophones use a pressure-release system to achieve improved sensitivity. Recently, voided PVDF materials have been used for making hydrophones having higher sensitivity and figure of merit than unvoided PVDF materials.

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