Although coatings cast from waterborne polymer dispersions are significantly more environmentally friendly than their solvent-based counterparts, their relatively poor mechanical properties limit their use. In this work, mechanically reinforced polymer films from waterborne dispersions are presented in which the stiffness is provided by the hydrogen bond-directed formation of a honeycomb microstructure. Blends of an acrylic copolymer latex containing a hydrogen bond accepting pyrrolidone group and tannic acid, a naturally occurring H-bond donating polyphenol, lead to a cellular structure with physically crosslinked tannic acid forming the cell walls and the acrylic polymer occupying the space inside the cell walls. It is demonstrated that the formation of the honeycomb microstructure was promoted by H-bond interactions and led to materials with greater mechanical performance. Furthermore, we show that the high strength of the phenol−amide interaction allows these mechanical properties to be retained even after extensive exposure to water. This approach opens the way to replacement of solventborne polymers in many applications that require hard polymer films.
The design and optimization of new processing approaches for the development of rare earth cuprate (REBCO) high temperature superconductors is required to increase their cost-effective fabrication and promote market implementation....
Polymers containing catechols are attractive for use in a diverse range of applications. However, the direct incorporation of catechols is challenging in polymers produced by radical polymerization due to transfer and termination reactions that readily occur between catechols and radical species. In this work, it is demonstrated that while monosubstituted olefins such as styrene and methyl acrylate readily undergo chain transfer to phenolic hydrogens, methacrylic monomers do not suffer any inhibitory activity and can be polymerized to high molecular weights without any influence of the catechol, even when the catechol is present in large amounts (50 wt %). In addition, it is demonstrated that even for the polymerization of monosubstituted olefins, the inhibitory activity of catechols can be substantially reduced by the selection of polar solvents such as dimethyl formamide. Thus, through appropriate selection of monomers and reaction conditions, it is shown that catechol-containing monomers can be readily incorporated into polymers obtained by free radical polymerization without any protection/deprotection of the catechol.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.