Preparation And Study On Properties Of Alcohol-based Polyurethane Adhesives Modified By OMMT

Polyurethane （PU） adhesives have the characteristics of adjustable softnessand hardness, low temperature resistance and bonding process is simple.According to the solvent, it was mainly divided into water soluble type, alcoholsoluble type, ester solution type and no solvent type, Because of alcohol solubletype has low water absorption, short construction period compared with watersoluble type; safe and green compared with ester soluble type; easier to synthesisand paint, lower viscosity than no solvent type, it was mainly used in foodpackaging. Due to the mechanical strength and barrier property of foodpackaging composite film was more demanding than ever before, in our country.Pure PU adhesive is hard to meet the requirements, this paper, alcohol-basedpolyurethane adhesives was modified by OMMT, and it improve the mechanicsperformance of polyurethane adhesive and reduce the permeability andproduction costs.In this paper, the alcohol-based polyurethane adhesive was synthesized bypolyether diol, TDI and diethylenetriamine, and modified by MMT. The optimalreaction time and temperature was determined by measuring the content of–NCO, in this paper, and determined the best ratio of the materials throughorthogonal test table of L₉（3⁴）. MMT was modified by OTAC; the interlayerspacing was increased, and easy to form intercalated even exfoliated structure.The component A of alcohol-based polyurethane adhesives modified by OMMTwhich content between1wt%⁵wt%were prepared, by in-situ polymerization,with OMMT was doping in the chain extender, component B was composed ofepoxy resin E-51and ethyl acetate. Component A and component B according toa certain proportion mixed, before used.Analysis the functional group of synthetic product by FT-IR; The change ofmicroscope structure of MMT and OMMT and the dispersion situation in polyurethane matrix indicated by XRD, SEM and AFM; The mechanical propertyof OMMT/PU film were tested by being used CSS–4430electronic universaltesting machine; Analysis the change of storage modulus and the glasstemperature through DMA.The results suggested that the-NH-stretching vibration of carbamateappeared at3297cm-1, and transmission C=O band appeared at1725cm-1, Si-O-Si backbone stretching vibration absorption peak was at1092cm-1, Al-O bendingvibration peak and Si-O bending vibration peaks were appeared at520cm-1and466cm-1, respectively, and showed that the compound was the target productOMMT/PU adhesive; the impurities from surface of OMMT have reduced,significantly, lamellar spacing increased, and achieved nanometer dispersing,uniformly dispersed and peeled completely in the polyurethane matrix; when thecontent of OMMT was4wt%in PU adhesive. The shear strength, the tensilestrength and maximum percentage elongation were increased by36.86%,76.86%,and134.90%, respectively, water absorption was reduced by17.54%, peelstrength was reduced by30.76%than that of pure alcohol-based PU adhesive.The storage modulus of PU film increased and the glass temperature decreasedafter doping4wt%of OMMT, So the OMMT/PU adhesive at the conditions oflow temperature and impact show a good condition. Considering variousindicators, the optimal doping amount of OMMT was4wt%was determined.