Srebrenkoska, Vineta (2009) Obtaining and characterization of polymer eco-composites: comparison with conventional and the possibility of reusing. PhD thesis, Faculty og Technology and Metallurgy, University St Cyril and Methodius, Skopje, R. Macedonia.
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Abstract
In this dissertation, the compression and injection molding of polypropylene (PP) and poly(lactic acid) (PLA) based composites reinforced with rice hulls or kenaf fibers have been carried out. Maleic anhydride grafted PP (MAPP) and maleic anhydride grafted PLA (MAPLA) were used as coupling agents (CA) to improve the compatibility and adhesion between fibers and matrix. The composites were characterized by mechanical and thermal analysis, and it was found that the applied techniques for manufacturing of the eco-composites under certain processing conditions do not induce significant changes of the mechanical properties. The flexural strength of the compressed composite sample based on PP and kenaf is 51,3 MPa in comparison with 46,7 MPa for the one produced by injection molding technique.
Also, the composites based on phenolformaldehyde/polyvinylbutiral as a matrix and reinforced with different kinds of fabrics: glass, polyamide, aramide and high-performance (HPPE) fiber, have been produced, in order to determine the properties of eco-composites and to "evaluate" them within the family of “conventional" composites.
The investigations of the possibilities for reuse of the polymer eco-composites have been carried out. The eco-composites based on recycled matrices and recycled composites were produced and structure/properties relationships were investigated as a function of the number of reprocessing cycles. It was found that the recycling processes do not induce significant changes of flexural strength and thermal stability of the composites. In particular, PP-based composites reinforced with kenaf fibers are less sensitive to reprocessing cycles with respect to PLA-based composites reinforced with rice hulls. Also, the properties of the recycled matrices remain almost unchanged after recycling processes. In fact, the flexural strength and modulus of these materials are comparable to conventional phenolformaldehyde wood medium density fiberboards. For "conventional" composites, the preliminary investigation of the possibility for their reuse has been carried out by mechanical recycling process which is more complicate and energy-consuming than recycling of the eco-composites.
As a result of comparison of the composites properties, the eco-composites based on PP and PLA are estimated in the category of materials which could be used as non load-bearing construction materials for different industries.
| Item Type: | Thesis (PhD) |
|---|---|
| Subjects: | Engineering and Technology > Materials engineering |
| Divisions: | Faculty of Technology |
| Depositing User: | Vineta Srebrenkoska |
| Date Deposited: | 10 Dec 2012 15:27 |
| Last Modified: | 03 Oct 2013 09:38 |
| URI: | https://eprints.ugd.edu.mk/id/eprint/3212 |
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