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| Author(s): |
Ana Paula Mayumi Nozaki
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | Campinas, SP. |
| Institution: | Universidade Estadual de Campinas (UNICAMP). Faculdade de Engenharia Química |
| Defense date: | 2019-02-04 |
| Examining board members: |
Liliane Maria Ferrareso Lona;
Claudia Sayer;
Rubia Figueredo Gouveia
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| Advisor: | Liliane Maria Ferrareso Lona |
| Abstract | |
The main hindrance in producing polymeric nanocomposite reinforced with nanocellulose is to achieve good dispersion. The hydrophilic nature of the filler imposes an incompatibility with the mostly hydrophobic polymers. In the literature, most research focuses on modifying the nanocellulose surface to enhance dispersion. However, industrial production of this type of nanocomposite is unfeasible due to its high cost and time consumption. For this reason, in this work, an in situ emulsion polymerization approach is used to obtain a nanocomposite reinforced with nanocellulose without any surface treatment. By using vinyl acetate as the monomer, the emulsion polymerization was carried out in the presence of the filler. For the filler, we used two different variants of nanocellulose: an aqueous suspension of microfibrillated cellulose (MFC) extracted from eucalyptus or an aqueous suspension of cellulose nanocrystals (CNC) extracted from wood pulp. From a reference formulation, we evaluated the effects of other parameters on the process. We observed that the surfactant concentration impacts in the dispersion stability. The water amount does not influence the process up to a certain point. The nanocellulose variant can influence both the process and the product characteristics, and its concentration affects mainly the system¿s viscosity. Within the evaluated conditions, one formulation was chosen to have its properties further characterized and compared to the pristine polymer and a nanocomposite produced by a simple mixture. Compared with the pristine polymer, we observed a large increase in mechanical resistance when the synthesis was carried out in the presence of CNC, but also a decrease with MFC as the filler. For the thermal properties, an increase in thermal stability occurred with the addition of the filler. However, this increase was more relevant for the mixed nanocomposite. Lastly, for the barrier properties, both pristine polymer and nanocomposites showed no significant difference (AU) | |
| FAPESP's process: | 16/18709-4 - Polymeric nanocomposites using nanocellulose with no surface treatment obtained by emulsion polymerization |
| Grantee: | Ana Paula Mayumi Nozaki |
| Support Opportunities: | Scholarships in Brazil - Master |