Polystyrene‐modified natural rubber (SNR) was prepared in the laboratory and subsequently used as compatibilizer in polypropylene/natural rubber (PP/NR) blends. The effect of SNR (at 5%, 10%, 15% and 20% by volume) in PP/NR (70/30) blend was studied by maintaining the rubber volume while PP volume was replaced by SNR accordingly. The sequence of mixing was found to affect the blend morphology and tensile properties. The effect of curatives on the tensile properties of the blends was also investigated. The addition of curatives into the rubbers in PP/NR/SNR improved the tensile properties significantly compared with the PP/NR reference blend. For a semi‐efficient curative system, SNR loading at 10% gave the best overall tensile properties, while for an efficient curative system, 5% SNR loading resulted in improvements in tensile strength and stiffness of over 20% and 40%, respectively, compared with the reference. © 2002 Society of Chemical Industry

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essential oil of Homalomena pineodora inhibits diabetic pathogens; however, the activity was not sustainable when applied as wound dressing. this study aims to synthesise the essential oil nanoparticle using chitosan. The nanoparticles were synthesised with ion gelation method, confirmed by spectroscopic analysis. The spherical nanoparticles display a size of 70 nm, with strong surface charge of +24.10 mV. The nanoparticles showed an initial burst release followed by a slow release pattern for 72 h, following the first order of kinetic. the release behaviour was ideal for wound dressing. the antimicrobial activity was broad spectrum. the formation of nanoparticle enhanced the antimicrobial efficacy of the essential oil. The nanoparticle also showed a concentration-dependent killing behaviour on time-kill assay. In the 3D collagen wound models, the nanoparticles reduced the microbial growth by 60-80%. In conclusion, H. pineodora nanoparticles showed pharmaceutical potential in inhibiting microbial growth on diabetic ulcers.

Petroleum based processing oils is the hydrocarbon oils derived from petroleum refining process and commonly used as extender or processing oils to improve the rubber processability. Hydrocarbon oils can be classified as paraffins, aromatics, naphthene and olefins oil based on their molecular structure. The studies on replacement of hydrocarbon oils with natural processing oils had been studied by vast number of researchers due to finite resources and the toxicity of the hydrocarbon oils which enhanced awareness in using natural based oils. These natural processing oils are from vegetable or animal. The vegetable oils contain mainly unsaturated fatty acids. Studies showed that the unsaturated fatty acids affect the cure characteristics and the mechanical properties of the filled vulcanizates as these fatty acids took part during the vulcanization and promote the filler-rubber interaction. In this study, natural rubber (NR) of grade Standard Malaysian Rubber 20 (SMR 20) with the loadings of paraffin oil (PO) and crude palm oil (CPO) between 1 to 5 phr was investigated. Within the loadings of PO and CPO studied, the unsaturated fatty acid in CPOs were reported to results in plasticizing effect which results in lower minimum and maximum torques. Though that the unsaturated fatty acid which took part during the vulcanization prolonged the cure time, it resulted in higher CB-SMR 20 interaction. The tensile properties, tear strength, hardness and abrasion resistance of the CPO recipes were affected by combination of plasticizing effect and better CB-SMR 20 interaction.

Pyrolysis is a thermal decomposition of biomass occurring in the absence of oxygen. Biochar (solid), bio-oil (liquid) and biogas (gas) are the typical products from pyrolysis of biomass. This endothermic process produced biochar with high carbon content. During pyrolysis, the material is heated up from ambient to a peak temperature and remains for a defined residence time. Therefore, the pyrolysis peak temperature and the residence time are the key parameters for pyrolysis. Studies on the effect of these parameters on the biochar characteristics and the pyrolysis products composition are numerous. However, there are limited findings of these parameters with palm kernel shell (PKS) as the biomass. This study focusses on the effect of the pyrolysis temperature and residence time of PKS on the yield of biochar produced and the biochar physio-chemical properties. The results showed that biochar yield decreased as the peak temperature and residence time increased. This finding is consistent with the findings by other researchers. However, those factors do not have distinct influence on biochar’s carbon content as found in other study which the peak temperature has the bigger impact instead of residence time. The effect of peak temperature or residence time on grindability; i.e. particle size of biochar after wet ball milled is insignificant. Smaller size of biochar may improve its function as reinforcing filler. As a conclusion, the optimum setup of pyrolysis is needed for a balance production in yield and biochar’s properties. It is recommended to produce biochar at higher peak temperature and shorter residence time to increase the total production. Additional analysis e.g. physical testing on the final polymer product can be used to investigate the effect of pyrolysis peak temperature and residence time.