Investigation of a non-isocyanate urethane functional monomer in latexes by emulsion polymerization

- Hydrogen bonding from carbamate acrylate monomer increased both elongation and tensile modulus for latexes.
- Compositional drift occurs in batch latexes using the carbamate monomer.
- The carbamate monomer can be located cleanly either in the core or shell in a core-shell latex.

A urethane methacrylate monomer, 2-[(butylcarbamoyl)oxy]ethyl methacrylate (BEM), methyl methacrylate (MMA), and butyl acrylate (BA) were used to prepare latexes. The effects of polymer process (batch versus semi-batch), polymer composition, and the locus (core-shell) of urethane functionality in the latex particles were studied. Urethane functional latexes were evaluated by FT-IR, solid state nuclear magnetic resonance (SS-NMR), dynamic light scattering (DLS), gas chromatography (GC), differential scanning calorimetry (DSC), tensile and dynamic mechanical thermal analysis (DMTA). A compositional drift was observed for the batch polymerization which resulted in early formed polymers rich in MMA and BEM. This accounted for the higher modulus and tensile strength in latexes derived from batch polymerization. Both homogeneous and core-shell structures were prepared. The tensile modulus, tensile strength and elongation-at-break were all dependent on BEM content.

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