MeIt reaction in blends of immiscible PHB and ENR-50
| dc.contributor.author | J., Ismail | |
| dc.date.accessioned | 2015-07-30T00:47:31Z | |
| dc.date.available | 2015-07-30T00:47:31Z | |
| dc.date.issued | 2003 | |
| dc.description.abstract | Melt reaction at the interface of immiscible blends compnsmg a biopolymer, poly(3- hydroxybutyrate )(PHB), and epoxidized natural rubber with 50 mol percent level of epoxidation (ENR-50), prepared by solution casting technique has been studied. Differential scanning calorimetry (DSC) technique was used to measure the enthalpy of reaction under isothermal annealing. Morphologies upon melting of PHB are highly unstable as observed using optical pol~rizing microscope. The enthalpy of reaction increases with PHB and ENR- 50 content respectively as long as they constitute the dispersed phases and· exhibits a maximum at about 40-50 % PHB. Enthalpy also increases with temperature for PHB/ENR-50 blends comprising PHB below 50% while remains practically independent of temperature in other compositions. The overall rate ofreaction expressed as the reciprocal ofthe half-time of the reaction, Ilto. 5, exhibits an exponential increase with temperature and also increases with .. / decreasing PHB content. A reaction mechanism comprising degradation of PHB chains to shorter chains bearing carboxyl end groups that subsequently reacted with epoxide group of the ENR-50 was proposed, providing the basis for kinetic analysis and determination of parameters that characterize the melt reaction. While the glass transition teinperatures observed at -18.4 and 1.2°C are associated with immiscible ENR-50 and PHB phases respectively, a mutual shift towards each other after annealing at 190°C is observed, increasing gradually with increasing annealing time, an indication of progressive enhancement of compatibility of the blends. There is evidence that crystallization and melting behavior of PHB in blends are affected by annealing. These observations are s~en as the jirect effects of the melt reaction. FTIR spectrum provides further evidence that supports the ing opening reaction of the epoxide group by the carboxyl group. ~eywords: Melt, blends, morphology, epoxidized natural rubber, poly(3-hydroxybutyrate). 2 | en_US |
| dc.identifier.uri | http://hdl.handle.net/123456789/886 | |
| dc.language.iso | en | en_US |
| dc.subject | Immiscible | en_US |
| dc.subject | ENR-50 | en_US |
| dc.title | MeIt reaction in blends of immiscible PHB and ENR-50 | en_US |
| dc.type | Thesis | en_US |
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