| Summary: | 碩士 === 元智大學 === 化學工程與材料科學學系 === 98 === Because of the seriously environmental protection issue of oil based synthetic plastics. There is a strongly counterforce to oppose the use of oil based synthetic plastics. Biodegradable plastic is one kind of oil based synthetic plastic like macromolecule polymer. It can be decomposed to CO2 and H2O by soil microorganism and won’t make the contamination. That is why this biodegradable plastic material has highly potential to instead of traditional oil based synthetic plastics.
Poly-3-hydroxybutyrate (PHB) is one kind of macromolecule polymer. We must decompose PHB to MHB by reaction with acidic methanolysis before the analysis of PHB relative purity. The traditional method is waste time and it provides the acidic methanolysis esterification energy by oven. In order to save time, this research takes a new method to provide the esterification energy by microwave. In closed system, we can get 76% PHB relative purity under the below condition:0.02g PHB,150W microwave ,2mL CH3Cl and 2mL 20% H2SO4/MeOH reaction time 100secs.
However, once heating the organic solution in the closed system, it will induce high pressure and high temperature. For safety issue concern, during the closed system microwave reaction we need certainly open the microwave to decrease the pressure and temperature.
This research develops an open system microwave, step up the pressure and temperature sensor to monitor the delta value. Finally, we can get 98% PHB relative purity under the condition one:0.02g PHB, 300W electrical microwave, 2mL 5% H2SO4 reaction time 10minutes, esterification 2mL CH3Cl and 92.3% PHB relative purity under the condition two:0.02gPHB, 800W mechanical microwave, 2mL H2SO4/MeOH reaction time 10 minutes, esterification 2mL CH3Cl and with microwave adjuster on/off time set to 18secs/10secs.
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