No abstract

In this work, a novelty solid propellant based on Isophorone Diisocyanate (IPDI) with Hydroxyl Terminated Natural Rubber (HTNR) binder network was successfully developed. The preparation of Liquid Natural Rubber (LNR) by chemical degradation Deprotenized Natural Rubber (DPNR) using cobaltous was carried out. From the FTIR spectroscopy, a broad hydroxyl group peak at 3444cm-1 was obtained from HTNR. Rubber network depict a strong carbonyl group C=O at 1714cm-1 and amine group N-H at 3433cm-1. NMR analysis also proves that there was hydroxyl group presence in the sample where broad peak at range 1-3 ppm and 3.5 ppm peak for -HOCH2CH2CH2-. Four different mol ratio of HTNR with IPDI was carried out to find the best formulation with good properties as propellant. Flory-Rehner equation depict that only slightly increasing occur with higher IPDI mol ratio but mixing with Ammonium Perchlorate (AP) and Aluminium Powder (AL) significantly improve the crosslink density. Melting point for HTNR is near to room temperature and it increase abruptly after crosslink with IPDI up to range of 148-150 °C. For all formulation, cross section morphology showed occurrence of porosity and brittle type of failure however HTNR has good contact with AL and AP. 2 : 1 molar ratio depict the best burning rate but the combustion characteristic shows less energy and spark compared to HTPB binder.

Xylitol-based polyesters such as poly(xylitol sebacate) PXS are said to be the potential new materials for tissue engineering due to their adjustable mechanical and degradation properties. However, the result indicates that the elastomers are very soft and have a low elongation at break. Therefore, to increase the mechanical strength and minimize the rate of degradation, glutamic acid was added as the third monomer into the PXS. Novel Poly (xylitol Sebacate Glutamate) (PXSG) was successfully synthesized through melt polycondensation without using any harsh solvents and catalysts. The mixture was synthesized at 120°C for about 8 hours. Post polymerization process was carried out in the oven at 100 °C for three days to develop the crosslink network formation. Several testing and characterization were conducted to evaluate the effect of glutamic acid concentration in the polymer. From the result, FTIR spectroscopy confirmed the ester bond formation, tensile strength and Young's modulus increased significantly while the percent of elongation at break and degradation rate decreased as the glutamic acid ratio increased.

Abstract. The development of polyurethane with hydroxyl access in a molecule leads to a new alternative of low toxicity green product. Palm oil is one of the major commodities in Malaysia. The potential of palm oil to be used as coatings raw material such as alkyd is limited due to low unsaturated side on fatty acid chains. To overcome this limitation, palm oil was modified through transesterification process to produce polyol. Acrylated isocyanate (urethane oligomer) was then grafted onto polyol to produce polyurethane with vinylic ends. The polyurethane was formulated with different cross-linkers (reactive diluents) and cured under UV radiation. The effect of three different diluents; monoacrylate, diacrylate and triacrylate on the properties of cured polymer were studied in this research. Fourier Transform Infrared (FTIR), Hydroxyl Value Titration, Gel Content, and Volatile Organic Compound (VOC) were used for characterization. Physical testing performed were Pencil Hardness and Pull-Off Adhesion test. Novel palm oil-based polyurethane coatings have been found to have good properties with mono acrylate functionality.

The epoxy primer coatings with various size of treated glass fiber was successfully developed using hand brushing technique on carbon steel plate. The glass fibers used were treated with silane coupling agent, 3-aminopropyl triethoxysilane. The Fourier Transform-Infared Spectroscopy (FTIR) affirmed the presence of silanol group at 1221.12cm-1 .Hence, the primer coating was prepared with three different sizes of treated glass fiber (45, 150, and 250 μm) and the corrosive properties has been studied. The corrosion rate was determined using Tafel plot and the immersion test was done in 3.5% NaCl and sea water for 9 days. Formulation of epoxy resin-GF-45μm displayed the optimum size to reduce the corrosion rate of epoxy primer coatings at 8.3713 mm/year and polarization resistance was the highest at 107.48Ω which indicates that epoxy coating have higher resistance towards corrosion, coating adherence and there was formation of more protective film on steel.Whilst immersion in 3.5% NaCl solution and sea water followed the same trend with 45 μm exhibited the less corrosive behavior for 9 days exposure. When the solution penetrated into the coating, the ultra-short glass fibers prevent the water from permeating and prolong the water diffusion path. Thus, it provided good anti-corrosive properties for formulation 2 at 45μm GF. In conclusion, the size of GF plays an important role in determining the corrosive behavior of epoxy primer coatings. The optimum size of GF at 45 μm proved to diminish the corrosiveness of carbon steel plate.