Study On The Preparation And Properties Of Cardanol Modified Phenolic Foam

Compared to traditional insulation materials, phenolic foams have outstanding abilitiessuch as flame retardant, low smoker, low toxicity and excellent heat resistance and thermalinsulation. But the phenolic foam is hard brittle, easily pulverized, severe dregs and so on. Inthe traditional phenolic foams production process, the phenolic resin was synthesized byphenol and37%formaldehyde solution, producing a large amount of industrial wastewater. Onthe other hand, because of the rising cost and foreseeable future scarcity of pertrochemicals,more and more attention is paid to natural renewable resources in the preparation of phenolicfoams. Cardanol is a very valuable raw natural biomass phenol can replace many kinds ofpetrochemical phenolic compounds in chemical synthesis. Cardanol as the alternative of phenolin preparation of the phenolic foams can reduce the generation cost of the phenolic foams,improve the performance of the phenolic foams, expand the application field of the phenolicfoams, and reduce the environmental pollution of phenolic foams productions.Firstly, the phenolic resol resin was synthesized by phenol and paraformaldehyde. Theinfluences of paraformaldehyde to phenol molar ratio (F/P), condensation temperature andcatalyst amount on the property of base phenolic resol resin were investigated. Physical andchemical techniques were used to analyse the property of base phenolic resol resin. The resultsshowed that paraformaldehyde and phenol as the raw materials in the production process of thebasis phenolic resol resin could make it possible that the wastewater would not be producedcompletely.The optimal conditions for preparation of basis phenolic resol resin were as follows:paraformaldehyde to phenol molar ratio（F/P）was1.8, condensation temperature was90℃, thecatalyst amount was5parts that were based on the100parts of phenol quality. The propertiesof the basis phenolic resol resin obtained were listed as: viscosity was2600mPa·s, freeformaldehyde content was1.23%, free phenolic content was5.13%, molecular weight in250was about300, mass residue was more than50%. The properties of the basis phenolic resol resin obtained could meet the basis phenolic resol resin performance requirements and the costwas low.Secondly, based on the optimal conditions of phenolic resol resin, the phenolic resol resinwas modified by cardanol. The influences of the cardanol amount on the properties of phenolicresol resin and phenolic foams were investigated. The results showed that the properties of theresin were as follows:viscosity was4650mPa·s, free phenolic content was5.45%, freeformaldehyde content was0.68%, the maximal bending strength of phenolic foams reached0.25MPa and the maximal compressive strength of phenolic foams reached0.20MPa whenthe cardanol amount was10parts that were based on the100parts of phenol quality. But thethermal stability of phenolic resin was reduced. When resol resin was prepared under theconditions of paraformaldehyde to phenol molar ratio （F/P）1.8, differential scanningcalorimetry (DSC) was applied to investigate resin resol reaction kinetics at differenttemperature, when the amount replacement of cardanol were10%and0%, reaction orderwere0.75and0.76, and curing activation energy were108.5KJ·mol-1and98.13KJ·mol-1.Finally, cardanol phenolic foam was modified by aluminum hydroxide, a kind ofnon-reactive filler. The influences of the aluminum hydroxide amount on the properties ofphenolic foam were investigated. The results showed that the introduction of aluminiumhydroxide in phenolic foams has great influence on their oxygen index and mechanicalproperties. The properties of the phenolic foam were as follows：oxygen index was42increased by12%, bending strength and the compression strength was0.30MPa and0.25MPa,increased by20%and25%respectively when the aluminium hydroxide amount was10partsthat were based on the100parts of phenolic resol resin quality. Cone calorimeter analysisindicated phenolic foams possessed shorter igniting time and lasting time. It had a decrease ineffective heat of combustion (EHC) and its peak values, heat release rate (HRR) and its peakvalues (PHRR), and Peak HRR delayed corresponding to the time. CO and CO2rateincreased a little, heat release results decreased (THR) with the increasing amount ofaluminium hydroxide.