Effect of the Temperature of Polyurethane Wet-Casting Membrane Formation on the Physico-Mechanical Properties

Abstract

A series of polyurethane membranes were prepared by direct immersion of a polyurethane/dimethylformamide solution into a water bath at different temperatures. Depending on the temperature of the water immersion bath the films exhibited variations in morphology and mechanical properties. As the temperature of the immersion bath was increased, the membrane structure changed from a cellular to a particulate morphology. The properties of polyurethane membrane such as mechanical and gas permeability were measured. It is proposed that the change in membrane structure is due to the variation of polymer chain mobility, influenced by the water bath temperature, during membrane formation

Thermal behavior, surface energy analysis, and hemocompatibility of some polycarbonate urethanes for cardiac engineering

“…PU solutions (30% w/w) were degassed for 15 min under vacuum (10-15 mmHg) and then were cast onto a glass slide using a doctor blade with a gap of 0.6 mm. The films were precipitated in deionized and distilled water at 45 C for 1 h. 18,19 During this time, the resulted PU films were detached from the glass plate and subsequently washed five times with 1 L of deionized and distilled water. The films were dried at room temperature and low pressure (1-2 mmHg) for 24 h. The thickness of PU films was around 0.33 mm.…”

Surface energy evaluation of casting and nanofiber polyurethane films by using different models

“…The function of this blade is to spread homogeneously the polymer solution onto the surface and to get a fixed thick film. Then, the membrane was precipitated in distilled water at 45°C for 1 h 26 . This improved technique is used in order to prepare microporous membranes with uniform porosity.…”

“…The function of this blade is to spread homogeneously the polymer solution onto the surface and to get a fixed thick film. Then, the membrane was precipitated in distilled water at 45 C for 1 h. 26 This improved technique is used in order to prepare microporous membranes with uniform porosity. The resulted PU membrane was detached from the glass plate, washed 5 times with distilled water and dried at room temperature and low pressure (1-2 mmHg) for 24 h. The thickness of the prepared PU membranes was 0.14 mm.…”

The Development and Study of Some Composite Membranes Based on Polyurethanes and Iron Oxide Nanoparticles

“…Therefore, in the phase inversion casting technique, the membrane layers are formed immediately when immersed in the coagulation bath and depend on the temperature of the non-solvent bath and also on the amount of time of the coagulation before and after immersion. The influence of the temperature of the solution bath was previously reported in another of our works [49], which was chosen as 45 • C, for was the optimum temperature for the formation of uniform, sponge-like pores. When the membrane was prepared by direct immersion in the non-solvent (water) coagulation bath, it presented a phase-separated structure with beads and a non-homogeneity of the layer (Figure 4e).…”