The structure and properties of acrylic‐polyurethane hybrid emulsions and comparison with physical blends

Abstract

Aqueous acrylic-polyurethane hybrid emulsions were prepared by semibatch emulsion polymerization of a mixture of acrylic monomers (butyl acrylate, methyl methacrylate, and acrylic acid) in the presence of polyurethane dispersion. Equivalent physical blends were prepared by mixing acrylic emulsion and polyurethane dispersion. The weight ratio between acrylic and polyurethane components varied to obtain different emulsion properties, microphase structure, and mechanical film properties of hybrid emulsions and physical blends. Particle size and molecular mass measurements, scanning electron microscopy, glass transition temperature, and rheological measurements performed characterization of the latex system. The mechanical properties were investigated by measuring tensile strength and Koenig hardness of dried films. The experimental results indicate better acrylic-polyurethane compatibility in hybrid emulsions than in physical blends, resulting in improved chemical and mechanical properties.

Polyurethane‐block‐polystyrene Prepared by Polymerization in Miniemulsion

“…The prepared grids were then left in presence of RuO 4 vapors for 5 min in order to selectively stain the PS. 1 H NMR spectra were recorded on a Bruker Avance 400 spectrometer at 400 MHz in deuterated DMSO (macroazoinitiator) or chloroform (polymer obtained from the miniemulsions) using tetramethylsilane (TMS) as internal standard. GPC experiments were performed in chloroform on Waters-Styragel columns (pores sizes: 10 5 , 10 4 , 10 3 , and 10 6 Å ) using a Waters 410 differential refractometer and a UV detector.…”

“…The IR measurement showed a shift of the C --0 band to 1 735 cm À1 , indicating the formation of the ester and absence of remaining carboxylic acid. 1 H NMR analysis in DMSO-d 6 gives the ratio of ester azoinitiator (42 mol-%) and unreacted diol (58 mol-%). The spectrum is given as Supporting Information.…”

“…Several approaches have been used to prepare hybrid dispersions composed of the two polymers: emulsion polymerization of vinylic monomers in the presence of a PU dispersion [1] or PU stabilizer, [2] hybrid miniemulsions [3][4][5] or interpenetrating network latexes. [6] Most of these approaches are two step processes, with first the synthesis of the PU in an organic solvent and secondly the preparation of the latex in water.…”

Calculation of Grafting and Property Characterization in Polyurethane‐Acrylic Hybrid Materials Prepared by Emulsion Process

“…To create effective chemical bonds between PU prepolymers and the acrylic chains becomes a crucial key point for these hybrid materials to have desired high performance. However, in comparison with abundant studies on PU modification by acrylics or other chemicals, most of the published works have been either comparing results obtained from simple blending to those from copolymerization, [10] or rating samples obtained from different pathways of copolymerization. [11] Only few reports are available with regard to the effectiveness of the copolymerization, i.e.…”

Synthesis of phosphorus-containing polyurethanes and poly(urethane-acrylate)s

“…Although it is a simple and effective way to achieve some of the hybrid properties, physical blending fails to provide the desired properties in performance coatings. 8 Another method researchers focus on is emulsion acrylic polymerization using polyurethane dispersions as the emulsifier. 9−12 In this case, the resulting polymer network generates more durable polymers compared to a simple blending system.…”