A Comparative Study on Polymerization Techniques of ALKYL Acrylates | Original Article
A series of C4-C12 alkyl acrylates and methacrylates was polymerized with starch by irradiating starch-monomer mixtures with 60CO. Homopolymers were extracted with cyclohexane. The amounts of insoluble versus soluble synthetic polymer in polymerizations run with alkyl acrylates varied less with the chain length of the alkyl substituent than in the polymerizations run with alkyl methacrylates: and the poly(alkyl acrylate) contents of cyclohexane-insoluble fractions were all in the 38-45% range. Synthetic polymer contents of the products from butyl, hexyl, and decyl methacrylates were also close to this range. In a series of polymerizations run with hexyl acrylate and hexyl methacrylate, lower irradiation doses led to more cyclohexane-soluble polymer and less synthetic polymer in the starch-containing fractions. Enzymatic digestion of starch-containing polymers gave synthetic polymer fractions that were largely insoluble in cyclohexane. Crosslinking is, therefore, probably taking place during these polymerizations; however, we could not eliminate the possibility that reduced solubility was caused by small amounts of residual carbohydrate in these polymer fractions. Here we present the polymerization of n-butyl acrylate (BA), ethyl acrylate (EA) and methyl acrylate (MA) in tri-component microemulsions, using a cationic surfactant such as dodecyl trimetyl ammonium bromide in water, as a function of temperature, initiator type and, monomer and initiator concentration. The final latexes are transparent and blue color, with particle size ranging between 20 and 60 nm determined by quasielastic light scattering (QLD) and SEC molar masses of the order of 106 g/mol. Reaction times are short and reaction rates are high with final conversions between 70 and 98% depending on the monomer and the reaction conditions.