Preparation And Application Of Urea-formaldehyde Resin Nanopartice By Reverse Microemulsion

Nanoparticle which is applied extensively as liquid-crystal spacer,drug carrier,zymophore,etc.is a kind of globule with nanoscale diameter.While reverse microemulsion method is a kind of effective method to prepare nano-particles which has been developed in recent years,with easy operation and simple experiment.It can control the globule size to some extent,it can generate product with stable size and even diameter.And the main research on nanometer materials synthesized from reversed-phase microemulsion includes inorganic metallic material,with less research on synthesis field of organic nanometer materials.Nanofluids has extremely high heat transfer property,so adhesive system constructed by the concept of nanofluids,energy-saving and cost-reducing artificial board industry can be realized by shortening curing time of adhesive or reducing curing temperature,which has practical significance.Therefore it is the key content to be investigated in the project to synthesize organic urea resin nanoparticle by using reversed-phase microemulsion,then to construct urea resin nanofluids adhesive system by nanoparticle,and to apply the system to preparation of plywood.The project takes urea and formaldehyde as reactive raw materials to prepare urea resin nanoparticle in reversed-phase microemulsion system by constructing the best reversed-phase microemulsion system.And the project discusses the effect of different reactive concentrations,molar ratio?F/U?,pH value on microstructure,chemical construction,crystallinity and thermal properties of urea resin nanoparticle by characterization methods including transmission electron microscopy?TEM?,fourier infrared spectrometer?FT-IR?,X-ray diffraction analysis?XRD?,differential scanning calorimetry analysis?DSC?,thermal gravimetric analyzer,etc..The the project added the synthesized urea resin nanoparticle into urea-formaldehyde resin adhesive to get urea resin nanofluids adhesive.Additionally the article investigates various physical and mechanical properties of urea-formaldehyde resin adhesive.And the main research results are as follows:?1?The reverse microemulsion systems is composed of CTAB and span85/n-butylalcohol/normaloctane.m?CTAB?:m?Span85?=1:5.m?CTAB+Span85?:m?n-butylalcohol?=1:6;m?CTAB+Span85+n-butyl alcohol?:m?normal octane?=3:7;The best reactive temperature of the system was30?;The system was in the W/O stage when solubilizing water quantity was below1g.?2?It could be seen from analysis on the morphology of urea resin nanoparticle by TEM that urea resin nanoparticles of dozens of nanometers and two hundred nanometers could be prepared when the reaction concentration was 4%and pH value was 1.0?the reaction concentration was 4%and pH value was 2.0 and the reaction concentration was 2%and pH value was 1.0.?3?It could be seen from analysis of chemical structure of urea resin nanoparticlebyFT-IRthaturearesinnanoparticlewasgovernedby—[NHCONHCH₂]—linear structure when reaction concentration was 4%and pH value was 1.0,and 2%and pH value was 1.0;The urea resin nanoparticlechanged from—[NHCONHCH₂]—linear structure into three-dimensional network structure as F/U increased,when reaction concentration was 4%and pH value was 2.0.?4?It could be seen from analysis of crystallinity of urea resin nanoparticle by XRD that the crystallinity of urea resin nanoparticle increased as F/U increased when reaction concentration was 4%and pH value was 1.0;crystallinity of urea resin nanoparticle decreased as F/U increased when reaction concentration was 2%,pH value was 1.0 and 4%,pH value was 2.0.?5?It could be seen from analysis of thermal stability of urea resin nanoparticle by DSC that the thermal stability of urea resin nanoparticle got better as F/U decreased when reaction concentration was 4%and pH value was 1.0;the thermal stability of urea resin nanoparticle is the best when F/U was 0.4,reaction concentration was 4%and pH value was 2.0;the thermal stability of urea resin nanoparticle got better as F/U increased when reaction concentration was 2%and pH value was 1.0.?6?It could be seen from thermogravimetic analysis of sediment nanoparticle by TG that the thermal weight loss of urea resin nanoparticle of various F/U at reaction concentration of 4%and pH of 1.0 was more than that at reaction concentration of 2%and pH of 1.0;and the thermal weight loss of urea resin nanoparticle of various F/U at reaction concentration of 2%,pH of 1.0 and F/U of0.8 was the maximum.?7?It could be seen from the figure of curing time of urea resin nanofluids adhesive that the curing time of urea resin nanofluids adhesive for urea resin nanoparticle was the shortest when the reaction concentration was 2%,pH value was1.0 and F/U was 0.8,which was shortened by 15.38%compared with that for blank group.?8?It could be seen from the figure of viscosity of urea resin nanofluids adhesive that the viscosity of urea resin nanofluids adhesive prepared from urea resin nanoparticle reduced the viscosity of urea resin base solution,wherein the viscosity of urea-formaldehyde resin adhesive prepared by urea resin nanoparticle with reaction concentration of 2%,pH of 1.0 and F/U of 0.8 was the minimum,which reduced by 23.81%compared to the viscosity of urea-formaldehyde resin adhesive not added with urea resin nanoparticle.?9?It could be seen from the figure of bonding quality of urea resin nanofluids adhesive that plywood prepared by the urea resin nanofluids adhesive of urea resin nanoparticle with reaction concentration of 2%,pH of 1.0 and F/U of 0.8 had the maximum bonding strength under the condition of reduced hot pressing temperature,which was higher by 28.81%of bonding strength of plywood prepared by urea resin under the condition of hot pressing temperature not reduced.?10?It could be seen from the figure of formaldehyde emission for urea resin nanofluids adhesive that the formaldehyde emission of plywood prepared by urea resin nanofluids adhesive added with nanoparticle apparently reduced,wherein plywood prepared by urea resin nanofluids nanofluids for nanoparticle with reaction concentration of 2%,pH of 1.0 and F/U of 0.4 had the best aldehyde reduction effect,it had lowest formaldehyde emission which reduced by 46.77%compared to that of plywood prepared by urea-formaldehyde resin adhesive without nano particle.In a word,urea resin nanoparticle was synthesized by constructing the best reversed-phase microemulsion;curing time and viscosity of urea-formaldehyde resin adhesivewasreduced,formaldehydeemissionofplywoodpreparedby urea-formaldehyde resin adhesive was reduced,and bonding strength of plywood prepared by urea-formaldehyde resin adhesive was enhanced as well by adding urea resin nanofluids adhesive prepared by urea resin nanoparticle.