2002 Fiscal Year Final Research Report Summary
Radiation-induced Graft-polymerization and Cocrystallization of Microbial Co-polyesters
| Project/Area Number |
11217201
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research on Priority Areas
|
| Allocation Type | Single-year Grants |
|---|
| Review Section |
Science and Engineering
|
|---|
| Research Institution | Gunma University (12301) |
|---|
Principal Investigator |
MITOMO Hiroshi Faculty of Engineering, Department of Biological & Chemical Engineering, Rrofessor, 工学部, 教授 (80008523)
|
|---|
| Project Period (FY) |
1999 – 2002
|
| Keywords | Poly (3-hydroxybutyrate) / Biodegradable polyesters / Biosynthesis / Radiation-grafting / Growth rate of spherulite / Cocrystallization / Heat-resistance / Poly (L-lactic acid) |
|---|
| Research Abstract |
Using Burkhoderia cepacia D1and Delftia acidovorans isolated from active sawage, the copolymers poly (3-hydroxybutyrate-c0-3-hydroxyvalerate) [P (3HB-co-3HV)] and poly (3-hydroxybutyrate-co-4-hydroxyvalerate) [P (3HB-co-4HB)] were biosynthesized from mixed carbon sources of butyric acid and valeric acid (VA) or γ-butyrolactone (γ-BL), respectively. The contents of 3IIV or 4IIB component increased with increasing in concentration of VA or γ-BL.. The curve of melting points of P (3HB-co-3HV) against the 3HV contents showed an eutectic point at ca. 40% 3HV, suggesting the 3HV component was included in P (3HB) crystal. Biodegradation rate of P (3HB) and its copolymer radiation-graft-polymerized with methyl methacrylate was retarded, while those with acrylic acid was promoted. The rate of spherulites growth of P (3HB) grafted with stylene was slightly decreased, while that grafted with vinyl acetate was significantly retarded. Heat resistance and mechanical property were improved by grafting. Cocrystallization was observed P (3HB-co-3HV) at 3HV content less than 40%, while it was not observed in other range of P (3HB-co-3HV) or all range of P (3HB-co-4HB). Crystallinity of the latter decreased by copolymerization. Enzymatic degradation of single crystals of P (3HB-co-4HB) occurredl not only at crystal laterals but also at folded chain regions. The small amounts of 4HB cornponents were included in P (3HB) crystals as crystal defects. Finally, poly (L-lactic acid) and Bionolle, which were considered to be the fastest ones to commercialize, were irradiated to introduce crosslinking in order to improve thermal stability or heat-resistance at temperature range above glass transition temperatures or even above melting points.
|
