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Authors
Abstract(s)
Os adesivos estruturais são amplamente utilizados na indústria civil, aeroespacial, automotiva, e outras aplicações de engenharia, devido à sua capacidade de unir materiais com propriedades distintas e proporcionar uma distribuição uniforme de tensões. No entanto, o desempenho desses adesivos pode ser severamente afetado em ambientes de alta temperatura, que pode afetar significativamente as propriedades mecânicas dos adesivos.
Este trabalho tem como objetivo principal investigar o comportamento de adesivos estruturais, tolueno diisocianato (TDI) e do metileno difenil isocianato (MDI) quando expostos a altas temperaturas, aquecendo da temperatura ambiente até a degradação do adesivo.
Foi realizado uma análise térmica utilizando um Analisador termomecânico - TMA 7100, por meio de testes de compressão e flexão, aplicando uma carga constante de valor mínimo a fim de apenas estar em contato com a amostra e registrar seu deslocamento, e uma variação de temperatura desde a temperatura ambiente até 400ºC.
Análise mecânica dinâmica (DMA) foi realizada no mesmo equipamento com teste de compressão, alterando as condições de teste. A carga aplicada tem uma função senoidal com amplitude de 75mN, primeiro com as mesmas condições de aquecimento e posteriormente mantendo a temperatura constante em 100 e 200ºC durante o processo.
Cada teste foi realizado em triplicata, para os dois tipos de adesivos.
Os resultados obtidos através do TMA com os valores de transição vítrea (𝑇𝑔) e temperatura de penetração (𝑇𝑝), em torno de 278ºC para o MDI e de 220ºC para o TDI, indicaram uma melhor resistência a altas temperaturas para o adesivo de MDI.
Os resultados do DMA, por meio do módulo de elasticidade a 100ºC de 9,56 MPa para MDI e 0,98 MPa para TDI e, para 200ºC, 8,54 e 2,94 MPa para o MDI e TDI respectivamente. Esses valores indicam que o MDI é um material mais rígido em comparação ao TDI.
Structural adhesives are widely used in civil, aerospace, automotive, and other engineering applications due to their ability to bond materials with distinct properties and provide evenly stress distribution. However, the performance of these adhesives can be severely affected in high temperature environments, which can significantly affect the adhesives' mechanical properties. The main purpose of this work is to investigate the behavior of structural adhesives, toluene diisocyanate (TDI) and methylene diphenyl isocyanate (MDI) when exposed to high temperatures, heating from room temperature to adhesive degradation. A thermal analysis was performed using a Thermomechanical analysis - TMA 7100, by means of compression and bending tests, applying a constant load of minimum value in order to only be in contact with the sample and register its displacement, and a temperature variation from room temperature up to 400ºC. Dynamic mechanical analysis (DMA) was performed in the same equipment with compression test, changing the test conditions. The applied load has a sine function with amplitude of 75mN, first with same of heating conditions and posteriorly keep a constant temperature of 100 and 200ºC during process. Each test was performed in triplicate for both adhesive types. The results obtained through TMA with the glass transition point (𝑇𝑔) and penetration temperature (𝑇𝑝) values, around 278ºC to MDI and 220ºC to TDI, indicated better high temperature resistance for the MDI adhesive. The DMA results, through modulus of elasticity at 100ºC of 9,56 MPa for MDI and 0,98 MPa for TDI, at 200ºC, 8,54 and 2,94 MPa for MDI and TDI respectively. These values indicate that MDI is a stiffer material compared to TDI.
Structural adhesives are widely used in civil, aerospace, automotive, and other engineering applications due to their ability to bond materials with distinct properties and provide evenly stress distribution. However, the performance of these adhesives can be severely affected in high temperature environments, which can significantly affect the adhesives' mechanical properties. The main purpose of this work is to investigate the behavior of structural adhesives, toluene diisocyanate (TDI) and methylene diphenyl isocyanate (MDI) when exposed to high temperatures, heating from room temperature to adhesive degradation. A thermal analysis was performed using a Thermomechanical analysis - TMA 7100, by means of compression and bending tests, applying a constant load of minimum value in order to only be in contact with the sample and register its displacement, and a temperature variation from room temperature up to 400ºC. Dynamic mechanical analysis (DMA) was performed in the same equipment with compression test, changing the test conditions. The applied load has a sine function with amplitude of 75mN, first with same of heating conditions and posteriorly keep a constant temperature of 100 and 200ºC during process. Each test was performed in triplicate for both adhesive types. The results obtained through TMA with the glass transition point (𝑇𝑔) and penetration temperature (𝑇𝑝) values, around 278ºC to MDI and 220ºC to TDI, indicated better high temperature resistance for the MDI adhesive. The DMA results, through modulus of elasticity at 100ºC of 9,56 MPa for MDI and 0,98 MPa for TDI, at 200ºC, 8,54 and 2,94 MPa for MDI and TDI respectively. These values indicate that MDI is a stiffer material compared to TDI.
Description
Mestrado de dupla diplomação com a UTFPR - Universidade Tecnológica Federal do Paraná
Keywords
Análise termomecânica Análise mecânica dinâmica Adesivos estruturais Altas temperaturas Temperatura de transição vítrea Módulo de elasticidade