Preparation Of Polymer Microsphere By Suspension Photopolymerization And Its Surface Modification

Conventional methods for preparing polymeric microspheres such as emulsion polymerization,precipitation polymerization,and suspension polymerization and so on all require the use of stabilizers or emulsifiers.Residual emulsifiers in microspheres would significantly affect the subsequent performance of microspheres.In addition,the conventional preparation methods of functional microspheres have many modification reaction steps,not only the process is complex but also easily brings about additional solvent contamination.First,this project combined with the photopolymerization and suspension polymerization,synthetic the microspheres with double acrylic double bond on the surface.The polyethyleneimine,which is a stabilizer in the process of suspension polymerization,is used as a surface modifier to surface aminated microspheres in the functionalization process.The whole reaction system of microspheres preparation and modification is simple,the design is reasonable,the energy consμumption is low,completely free of organic solvents so that has the potential for industrial production.The main work is as follows:1:Poly-(trimethylolpropane triacrylate)(PTMPTA)microspheres with acrylate double bond groups remaining on the surface were prepared by suspension photopolymerization.The relationship between the various variables in the reaction system and the average particle size and yield of the microspheres was studied.The results show that the average particle size of the microspheres was controlled by the mechanical shear rate and the TMPTA-Water mass ratio,the minimum particle size can reach around 7.5μ m.Additionally,the maximum yield can be reached 80%by increasing either factor of the initiator concentration,the irradiation intensity and the irradiation time.2:Michael addition of residual acrylate double bond on the surface of microspheres and primary amine groups on polyethyleneimine(PEI),amination of PTMPTA microspheres was achieved by one-step.Using PEI modified PTMPTA microspheres for copper ion(Cu2+)adsorption experiments,the effect of solution pH value,adsorption time,and initial Cu2+ initial concentration on the adsorption capacity of microspheres was investigated.At pH of 5,the adsorbent has an adsorption capacity of up to 40.5 mg·g-1.Adsorption equilibrium was reached after about 60 minutes in the adsorption process,and the adsorption satisfies the pseudo second-order reaction model,indicating that adsorption is mainly chemical adsorption.The larger the Cu2+ initial concentration,the stronger the adsorption capacity and the adsorption conformed to the Langmuir adsorption isotherm,suggesting that the adsorption is mainly monolayer adsorption.After 5 times of adsorption-desorption experiments,this adsorbent still has good adsorption capacity 35.8 mg g-1.