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The influence of HLB (hydrophilic-lipophilic balance) and surfactant blend concentration (SBC) on flocculating performance of latex particles of acrylamide and [2-(acryloyloxy)ethyl]trimethylammonium chloride copolymers with a cationic charge density of 40%, obtained by inverse microemulsion copolymerization by using a surfactant blend of Arlacel 83 and Softanol 90 as emulsifier and Rolling M-245, a mixture of n-decane and n-tetradecane in about 40/60 weight ratio, as oil phase, has been studied for a total comonomer concentration of 32.5% (w/w). Comonomer inverse microemulsion copolymerizations were carried out in the semicontinuous mode by adding continuously an aqueous solution of sodium metabisulfite (SMB) as initiator into stirred inverse comonomer microemulsions. From 7.75 to 8.26, HLB has a strong influence on average molar mass (Mw) and flocculating performance (FP), the higher the HLB the higher the FP. A small decrease in SBC causes a dramatic increase in Mw and a decrease in FP although the influence on copolymer viscosity is small. Results are explained in terms of copolymer structuring degree and collapsed state of copolymer chains inside latex particles as well as in terms of the observed composition drift with conversion. [ABSTRACT FROM AUTHOR]

The influence of initiator concentration, specific flow rate of initiator addition (Qsp), initial copolymerization temperature (Ti), aqueous phase pH and total comonomer concentration (TCC) on flocculating performance of latex particles of acrylamide and [2- (acryloyloxy)ethyl]trimethylammonium chloride copolymers with a cationic charge density of 40%, obtained by inverse microemulsion copolymerization by using a surfactant blend of Arlacel 83 and Softanol 90 as emulsifier and Rolling M-245, a mixture of n-decane and n-tetradecane in about 40/60 weight ratio, as oil phase, has been studied for high TCC, ranging from 28 to 34.5% (w/w). Comonomer inverse microemulsion copolymerizations were carried out in the semicontinuous mode by adding continuously an aqueous solution of sodium metabisulfite as initiator into stirred inverse comonomer microemulsions. Initiator concentration has a strong influence on viscosity, viscometnc structunng degree (VSI) and average weight molar mass (Mw) of copolymers in the range from 5 to 25 g/L. Both viscosity and Mw decrease with increasing initiator concentration. Best flocculating performance is obtained from 10 to 20 g/L, values at which VSI shows a minimum. Under the experimental conditions used, Qsp (153 to 310 mL/h/kg of comonomer), T (25 to 35°C) and aqueous phase pH (2.5 to 4.5) have almost no influence on both viscosity and VSI and, hence, on flocculating performance. On the contrary, TCC has a slight influence on copolymer viscosity but a strong one on VSI which increases dramatically with TCC, being the worst flocculating performance obtained at the highest TCC studied (34.5% (w/w)). Flocculating performance results are explained in terms of copolymer structuring degree and collapsed state of copolymer chains inside latex particles as well as in terms of the composition drift with conversion. [ABSTRACT FROM AUTHOR]

Abstract: The polymerization of n-hexyl methacrylate (n-HMA) in three-component microemulsion stabilized with dodecyltrimethylammonium bromide (DTAB) is reported as a function of monomer and initiator concentrations and temperature. The obtained latices were bluish, transparent, and translucent. Particle sizes and molar masses were on the order of 20 nm and , respectively. In all cases, high reaction rates and final conversions of 98% were obtained. Polymerization temperature has a strong effect on reaction rate and conversion. [Copyright &y& Elsevier]

The inverse emulsion copolymerization of acrylamide (AM) with dimethylaminoethylacrylate methyl chloride (Q9) using redox initiation with low surfactant concentration in an isoparaffinic solvent has been studied. The kinetics of conversions of inverse-emulsion polymerizations were investigated by HPLC method. It was an interesting way to know rapidly the conversion of each monomer with high reproducibility. In all experiments the monomer concentration was 25% respect the total weight or higher and the experiments were carried out at 50∘C. The effects of initiator concentration, composition of the monomer mixture and monomer concentration on the polymerization conversion and viscosity of copolymers solutions have been examined. For copolymer characterization, the results of viscosity were compared with commercial copolymer viscosities. The formulations with 3,000 ppm of initiator were the most interesting of all copolymer compositions since they presented very high conversions and their viscosities were higher than those of commercial copolymer solutions. The analysis of monomer concentration was carried out with 3,000 ppm and the conversion and viscosity were higher when the monomer concentration was increased. [ABSTRACT FROM AUTHOR]