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Novel eco-friendly sulfonated polyurethane/polyacrylate (SPUA) emulsions were synthesized by surfactant-free emulsion polymerization method using PU as seeds. The sodium sulfonate modified polyester polyol (SDNP) was used as internal emulsifier to make the PU emulsion disperse in deionized water. Effects of the SDNP content on the properties of the emulsions and membranes were studied. Dynamic light scattering (DLS) result showed that the average particle sizes of SPUA emulsions decreased first from 124.1 nm to 102 nm when the SDNP content was lower than 40 wt% and then increased to 138 nm. Transmission electron microscopy (TEM) morphology showed that the particle sizes were all spherical and an apparent core-shell structure was observed. Fourier transform infrared spectroscopy (FT-IR) result ascertains that SPUA was successfully prepared. X-ray photoelectron spectroscopy (XPS) analysis demonstrates that the carbon, oxygen, nitrogen, sulfur, and sodium peaks were all revealed and the polyurethane component was rich in the upper surface. Thermo gravimetric analysis (TGA) of the membranes showed that the thermal stability of the SPUA membranes was enhanced by increasing the SDNP content. Scanning electron micrograph (SEM) results demonstrates that the coexistence of a dual phase. The SPUA could be used as adhesives in footwear industry, and the T-peel strength of the SPUA membranes increased from 5.98 N/mm to 12.06 N/mm when the SDNP content was up to 40 wt%. The wettability of SPUA emulsions on the rubber surface results showed that the emulsions could wet the rubber surface well. [ABSTRACT FROM AUTHOR]

Novel polyurethane/polyacrylate (PUA) composite emulsions were synthesized by soap-free emulsion polymerization method from methyl methacrylate (MMA), butyl acrylate (BA), and 2-Hydroxyethyl acrylate (HEA) in the presence of PU as seeds and a polymerizable emulsifier-Allyloxy hvdroxyl propanesulfonic salt (AHPS). Effects of the AHPS content on the properties of the emulsions and films were studied. Dynamic light scattering (DLS) result showed that the average diameters and polydispersity were decreased with the increment of AHPS content. Fourier transform infrared spectroscopy (FT-IR) result shows that AHPS was introduced into the PUAS chains. Their thermal stability and Tg of the films increased gradually with augment of AHPS amount in polymer. X-ray photoelectron spectroscopy (XPS) analysis showed that sodium was preferably enriched on the surface of latex particles. Atomic force microscopy (AFM) observation performed the extremely flat membrane. [ABSTRACT FROM AUTHOR]

Highlights: [•] A new epoxide modified polyurethane/polyacrylate emulsion was synthesized. [•] Surface tension analysis assured the surface activity of the polyurethane emulsion. [•] The ring-opening mechanism between epoxide and carboxylic acid groups was discussed. [•] The fitting peak results confirm the formation of polyurethane/polyacrylate. [Copyright &y& Elsevier]

[Display omitted] • Introduce the end-blocked structure into the water-based functional polyurethane segments applied as a "latent cross-linker" for surface sizing, • A novel compound sizing system containing water-based blocked polyurethane and polyvinyl alcohol, • Chemical bonding and hydrogen bonding between highly active isocyanate groups and paper fiber after unblocking, • Application of water-based blocked polyurethane in surface sizing of special paper. Efficient improvement of paper strength while optimized sizing technique remains challenging and fascinating since specialty paper are required to low-cost, high printing quality and environmental sustainability. Herein, a novel controlled reactivity polyester glycol-based cross-linker (TBPU) applied in paper surface sizing was exploited by simple two-steps polymerization and blending process. An end-blocked structure design strategy of containing densely distributed multiple soft segments and active hydrogen nucleophilic segments (Butanone oxime, MEKO as end closure units) in isocyanate dispersion was achieved to address the scarcity of mechanical properties and the inconvenient in surface-sizing progress. TBPU can block the NCO groups in IPDI segments at 60 °C, and NCO groups can be deblocked at the temperature higher than 110 °C, which endow TBPU with latent cross-linking property. Afterward, we took advantage of the structural feature of polyhydroxy compounds and the adhesion to cellulose via using polyvinyl alcohol (PVA) as a blending component to form TBPU/PVA emulsion. The organization of NCO groups react with hydroxyl groups, carbamate groups cross-linked with hydrogen bonds, and crystallized PCL segments generates phase-separated hierarchical domains. Serving as high-reactivity paper-sizing fillers capable of cross-linking and disintegration under an external change of temperature, the hierarchical domains can strengthen the specialty papers and enhance their water resistance and ink adhesion. The influences of TBPU content, PVA content and NCO/ OH molar ratio on the physicochemical properties of the resultant emulsions and sized paper have been investigated. As a result, the paper sized with TBPU-1.6/PVA emulsion exhibit a tensile index of ≈107.19 Nm/g, a tearing index of ≈11.79 m N • m2/g, a folding resistance of ≈4511 s, an optimum blending temperature of 70 °C and exceptional cooperation ratio with PVA and TBPU (4.0 wt%, 3.0 wt%), which are 1.649 times, 1.966 times, and 2.652 times than those of untreated papers (65 Nm/g, 6 m N • m2/g, 1701 s). Furthermore, sizing liquid can be conveniently applied and recycled due to their excellent environmental friendliness and Biodegradability, this work provides a promising solution for optimizing surface sizing technology. [ABSTRACT FROM AUTHOR]

Hydroxyl-terminated polyurethane (EPPU) modified by epoxy resin was synthesized. The structure of polyurethane (PU) was characterized by Attenuated total reflection Fourier transform infrared spectrometer (ATR-FTIR) and transmission electron microscope (TEM). The effect of w(E-44) on thermal stability and mechanical properties of the membranes were also measured. ATR-FTIR and TEM indicates that epoxy resin has been successfully incorporated into the copolymer's main chain, and the thermal stability has improved. It was found that greater mechanical properties of PU were obtained when chemical networks were formed between PU and epoxy resin. The maximum tensile strength is up to 6.99 MPa. [ABSTRACT FROM AUTHOR]

Waterborne cationic fluorinated polyurethane (WCFPU) micro-emulsion was prepared by the reaction of isophorone diisocyanate (IPDI), polytetramethyleneether glycol (PTMG1000), 1,4-butanediol (BDO), N-methyldiethanolamine (MDEA), trimethylolpropane (TMP) and perfluoroalkylethyl octanol (FEOH), and then the films of the WCFPU were prepared. The influence on the mechanical properties and water absorption of the films, such as the molar ratio of NCO to OH, the dosage of MDEA, TMP and FEOH, was investigated. Their structure, morphology and heat performance were characterized by fourier transform infared spectrometer (FT-IR), dynamic light scattering (DLS), transmission electron microscope (TEM), X-ray diffraction (XRD), differential scanning calorimeter (DSC) and thermogravimetry (TG). The results revealed that the best mechanical properties and water resistance could be obtained under the condition that NCO/OH molar ratio was 1.25, w(TMP) was 1.1%, w(MDEA) was 7.29% and w(FEOH) was 22.3%. In addition, WCFPU was endowed with low surface energy of its film and the membrane surfaces had excellent water and oil repellency. Furthermore, the thermal stability of the waterborne cationic fluorinated polyurethane increased with the incorporation of perfluoroalkyl chain. And XRD, DSC and TG showed that micro-crystallinity of polyurethane increased with the increase of FEOH, which was benefit to the micro-phase seperation. [ABSTRACT FROM AUTHOR]

Self-crosslinkable polyurethane emulsion containing active carbonyl group was obtained using dihydroxyketon N-[(1,1-dimethyl-2-acetyl)ethyl]-β-dihydroxyethylamino propanamide(DDP) and 1,4-butanediol as chain extenders, isophorone diisocyanate (IPDI), polyether polyol (PTMG1000), dimethylol propionic acid (DMPA) and trimethylol propane (TMP) as main materials, γ-aminopropyltriethoxysilane (APTES) as end capping agent. Then adipic dihydrazide was added into the emulsion. The structure and composition of DDP and the films were confirmed by means of FTIR and H nuclear magnetic resonance (H-NMR) spectrometer, the test results indicated that the reaction between ketone carbonyl and hydrazine has happened during the film curing. The effects of n(NHNH-)/ n(C=O) and DDP content on the properties of the films were studied. The results show that water absorption of the films decreases from 39.3% to 18.9%, crosslinking degree increases from 51.5% to 90.2%, tensile strength increases from 20.1 MPa to 28.3 MPa and pencil hardness is 2H when the DDP content increases from 0% to 6.13%. TGA analysis indicates that the Ketone-Hydrazide crosslinking structure can improve thermal stability of the films. [ABSTRACT FROM AUTHOR]

Abstract: The cationic polyurethane-fluorinated acrylic (PUFA) hybrid latexes were obtained from double bond-end capped polyurethane macromonomer having quaternary ammonium groups with perfluoroalkyl acrylate (FA) by radical copolymerization. Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS) confirmed that the FA monomer had been introduced into the chain of the PUFA hybrid polymer. Particle size distribution (PSD) analysis showed that the particle size of PUFA increased with the increase of the FA content. TEM indicated that the PUFA hybrid possessed core–shell structure. The analysis of the contact angles (CAs), XPS and atomic force microscopy (AFM) had shown that there was a remarkable enrichment of fluorine on the film–air interface, which was more evident when the PUFA hybrid film annealed at higher temperature. At the same time, the influences of the soft segment molecular weight, the N-methyldiethanolamine (MDEA) content and the FA content on other properties such as the surface tension of the PUFA latexes, the surface free energy of the PUFA films and the thermal properties were studied. The results showed that the MDEA content had contrary influence on latex''s and film''s surface properties. Thermal stabilization usually brought by fluorine was not observed in our investigated systems. [Copyright &y& Elsevier]

The polyurethane prepolymer was synthesized, and hydrophilic nano-sized silica (A200) was added to the prepolymer with KH550 as a coupling agent, then a waterborne polyurethane/nanosilica hybrid material (WPUNS) was obtained by a sol-gel process. The structure and performance of the WPUNS films were studied by FTIR, TG, DSC and physical mechanical testing. The particle size and distribution of WPUNS hybrid emulsion was analyzed by a dynamic light scatter (DLS). The morphology of emulsion and films were observed by Transmission Electron Microscope (TEM) and Atomic Force Microscope (AFM), respectively. FTIR analysis indicates the formation of chemical bond between WPU and A200. TEM images display that A200 particles were encapsulated by PU macromolecules and formed a composite particles structure. As the mass fraction of A200 increased from 0 to 2%, the particle size increased from 79.9 nm to 139.9 nm, the tensile strength of the films increased from 6.32 MPa to 20.46 MPa, water absorption decreased from 28.3% to 6.3%, and the hardness was also improved. The TG result indicates that A200 can improve thermal stability of WPUNS. DSC shows that there is no clear effect of nanosilica on the glass transition of soft segments. AFM displays that the smoothness of the films increases with A200 addition. [ABSTRACT FROM AUTHOR]

Waterborne polyurethane prepolymer was prepared by the reaction of isophorone isocyanate(IPDI), polyether polyol(PTMG), dimethylol propionic acid(DMPA) and trimethylol propane(TMP), which was modified by silicane coupling agent(APTES) to form highly crosslinked polyurethane emulsion. The films of the waterborne polyurethane were prepared. The structure of the polyurethane was characterized by Fourier transform infared spectrometer (FTIR), X-ray diffraction (XRD) and differential scanning calorimeter (DSC). The mechanical properties and water absorption of the films were measured. FT-IR indicates that APTES reacted with -NCO of polyurethane. XRD and DSC shows that crystallinity of polyurethane decreased with the increase of w(APTES). Tensile strength increases as the NCO/OH ratio increases. Tensile strength of films increases with increase of w(DMPA) and elongation at break decreases. The water absorption decreases with the increase of w(TMP) when w(TMP) is lower than 1.8%. As the mass fraction of APTES increases from 0% to 10%, the tensile strength of PU films increased from 18 MPa to 28 MPa, water absorption and ethanol absorption decreased. [ABSTRACT FROM AUTHOR]

Waterborne fluorinated polyurethane–acrylate hybrid emulsion modified by long aliphatic chains (WFPUA) is prepared by two steps, which include that the stearyl alcohol (SA)-blocked (end-capped) polyurethanes (SPU) are carried out in the mixtures of vinyl monomers, and then, the WFPUA is prepared via the free radical polymerization after the pre-emulsification of the said system. The characteristic of the reaction is the phase-inversion polymerization. The results show that the emulsifiability of SPU is firstly improved then decreased with the continuous increase in SA content. When the molar ratio of SA to 2-hydroxyethyl methacrylate (HEA) in the SPU is 1:1, the stability, zeta potential, viscosity and particle sizes of the WFPUA emulsion have the best results. The mechanical properties of WFPUA hybrid films deteriorate with the increase in SA content at 20 °C, but the mechanical properties of WFPUA films with more SA content achieve better results at 80 °C. The fluorinated groups migrated to the surfaces more easily with more SA content. In order to form the liquid crystalline-like structure on the WFPUA's surface, the gradient heating treatment to an elevated temperature (i.e., 120 °C) to properly orient the fluorinated chains is necessary. [ABSTRACT FROM AUTHOR]

Self-crosslinkable aqueous polyurethane (PU)/polyacrylate (PA) composite emulsion was obtained by radical copolymerization. Fourier transform infrared spectroscopy (FT-IR) result shows that the cross-linking reaction between the carbonyl group and the hydrazine group has happened. The influence of the hydrazide-carbonyl molar ratio and the PA content on the properties of the composite emulsions and their films were investigated. The results show that, under the optimal hydrazide-carbonyl molar ratio ( n (hydrazine group)/ n (carbonyl group) =1:1), the water absorption is 10.56 %, and the mechanical properties and thermal stabilities are both improved. As the PA content increases from 0 wt% to 15 wt%, the tensile strength increases from 5.7 MPa to 7.3 MPa and the gel content increases from 70.3 % to 87 %. [ABSTRACT FROM AUTHOR]

The aqueous environmental polyurethane/polyacrylate (PUA) microemulsions were obtained through in situ surfactant-free emulsion polymerization exempt of any organic solvents. Hydroxyethyl acrylate (HEA) and pentaerythritol triacrylate (PETA) of different functionalities were adopted as cross-linker to connect polyurethane (PU) and polyacrylate (PA) to obtain PUAH and branched multi-cross-linking PUAP, respectively. It is interesting to note that PUA microemulsion was unstable if no connection was built between PU and PA when in situ surfactant-free emulsion polymerization was adopted, which is different from conventional seed emulsion polymerization. The particle size decreased from 75.27 to 51.24 nm and dispersibility index (DPI) decreased from 0.394 to 0.122 with the increase of vinyl content, and DPI was further decreased with the incorporation of PETA with three vinyl groups at the same vinyl content. Effects of HEA and PETA on the physicochemical properties of PUA films including micromorphology, gel content, surface composition, phase behavior, thermal stability, and water resistance were investigated. TEM and XPS analysis demonstrated that the micromorphology transferred from multi-morphology to single core-shell morphology with PA as the core and PU as the shell and then changed to uniform morphology with homogeneous distribution of PU and PA inside PUAP. High cross-linking density, together with uniform distribution of PU and PA inside PUA system, is beneficial to improve the PUA performance. In addition, the as-prepared microemulsions can be utilized as the surface sizing agent for cellulose fiber paper to greatly increase the physical strength and water resistance. [ABSTRACT FROM AUTHOR]

Stable alkoxysilane-functionalized poly (urethane-acrylate) (IPUASi) VOC-free hybrid microemulsion was successfully prepared through in-situ surfactant-free emulsion polymerization. Two approaches of introducing silane coupling agent (MPTS) were compared. The stability of microemulsion was determined by light scattering technique and rheology. The surface property and morphology were evaluated through X-ray photoelectron spectroscopy and atomic force microscopy. In addition, the static and dynamic mechanical properties, thermal behavior and water resistance of IPUASi films were systematically investigated. When MPTS was introduced during polyurethane prepolymer preparation, slight change took place in the particle size and distribution of IPUASi10 microemulsion even after being stored for a year. And the modulus of IPUASi10 microemulsion kept almost invariable with time at 60 °C. In contrast, when the MPTS was added in the process of water dispersion, the particle size and modulus of IPUASi10A microemulsion greatly increased due to the enhanced instability. Si and C-Si compositions on the surface of IPUASi10A film were much higher than those of IPUASi10 film, and improved phase mixing characteristic nature was detected for IPUASi10, as well as higher mechanical property and water resistance. In the presence of MPTS, the particle size decreased from 95.51 nm to 50.23 nm, the morphology of IPUASi microemulsion transformed from irregular morphology to more uniform globular structure, the interaction between colloidal particles decreased, while the viscoelasticity increased. In addition, the intermolecular interaction was enhanced with increasing MPTS content, resulting in increased mechanical property, thermal property and water resistance. However, excessive MPTS was unfavorable to the performance of IPUASi film. [ABSTRACT FROM AUTHOR]