Caracterização das propriedades mecânicas da espuma, com superfície densa, de poliuretana derivada de óleos vegetais

Abstract

Polyurethane foams (PU) are low density materials, presenting good energy-absorbing capabilities, besides being used as thermal insulators. Focusing on these characteristics, this work aims to study the feasibility in applying green PU foams, derivative from vegetable oils, as construction panels. However, PU foams tend to be flammable, which limits their use; ergo flame-retardants are added to it, improving its flame-retardancy properties, as alumina trihydrate (ATH). Different concentrations of ATH were added to PU (10, 20, 30, 40 and 50%) to evaluate the material’s mechanical and flammable properties. Flexural properties were determined utilizing a three-point loading system to apply a load to a simply supported beam and flammability tests were performed in vertical and horizontal position, classifying the specimens through comparative methods. It was observed that adding ATH to PU influenced the foam’s flexural strength proportionally, exhibiting a gradual increasing on the samples stiffness between 10 and 40 per cent of ATH in mass, slightly decreasing for the 50% of ATH sample. In the flammability tests, only 40 and 50% specimens presented good flame-retardancy and were classified according to the standard. Novel composite materials must be studied to improve the use of ATH as flame retardant, combining additives or using reinforcing fibers into the material to acquire a synergistic effect, aiming to reduce the quantity of ATH added to PU, obtaining a ductile, light weight material with good flame-retardancy properties, once these characteristics are required by the construction industry to the panel manufacturing.