Study On Synthesis Of Phenolic Resin-Boron Macromolecule-Metal Complexes And Carbon Dioxide Foaming

Phenolic foam is curing by strong acid at room temperature now,for example hydrochloric acid.There are several problem when curing by strong acid,such as, complicated technics,nonuniform bubble,easy to corrosion and discoloration.In this paper,we used phenolic resin-boron macromolecule-metal complexes,foaming by controlling systematic PH use carbon dioxide.We used calcium oxide as catalyst, propylene carbonate as modifier,research and synthesis the phenolic resin-boron macromolecule-metal complexes,exploit a new environmentally friendly pehnolic foaming technics at room temperature.First,the rule of phenolic resin fasculation used calcium oxide as catalyst were studied,the influence of the added amount and species of catalyst and that of reaction temperature and time and initial formaldehyde to phenol molar ratio(F/P) on the free formaldehyde content,free phenol content,gelation time,solids content and turbidity point of the phenolic resin were studied.The result showthat optimal technological factors of phenolic resin with low free formaldehyde,free phenol and higher hydroxymethyl content were that the reaction temperature was 80℃,reaction time was 2 h,catalysts content was 1%,and F/P molar ratio was 1.4.The monomer content of phenolic resin used calcium oxide as catalyst are lower than that used other catalyst,the hydroxymethyl content of phenolic resin used calcium oxide as catalyst are higher than that used other catalyst.Secondly,the reaction of propylene carbonate modify phenolic resin were studied by in-situ FT-IR spectra,nuclear magnetic resonance(NMR),gel permeation chromatography(GPC) and DSC-TG..Comparing the free formaldehyde content,free phenol content,solids content,gelation time and mechanical property,FT-IR and DSC-TG.,NMR and GPC of modified phenolic resin and pure phenolic resin.The results show that the contents of free phenol,turbidity point of modified phenolic resin are much less than that of the pure resin,and solids content of modified phenolic resin are much more than that of the pure resin.At the same time,we can know that modified phenolic resin contain flexible long chain group,increase the ortho-para-ratio to raise modified phenolic resinic activity by FT-IR.The mechanical property of modified phenolic resin are stronger than that of the pure one,the goal of toughen has been preliminary achieved.We can know that modified phenolic resin keep the thermal behavior by DSC-TG.In this paper,the complexation reaction of borate and phenolic resin has been happened,then the pure phenolic resin and modified phenolic resin have been foaming by CO₂.Universal testing machine and SEM determined respectively the compression strength and the porous framework of foams.The result show that the apparent density,water absorbing capacity and compressive strength of CO₂ foaming method are batter than that of traditional foaming method,but the quality of foam should be improved in the future research because of the quality reduction. Comparing with the pure phenolic foam,the modified phenolic foam has many excellent performances,such as uniform and compact porous framework of foams, small pore diameter,high closed pore rate and excellent compressive strength, toughness and steady structure.