Preparation Of Monodisperse P(St-co-nBA)-g-PS/Ni Composite Microspheres

Polymer/metal composite microspheres have been widely used in various fields because of their special structure and excellent properties of both metal and polymer.However,most of the polymer/metal composite microspheres were based on polystyrene.Although polystyrene has many excellent properties,it was brittle and has low impact strength.In order to solve this problem,butyl acrylate(nBA)was introduced.The copolymer microspheres prepared by adding butyl acrylate had certain elasticity,which successfully solves the problem of brittleness and fragility of microspheres.P(St-co-nBA)copolymer microspheres were prepared by dispersion polymerization.The results of ~1H-NMR,SEM and thermal properties showed that nBA content had an effect on the conversion,morphology,glass transition temperature,particle size and size distribution of the microspheres.When the content of nBA was 2.5 wt%of the total amount of monomers,the copolymer microspheres were monodisperse and uniform spherical,and the particle size was 3?m.The content of nBA increased to 15 wt%The results showed that the modulus of microsphere decreases and the microsphere was easy to deform during centrifugal washing.In order to improve the thermal stability and solvent resistance of the microspheres,crosslinking agent was added to prepared high crosslinking copolymer microspheres.The influence of the type and content of crosslinking agent on the microspheres was studied.The morphology of crosslinked microspheres was observed by SEM,The thermal properties of the microspheres were analyzed by DSC.In addition,the crosslinked microspheres were put into toluene solvent to test the solvent resistance of the microspheres.The results showed that the crosslinked P(St-co-nBA)microspheres prepared by adding dicyclopentadiene acrylate(DCPA)have the best properties.In order to improve the chemical stability of microspheres,P(St-co-nBA)-g-PS microspheres with different core/shell ratios were prepared by seed emulsion polymerization.The morphology of the microspheres was observed by SEM,and the thermal properties of the microspheres were analyzed by DSC.The results showed that the surface of the microspheres is uneven and there are two absorption peaks of P(St-co-nBA)core and PS shell in DSC curve.P(St-co-nBA)-g-PS/Ni composite microspheres were prepared by electroless plating method.The effects of coarsening,sensitization and activation on the microspheres were studied.In addition,the effects of reducing agent,complexing agent,main salt concentration,electroless plating method,reducing agent and adding method of reducing agent on the microspheres were studied.The effect of reducing agent concentration on the shell roughness of electroless nickel plating was obvious.When the reducing agent concentration was 0.26 mol,the surface of the microspheres was smooth.Complexing agent also has an effect on electroless nickel plating,but the overall effect was relatively small.The main salt concentration has an effect on the electroless nickel plating rate and shell thickness,When the main salt concentration increased from 0.05 mol to 0.2 mol,the nickel shell percentage increased from 35.8%to 46.5%.When the concentration of main salt was 0.15 mol,the surface of microspheres was smooth and intact.In addition,the surface of P(St-co-nBA)-g-PS/Ni microspheres prepared by dropping reducing agent into plating bath and in ultrasonic environment is more smooth and compact.