Study on polyethylene glycol/polydimethylsiloxane mixing soft-segment waterborne polyurethane from different mixing processes

Abstract

ABSTRACT:The surface structure and physical properties of polyethylene glycol series polyurethane (PEG-PU) membranes, in which were introduced hydrophobic polydimethylsiloxane (PDMS) component by the procedure of PU blending or of soft-segment copolymerization, were studied in this investigation. In the case of the blending process, the synthesized waterborne polyurethanes (WBPUs) of PEG-PU and of polydimethylsiloxane series polyurethane (PDMS-PU) were combined, whereas in the copolymerization process PEG and PDMS were taken as mixed soft segments to polymerize the WBPU. For the blending method, glass-transition and melting temperatures increased rapidly when a small amount of PDMS-PU was added to PEG-PU and reached a maximum with 5% PDM-S-PU mixed in. However, in the case of the copolymer method, thermal properties closely followed predicted values. From dynamic mechanical analysis studies it was found that a low PDMS-PU content ratio could increase the rubbery elasticity of PEG-PU membrane and improve its strength simultaneously in the blending method, and the copolymer method only caused PU to gain some natural complementary strength and elasticity. Electron spectroscopy for chemical analysis studies indicated that PDMS migrated to the surface much more easily in the blending method than in the copolymer method. The SEM studies also found that, in the blending method, the numbers of pores were less than those in the copolymer method.

Enhanced Properties of Hyperbranched Polyurethane Elastomers Based on Polydimethylsiloxane/Polyether Mixed Soft Segments

“…Moreover, with the incorporation of HPMS-APE, the water absorption for HBPUs based on mixed soft segments kept mostly unchanged above 48 h in comparison with HBPU0. In this study, 0-20 wt% of HPMS-APE content was incorporated in polyurethanes, so the degree of microphase separation didn't influence the water resistance of HBPUs 26 , and HPMS-APE content appeared to be the sole factor. Due to the strong hydrophobic Si-O-Si bonds and the low surface energy of HPMS-APE segments, polyurethanes had a highly hydrophobic nature, and it brought polyurethanes good hydrolytic stability and fast water release on drying 27 .…”

Polydimethylsiloxane and Castor Oil Comodified Waterborne Polyurethane

“…This should be attributed to the hydrophobicity of the PDMS molecules. During film formation, the PDMS soft segment has migrated to the surface layer because its water affinity is much lower than that of WPU chain [12,17]. When PDMS was rich in the surface layer, the film could not be immerse in water because of strong hydrophobic Si-O-Si bonds in PDMS [10].…”

“…These interesting properties include low surface energy, biocompatibility, high thermal and oxidative stability, good water resistance, chemical inactivity, insulating stability, low glass transition temperature, and great molecular flexibility [8]. Combining the advantages of PDMS with those of WPU has attracted the attention of many researchers for a long time and PDMS has been introduced to WPU through both blending and copolymerization methods [8][9][10][11][12][13][14][15][16]. Although these linear PDMS-WPU "hybrids" showed much better heat and water resistance than that of WPU, the incorporation of PDMS often has a negative effect on the physical mechanical properties of WPU, because PDMS demonstrates poor mechanical property and abrasion resistance property.…”

Study on reactive polydimethylsiloxane-modified waterborne polyurethanes

“…It is well known that PDMSs have interesting properties including low surface energy, biocompatibility, high thermal and oxidative stability as well as good water resistance [5]. Therefore, the incorporation of siloxane segments into WPU chains is expected to be effective to enhance water resistance of WPU.…”