The Research Of Cardanol Modified Polyurethane Rigid Foam

Rigid polyurethane foam(RPF) has a broad application prospect of building insulation arise from its low thermal conductivity and excellent mechanical properties. However, with the idea of environment protection being enhanced and the harm of fire disasters being paid important attention, it is very significant to improve the fire resistance properties of RPF.Phenolic resin is sort of polyhydric alcohols because it has many active hydroxyl methyls. And can easily been fabricated into RPF with some additives and isocyanates. Phenolic resin have a great fire resistance property because there are many benzene rings in it. And introduce benzene ring structure into RPF by foaming method can improve its fire resistance property. However, RPF synthesized by such method may have a bad mechanical properties such as low toughness, low tensile strength etc. In order to improve RPF’s mechanical properties, it is necessary to add some flexible materials to meet a balance.In this paper, we partially used some cardanol instead of phenol to fabricate toughing RPF. Cardanol has both aromatic and aliphatic characters mainly because there is a long flexible aliphatic chain in meta-position of benzene ring. In theory, to use some cardanol instead of phenol to fabricate RPF may introduce the long flexible aliphatic chain into RPF, therefore, RPF’s mechanical properties could be improved.For specific, we fabricated expandable phenolic resins in different F/P ratio, and use these phenolic resins fabricated PR/RPF to find out the best ratio, the next step was to use different content of cardanol to replace phenol to fabricate phenolic resins, and further to make cardanol/RPF. We tested the different RPF’s mechanical properties and fire resistance. The results showed: PR/RPF has a better fire resistance compared with normal RPF, but PR/RPF has a worse mechanical properties. However, cardanol/RPF has better mechanical properties compared with PR/RPF and better fire resistance compared with normal RPF. The best F/P ratio is 1:1.2, and the content of cardanol is 20%. All these subjects were reacted under catalysts to fabricated cardanol phenolic resin and further reacted with some additives to get cardanol/RPF which has excellent performance. The fabricated cardanol/RPF conform the materials flame retardant standard.