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| Author(s): |
Tamires de Souza Nossa
Total Authors: 1
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| Document type: | Doctoral Thesis |
| Press: | São Carlos. |
| Institution: | Universidade de São Paulo (USP). Escola de Engenharia de São Carlos |
| Defense date: | 23 out. 2014 |
| Examining board members: |
Antonio José Felix de Carvalho;
Sílvia Helena Prado Bettini;
Marcelo Aparecido Chinelatto;
Eliana Aparecida de Rezende Duek;
Luiz Antonio Pessan
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| Advisor: | Antonio José Felix de Carvalho |
| Abstract | |
Thermoplastic starch (TPS) is a biodegradable material, inexpensive, with high potential of usage in the biodegradable plastics composition. Many studies have been performed to improve some properties, mainly its low mechanical strength, high hydrophilicity and low miscibility with commercial polymers, factors that hinder the usage expansion such material as plastic. An alternative to improve these properties is the polymer blends of starch production with other polymers. However, when the materials chemical nature is quite variable then is necessary to make the polymers compatible. Usually, the reactive compatibility is obtained by the addition of coupling agents or promoting reactions during extrusion. In the present study, new alternatives were studied in order to increase the starch application potential including: the citric acid effect on starch modification; use of urea to stabilize the starch molecular weight by reactive extrusion allowing its reprocessing; the starch modification with citric acid and 4,4\'-diphenyl methane diisocyanate and the use of two reactive extrusion processes for thermoplastic starch producing; starch blends production with poly (butylene adipate co-terephthalate) and poly (lactic acid); the starch modification by incorporating crosslinking thermoreversible Diels-Alder adduct. Several characterizations were made including thermal analysis by means of thermogravimetry (TGA), differential scanning calorimetry (DSC), dynamical mechanical analysis (DMA) mechanical testing, moisture absorption, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), rheology analysis, chromatography (HPSEC) and viscometry. The research results have contributed to the development of new thermoplastic polymers or thermosetting from corn starch and helped to clarify issues not addressed in the literature about the starch modification by reactive extrusion process. (AU) | |
| FAPESP's process: | 10/20155-0 - Blends of Thermoplastic Starch Modified by Reactive Extrusion |
| Grantee: | Tamires de Souza Nossa |
| Support type: | Scholarships in Brazil - Doctorate |