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過熱水蒸気中でのポリ（３－ヒドロキシ酪酸-co-３－ヒドロキシヘキサン酸）の分解機構とバイオマテリアルとしての応用のための分解生成物の特性評価
https://doi.org/10.18997/00006933
https://doi.org/10.18997/0000693338486286-fe28-4ca7-995d-5d929ef8410a
| 名前 / ファイル | ライセンス | アクション |
|---|---|---|
sei_k_299.pdf (12.9 MB)
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| アイテムタイプ | 学位論文 = Thesis or Dissertation(1) | |||||||
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| 公開日 | 2018-10-01 | |||||||
| 資源タイプ | ||||||||
| 資源タイプ識別子 | http://purl.org/coar/resource_type/c_db06 | |||||||
| 資源タイプ | doctoral thesis | |||||||
| タイトル | ||||||||
| タイトル | Mechanism of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) depolymerization in superheated steam and characterization of the degradation products for biomaterial applications | |||||||
| 言語 | en | |||||||
| タイトル | ||||||||
| タイトル | 過熱水蒸気中でのポリ（３－ヒドロキシ酪酸-co-３－ヒドロキシヘキサン酸）の分解機構とバイオマテリアルとしての応用のための分解生成物の特性評価 | |||||||
| 言語 | ja | |||||||
| 言語 | ||||||||
| 言語 | eng | |||||||
| 著者 |
Dhurga Devi Rajaratanam
× Dhurga Devi Rajaratanam
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| 抄録 | ||||||||
| 内容記述タイプ | Abstract | |||||||
| 内容記述 | Polyhydroxyalkanoates (PHAs) are microbial polyesters produced by wide range of bacteria as an intracellular energy reserve material under substrate limiting and at elevated carbon sources. Poly((R)-3-hydroxybutyrate-co-(R)-3-hydroxyhexanoate) (PHBHHx) is a copolymer in PHA family that is highly favorable due to its biodegradability, flexible mechanical properties, good melt-processability and biocompatibility. However, the intracellularly produced PHAs with high molecular weight (Mw) of 200-3000 kDa makes them undesirable for the production of specialty polymers that require a low, specific range of 1-25 kDa. Therefore, an effective degradation method is necessary to produce oligoesters with desired Mw range to produce specialty polymers for various applications. Thus, the present study aimed at the unprecedented oligoester production using superheated steam (SHS) treatment. The effect of SHS temperature and reaction time on the characteristics of hydrolyzed products were determined for PHBHHxs with different comonomer units, poly((R)-3- hydroxybutyrate-co-6%-(R)-3-hydroxyhexanoate and poly((R)-3-hydroxybutyrate-co- 11%-(R)-3-hydroxyhexanoate. The PHBHHx films that were prepared using compressed molding technique was used for hydrothermal degradation by SHS at the temperature range of 130?190 °C for 600? 200 minutes and the MW reduction was monitored precisely using size-exclusion chromatography (SEC). The obtained SHS hydrolyzed products were analyzed for their changes in chain-end structures, and thermal properties using proton nuclear magnetic resonance (1H NMR) spectroscopy, thermogravimetric analyzer (TGA) and differential scanning calorimetry (DSC). Based on the chain-end structure analysis, the PHBHHx oligoesters mainly had hydroxyl, crotonoyl and 2-hexenoyl groups. Moreover, the changes in diad sequence distribution during SHS hydrolysis was determined using carbon nuclear magnetic resonance (13C NMR) spectroscopy and thermal degradation was conducted in TGA to clarify the SHS hydrolysis mechanism that resulted in the crotonoyl-chain ends. Based on the thermal degradation behaviors of PHBHHx, it was considered that HHx unit was relatively reactive to thermal β-elimination reaction at higher temperatures and the higher activation energy, Ea values of PHBHHxs during thermal degradation suggest that in the SHS hydrolysis, the β-elimination reaction gradually becomes a preferential mechanism with increased temperature. The PHBHHx oligoesters with unsaturated chain ends and untreated PHBHHx were further evaluated for their in vitro cytotoxicity, using mouse fibroblast cell line NIH 3T3 to be used as a biomaterial. Based on the in vitro cytotoxicity results of 24 and 48 hr, the SHS treated PHBHHx oligoesters with unsaturated chain ends were found to be not toxic to the growth of mouse fibroblast NIH 3T3 cell line with cell viability percentage of more than 95%. In order to serve as a potential resorbable medical suture, PHBHHx oligoesters was blended with poly(L-lactic acid) (PLLA). The PHBHHX/PLLA (20:80) blend films were evaluated for their thermal, mechanical and surface wetting properties. The thermal properties measured in TG and DSC showed a good compatibility between PHBHHx oligoesters and PLLA components. The tensile strength of oligo(PHB-co- 6%HHx)/PLLA and oligo(PHB-co-11%HHx)/PLLA were determined as 27 and 34 MPa respectively, which values were close enough to the desirable range of strength of medical sutures: 37±10 MPa. In general, the current approach of SHS treatment for PHBHHx oligoester production appears to be a cost effective and greener method for the production of fast degrading medical sutures with improved mechanical properties by further consideration of blending method with PLLA. | |||||||
| 言語 | en | |||||||
| 目次 | ||||||||
| 内容記述タイプ | TableOfContents | |||||||
| 内容記述 | 1 Introduction||2 Literature Review||3 Controlled Depolymerization of Poly(3-Hydroxybutyrate-Co-3-Hydroxyhexanoate) into Oligoester and The Characteristics of Oligoester Produced||4 Evaluation of Kinetics and Degradation Behavior During The Hydrothermal Degradation of Poly(3-Hydroxybutyrate-Co-3hydroxyhexanoate)||5 In Vitro Cytotoxicity Study of Superheated Steam Hydrolyzed Poly(3-Hydroxybutyrate-Co-3-Hydroxyhexanoate) Oligoesters And The Characteristics of Poly(3-Hydroxybutyrate-Co-3-Hydroxyhexanoate) Oligoester/Poly(L-Lactic Acid) Blend for Biomaterial Applications||6 Summary, General Conclusions and Recommendation for Future Research | |||||||
| 備考 | ||||||||
| 内容記述タイプ | Other | |||||||
| 内容記述 | 九州工業大学博士学位論文 学位記番号：生工博甲第299号 学位授与年月日：平成29年9月22日 | |||||||
| キーワード | ||||||||
| 主題Scheme | Other | |||||||
| 主題 | PHBHHx | |||||||
| キーワード | ||||||||
| 主題Scheme | Other | |||||||
| 主題 | Superheated steam | |||||||
| キーワード | ||||||||
| 主題Scheme | Other | |||||||
| 主題 | Depolymerization | |||||||
| アドバイザー | ||||||||
| 西田, 治男 | ||||||||
| 学位授与番号 | ||||||||
| 学位授与番号 | 甲第299号 | |||||||
| 学位名 | ||||||||
| 学位名 | 博士（工学） | |||||||
| 学位授与年月日 | ||||||||
| 学位授与年月日 | 2017-09-22 | |||||||
| 学位授与機関 | ||||||||
| 学位授与機関識別子Scheme | kakenhi | |||||||
| 学位授与機関識別子 | 17104 | |||||||
| 学位授与機関名 | 九州工業大学 | |||||||
| 学位授与年度 | ||||||||
| 内容記述タイプ | Other | |||||||
| 内容記述 | 平成29年度 | |||||||
| 出版タイプ | ||||||||
| 出版タイプ | VoR | |||||||
| 出版タイプResource | http://purl.org/coar/version/c_970fb48d4fbd8a85 | |||||||
| アクセス権 | ||||||||
| アクセス権 | open access | |||||||
| アクセス権URI | http://purl.org/coar/access_right/c_abf2 | |||||||
| ID登録 | ||||||||
| ID登録 | 10.18997/00006933 | |||||||
| ID登録タイプ | JaLC | |||||||
