Efeito da lignina kraft e do óleo de palmiste na substituição parcial do poliol de origem petroquímica para produção de espumas flexíveis viscoelásticas de poliuretano
Data
2022-02-18
Autores
Flôres, Camila Campos 
Orientadores
Oliveira, Maurício
Tipo
Tese de doutorado
Título da Revista
ISSN da Revista
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Resumo
Objetivo: Desenvolver espumas flexíveis de poliuretano com propriedades viscoelásticas, empregando diferentes concentrações de lignina Kraft e óleo de palmiste, sem modificação química, em substituição parcial ao poli(etileno gicol) metil éter, de origem petroquímica. Este estudo visa, ainda, entender o efeito da substituição do poliol poliéter pela lignina Kraft, óleo de palmiste e mistura deles nas propriedades das espumas viscoelásticas, a fim de encontrar a relação mais adequada, dentre as máterias-primas, para produção de espumas com propriedades de aplicação próximas às espumas produzidas com poliol de origem petroquímica. Métodos: A dispersão da lignina Kraft em poli(etileno gicol) metil éter foi avaliada por diferentes metodologias e caracterizada em relação ao rendimento, diâmetro de partícula, viscosidade dinâmica e número de hidroxilas. As espumas de poliuretano foram avaliadas em relação ao perfil de crescimento, propriedades térmicas via análise termogravimétrica e análise dinâmico termomecânica. Foram realizados ensaios de espectroscopia no infravermelho com transformada de Fourier, microscopia eletrônica de varredura, ensaios de inflamabilidade e análise sensorial. Propriedades mecânicas foram ainda avaliadas em relação à densidade, resistência ao rasgo, resiliência, força de indentação, tempo de retorno e deformação permanente à compressão. Resultados: Foi verificado que o uso da lignina kraft e do óleo de palmiste resultou em maior tempo de crescimento das espumas. Foi verificada uma tendência de aumento do diâmetro das células e da densidade das espumas, sendo
mais acentuado para espumas produzidas com lignina Kraft. Os impactos benéficos observados foram o aumento da resistência ao rasgo e redução da deformação permanente à compressão, porém, os resultados de resiliência e tempo de retorno demonstram que a adição das matérias-primas estudadas distanciam as espumas das propriedades de espumas típicas viscoelásticas. O óleo de palmiste não resultou em benefícios sensoriais à espuma, com até 15 partes para cada 100 partes de poliol. Conclusão: Espumas de poliuretano com lignina Kraft e óleo de palmiste foram produzidas e, mesmo com densificação e aumento da resiliência, elas podem ser utilizadas para aplicações em embalagens ou colchões, desde que cor e odor não sejam fatores reprovativos.
Objective: To develop flexible polyurethane foams with viscoelastic properties, using different concentrations of Kraft lignin and palm kernel oil, without chemical modification, in partial replacement of poly(ethylene glycol) methyl ether, of petrochemical source. This study also aims to understand the effect of replacing polyether polyol by Kraft lignin, palm kernel oil and their mixture on the properties of viscoelastic foams, in order to find the most appropriate relationship, among the raw materials, for the production of foams with application properties close to those obtained by foams produced with polyol of petrochemical origin. Methods: The dispersion of Kraft lignin in poly(ethylene glycol) methyl ether was evaluated by different methodologies and characterized in terms of yield, particle diameter, dynamic viscosity and number of hydroxyls. Polyurethane foams were evaluated in relation to growth profile, thermal properties via thermogravimetric analysis and thermomechanical dynamic analysis. Fourier transform infrared spectroscopy and scanning electron microscopy tests, flammability tests and sensory analysis were carried out. Mechanical properties were also evaluated regarding density, tear strength, resilience, indentation force, recovery time and compression set. Results: It was verified that the use of kraft lignin and palm kernel oil resulted in longer foam growth time. There was a tendency to increase the diameter of the cells and the density of the foams, being more pronounced for foams produced with Kraft lignin. The positive impacts observed were the increase in tear strength and the reduction of compression set. Resilience and recovery time results show that the addition of the studied raw materials distances the foams from the properties of typical viscoelastic foams. Palm kernel oil provides no sensory benefits to the foam, with up to 15 parts to 100 parts of polyol. Conclusion: Polyurethane foams with Kraft lignin and palm kernel oil were produced and, even with densification and resilience increasement, it can be used for applications in packaging or mattresses, as long as color and odor are not reproving factors.
Objective: To develop flexible polyurethane foams with viscoelastic properties, using different concentrations of Kraft lignin and palm kernel oil, without chemical modification, in partial replacement of poly(ethylene glycol) methyl ether, of petrochemical source. This study also aims to understand the effect of replacing polyether polyol by Kraft lignin, palm kernel oil and their mixture on the properties of viscoelastic foams, in order to find the most appropriate relationship, among the raw materials, for the production of foams with application properties close to those obtained by foams produced with polyol of petrochemical origin. Methods: The dispersion of Kraft lignin in poly(ethylene glycol) methyl ether was evaluated by different methodologies and characterized in terms of yield, particle diameter, dynamic viscosity and number of hydroxyls. Polyurethane foams were evaluated in relation to growth profile, thermal properties via thermogravimetric analysis and thermomechanical dynamic analysis. Fourier transform infrared spectroscopy and scanning electron microscopy tests, flammability tests and sensory analysis were carried out. Mechanical properties were also evaluated regarding density, tear strength, resilience, indentation force, recovery time and compression set. Results: It was verified that the use of kraft lignin and palm kernel oil resulted in longer foam growth time. There was a tendency to increase the diameter of the cells and the density of the foams, being more pronounced for foams produced with Kraft lignin. The positive impacts observed were the increase in tear strength and the reduction of compression set. Resilience and recovery time results show that the addition of the studied raw materials distances the foams from the properties of typical viscoelastic foams. Palm kernel oil provides no sensory benefits to the foam, with up to 15 parts to 100 parts of polyol. Conclusion: Polyurethane foams with Kraft lignin and palm kernel oil were produced and, even with densification and resilience increasement, it can be used for applications in packaging or mattresses, as long as color and odor are not reproving factors.