![]() ![]() Lecture 5 -Semi-Continuous Emulsion Polymerization and Structured Latexes Three alternatives to conventional surfactants, including ionic monomers, block copolymers, and the recent work on reactive surfactants in emulsion polymerization and characterization results of their loci in the final copolymer latex particles as well as properties of films cast from these latexes be discussed. mixtures of anionic and non-ionic surfactants on the kinetics results of emulsion polymerization will also presented and discussed. The influence of water-solubility of monomers, partition of the surfactant between the monomer and aqueous phases, and the use of single vs. The specific role of surfactants (single and mixtures of surfactants) on the kinetics of emulsion polymerization (rate of polymerization and evolution particle number as a function of polymerization time according to the various nucleation mechanisms) will be described. The general characteristics of surfactants and their adsorption profiles on latex particles will be reviewed. Surfactants are also essential during post-polymerization processes: stripping, storage, shipping, and formulation for several applications. Surfactants play major roles in emulsion polymerization during the particle nucleation and growth stages, with direct impact on latex particle size, size distribution, polymerization rate, polymer molecular weight, and particle morphology. Lecture 4 – The Role of Surfactants in Emulsion Polymerization Processes and Kinetics The chemical processes which the most commonly-used water-soluble polymers may undergo during emulsion polymerization will be illustrated through case studies that highlight the key principles for their control. This will provide the basis for considering grafting of water-soluble polymers used as colloid stabilizers in emulsion polymerizations. Case studies of branching in acrylate and vinyl acetate homopolymerizations and synergistic effects in copolymerization will then be presented, together with strategies for controlling the level of branching. Lecture 3 – Branching and Grafting in Emulsion Polymerizationsīranching in polymers produced by free-radical polymerization arises from chain transfer to polymer and has important effects on polymer properties. In emulsion polymerization, intermolecular chain transfer to polymer can lead to grafting of water-soluble polymers to latex particles, facilitating control of colloidal stability and latex rheology. Such branching and grafting is used to good effect in the emulsion polymer industry to control the end-use performance of latexes and emulsion polymers. This lecture will begin with an overview of the chemistry of branching and grafting. Kinetic theories due to Smith & Ewart, Stockmayer, O’Toole, Roe, Fitch, Ugelstad, and Gilbert will be discussed. The unique features of emulsion polymerization will be outlined and the influence of the colloidal size of the reaction sites discussed. Reaction mechanisms and kinetics of free radical polymerization will be reviewed. Lecture 2 – Emulsion Polymerization Mechanisms and Kinetics Lecture 1 – Free Radical Polymerization Mechanisms and KineticsĪ review of the principles of free radical-initiated polymerization, including the four basic reactions of initiation, propagation, termination and transfer, inhibition, molecular weight and molecular weight distribution, effect of temperature and pressure, autoacceleration and diffusion control of termination and propagation, and copolymerization including copolymerization reactivity ratios and copolymer sequence distribution. Course Overview | Course Schedule | Abstracts | Lecturer Bios ![]()
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