| Summary: | 碩士 === 萬能科技大學 === 材料科學與工程研究所 === 101 === In this research, the copolymer of polycaprolactone/polyurethanes has been synthesized, of which the soft segment is PCL and hard segment is H12MDI and 1,3-PDO acts as a chain extender, to investigate the heat degradation of the copolymer with the different contents of hard segments. Through GPC, the Mw range of the coploymer is 9.87×104-14.02×104 and PDI is 1.31-1.46, and through FTIR the structure of the copolymer has been determined.
The TGA results indicated that as the content of hard segment increased, the temperature of the characteristic heat degradation peak of the second stage dropped. In other words, only one characteristic heat degradation peak has been found at the two heat degradation stages. For the degradation kinetics of the copolymer, two kinetics analyses were used– Kissinger and Ozawa methods. With the increase of hard segment, the activation energy of the copolymer decreased. Through DSC, the phase behavior of copolymer was explored. The results showed that the transition of the glass phase was more difficult since the soft segment was affected by the increase of hard segment.
The biodegradation in this research was divided into internal simulated degradation and external simulated degradation. In external degradation, the copolymer was put into the solutions of NaOH, HCl and H2O2 for 24 hours and then the rate of weight loss was gained; through SEM the surface degradation was observed, in which the sample PU1 showed the best degradation in the solutions of NaOH and H2O2. In internal degradation, the copolymer was put into the oxidized solution of CoCl2/H2O2 for 15 days, which aimed to simulate the degradation inside human body for 10 weeks. Again, the rate of weight loss was gained and the surface degradation was observed. The results indicated that the sample PU1 showed the best degradation in the oxidized solution of CoCl2/H2O2.
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