The Study On Synthesis And Modification Of Phenolic Resin And Its Foam

Traditional building materials, such as polyethylene foam,polyurethane foam and so on, can easily be combusted that produce alarge number of harmful substances. Phenolic foam is a new type ofthermal material, which doesn’t only has excllent performance in flameretardant, but also has other advantages, such as low toxicity, low smoke,light, flame resistance, insulation, low temperature resistance and so on.As a result of brittleness, easy powder and other shortcomings, itsapplication is greatly restricted. So it makes sense to study onmodification of phenolic foam to reduce brittleness and improvetoughness.There are many factors that effect sythesis of phenolic foam,Foaming process conditions and properties of phenolic resin have greatinfluence on quality of phenolic foam. To solve these problems, asystematic study of synthesis and modification of phenolic resin andphenolic foam has been done in this paper.Phenol, formaldehyde and sodium hydroxide are slected as the rawmaterials of synthesis of phenolic resin. Effects of reaction temperature, reaction time, amount of catalyst and F/P are studied by orthogonalexperiment and single factor analysis. The optimum conditions: F/P=2,reaction temperature75℃, reaction time5h, catalyst dosage1.4g.In this paper, phenolic resin (viscosity of3000~4000mPa s),Tween-80, n-pentane, p-toluenesulfonic acid and phosphoric acid areselected as raw materials. Effects of synthesis conditions are studied byorthogonal experiment and single factor analysis. The optimumconditions: surfactant dosage4～6%, foaming temperature65℃, curingagent dosage12～14%, vesicant dosage10～14%。The1,4–butanediol is selected as a modifier to prepara modifiedphenolic resin and its foam. Experimental results show that（:1）molecularweight and viscosity of phenolic resin are increased, the content of phenolis decreased, and the gelation time is shortened.（2）1,4–butanediol has atiny effect on thermal stability and oxygen index of phenolic foam. It caneffectively improve compressive strength, flexural strength and toughnessof phenolic foam. when the quantity of1,4–butanediol is10%,compression strength and Flexure fracture force of phenolic foam areimproved by34%and32%，modified phenolic foam basically meet therequirements of industrial production. It can be seen that1,4-butanediol,phenol and formaldehyde occurre polycondensation reaction through theIR spectra of modified phenolic foam and unmodified phenolic foam. It introduces the long carbon chain between the benzene ring in order toimprove the structure and toughness of phenolic foam.