Preparation And Application Of Montmorillonite Composite Foaming Agent

Azodicarbonamide,4'4-oxobenzene sulfonyl hydrazide,and montmorillonit were used as raw materials using aqueous solution intercalation method,sol-gel method and supercritical carbon dioxide as the intercalation solvent.Two groups of montmorillonite-based composite foaming agents were prepared by intercalation Azodicarbonamide and 4'4-oxobenzene sulfonyl hydra-zide to montmorillonit.The foaming agents were characterized by Infrared spectra analysis,Thermogravimetric analysis,X-ray diffraction and scanning electron microscopy.The effects of montmorillonite structure,intercalation conditions and preparation methods on the intercalation effect were investigated.The prepared Azodicarbonamide/montmorillonite composite foaming agent was applied to polypropylene to observe its foaming effect in polypropylene.The 4'4-oxydiphenylsulfonyl/montmorillonite composite foaming agent is added to the epoxy resin to raise the decomposition temperature to obtain the foamed material.The product was analyzed by Nano Measurer particle size measurement software and scanning electron microscopy.The effects of montmorillonite structure,curing temperature,curing agent type,curing time on foam cell density,cell size and cell distribution were investigated.Experimental results showed that:(1)Azodicarbonamide/montmorillonite composite foaming agent can be successfully intercalated into the montmorillonite lamellar structure by both two different intercalation methods.The content of azodicarbonamide in sodium-montmorillonite was 9.2%,the content of azodicarbonamide in montmorillonite modified by chlorobenzyltriphenyl quaternary phosphonium salt was 8.6%,the content of azodicarbonamide in montmorillonite modified by cetyltriphenyl quaternary phosphonium salt was 5.0%,the content of azodicarbonamide in montmorillonite modified by hydroxyethyl triphenyl quaternary phosphonium was 6.3%.The optimal intercalation conditions of Azodicarbonamide/montmorillonite composite foaming agent with supercritical carbon dioxide intercalation were 40? with supercritical pressure of 20 MPa on stir speed of 100r/min.(2)The decomposition temperature of Azodicarbonamide in modified montmorillonite is mainly effected by the synergistic catalysis of Lewis acid-base catalysis,while the decomposition temperature of Azodicarbonamide in unmodified sodium montmorillonite is mainly affected by the reaction medium.When using water/dimethyl sulfoxide as the medium the decomposition temperature of Azodicarbonamide is more obvious,to supercritical carbon dioxide as the medium can make the montmorillonite structure becomes fluffy disorder.(3)Azodicarbonamide composite foaming agent masterbatch under the condition of without foaming auxiliaries,the injection temperature is 190?,and the foaming material with cell structure can be obtained by injection with polypropylene,and the cell size is more uniform 250 ?m.(4)4'4-Oxobenzene sulfonyl hydrazide/montmorillonite composite foaming agent can be successfully prepared by three different intercalation methods.The content of 4'4-oxobenzene sulfonyl hydrazide in the composite foaming agent prepared by aqueous intercalation method gave the highest content,which was 12.2%,Followed by colloidal modification method was 11.4%,Supercritical carbon dioxide intercalation method is the lowest 10.7%.Supercritical carbon dioxide intercalation method can significantly improve the montmorillonite aggregate structure,the montmorillonite structure becomes more fluffy and disorder.Colloid modification method followed by aqueous solution intercalation method is the most obvious.(5)The 4'4-oxobenzene sulfonyl hydrazide composite foaming agent was prepared by colloidizing method,the content of 4'4 oxobenzene sulfonyl hydrazide was 11.4%,the content of 4'4 oxobenzene sulfonyl hydrazide in montmorillonite modified by cetyltriphenylphosphonium salt was 7.7%.Hydroxyethyl triphenyl quaternary phosphonium was 6.1% and that of chlorobenzyltriphenyl quaternary phosphonium salt was 5.3%.(6)Under the same conditions,the sodium-based montmorillonite composite foaming agent obtained epoxy resinbased foam material the largest average cell size,cell size distribution is not uniform,chlorobenzyl quaternary phosphonium salt modified montmorillonite Slightly better than sodium montmorillonite,hydroxyethyl quaternary phosphonium modified montmorillonite foam material cell size is small,relatively uniform;cetyl quaternary phosphonium modified montmorillonite minimum 90?m,distribution Also the most uniform.However,the foam density of the epoxy resin-based foaming material obtained by the sodium-montmorillonite composite foaming agent is the largest,and the density of the hexadecyl quaternary phosphonium salt-modified montmorillonite is the smallest.(7)Curing agent type,curing agent dosage,curing temperature of foam material foam effect has a significant impact.Ethylene diamine as curing agent,curing agent dosage of 8%,curing temperature of 80 ?for the composite blowing agent in the epoxy resin in the optimal curing conditions and under this conditions foam material cell size can reach 80?m Below,cell size distribution evenly.