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A type of polyester-based self-matting waterborne polyurethane (ESMWPU) with an excellent matte effect of 0.8° and transmittance of 78.5% for PVC artificial leather was synthesized. The influence of synthesis parameters, including R value, crosslinking and hydrophilic group content, on coating gloss and transmittance was investigated. Meanwhile, the properties necessary for applying water-based resins to plasticized PVC were detailed. The results demonstrated that R value, crosslinking degree and hydrophilic group content synergistically decided the morphological changes of latex particles during their film-forming process in three aspects: particle stiffness, three-dimensional structure and particle size, respectively. With optimized parameters of R = 1.9, TMP = 2 wt% and DMPA = 1.75 wt%, ESMWPU latex particles stabilized their spherical shapes without collapsing in the film-forming process and created a rough surface, resulting in a matte effect. In terms of application performance, good wetting and adhesion for ESMWPU to a plasticized PVC surface was achieved with a 2 wt% leveling agent load. Moreover, due to the high cohesion energy of ester bonds and intermolecular hydrogen bonds, this type of polyester-based ESMWPU also depicted admirable thermal adhesion resistance. All aforementioned results distinctly demonstrate a feasible yet promising paradigm for applying ESMWPU on PVC artificial leather. [ABSTRACT FROM AUTHOR]

The curing process of polydimethylsiloxane (PDMS) coating was systematically investigated by nonisothermal differential scanning calorimeter (DSC), and accordingly, the thermodynamic as well as kinetic parameters were obtained. Meanwhile, effect of structural factors, including different divinyl-terminated polydimethylsiloxane (ViPDMSVi), divinyl-terminated polymethylvinylsiloxane (ViPMVSVi), polymethylhydrosiloxane (PMHS), and reinforcing filler content, on mechanical and thermal properties of coating was studied. The results demonstrated that platinum compounds could significantly accelerate the hydrosilylation and reduce the curing temperature and activation energy. The viscosity, vinyl/hydrogen sites, and quantities of ViPDMSVi, ViPMVSVi, and PMHS were important factors to influence mechanical and thermal properties. Low viscosity ViPDMSVi and PMHS with side hydrogen atoms could increase crosslinking density, and then enhance the tensile strength and heat resistance. ViPMVSVi with higher viscosity and vinyl content could dramatically improve tensile strength while maintaining breaking elongation. Reinforcing filler was another vital factor to enhance strength and thermostability. 550% improvement in tensile strength occurred when reinforcing filler content was 40 wt%. All aforementioned results provided a comprehensive guidance for the preparation and property regulation of PDMS coating. This kind of PDMS coating can be applied in synthetic leather manufacturing. [ABSTRACT FROM AUTHOR]

A fluorine-free anti-smudge waterborne polyurethane coating was constructed via the dispersion of hexamethylene diisocyanate trimer into organosilicon-grafted waterborne polyurethane. In the film-forming process, the interaction among carboxyl, hydroxyl and isocyanate groups blocked the hydrophilic groups and improved the density of the coating, thereby preventing contaminants from penetrating into it. Furthermore, the organosilicon side chain migrated onto the coating surface to form a low surface energy amphiphobic layer, which endowed the coating with superior anti-graffiti performance. The surface energy of the as-constructed coating was 24 mN m−1. The water, diiodomethane and hexadecane contact angles were 95°, 70° and 36°, respectively, with corresponding sliding angles of 35°, 10° and 1°, thereby showing that the coating had no affinity to oil- and water-based ink graffiti. More strikingly, the anti-graffiti performance remained after 400 abrasion cycles under a pressure of 110 kPa and under harsh chemical treatment (strong acids, bases and salts). The constructed coating also showed an optical transparency as high as 93 % due to the high crosslinking degree. [Display omitted] • A coating with superior anti-smudge performance, admirable wear resistance and high transparency were constructed. • The anti-smudge mechanism of the coating was revealed. • This study provides a new way to synthesized excellent comprehensive performance waterborne polyurethane coating. [ABSTRACT FROM AUTHOR]

[Display omitted] • A kind of reactive surface energy regulator for solvent-free 2 K-PU was synthesized. • Wetting and adhesive ability of 2 K-PU on non-polar substrates were enhanced. • Enhanced water repellency of 2 K-PU was achieved. • Mechanical properties of 2 K-PU coatings were improved. • The transmittance of PDMS modified 2 K-PU was higher than 90%. A novel polyether siloxane diol (PESD) was synthesized via a hydrosilylation between dihydride-terminated polydimethylsiloxane and allyl polyoxyethylene epoxy ether and a ring-opening reaction. As reactive surface energy regulator for solvent-free two-package polyurethane (2 K-PU), the effect of PESD loading on the wetting and adhesive ability of 2 K-PU on non-polar substrates was investigated. Results showed that with introduction of PESD, surface tension of 2 K-PU was decreased from 37.0 to 25.0 mN/m, and the wetting and adhesive ability of modified 2 K-PU on non-polar substrates were significantly improved. Furthermore, ≤4 wt% PESD modified 2 K-PU coatings showed high transmittance, enhanced water repellency and mechanical properties. [ABSTRACT FROM AUTHOR]

• PDMS coating was covalently modified with polyurethane (PU). • Surface energy and re-coatability of PDMS coatings were enhanced. • Decreased energy consumption in PDMS curing was achieved via PU modification. • Mechanical properties of PDMS films were enhanced. In the present study, with 2-Allyloxyethanol-terminated polyurethane (AEPU) and allyloxy (polyethylenene oxide) methyl ether-graft-polymethylhydrosiloxane (PMHS-g-AEM) as modifier and reactive compatibilizer respectively, a type of polyurethane modified polydimethylsiloxane (PUMS) coating with increased surface energy and re-coatability was obtained via solvent-free two-component hydrosilylation reaction. The structures of as-prepared AEPU and PMHS-g-AEM were characterized by FTIR and 1H NMR, and the AEPU distribution in PUMS together with the characteristics of resultant coatings, such as dynamic wetting properties, surface roughness, surface energy and re-coatability, variation in curing behavior and mechanical properties were also elaborately evaluated. From scanning electron microscope (SEM) observation, it is found that in presence of 2 wt% compatibilizer, AEPU can be distributed in PUMS uniformly. With the increase of AEPU loading, the coating surfaces show a decreased water contact angles (WCAs), increased surface roughness and enhanced surface tension from 29.4–52 mN/m as well as re-coatable feasibility. Intriguingly, curing kinetics study reveals that the conjugation of 10 wt% AEPU into two-component hydrosilylation system can significantly reduce the reaction activation energy by 43.6 %. Another interesting result is that the chemical incorporation of AEPU dramatically improves elongation at break of PUMS film from 460 to 808 % while well-maintains tensile strength. All aforementioned results distinctly demonstrate a feasible yet promising paradigm for modifying PDMS coating with polyurethane. [ABSTRACT FROM AUTHOR]