Research On Strengthening And Toughening And Preparation Of Urea-formaldehyde And Phenol-formaldehyde Blend Foam

Global energy consumption surged rapidly and China is a big country in energyconsumption, of which building energy consumption accounts for about1/3. Exteriorwall thermal insulation materials occupy a prominent position in the building energysaving. However, he commonly used polystyrene and polyurethane foam insulationmaterials are easy to burn. Therefore, the development of a flame retardant and low-costfoam insulation is imminent.Since urea-formaldehyde resin and phenol-formaldehyde resin are extremelydifficult to burn, and urea-formaldehyde resins is low cost, so this paper useurea-formaldehyde and phenol-formaldehyde blend resin as matrix solution to preparefoam. And discuss how these elements the foaming method, the curing agent(phosphoric acid, p-toluenesulfonic acid and a mixture of anhydrous ethanol), thefoaming agent (iso-pentane and carbonate) and surfactants (Span80and Tween20) toeffect the properties of the foam. The result shows that the use of chemical and physicalshared method is better, and the optimal ratio is200parts of urea-formaldehyde resin,15parts of phenol-formaldehyde resin,2.5parts of calcium carbonate,4.5parts ofsurfactant,14parts of curing agent and4parts of isopentane. However, the mechanicalproperties of the prepared blend of urea-formaldehyde and phenol-formaldehyde foamis poor, so I need to study its strengthening and toughening modification, expecting tohave a better performance to meet the requirements of practical applicationsThen this article studies the toughening effect of nano-zinc oxide (ZnO),polyethylene glycol (PEG), polyvinyl alcohol (PVA) fibers and recycled rubber powderon urea-formaldehyde and phenol-formaldehyde blend foam. The results show thatnano-ZnO is best. The foam’s cells become uniformity and its oxygen index can be ashigh as38.67%, meanwhile the chalking rate is only0.27%after the modification. Theimportant is that The mechanical properties are improved. Glass fiber(GF) which isused as reinforcing material commonly is selected in this research, studying theinfluence of the adding amount on the properties of foam. The changes on the apparentdensity, chalking rate, thermal coefficient and the thermal stability of the foam are smallafter the addition of GF, but mechanical properties have been greatly improved and theoxygen index increased to40.84%.The The performance index of the urea-formaldehyde and phenol-formaldehydeblend foam as shown below: the apparent density is between0.24~0.32g/cm3, thethermal conductivity is below0.036W/(m K), the chalking rate is below0.42%, theoxygen index can be up to40%and it can be used under246℃. Through the strengthening and toughening modification, the bending strength and compressionstrength are increased to0.27MPa and2.62MPa respectively.