Study On Polymerization Technology Of Polymethyl Methacrylate Microspheres

The crosslinked monodisperse PMMA microspheres with uniform particle size and high heat resistance property were obtained with water as reaction medium by improving the process and optimizing cross-linking agent,emulsifier on the base of the micro-suspension polymerization and emulsion polymerization process.According to the "particle design" theory,the certain size micro-reactor of small droplets were formed to polymerize the PMMA microsphere material on the effect of special emulsifier.FT-IR,SEM and XRS were empolyed to analyze the samples.It indicated that the synthetic material does PMMA microspheres with particle size of 1 ~ 10?m.The influence of different parameters such as: polymerization temperature,initiator metering,monomer concentration,emulsifier selection and dosage and other factors on polymerization stability of the system,particle size and size distribution were researched.The perfect polymerization conditions were ascertained to produce the special particle size and monodisperse PMMA microspheres via repeating test.The dispersion mechanism of microsphere was studied by analyzing the test and the following conclusions were drown: 1)increasing the amount of emulsifier can improve the stability of polymerization system,micro-particle size tends to decrease.As the initiator concentration increased microsphere size increases.The amount of emulsifier and initiator should be controled on the preparation of microsphere.2)Increasing the amount of monomer was helpful to increase microsphere size,but if the amount of the monomer is greater than 45%,the particle size distribution is significantly wide.With the increase of cross-linking agent,degree of crosslinking was increased.The strength and heat resistance of polymer microspheres were improved with the increase of cross-linking agent.3)Oligomers have enough time to link uniformly by late dropping to so that the microspheres with the uniform particle size and regular shape nearly spherical structure were produced.4)SEM results demonstrated that the PMMA microspheres presented the particle size of 2-8?m.On the base of experimental scale,the manufacture PMMA microsphere was tentatively carried out in industrial scale by farther optimizing the combination and technology of polymerization.It showed that the obtained microsphere materials presented a perfect structure and uniform particle size.It can be applied in the manufacture of powder coating and plastic process instead of the import samples.