Whey, a by-product of cheese making, contains whey proteins, lactose, vitamins, and minerals. Whey and whey proteins are still not fully used. In this study, whey protein-based aqueous polymer-isocyanate (API) adhesives were developed and characterized by bond test, Fourier transform infrared (FTIR) spectroscopy, and scanning electron microscope (SEM) for bond strength, chemical structures, and morphology. The optimized whey protein-based API adhesive for Glulam had a 28-h boilingdry-boiling wet strength of 6.81 MPa and a dry strength of 14.34 MPa. Results indicated that the addition of polyvinyl acetate emulsion can prolong the work life of the API adhesive. Addition of crosslinker polymeric methylene bisphenyl diisocyanate (P-MDI) not only increased the cohesive strength of the cured adhesive by crosslinking whey proteins but also resulted in strong chemical bonds via urethane linkage in wood bondlines. Addition of polyvinyl alcohol (PVA) further increased the crosslinking density of the cured adhesive due to its capability of crosslinking whey proteins through the reaction with P-MDI. Nanoscale CaCO 3 powder (3.5 wt %) as filler significantly improved bond strength due to its mechanical interlock with the polymers in the adhesive. SEM examinations confirmed that both PVA and nanoscale CaCO 3 improved the compatibilities of the components in the optimized whey protein-based API adhesive. FTIR results revealed that P-MDI reacts mainly with the residual amino groups rather than the hydroxyl groups of whey proteins. V C 2010Wiley Periodicals, Inc. J Appl Polym Sci 120: [220][221][222][223][224][225] 2011
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A double metallacycle was prepared via the size-selective integrative self-sorting of four different building blocks driven by a reversible metal-ligand coordination interaction. A hydrophobic dendron was placed on a metallacycle and a hydrophilic dendron was attached to the other metallacycle, producing a two-faced Janus-type supramolecule with two distinct functionalities. In aqueous media, hierarchical self-assembly of the supramolecular system was induced by the combination of coordination interactions and hydrophobic-hydrophilic interactions resulting in the formation of micrometer-sized fiber-like structures, a morphology distinct from metallacycles bearing only one type of functionality. This study provides a versatile approach for the construction of Janus-type molecules and demonstrates that integrative self-sorting of a supramolecular coordination system can be utilized for the preparation of complex supramolecular systems with pre-designed functionalities and morphologies
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