Pulsed field gradient NMR (PFGNMR) permit signal editing of emulsion polymers that enables the detection of low level components of high Mw species such as RMs in the aqueous phase in the presence of ubiquitous water soluble species of emulsion polymers. We have extended diffusion filtered methods to 2D NMR experiments that have significantly aided the signal identification and assignment in complex emulsion polymers. In this study, it provides an unprecedented access to signals of hydrophobe end groups and urethane linkers of rheology modifiers in RM-latex composites in-situ. We have also been able to probe these interactions as a function of latex surface hydrophilicity. The approach is robust enough to enable us construct adsorption isotherms of a composite of any HEUR molecule with any latex of commercial grade without any special treatment. Our observation has lead to a new model of RM-latex interaction that sheds light on the elusive mechanism of high shear viscosity of RM-latex composites. Its implication to shear thinning rheology of RM-latex composites will be discussed. Figure 1. <img src='https://acs-archive-assets2.s3.amazonaws.com/241nm/uploads/69082_graphical_abstract_kopie.jpg' alt='' />

Molecular level studies of HEUR rheology modifiers (RM) and latex particles interactions: PFGNMR study

245th National Meeting (2013)

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