| Co-Investigator(Kenkyū-buntansha) |
USHIO Kazutoshi Niihama National College of Technology, Department of Applied Chemistry and Biotechnology, Professor, 生物応用化学科, 教授 (30203508)
HAYASE Nobuki Niihama National College of Technology, Department of Applied Chemistry and Biotechnology, Professor, 生物応用化学科, 教授 (00311100)
TSUTSUMI Chikara Niihama National College of Technology, Department of Applied Chemistry and Biotechnology, assistant, 生物応用化学科, 助手 (00300640)
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| Research Abstract |
1) Composite films of 5,10,15,20-tetraphenylporphyrin(TPPH_2) derivatives containing electron-releasing groups such as alkyl and alkoxy group embedded in various biodegradable polymer(BDP) matrices were prepared and their optical response to HCl gas were examined in comparison with nonbiodegradable polymer(NBDP) matrices. Absorbance of the Soret and Q-bands for TPPH_2 derivatives-BDP composite films are reversibly, more sensitive to sub-ppm levels of HCl gas than for those-NBDP composite films. A high sensitivity to sub-ppm levels of HCl gas was achieved by using a 5,10,15,20-tetra(4'-butoxyphenyl)- porphyrin(TP(OC_4H_9)PH_2)-poly(butylene succinate adipate)composite film. Hence the retardant effect on the degradability of BDPE for the electron-releasing groups substituted TP(R)PH_2-PCL was found to decrease in the following order : -OH, -CH_3 > -H > -OC_4H_9 > -t-C_4H_9, since a polymer was affected by the hydrophilicity-hydrophobicity balance of the polymer and steric balance of it.
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) Diblock Copolymerizations of L- or D,L-Lactide(LA) with trimethylene carbonate(TMC) or 2,2-dimethyltrimethylene carbonate(2,2-DTMC) with SmMe(C_5Me_5)_2-(tetrahydrofuran) as an initiator and triblock copolymerization of L- or D,L-LA/cyclic carbonates/L-, or D,L-LA with [SmMe(C_5Me_5)_2]_2 (PhC=C=C=CPh) as an initiator generated the desired block copolymers. These results desired the comparison of biodegradabilities by proteinase K and a compost and mechanical properties between the resulting di- or triblock copolymers and random copolymers composed of L- or D,L-LA and cyclic carbonates. Hence Microwave copolymerization of L-LA with CL was carried out effectively with constant microwave powers of 500 W(2.45 GHz). The polymerization temperature ranged from 140 to 190℃. The Mn and yield of poly(L-LA-ran-CL) (32/68) was 20,000 g/mol and 56%, respectively, after the reaction mixture was irradiated for 4 min.
3) Poly(butylene succinate-co-butylene adipate) (PBSA)-degrading bacterium, strain 1-A, was isolated from soil. Strain 1-A was identified as Bacillus pumilus on the basis of its physiological properties and partial 16S rRNA gene sequence. Strain 1-A also degraded poly(butylene succinate) (PBS) and poly(rounded small epsilon, Greek-caprolactone). Biodegradable polyesters were evaluated about degradability for enzymatic degradation by lipases and chemical degradation in sodium hydroxide solution. In enzymatic degradation, PBSA was the most degradable by lipase PS, on the other hand, PBAT containing aromatic ring was little degraded by eleven kinds of lipases. Interestingly the degradation rate of PBSA in enzymatic degradation by lipase PS was faster than in chemical degradation. Less
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