The friction coefficient of the sulphurprevulcanized natural rubber (SPNR) film could be effectively reduced by deposition of poly(methyl methacrylate) (PMMA) particles. The nanoscale surface roughness of rubber, determined by atomic force microscope, was directly proportional to the particle size of PMMA particle at 12% surface coverage (Cs). The %Cs and surface roughness of the modified SPNR increased, while the friction coefficient decreased, with increasing PMMA latex concentration and immersion time. By using a mixture of latexes having both large and small sizes, the increase in the amount of small particles resulted in the better distribution of large particles deposited on the rubber surface.

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In this study, a micellar delivery system with an amphiphilic diblock copolymer of poly (ethylene glycol) and poly (ɛ-caprolactone) was synthesised and used to incorporate hydrophobic clove essential oil (CEO). To determine an optimal delivery system, the effects of the copolymer's hydrophobic block length and the CEO-loading content on the encapsulation of CEO were investigated. Percentages of entrapment efficiency (%EE), CEO loading (%CEO), and in vitro release profiles were determined. The size, size distribution, zeta potential, and morphology of the obtained micelles were determined by DLS, FE-SEM, and TEM. The %EE, %CEO, and in vitro release profiles of CEO incorporated in micelles were analysed by HPLC. The study revealed a sustained release profile of CEO from CEO-loaded micelles. The results indicate the successful formulation of CEO-loaded PEG-b-PCL micelle nanoparticles. It is suggested that this micelle system has considerably potential applications in the sustained release of CEO in intravascular drug delivery.

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The effect of epoxidation and surface modification by acrylamide grafting on backingrequired properties of peroxide prevulcanized natural rubber (PPNR)-based films was investigated. Backing-required properties including oxygen transmission rate (OTR), water vapor transmission rate (WVTR) and Young's modulus were determined. In situ epoxidation of natural rubber (NR) latex was carried out using hydrogen peroxide/ formic acid system. Both NR and epoxidized natural rubber (ENR) latexes were prevulcanized by tert-butyl hydroperoxide/fructose system before film casting. In the case of surface modification, acrylamide was grafted on PPNR surface by dipping the PPNR strip treated with O 2 plasma into an aqueous solution of acrylamide monomer (AAm). Epoxidation showed more pronounced effect on the backing-required properties than surface grafting. As mole percentage epoxide increased, OTR decreased by 22-35%, whereas WVTR and Young's modulus increased by 116-170% and 56-138%, respectively, depending on mole percentage epoxide. In the case of surface grafting, it was found that all OTR, WVTR and Young's modulus were slightly higher than those of unmodified films.