Enhanced thermal and surface properties of waterborne UV-curable polycarbonate-based polyurethane (meth)acrylate dispersion by incorporation of polydimethylsiloxane

Analysis of dynamic mechanical, thermal and surface properties of poly(urethane-ester-siloxane) networks based on hyperbranched polyester

“…The observed thermal behavior is quite complex and similar to other PU systems presented in the literature [32]. Thermal stability of the synthesized PUs based on HBP and EO-PDMS-EO is similar to the thermal stability of other PU networks based on PDMS [16] and slightly higher in the initial stages of thermal degradation than thermal stability of some PUs based on HBP [8].…”

“…This may be attributed to the hydrophobic character of PDMS and its surface activity. Namely, during the synthesis of PUs, EO-PDMS-EO can migrate to the surface of samples due to its lower surface energy in comparison to the surface energy of polyurethane [16]. Therefore, PUs with higher EO-PDMS-EO content have more hydrophobic surface and better water resistance.…”

“…The incorporation of poly(dimethylsiloxane) (PDMS) macrodiols into PUs, using appropriate synthetic procedure, has been frequently used to improve and modify thermal, oxidative and hydrolytic stability and surface properties of PUs, since poly(dimethylsiloxane)s have good thermal and oxidative stability, low glass transition temperature, high flexibility, good biocompatibility, low surface tension, low moisture and good gas permeability and UV stability [14][15][16][17].…”

Surface and thermomechanical characterization of polyurethane networks based on poly(dimethylsiloxane) and hyperbranched polyester

“…From the results, it is also quite apparent that the synthesized PUs had higher water contact angles than the con- trol sample. This behavior may be ascribed to the tendency of the PDMS segments to migrate to the surface, due to the very low surface energy of PDMS, resulting in a part of the PU surfaces being covered by PDMS [31]. As can be seen (Table 3), the change of the formamide and diiodomethane contact angles of PU samples followed the same trend as the water contact angle.…”

“…This method has been widely used to investigate the surface free energy of polymer films that are used as coatings. For reliable determination of the surface energy, three test liquids (distilled water, formamide and diiodomethane) with known surface tensions [31,32], ranging from very polar to nonpolar, were utilized to determine the surface free energy of the PU films, as shown in Table 2. The surface free energy and its components were calculated by solving the following set Equations (2) [30]: (2) where & s is the surface free energy that can be divided into two components: the dispersive (& LW ) The surface composition of the PU films was determined by X-ray photoelectron spectroscopy (XPS) using a VG ESCALAB II electron spectrometer (East Grinstead, England) under a base pressure of 1·10 -8 Pa.…”