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The process of enzyme assisted extraction of essential oil from the leaves and branches of the Vietnamese aromatic plant Cinnamomum cassia was studied and optimized using a Box-Wilson central composite design consisting of 05 independent variables (pH, temperature T, time τ, concentration of the enzyme Laccase, and concentration of the enzyme Cellic Htec2) and two dependent variables (reducing sugar and yield of essential oil). Second-order polynomial equations were obtained for the responses, which fitted well with the experimental data. Optimal conditions for oil yield were found at pH = 5.2; T = 440C; τ = 5h30'; Laccase = 0.42 ml/g, and Cellic Htec2 = 1.15%. The experimental value (0.982% oil yield) was close to the predicted value (0.978%). The application of enzyme assisted extraction  in combination with optimization using response surface methodology substantially improved the oil yield as compared with traditional method.

Rubber nanocomposites based on natural rubber (NR)-butadiene nitrile rubber (NBR) blend filled with silane modified nanosilica (NSBT) and carbon black (CB) were prepared by melt mixing method by using an internal mixer. The effect of CB and NSBT on thermo-mechanical properties of the materials was investigated by scanning electron microscopy (SEM), thermogravimetric analysis (TGA), dynamic-mechanical analysis (DMA) and tensile testing method. The results show that the NR/NBR blends reinforced with both CB and NSBT possess the properties much better than that reinforced with only CB or NSBT. With the CB/NSBT ratio of 25/5, the properties of the NR/NBR blends were remarkably enhanced, especially the increase in tensile strength by about 64 % and the increase in the thermal stability by about 13 o C. The reasons for the improvement of NR/NBR blends' properties are due to better compatibility of the components in the rubber blend as well as the better compactness in their structure with the presence of NSBT.

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