Preliminary Study On Recovers Polyol From Waste Rigid Polyurethane Foam By Alcoholysis

Asa polymer material, polyurethane materials are widely used in various industries,and with the extensive application, there are more and more polyurethane wastes needto be treated. Most of polyurethane materials belong to thermosetting polymers, whichwere treated by the major methods including landfill and incineration．Those methodsnot only waste a large number of chemical raw materials, but also result in air pollutionof land. Therefore, how to recycle and reuse polyurethane waste effectively andreasonably has become an issue.Recently, more and more researchers have studied in the degradation of PU,many new methods have been invented, those methods can be divided into twocategories: physical recovery and chemical recovery. They developed differentrecycling process from their own technology, and expanded polyurethane wasterecycling path.In this paper, the article first made a brief overview of the technologies anddevelopment trends about recycling and degradation of polyurethane wastes. And thearticle focused on the principles and technology of chemical degradation. Then, adegradation method and experiment was investigated to treat waste rigid polyurethanefoam.In this paper, glycolysis has been investigated to degrade the thermosetting rigidpolyurethane foam waste with1，4-butanediol and KOH as alcoholysis agents. KOH asa catalyst for alcoholysis reaction, the reaction temperature is175-180°C, theoptimum reaction time of240min, Completion of the reaction can get a uniform,transparent, liquidity light brown degradation products. Then, purification of thedegradation products can get end products------renewable polyols. The article discussedthe influence of reaction temperature and reaction time to products’ viscosity andhydroxyl value. Analyzed the influence of reaction temperature, the reaction time andthe catalyst density to the alcoholysis craft, the best glocoholysis craft is: BDO：KOH：PU=1:0.02:0.8. The glycolysis predominant glycolysis product was renewablepolyols, its viscosity approximately equal to6000mPa.s and hydroxyl valueapproximately equal to450mg KOH/g.In this paper, the magnetic solid catalyst CaO/MgO/SrFe₁₂O₁₉and MgO/SrFe₁₂O₁₉have been used to polyurethane alcoholysis. This article discussed the influence factor of alcoholysis experiments and the best glocoholysis craft.The glycolysis products wereanalyzed by hydroxyl values、viscosity and identified by different techniques,such as IR,optical microscope. The result shows: two magnetic solid catalyst can be used for thealcoholysis experiments of waste rigid polyurethane foam, and catalyst can be recoveddirectly by magnet.