Raw Lacquer Materials And Their Composites Prepared By Facile Water-borne Approaches

Raw lacquer,well-known as the "King of the Coating",constitutes one of the Chinese most important specialties.During the past decades,a number of researcher inland and abroad have undertaked significant research work to modify raw lacquer whereby to provide remarkable coatings for industrial anticorrosion.However,these modified materials all belong ot organic solvent-based coatings,which is in contrast to the trend of the furture direction of coatings development aiming at no solvent coatings and waterborne coatings.Therefore,it is of vital importance to develop waterborne raw lacquer in which to transform raw lacquer of W/O type into that of O/W type through a facile approach.Thanks to the structural characteristics of urushiol(U)that consists of two hydroxy groups in its aromatic ring,Urushiol-based emulsifier(UE)was synthesized from urushiol. According to the principle of structure similarity for emulsification,the O/W type raw lacquer emulsion(RLE)was prepared by using UE as emulsifier.The stability and the rheological behavior of the resulted RLE,the property of the resulted RLE coatings were investigated.The results showed that UE is of capability to transfer raw lacquer into O/W type emulsion(RLE).The stability of RLE was enhanced by mixed emulsifier of UE/PVA (ME).The viscosity of RLE increased with increasing the concentration of ME(c_ME). When the c_MEis lower,RLE belonged to pseudoplastic fluid,when c_MEis above 10%, RLE belonged to swell fluid.The viscosity of RLE increased with increasing storage time but the pseudoplastic fluid characteristic remained.RLE prepared using emulsifier of UE8/PVA and UE10B/PVA shows higher stability for storage,and it can be stored at ambient temperature for more than 3 months without creaming,when the c_MEis 3.3%,the shape of RLE particles is of irregularity,and c_MEis 6.7%,the RLE particle is of sphere with a diameter of less than 400nm.The RLE film possess excellent anticorrosive properties,high thermal stability,and good mechanical property similar to those of natural raw lacquer.Chosen UE10B as an emulsifier,the waterborne dispersions of rushiol-formaldehyde condensation polymer(UFP)with good stability was achieved by phase-inversion emulsification technique.The waterborne particles of UFP were of multiporous sphere of 5～20μm diameter and with its orifice diameter of less than 1μm.Simiarly chosen UE18 as an emulsifier,the waterborne dispersions of cardanol-formaldehyde condensation polymer(CFP)were prepared.The waterborne particles of CFP were of sphere with size less than 0.2μm.The rheological behavior of blend system of RLE/PSA(PA),mechanical propertiy, anticorrosive properties,as well as thermal stability of RLE/PSA(PA)coating were investigated.It was found that the blends coating possesses excellent anticorrosive properties and high thermal stability.The structure and mechanical properies of RLE/SiO₂(TiO₂)nano composite were examined by IR,TEM,TGA,and DMTA;test anticorrosive properties of RLE/SiO₂(TiO₂).The results showed that RLE/SiO₂(TiO₂)coatings had lubricous and level-up surface,SiO₂(TiO₂)enhanced composite integrate properties,SiO₂(TiO₂) distribute evenly in raw lacquer.