| Summary: | 碩士 === 國立中興大學 === 生物產業機電工程學系所 === 95 === In this study, response surface methodology (RSM) was used to analyze the effect of different plasticizers (glycerol and ethylene-co-methacrylic acid (EAA)) on the chemical, mechanical and thermal properties of a biodegradable plastic pellets as well as the surface structure analysis and biodegradability. A rotatable central composite design (CCD) was used to develop models for the objective responses. The experiments were run at barrels temperatures 100°C, 100°C, 105°C, and 105°C, respectively with screw speed 25 rpm and feed rate 20g/min. Individual contour plots of the different responses were overlaid, and regions meeting the optimum water solubility index (WSI) of 6.10％, water absorption index (WAI) of 5.57％ and maximum load of 62.14N were identified at the glycerol level of 72.41ml（7.24％） and the EAA level of 36.03g（3.60％）, respectively. Another objective of this study is to focus on the composition levels affecting the thermal properties (melting point (Tm)) and thermal degradation temperature (Td) of extruded pellets. The results indicated that the melting point (Tm) of extruded pellets was ranged from 203.10°C ~213.40°C as well as the thermal degradation temperature (Td) which was ranged from 311.73°C~328.38°C. In order to evaluate the possibility of using extruded pellets as biodegradable plastic raw materials, the biodegradability of the extruded pellets was being tested according to the CNS14432 standard. The result indicated that the biodegradability of the extruded pellets reached 70.54% after 34 days and 77.60% after 45 days, respectively. Moreover, by using the enzymes analysis method, the weight loss reached 71.00% after 240 mins. Therefore, it could be concluded that the plastic pellets developed in this study consist of biodegradable properties, and it can help to resolve the refuses reduction problem.
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