Novel applications of cashew nut shell liquid in the polymer field

This research project aims at developing new applications for CNSL in the polymer field. Cashew nut shell liquid (CNSL) is a cheap agro-byproduct and renewable resource which consists mainly of substituted phenols. By using CNSL in place of phenol, phenol derived from petrochemicals can be conserved and a cheap agro-byproduct utilized.In this study CNSL based resin is prepared by condensing a mixture of phenol and CNSL with hexamethylenetetramine and the effect of P: F ratio and CNSL: P ratio on the properties of synthesized resin is studied. The adhesive properties of CNSL based resin in combination with neoprene rubber are investigated. The effect of varying the stoichiometric ratios between total phenol and formaldehyde and CNSL and phenol of the resin, resin content, choice and extent of fillers and adhesion promoters in the adhesive formulation are studied. The effect of resin on the ageing properties of various elastomers is also studied by following changes in tensile strength, elongation at break, modulus, tear strength, swelling index and acetone soluble matter. Crude CNSL and resins with different P: F ratios and CNSL: P ratios are incorporated into elastomers. Lastly, utility of CNSL based resin as binder for making particleboard is investigated.The results show that CNSL based resin is an effective ingredient in adhesives for bonding aluminium to aluminium. The resin used for adhesive fonnulation gives the best performance at 45 to 55 phr resin and a total phenol: formaldehyde of l:2.9. The resin when added at a rate of l5 phr improves ageing characteristics of elastomers with respect to mechanical properties. The reaction mixture of CNSL and hexa and the resin resulting from the condensation of CN SL, phenol and hexa can be used as effective binders for moulding particleboard.

Electrical Characteristics of n-ZnO/p-Si Heterojunction Diodes Grown by Pulsed Laser Deposition at Different Oxygen Pressures

Heterojunction diodes of n-type ZnO/p-type silicon (100) were fabricated by 12 pulsed laser deposition of ZnO films on p-Si substrates in oxygen ambient at 13 different pressures. These heterojunctions were found to be rectifying with a 14 maximum forward-to-reverse current ratio of about 1,000 in the applied 15 voltage range of -5 V to +5 V. The turn-on voltage of the heterojunctions was 16 found to depend on the ambient oxygen pressure during the growth of the ZnO 17 film. The current density–voltage characteristics and the variation of the 18 series resistance of the n-ZnO/p-Si heterojunctions were found to be in line 19 with the Anderson model and Burstein-Moss (BM) shift.

Transparent p-AgCoO2/n-ZnO diode heterojunction fabricated by pulsed laser deposition

Transparent diode heterojunction on ITO coated glass substrates was fabricated using p-type AgCoO2 and n-type ZnO films by pulsed laser deposition (PLD). The PLD of AgCoO2 thin films was carried out using the pelletized sintered target of AgCoO2 powder, which was synthesized in-house by the hydrothermal process. The band gap of these thin films was found to be ~3.89 eV and they had transmission of~55% in the visible spectral region. Although Hall measurements could only indicate mixed carrier type conduction but thermoelectric power measurements of Seebeck coefficient confirmed the p-type conductivity of the grown AgCoO2 films. The PLD grown ZnO films showed a band gap of ~3.28 eV, an average optical transmission of ~85% and n-type carrier density of~4.6×1019 cm− 3. The junction between p-AgCoO2 and n-ZnO was found to be rectifying. The ratio of forward current to the reverse current was about 7 at 1.5 V. The diode ideality factor was much greater than 2.