Chemical recycling of rigid polyurethane foam

Abstract

Chemical recycling of rigid polyurethane (PU) foams been investigated in this work. PU foam was decomposed through the transesterification reaction. Diethanolamine was used as a decomposer for glycolysis of PU foam. This novel method has been created to use these products to harden epoxy resin. In order to avoid difficult separation of glycolyzed products, such products containing sodium hydroxide were used directly as hardener of epoxy resin. The crosslinking reaction was studied using Differential Scanning Calorimetry. The glycolyzed products were characterized by Infrared Spectroscopy, Nuclear Magnetic Resonance Spectroscopy and Gel Permeation Chromatography. Thermal properties of the cured epoxy samples were investigated using HDT - Vicat, DSC and Dynamic Mechanical Analysis. Hardness of cured epoxy resin was measured by the Shore Durmeter Type D. The results show that the glycoyzed products are mainly aromatic primary amines, polyols, aliphatic secondary amine and some unreacted diethanolamine. These glycolyzed products can used as a curing agent for DGEBA epoxy resin. The cured epoxy resins exhibit good themal and mechanical properties as commercial rigid thermosetting materials.