||January 1, 2007
Although emulsion polymerization of synthetic styrene butadiene latex polymers has been around for many years, new high-performance polymers include functional monomers and engineered latexes that cost-effectively improve end-use performance in many applications. Modern latexes include up to three different co-monomers for functionality, such as solvent resistance. Advanced knowledge based on thermodynamic properties drives polymer design, while process advancements allow refinements to the polymer architecture beyond core-shell particles. Additionally, in-process particle size variations allow optimizing latex's packing capability in pigmented coatings and compounds. We are introducing viscoelastic latex film testing which describes molecular architecture, specifically the chain length between crosslinks of a styrene-butadiene polymeric network, and show how it influences binding strength development in pigmented paper coatings. As the molecular weight between crosslinks increases, so does strength. The challenge is how one changes the emulsion polymerization process to affect molecular architecture. Combination of thermal and dynamic latex film properties, their connection to polymeric molecular architecture, and precise polymerization control enables engineering new high-performance styrene butadiene latexes.