Microwave Irradiation Synthesis Soapless Of Polymeric Particles At Expected Pressure

Having encircled the title of "Microwave Irradiation Synthesis Soap-less of Polymeric Particles at Expected Pressure", the article discussed detailedly soapless emulsion polymerization by microwave irradiation at a certain pressure with the microwave chemical reactor designed ourselves. With comparing microwave irradiation with a conventional heating, the formation and constitution of the soapless polymeric particles, and the mechanism of particle nucleation in polymerization, and the stability of particle and so on, have been widely discussed by using the laser light scattering (LLS) including emulsion polymerization of copolymer and homopolymer. It was found that the mechanism of particle nucleation in soapless emulsion polymerization by microwave irradiation under a certain pressure differed from the conventional methods. The works provide an effective way to prepare stably monodisperse polymeric nanoparticles and a base for improving industrialization of polymeric nanomaterials.The lattices particles of poly(styrene- acrylamide ), poly(styrene-co-1-vinyl-2-pyrrolidone), poly(styrene- methyl methacrylate), polystyrene, and polymethylmethacrylate were prepared by using soapless emulsion polymerization. With comparing its reaction kinetics, the amounts of composition, adding the different organic solvents and changing the expected pressure, it is concluded that the different mechanism of particle nucleation would be operated when using microwave irradiation at an expected pressure or at a normal pressure at the different reaction condition. Microwave irradiation could be in favor of improving reactionspeed, creating smaller particles, and forming more stably and monodispersed polymeric particles.The mechanism of particle nucleation of microwave irradiation at normal pressure is the same as the conventional emulsifier-free emulsion polymerization. However, it is rather complicated in microwave irradiation at an expected pressure. In copolymerization, when the monomer with water-solubility or relative high solubility in water was added in, the procession of soapless emulsion polymerization would have a course from "conglomeration particles" to "disassembly particles". And as a result of its, more smaller and stably polymeric nanoparticles would be created. It should be pointed out that just because the special structure of l-vinyl-2-pyrrolidone with the five-cirque, the same procession was not found, furthermore the hydrodynamic radius of the particle was increased and with a lower stability. So it is an exception in such a reaction condition. In homopolymerization by using microwave irradiation at an expected pressure, it was found that the water-solubility of monomer has an important effect upon the procession of the particle nucleation. When the monomer is oil-solubility, the mechanism is as same as oligomer micell nucleation in conventional soapless emulsion polymerization. And when the monomer has certain solubility in water, the procession of particle nucleation shall appear the same course from "conglomeration particles" to "disassembly particles".Moreover, by using a combination of static and dynamic laser light scattering, it was found that the distribution of colloid particle has not a obvious relation to the size and distribution of polymeric chain, that is to say, although with the different size of the polymeric chain, the colloid particle 's distribution is monodisperse.