Application Research Of Modified Phenolic Resin And Its Foam

Phenolic foam is a kind of flame retarding material which is widely used in construction filed due to its excellent flaming retarding property, remarkable light weight as well as low costs.However, as traditional PF foam possess poor pulverulent ratio which limits the growth and spread of PF foams.It is valuable to make a new type modified PF foam with low pulverulent ratio and low flammability.The traditional PF foam was modified by chemical method and physical mixing method to make new PF foam with excellent mechanical properties and high flame retardance.The main contents of the paper are as follows:The PF fomas were modified by flexibility agents, such as SBS, epoxy reactive diluents and polyurethane pre-polymer(PUP).The compressive strength, bending strength,OI index and the microstructure of the phenolic foam are discussed. The microstructure of the phenolic foam was investigated by SEM, FTIR and TGA.The results show how flexibility agents influence the mechanical properties and flame retardance of modified foam.1. Modify phenolic resin with SBS. Firstly we found out the optimal solvent according to the solubility coefficients. Then mix up the SBS with a phenolic resin. The microstructure of the phenolic foam was studied by SEM and TGA. The phenolic foam was evaluated by compression strength, pulverization rate and oxygen index. The results showed the addition of SBS would introduce the flexible segments into phenolic foam and resulted in better property. However, SBS brought flammable solvents into phenolic foam which contributed to lower oxygen index and poorer thermal stability.2. Modify phenolic resin with PUP. Firstly, we made PUP with isocyanate group through the reaction of crude MDI with polyether polyol. PUP3050was three dimensional net structures with higher cross linking rate; PUPTDiol1000was linear structure with lower cross linking rate. In the synthesis stage of resin, PUP was added, which introduced flexible segments into phenolic resin through the reaction of polyisocyanate with polyether alcoholand and resulted in excellent mechanical properties and a little lower flame retardance.Compared with PUPTDIol1000, PUP3050had a higher degree of faculties, which formed more complex crosslinking structure with phenolic resin. The phenolic foam modified by PUP3050performed better and showed better mechanical properties, oxygen index and lower pulverization rate. And the TGA curve of this modified phenolic foam was more similar to pure phenolic foam. 3. Modify phenolic resin with epoxy reactive diluents. Firstly, we selected appropriate epoxy reactive diluents with different structure. EP636was tri-functionality, which formed a more complex crosslinking structure with phenolic resin; EP215was bifunctionality which formed a less complex crosslinking structure with phenolic resin. In the synthesis stage of resin, epoxy reactive diluents was added, which introduced flexible segments into phenolic resin through the reaction of polyisocyanate with polyether alcoholand and resulted in excellent mechanical properties and a little lower flame retardance.Compared with EP215, EP636had a higher degree of faculties, which formed more complex crosslinking structure with phenolic resin. Thus the phenolic foam modified by EP636performed better and showed higher compression strength, oxygen index and lower pulverization rate. And the TGA curve of this phenolic foam was more similar to pure phenolic foam.