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Desenvolvimento de biopolímeros de base proteica
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Abstract(s)
Com as crescentes exigências do mercado e fortes restrições a nível ambiental, as
indústrias modernas tendem a progredir no sentido da eficiência, sustentabilidade e
rentabilidade dos seus processos produtivos. Uma vez que a indústria dos curtumes é uma
forte geradora de resíduos sólidos, é indispensável criar alternativas à valorização desses
mesmos resíduos.
Esta dissertação tem como objetivo a valorização do retalho verde e tripa, através
do estudo e desenvolvimento de biopolímeros de base proteica. Os resíduos em causa
consistem maioritariamente em colagénio, que apresenta um grande potencial para a
produção de biopolímeros.
Desta forma, este trabalho tem como objetivos específicos a extração de colagénio
do retalho e a sua utilização na produção de biofilmes, a sua aplicação no processo de
recurtimento do couro e ainda a sua aplicação na produção de aglomerados de couro.
O retalho verde e tripa foi caracterizado através de uma análise imediata e
elementar, o que demonstrou condições desejáveis para a produção de biopolímeros,
nomeadamente devido ao elevado teor em proteína. A extração do colagénio foi realizada
através de uma hidrólise térmica e alcalina, baseando os ensaios num plano experimental
de modo determinar as melhores condições de extração, sendo estas: 80°C, 10% de NaOH
e 2 horas. Definidas as condições, procedeu-se à hidrólise em larga de escala dos retalhos
e posterior caracterização dos hidrolisados proteicos.
Foram elaborados diferentes biopolímeros através da adição de glicerol,
glutaraldeído e Retanal VN, uma resina vinílica. Produziu-se biofilmes através da técnica
de casting, com boas propriedades mecânicas. No entanto, os filmes não apresentaram
hidrofobicidade.
No processo de recurtimento do couro, a adição do biopolímero conferiu ao couro
uma cor mais viva relativamente a um processo padrão, tendo-se verificado que o toque
e a firmeza da flor do couro resultaram semelhantes, além de se ter obtido valores de
resistências físico-mecânicas da mesma ordem de grandeza do padrão e adequados à
utilização do couro em calçado. Por fim, na produção de aglomerados de couro, apesar de não se conseguir
quantificar a influencia do biopolímero nas propriedades mecânicas dos aglomerados,
concluiu-se que o melhor ligante é o Retanal VN.
With the growing market demands and strong environmental restrictions, modern industries tend to progress towards efficiency, sustainability and profitability of their production processes. Since the tanning industry is a strong generator of solid waste, it is essential to create alternatives to the valorization of this waste. This dissertation aims at the valorization of green and limed scraps, through the study and development of protein-based biopolymers. The waste in question consists mostly of collagen, which has great potential for the production of biopolymers. Thus, this work aims at the extraction of collagen from the scraps and its use in the production of biofilms, its application in the leather retanning process and also its application in the production of leatherboards. The green and limed scraps were characterized through immediate and elemental analysis, which showed desirable conditions for the production of biopolymers, namely due to the high protein content. Collagen extraction was performed through thermal and alkaline hydrolysis, basing the tests on an experimental plan in order to determine the best extraction conditions, these being: 80°C, 10% NaOH and 2 hours. Once the conditions were defined, we proceeded to large-scale hydrolysis of the scraps and subsequent characterization of the protein hydrolysates. Different biopolymers were prepared through the addition of glycerol, glutaraldehyde and Retanal VN, a vinyl resin. Biofilms were produced through the casting technique, with good mechanical properties. However, the films did not present hydrophobicity. In the leather retanning process, the addition of the biopolymer gave the leather a brighter color comparing to a standard process, and it was verified that the touch and grain tightness of the leather were similar, in addition to have obtained physical-mechanical resistance values of the same order of magnitude as the standard and suitable for the use of leather in footwear. Finally, in the production of leatherboards, although it was not possible to quantify the influence of the biopolymer on the mechanical properties of the leatherboard, it was concluded that the best binder is Retanal VN.
With the growing market demands and strong environmental restrictions, modern industries tend to progress towards efficiency, sustainability and profitability of their production processes. Since the tanning industry is a strong generator of solid waste, it is essential to create alternatives to the valorization of this waste. This dissertation aims at the valorization of green and limed scraps, through the study and development of protein-based biopolymers. The waste in question consists mostly of collagen, which has great potential for the production of biopolymers. Thus, this work aims at the extraction of collagen from the scraps and its use in the production of biofilms, its application in the leather retanning process and also its application in the production of leatherboards. The green and limed scraps were characterized through immediate and elemental analysis, which showed desirable conditions for the production of biopolymers, namely due to the high protein content. Collagen extraction was performed through thermal and alkaline hydrolysis, basing the tests on an experimental plan in order to determine the best extraction conditions, these being: 80°C, 10% NaOH and 2 hours. Once the conditions were defined, we proceeded to large-scale hydrolysis of the scraps and subsequent characterization of the protein hydrolysates. Different biopolymers were prepared through the addition of glycerol, glutaraldehyde and Retanal VN, a vinyl resin. Biofilms were produced through the casting technique, with good mechanical properties. However, the films did not present hydrophobicity. In the leather retanning process, the addition of the biopolymer gave the leather a brighter color comparing to a standard process, and it was verified that the touch and grain tightness of the leather were similar, in addition to have obtained physical-mechanical resistance values of the same order of magnitude as the standard and suitable for the use of leather in footwear. Finally, in the production of leatherboards, although it was not possible to quantify the influence of the biopolymer on the mechanical properties of the leatherboard, it was concluded that the best binder is Retanal VN.
Description
Keywords
Couro Resíduos Colagénio Biopolímeros Recurtimento Aglomerados Leather Waste Collagen Biopolymers Biofilms Leatherboards