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

Abstract

Two series of polyurethane (PU) networks based on Boltorn® hyperbranched polyester (HBP) and hydroxyethoxy propyl terminated poly(dimethylsiloxane) (EO-PDMS) or hydroxy propyl terminated poly(dimethylsiloxane) (HPPDMS), were synthesized. The effect of the type of soft PDMS segment on the properties of PUs was investigated by Fourier transform infrared spectroscopy (FTIR), contact angle measurements, surface free energy determination, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), atomic force microscopy (AFM), dynamic mechanical thermal analysis (DMTA) and differential scanning calorimetry (DSC). The surface characterization of PUs showed existence of slightly amphiphilic character and it revealed that PUs based on HP-PDMS have lower surface free energy, more hydrophobic surface and better waterproof performances than PUs based on EO-PDMS. PUs based on HPPDMS had higher crosslinking density than PUs based on EO-PDMS. DSC and DMTA results revealed that these newlysynthesized PUs exhibit the glass transition temperatures of the soft and hard segments. DMTA, SEM and AFM results confirmed existence of microphase separated morphology. The results obtained in this work indicate that PU networks based on HBP and PDMS have improved surface and thermomechanical properties

Polyisobutylene-based polyurethanes: VII. structure/property investigations for medical applications

“…(c)] also clearly indicates surfaces changes. Annealing reduces the average surface root mean square (RMS) roughness from 4.8 to 4.2 Å, which indicates enrichment of surface with soft segments, also observed in PDMS‐based polyurethane networks …”

Synthesis and characterization of phenyl polysiloxane modified polyurea/polyurethanes

“…The morphology of PU and SPUs films were shown in Figure . Obvious microphase separations were observed for PU film, in which the hard segments dispersed irregularly in shapes and unevenly in the flat and smooth matrix . Crosslinking in PU resulting from the three functional groups polyether polyol N307 as soft segments made the hard segments easier to form massive agglomeration.…”

Thermal and surface properties of hybrid materials obtained from epoxy-functional urethane and siloxane

“…The synthesis of hybrid materials combining the properties of both polymers seems to be justified, which is additionally reflected by the latest research reports [4][5][6][7][8][9][10][11][12] confirming that polyurethanes modified with siloxanes are characterized with lower glass transition temperature and enhanced thermal stability with simultaneously increased hydrophobicity. Because of this they have been used as protective coatings, selective membranes, medical implants and surface modifiers for various polymers and fibers [7,8,13].…”