Reparation Of Solvent-free Single Group Polyurethane Adhesive Modified By Submicron Functional Polystyrene Microsphere

Polyurethane adhesive(PU)is widely used in civil,aerospace,military and other fields due to its excellent comprehensive performance.The solvent-free polyurethane adhesive has catched more attention because of its green environmental protection concept.While there is no solvent,the viscosity,result that in some occasion it has poor construction and its adhesive strength,heat resistance,room temperature curing speed and so on all need to be improved.Especially,the application of cars,planes and other high-end neighborhood need further modification.In this paper,we got surface functionalized polystyrene microsphere through soap-free emulsion polymerization,and then obtained the microsphere powder by different post-treatment.Next,introducing the microsphere powder into polyurethane by in-situ polymerization to get one-group polyurethane composite adhesive.In the preparation of microspheres,the functional particles of different particle sizes and groups were obtained by adjusting the monomer ratio and emulsification process.In the preparation of polyurethane adhesive,we controlled the NCO%value of polyurethane polymer,the mass fraction of microspheres and the different particle sizes of microspheres,researched the change of adhesive properties.The properties of the products include the mechanical properties of the film,the microstructure and the adhesion properties of the adhesive,etc.,are tested by SEM,AFM,DMA and universal tensile machine.The results show that the functional microspheres can reduce the viscosity of adhesive and improve the construction technology.The hydroxyl group on the surface of the microsphere participates the polymerization reaction that result the formation of chemical crosslinking between the particles and the polyurethane molecules,which helps to improve the crosslinking degree after curing,And then improve the physical mechanical properties of the adhesive.With the increase of addition amount,tensile strength increase first.when quality is higher(more than 7%or 9%),the tensile strength began to decline.applied this adhesive into the aluminum,shear strength also show similar change as tensile strength.In addition,the preparation of solid microspheres powder from emulsion post-processing and the method of dispersion microspheres into polyether polyol has a great influence on the product performance,post-processing using centrifugal-drying-grinding,microspheres dispersed by ultrasonic oscillation to get better performance of adhesives.