Publicação
Development of polymer composites based on agro-industrial and forest solid residues
| Resumo: | The current environmental situation has been a growing concern for the World population, as the extent of its damages are being increasingly felt. Plastics represent one of the major classes responsible for this scenario, given their petrochemical base, widespread usage, and inefficient and incorrect manners to deal with generated wastes. On the run to develop more sustainable and renewable materials, composites assembled with natural polymers as reinforcing phase, also called green composites, constitute a popular approach. The reuse of natural residues from forest and agro-industries, to be employed as reinforcing phase in these materials, holds increased interest given the reduced associated costs. Aiming the preparation of sustainable materials with properties capable of competing with currently leading solutions, green composites using polypropylene (PP) or polylactic acid (PLA) as matrix phase, and different contents of woof flour (WF) as reinforcing phase, were herein developed by twin-screw extrusion. To improve the adhesion of WF to the polymer matrix, a previous surface modification of the residue, with soybean oil solutions was also studied, by FTIR-ATR and TGA. The results showed that the treatment with a 5 wt.% soybean oil/ethanol solution was the most effective at promoting the intended hydrophobicity on the natural residue. WF treated by this method was also compounded with the two selected polymers, having the thermal, rheological, physical, and morphological properties of all developed compositions been assessed. The wood content showed to play major role on composites’ properties, where higher moisture and water absorptions, lower thermal stabilities and lower melt flow indexes were generally obtained. However, these were in some cases compensated by the previous functionalisation of WF. In general, better results of these properties were achieved in compositions using PP and 15 wt.% and 20 wt.% of oil-treated WF. Furthermore, in these cases, indications of higher adhesions established between reinforcements and the matrix were also provided by SEM analysis, suggesting that materials with interesting features were achieved. |
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| Autores principais: | Oliveira, Renata Fernandes |
| Assunto: | Green composites Wood flour Reinforcement / matrix adhesion Soybean oil treatment Compósitos verdes Pó de madeira Adesão reforço / matriz Tratamento com óleo de soja Ciências Agrárias Engenharia e Tecnologia Engenharia e Tecnologia |
| Ano: | 2017 |
| País: | Portugal |
| Tipo de documento: | dissertação de mestrado |
| Tipo de acesso: | acesso aberto |
| Instituição associada: | Universidade do Minho |
| Idioma: | inglês |
| Origem: | RepositóriUM - Universidade do Minho |
| Resumo: | The current environmental situation has been a growing concern for the World population, as the extent of its damages are being increasingly felt. Plastics represent one of the major classes responsible for this scenario, given their petrochemical base, widespread usage, and inefficient and incorrect manners to deal with generated wastes. On the run to develop more sustainable and renewable materials, composites assembled with natural polymers as reinforcing phase, also called green composites, constitute a popular approach. The reuse of natural residues from forest and agro-industries, to be employed as reinforcing phase in these materials, holds increased interest given the reduced associated costs. Aiming the preparation of sustainable materials with properties capable of competing with currently leading solutions, green composites using polypropylene (PP) or polylactic acid (PLA) as matrix phase, and different contents of woof flour (WF) as reinforcing phase, were herein developed by twin-screw extrusion. To improve the adhesion of WF to the polymer matrix, a previous surface modification of the residue, with soybean oil solutions was also studied, by FTIR-ATR and TGA. The results showed that the treatment with a 5 wt.% soybean oil/ethanol solution was the most effective at promoting the intended hydrophobicity on the natural residue. WF treated by this method was also compounded with the two selected polymers, having the thermal, rheological, physical, and morphological properties of all developed compositions been assessed. The wood content showed to play major role on composites’ properties, where higher moisture and water absorptions, lower thermal stabilities and lower melt flow indexes were generally obtained. However, these were in some cases compensated by the previous functionalisation of WF. In general, better results of these properties were achieved in compositions using PP and 15 wt.% and 20 wt.% of oil-treated WF. Furthermore, in these cases, indications of higher adhesions established between reinforcements and the matrix were also provided by SEM analysis, suggesting that materials with interesting features were achieved. |
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