Crosslink concentration is an important property affecting the major characteristic of cured rubber. One of the important parameter to determine the crosslink concentration of a vulcanized rubber by swelling measurement is the rubber-solvent interaction parameter known as ‘kai’ value denoted as χ. For single rubber, the χ value is known however, the χ1,2 for rubber blends are unknown. This research concerned with the investigation to determine the χ1,2 for rubber blends solution (uncured rubber). Natural rubber (NR) and styrene butadiene rubber (SBR) rubber blends solution were blend at 7 different ratios of 100/0, 80/20, 70/30, 60/40, 50/50, 40/60 and 0/100 and were dissolved in toluene. The χ1,2 value of each rubber blends were determined based on the intrinsic viscosity measurement. Crosslink concentrations of vulcanized rubber blends obtained from the swelling measurement were then compared against the value determined from simple extension measurement (stress-relaxation method). This cross-checking was to ensure the accuracy and reliability of χ1,2 value for rubber blends solution.
In this study, palm oil-based polyols were prepared and characterized. In order to prepare the polyol, Epoxidized palm oil (EPO) was reacted with glycerol and undergoes ring opening reaction. The synthesized oil was characterized by oxygen oxirane content titration (OOC), hydroxyl value test (HV), fourier transform infrared (FTIR) and nuclear magnetic resonance (NMR). Based on the FTIR spectrum of polyols, the disappearance of epoxy groups at 825cm-1, 843cm-1 and the emergence of hydroxyl group at 3394cm-1 are obvious indicating that hydroxyl group of the polyols formed. In NMR, the presence of new signal at δ 3.46ppm (-CH-OH) showed the attachment of hydroxyl group onto the epoxidized palm oil.
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.
Epoxidized oil (EO) is a sustainable oil that can be obtained form edible or non-edible naturals oil. The incorporation of epoxidized oil can increase the green component in rubber compound. It can contributes to worldwide technology specially in green tyre manufacturing. Epoxidized oil has the potential to replace aromatic oil (AO) to rubber and polymer industry. The effect of incorporation of EO and AO into natural rubber vulcanizates (NR) was studied via tensile and tear strength tests according to ISO 31-1977 and ISO 6133, respectively. Tensile strength of AO value showed greather value compared to EO. Gradual increases of elongation were observed form both AO and EO. Both moduli at 100% and 300% elongation, showed reductions as oil loading were increased. The tear strength results showed that tearing energy insignificantly increased with oil loading. EO compound was found to possess higher tearing energy compared to AO compound for most composition except for 15 pphr EO.
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