New approach on the modification of liquid natural rubber production using microwave technique

High-speed synthesis using microwave technique has attracted considerable intentions among researchers as it provides an efficient time of doing reactions. Modification of liquid natural rubber (LNR) via hydrogenation using of 2,4,6-trimethylbenzenesulfonylhydrazide (MSH) produced hydrogenated liquid natural rubber (HLNR). The results showed that microwave-assisted hydrogenation of LNR was experimentally found to give expected product in a short time (10–20 min). The structure of products was characterized by Fourier-transform infrared (FTIR) and the percentage of hydrogenation was determined from the 1H-NMR spectrum. The highest hydrogenation percentage of HLNR for hydrogenation of LNR by microwave heating were obtained; an LNR hydrogenation percentage of 41.18% at a MSH:LNR weight ratio of 1.5:1, a microwave power of 600 W and a reaction time of 20 min. Diimide molecules have been generated more quickly at microwave frequencies and yield HLNR in a shorter time compared to reflux heating method

Pengoptimuman tindak balas penghidrogenan getah asli cecair melalui kaedah rangsangan permukaan

Pengoptimuman parameter kajian menggunakan rangsangan permukaan (RSM) merupakan kaedah yang dijangka dapat membantu penjimatan masa dan kos tindak balas keseluruhan jika dibandingkan dengan kaedah pengoptimuman secara tradisi. Dalam kajian ini, kaedah RSM digunakan untuk mengoptimumkan parameter tindak balas penghidrogenan LNR menggunakan sumber diimida daripada termolisis p-toluenasulfonil hidrazida (TSH) dalam pelarut o-xilena. Reka bentuk komposit putaran tengah (CCRD) menggunakan RSM digunakan dengan 3 parameter iaitu nisbah berat TSH: LNR, suhu dan masa tindak balas. Melalui reka bentuk ini, model kuadratik untuk peratusan penghidrogenan berjaya diperoleh. Model kuadratik ini adalah signifikan dengan pekali kolerasi iaitu 0.9177. Berdasarkan data ANOVA yang diperoleh, masa dan suhu tindak balas memberi kesan yang signifikan terhadap peratus penghidrogenan getah asli cecair berbanding faktor nisbah berat TSH: LNR. Keadaan optimum bagi tindak balas penghidrogenan ini adalah pada nisbah berat TSH: LNR, 1.41, masa tindak balas 2.22 jam dan suhu tindak balas 114.05°C dengan peratus penghidrogenan 81.83%. Penggunaan RSM dalam penghasilan HLNR memudahkan kajian dalam memberikan keputusan dengan peratusan penghidrogenan yang dikehendaki menggunakan persamaan polinomial kuadratik yang diperoleh

Hydrogenated liquid natural rubber for compatibility enhancement of poly (lactic acid) and natural rubber blends

Non-catalytic hydrogenation of liquid natural rubber (LNR) via thermal decomposition of 2,4,6-trimethylbenzenesulfonylhydrazide (MSH) is reported in this study. Parameter studies of the hydrogenation reaction were performed by utilizing the combination of response surface methodology and central composite rotatable design (RSM/CCRD). The effects of each variable and the interaction between two variables (i.e. the MSH:LNR weight ratio and reaction time) were studied. Statistical analysis showed that the reaction time had significantly affected the hydrogenation percentage. A reduced quadratic model equation with the coefficient of determination (R2) value of 0.9875 was developed. The optimized condition as predicted by the software was compared with the experimental data, which deviated in only 0.67, hence indicating that this model was reliable and able to predict the hydrogenation percentage accurately. Fourier-transform infrared (FTIR) and nuclear magnetic resonance (NMR) spectroscopies were used to characterize the microstructure of LNR and hydrogenated liquid natural rubber (HLNR). HLNR was then used as compatibilizer to improve the miscibility of poly(lactic acid)/natural rubber blends. With an addition of 4% HLNR, the tensile strength and impact strength of the blends were slightly improved

Penghidrogenan getah asli cecair menggunakan sistem mangkin selenium

Kaedah rangsangan permukaan (RSM) dengan reka bentuk komposit putaran tengah (CCRD) telah digunakan untuk mengoptimumkan parameter bagi penghidrogenan getah asli cecair (LNR) dalam sistem hidrazin hidrat (HH) dan hidrogen peroksida (H2O2) dengan kehadiran selenium sebagai mangkin. Parameter yang dikaji bagi tindak balas ini adalah nisbah mol HH:LNR (1.25-2.25), nisbah mol H2O2:LNR (1.25-2.25), suhu (40-80°C) dan masa tindak balas (4-8 jam). Berdasarkan data yang diperoleh, penghasilan getah asli cecair terhidrogen (HLNR) sesuai dijelaskan dengan model kuadratik. Model kuadratik ini mempunyai nilai pekali penentuan (R2) sebanyak 0.9596 yang menunjukkan korelasi yang tinggi antara peratus penghidrogenan sebenar dengan peratus yang telah diramalkan. Berdasarkan plot permukaan tindak balas 3D, suhu tindak balas memainkan peranan penting dalam penghidrogenan LNR. Keadaan optimum yang diperoleh melalui RSM bagi kajian ini adalah nisbah mol HH:LNR pada 1.50, nisbah mol H2O2:LNR pada 2.00, suhu tindak balas pada 53.34°C dengan masa tindak balas selama 5.21 jam yang memberikan peratusan penghidrogenan HLNR sebanyak 68.98%. Persamaan polinomial kuadratik yang diperoleh daripada RSM ini berguna untuk menghasilkan HLNR dengan peratusan penghidrogenan yang dikehendaki

Effect of Temperature, Time and Diimide/Rubber Ratio on the Hydrogenation of Liquid Natural Rubber by Response Surface Methodology

Hydrogenated liquid natural rubber (HLNR) was synthesized from liquid natural rubber (LNR) by thermolysis of p-toluenesulfonyl hydrazide (TSH). The HLNR structure was characterized by Fourier-transform infrared (FTIR) and nuclear magnetic resonance (NMR) spectroscopies. Thermogravimetric analysis (TGA) showed that the HLNR had higher decomposition temperature compared to LNR. A response surface methodology (RSM) based on a central composite rotatable design (CCRD) with five-level-three-factors was used to optimize the main important reaction parameters, such as the TSH:LNR weight ratio (1–3), reaction temperature (110–150 °C), and reaction time (1–8 h). A quadratic model was developed using this multivariate statistical analysis. Optimum conditions for the non-catalytic hydrogenation of LNR using TSH were obtained; an LNR hydrogenation percentage of 83.47% at a TSH:LNR weight ratio of 1.41, a reaction temperature of 118.11 °C, and a reaction time of 3.84 h were predicted. The R2 value of 0.9949 indicates that the model provides data that are well matched with those from the experiment