Effect of total acrylic/fluorinated acrylic monomer contents on the properties of waterborne polyurethane/acrylic hybrid emulsions

Synthesis and Properties of Cationic Core-Shell Fluorinated Polyurethane Acrylate

Vinyl-capped cationic waterborne polyurethane (CWPU) was prepared using isophorone diisocyanate (IPDI), polycarbonate diol (PCDL), N-methyldiethanolamine (MDEA), and trimethylolpropane (TMP) as raw materials and hydroxyethyl methacrylate (HEMA) as a capping agent. Then, a crosslinked FPUA composite emulsion with polyurethane (PU) as the shell and fluorinated acrylate (PA) as the core was prepared by core-shell emulsion polymerization with CWPU as the seed emulsion, together with dodecafluoroheptyl methacrylate (DFMA), diacetone acrylamide (DAAM), and methyl methacrylate (MMA). The effects of the core-shell ratio of PA/PU on the surface properties, mechanical properties, and heat resistance of FPUA emulsions and films were investigated. The results showed that when w(PA) = 30~50%, the stability of FPUA emulsion was the highest, and the particles showed a core-shell structure with bright and dark intersections under TEM. When w(PA) = 30%, the tensile strength reached 23.35 ± 0.08 MPa. When w(PA) = 50%, the fluorine content on the surface of the coating film was 14.75% and the contact angle was as high as 98.5°, which showed good hydrophobicity; the surface flatness of the film was observed under AFM. It is found that the tensile strength of the film increases and then decreases with the increase in the core-shell ratio and the heat resistance of the FPUA film is gradually increased. The FPUA film has excellent properties such as good impact resistance, high flexibility, high adhesion, and corrosion resistance.

Preparation of Polydimethylsiloxane-Modified Waterborne Polyurethane Coatings for Marine Applications

A series of waterborne polyurethane dispersions (WPUs) modified with hydroxyl-terminated polydimethylsiloxane (PDMS) were prepared by incorporating PDMS into the soft segments of polyurethane chains. The structural characteristics of the prepared samples were analyzed by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and particle size analysis (PSA). The effect of PDMS content on the thermal and mechanical properties of PDMS-modified waterborne polyurethanes (PS-WPU) was investigated. In addition, the water resistance and dimensional stability of the PS-WPU were investigated by measuring its water absorption ratio and water contact angle along with universal testing machine measurements.

Optimization of Waterborne Poly(Urethane-Acrylate) Nanoemulsions Based on Cationic Polymerizable Macrosurfactants with Different Hydrophobic Side Chain Length

In situ surfactant-free emulsion polymerization can help avoid the utilization of harmful co-solvents and surfactants in the preparation of waterborne poly(urethane-acrylate) (WPUA) nanoemulsion, but the solid content is extremely limited, which will affect the drying rate and film-forming properties. The utilization of polymerizable macrosurfactants can overcome the above problems. However, the research on cationic polymerizable macrosurfactants is extremely scarce. In this work, cationic dimethylaminoethyl methacrylate-b-alkyl methacrylates block copolymers (PDM-b-PRMA) with terminal double bonds and different hydrophobic side chain (HSC) lengths were fabricated via catalytic chain transfer polymerization (CCTP). HSC length of PDM-b-PRMA played an important role in the phase inversion, morphology, rheological behavior of WPUA nanoemulsions, as well as the comprehensive performance of WPUA/PDM-b-PRMA films. Polymerizable PDM-b-PBMA macrosurfactant had smaller molecular weight, lower surface tension and colloidal size than the random copolymer (PDM-co-PBMA) by traditional free radical polymerization. It was easy for PDM-b-PRMA to orientedly assemble at the oil/water interface and provide better emulsifying ability when the carbon number of HSC was four. Compared with WPUA/PDM-co-PBMA, WPUA/PDM-b-PBMA had a smaller particle size, stability and better film-forming properties. This work elucidated the mechanisms of HSC length in the fabrication of cationic PDM-b-PRMA and provides a novel strategy to prepare cationic WPUA of high performance.

Preparation and properties of emulsifier-/NMP-free crosslinkable waterborne polyurethane-acrylic hybrid emulsions for footwear adhesives (II) – effect of dimethylol propionic acid (DMPA)/pentaerylthritol triacrylate (PETA) content

Stable emulsions (solid content: 38%) of emulsifier-/N-methylpyrrolidone (NMP)-free crosslinkable waterborne polyurethane-acrylic hybrids with a fixed acrylic monomer content (20 wt.%) and different molar ratios (mole%) of dimethylol propionic acid (DMPA)/crosslinkable pentaerythritol triacrylate (PETA)(17/23, 22/17, 27/11, 32/5) were successfully prepared. This study examined the effect of mole% of DMPA/PETA on the stability and viscosity of hybrid emulsions, the tensile properties/dynamic mechanical thermal properties of hybrid film samples and the adhesive strengths of formulated adhesives for footwear at both dry and wet states. The tensile strength/modulus, storage modulus and Tgs increased with increasing PETA content. The adhesive strength at dry state increased with increasing DMPA content up to 27 mole%, and then decreased a little. However, the adhesive strength at wet state decreased with increasing DMPA content. The optimum DMPA/PETA contents were found to be 27/11 mole% to achieve high performance adhesive properties.

Crosslinked waterborne polyurethane with high waterproof performance

Fluorinated acrylate and siloxane waterborne polyurethanes with crosslinked structure exhibit low water absorption, high water contact angles, and high mechanical/thermal properties.

Structural engineering of waterborne polyurethane for high performance waterproof coatings

Novel waterborne polyurethane containing fluorine and siloxane (FSPU) for excellent thermal performance, waterproof and mechanical properties.