R.K. Goyal

Thermal expansion behaviour of high performance PEEK matrix composites

The thermal expansion behaviour of high performance poly(ether-ether-ketone) (PEEK) composites reinforced with micro- (8 µm) and nano- (39 nm) sized Al2O3 particles was studied. The distribution of Al2O3 in the PEEK matrix was studied by scanning electron microscopy and transmission electron microscopy. The coefficient of thermal expansion (CTE) was reduced from 58 × 10−6 °C−1 for pure PEEK to 22 × 10−6 °C−1 at 43 vol% micro-Al2O3 and to 23 × 10−6 °C−1 at 12 vol% nano-Al2O3 composites. For a given volume fraction, nano-Al2O3 particles are more effective in reducing the CTE of composites than that of micro-Al2O3 particles. This may be attributed to the much higher interfacial area or volume of nanocomposites than that of microcomposites. The upper limit and lower limit of the Schapery model separately fit closely the CTE of the micro- and nano-composites, respectively. Other models such as the rule of mixture and Kerner and Turner models were also correlated with the data.

Potential Applications of Polystyrene in Optoelectronics

Organic polymer based materials are becoming the workhorse in the area of photonics and optoelectronics. These materials are rapidly replacing their inorganic counter parts due to their flexibility in manufacturing combined with the ease in fabrication and manufacturing. Polystyrene, being a low cost commercial commodity plastic material has been utilized as one of the important polymeric material for various NLO active devices. Guest-Host systems based on polystyrene and NLO active chromophores have been extensively studied. As a host polymer it can easily accommodate the NLO guest molecules by simple modification by solution casting and other processes. Thus, polystyrene based NLO active systems offers a relatively cost-effective NLO active systems. Recent investigations have confirmed the suitability of disposable recycled polystyrene as a host polymer to accommodate NLO active chromophores that can lead to dirt-cheap NLO active device materials. This review summarizes the applications of polystyrene based materials in the area of Optoelectronics. The fundamental aspects pertaining to Guest-Host NLO chromophore is also discussed. Some of the recent investigation about the usage of recycled polystyrene system is highlighted.