Study of the effect of phospho-halogenated flame retardant on the chemical recycling of polyisocyanurate foams

The aim of this work was to find a method to recycle polyisocyanurate foams containing a flame retardant compound, namely TCPP. The challenge was not trivial because the TCPP had significant effects on the recycling process by interacting with the materials involved in the process. Through the use of GPC analyses the interactions of TCPP with other compounds used during the recycling operations, namely glycolysis and deamination, were investigated. The first part of the experimental work consisted in the observation of systems composed by key components for the recycling process, like epoxide, glycol, catalyst and flame retardants compounds. These systems were very useful to understand what interactions occurred between those chemicals. Considerations were made regarding the selectivity of the reactions occurring during the deamination step, followed by an investigation of the interactions between TCPP and the glycol. From these systems a method was developed to limit the effects of the presence of the TCPP exploiting the potassium acetate, namely a catalyst that can be used during the glycolysis, which also helped improve the properties of the recycled products. The experimental part continues with the application of the knowledge obtained before in order to carry out some glycolysis and deamination tests to assess if the intuition from the previous experimental part was right. It was seen that the results matched the expectations and the conditions for a recycle process for the polyurethane foam were found. After all of this, the work ends with the production and the characterization of the properties of new rigid foams with different recycled product quantities. It was seen that the foams produced had in general good properties if compared to a reference foam made only with virgin product.