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Estudo do Comportamento Reológico de Produtos de Limpeza e Desinfeção
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Orientador(es)
Resumo(s)
O conhecimento da reologia de produtos de limpeza e desinfeção permite prever o comportamento em
diferentes modos de aplicação, bem como compreender a sua estabilidade, tornando-se uma mais-valia
para as indústrias deste setor de atividade e para os consumidores.
O presente trabalho teve como principal objetivo o estudo do comportamento reológico destes produtos,
nomeadamente um sabonete líquido para as mãos, GC02/21, e um detergente para lavagem manual da
loiça, CG06/21. Para tal, estudou-se o efeito da velocidade de rotação, a influência da quantidade de
espessante e o efeito da temperatura na viscosidade. Também se realizaram testes de estabilidade, de
curto período de tempo, para perceber o impacto da temperatura de armazenamento na estabilidade. A
viscosidade foi medida em dois equipamentos: Copo Ford e viscosímetro rotativo Brookfield.
Os resultados obtidos permitiram concluir que ambos os produtos são predominantemente fluídos não
Newtonianos dilatantes, quando ajustados à Lei da Potência. Relativamente ao CG02/21, observou-se
que a viscosidade quebra a partir de 1,15% de espessante e que o comportamento reológico se mantém
independentemente da temperatura. Quanto ao CG06/21, o comportamento reológico apenas se mantém
a partir da quantidade de 0,75% de espessante. Como esperado, em ambos os produtos, a viscosidade
diminui com o aumento da temperatura, apresentando um comportamento caraterizado,
aproximadamente, pela lei de Arrhenius. Para cada um dos produtos determinou-se uma equação para
corrigir medições de viscosidade para 20°C e verificou-se que o viscosímetro Brookfield é mais sensível
à temperatura nas suas medições do que o Copo Ford. A temperatura elevada (45°C) e drásticas
mudanças de temperatura mostraram ter um impacto significativo na estabilidade dos produtos,
sugerindo que o prazo de validade (1 ano) deve ser reduzido para 6 meses para evitar as alterações de
temperatura com a mudança de estação do ano.
Este estudo possibilitou desenvolver um método de validação do viscosímetro rotativo, ajudando na
futura implementação do equipamento e do parâmetro da viscosidade no Controlo de Qualidade.
Permitiu também elaborar um método de testes de estabilidade, que poderá ser adaptado a outras
variáveis e/ou condições de armazenamento, proporcionando o estudo de outros produtos.
The knowledge of rheology of cleaning and disinfection products allows to predict behaviour in different ways of application as well as understand their stability, making it an added value for the industries of this activity and for the consumers. The present work had as main objective the study of rheological behaviour of these products, namely a liquid hand soap, CG02/21, and a manual dishwashing detergent, CG06/21. To this end, the effect of the speed of rotation, the influence of the quantity of thickening agent and the effect of temperature on viscosity were studied. Also, short-length stability tests were performed to perceive the impact of stability storage temperature. The viscosity was measured in two equipments: Ford Cup and Brookfield rotational viscometer. The results obtained allowed to conclude that when the power law fits the experimental results both products are predominantly non-Newtonian fluids with dilatant behaviours. Regarding CG02/21, the viscosity breaks from 1.15% of thickening agent and the rheological behaviour remains independently of the temperature. As for CG06/21, the rheological behaviour is only maintained from 0.75% of thickening agent. As expected, in both products, viscosity decreases with increase in temperature, presenting a behaviour characterized approximately by Arrhenius law. For each of the products an equation was determined to correct viscosity measurements to 20°C. It was found that the Brookfield viscometer is more sensitive to temperature in its measurements than the Ford Cup. The high temperature (45°C) and drastic temperature changes have shown a significant impact on the stability of the products, suggesting that the expiration date of 1 year should be reduced to 6 months to avoid the temperature changes with the seasons. Through this study, a method of validation of the rotational viscometer was developed to help in the future implementation of the equipment and viscosity as a parameter in quality control. It also enabled to elaborate a method of stability tests, which can be adapted to other variables and/or storage conditions, providing studies of other products.
The knowledge of rheology of cleaning and disinfection products allows to predict behaviour in different ways of application as well as understand their stability, making it an added value for the industries of this activity and for the consumers. The present work had as main objective the study of rheological behaviour of these products, namely a liquid hand soap, CG02/21, and a manual dishwashing detergent, CG06/21. To this end, the effect of the speed of rotation, the influence of the quantity of thickening agent and the effect of temperature on viscosity were studied. Also, short-length stability tests were performed to perceive the impact of stability storage temperature. The viscosity was measured in two equipments: Ford Cup and Brookfield rotational viscometer. The results obtained allowed to conclude that when the power law fits the experimental results both products are predominantly non-Newtonian fluids with dilatant behaviours. Regarding CG02/21, the viscosity breaks from 1.15% of thickening agent and the rheological behaviour remains independently of the temperature. As for CG06/21, the rheological behaviour is only maintained from 0.75% of thickening agent. As expected, in both products, viscosity decreases with increase in temperature, presenting a behaviour characterized approximately by Arrhenius law. For each of the products an equation was determined to correct viscosity measurements to 20°C. It was found that the Brookfield viscometer is more sensitive to temperature in its measurements than the Ford Cup. The high temperature (45°C) and drastic temperature changes have shown a significant impact on the stability of the products, suggesting that the expiration date of 1 year should be reduced to 6 months to avoid the temperature changes with the seasons. Through this study, a method of validation of the rotational viscometer was developed to help in the future implementation of the equipment and viscosity as a parameter in quality control. It also enabled to elaborate a method of stability tests, which can be adapted to other variables and/or storage conditions, providing studies of other products.
Descrição
Palavras-chave
Reologia Viscosidade Sabonete Líquido Detergente Líquido Estabilidade