Microstructure and properties of poly(urethane-siloxane)s based on hyperbranched polyester of the fourth pseudo generation

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

“…The water contact angle of PUs was higher but the surface free energy was lower than the values obtained for previously synthesized PU networks based on EO-PDMS and hyperbranched polyester of the fourth pseudo generation (% 1 = 82.6-87.3° and & s(total) = 38.7-43.8 mJ/m 2 ) [21].…”

“…The large number of terminal hydroxyl groups present in Boltorn ® HBPs enables fast formation of networks that have good mechanical properties, as well as good resistance to chemicals [11][12][13][14], while the presence of PDMS contributes to the good thermal and surface properties, and to elasticity of the highly crosslinked materials. In our previous studies, we have investigated the influence of the content of !,"-dihydroxyethoxy propyl-poly(dimethylsiloxane) (EO-PDMS) and type of HBPs on the swelling behavior, morphological, thermal and thermomechanical properties of PU networks [15][16][17][18][19][20][21]. These results confirmed that physical and thermal properties are related to the crosslinking density, hydrogen bonding interactions, microphase separation and content of EO-PDMS soft segment.…”

“…Catalyst concentration was kept at 0.02 wt% [25][26][27]. The details for the synthesis of similar PU networks are given in our previously published papers [16][17][18][19][20][21]. Compositions of the synthesized PUs and weights of the reactants used for the synthesis of PUs are presented in Table 1.…”

“…The measurements were carried out using rectangular specimens (15.0 mm&' 7.8 mm&' 1.0 mm±0.2 mm), under torsion mode, using torsion fixture (rectangle) geometry. All details of the calculation of crosslinking density and average molecular weight between two crosslinks using the rubber elasticity theory and calculated from DMTA results, are described in the literature [19][20][21]33]. Some clarification of the calculation of crosslinking density is given.…”

Synthesis and structure-property relationships of biodegradable polyurethanes

“…The synthesis of PU copolymers using siloxane-containing prepolymers with PCL and ethylene oxide terminal units has been described [90][91][92][93][94][95][96][97][98]; these terminal units of siloxane-containing prepolymers were used in order to increase the miscibility of polar and non-polar reactants. Thermoplastic PU elastomers based on PDMS were synthesized by a two-step polyaddition procedure in solution, from MDI, 1,4-BD and α,ω-dihydroxy-PCL-b-PDMS-b-PCL [94].…”