Mechanical properties and degradation of starch-based biopolymers as a result of processing
The development of plastics from renewable resources is a growing market. However, when processed, biopolymers undergo molecular weight degradation which influences their properties. In order to improve these properties and to increase the lifetime of a product based on biopolymers, the degradatio...
| Autor Principal: | Forsch, Philipp |
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| Formato: | Tesis de Maestría |
| Idioma: | Inglés |
| Publicado: |
Pontificia Universidad Católica del Perú
2017
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| Materias: | |
| Acceso en línea: |
http://tesis.pucp.edu.pe/repositorio/handle/123456789/8021 |
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| Sumario: |
The development of plastics from renewable resources is a growing market. However, when processed,
biopolymers undergo molecular weight degradation which influences their properties. In order to improve
these properties and to increase the lifetime of a product based on biopolymers, the degradation
behaviour during processing has to be identified. In this thesis, degradation mechanisms for starch-based
biopolymers are described. Based on the relation between average molecular weight and zero shear
viscosity, degradation of PHBV was examined. In preliminary testing, it was found out that PHBV is
highly prone to thermal load resulting in degradation. Mechanical shear shows only minor effect on the
change in zero shear viscosity. Hydrolysis and (thermo-)oxidative effects did not show significant influence
on degradation of PHBV. It was found out that the parameters, temperature, screw speed and
throughput affect degradation of PHBV in twin screw extrusion processing. A relation between degradation
and influencing factors was formulated. The effect of degradation on mechanical properties,
Young’s modulus, tensile strength, elongation at break and impact strength has been investigated. |
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