OBJECTIVE Elastomeric materials play an important role in the orthodontic practice, including the retraction force to move teeth into extraction sites, closing diastemas, selective shifting of the midline and generalized space closure. Frictional resistance and ligating strength of archwire-bracket-ligature complex occurs during utilization of elastomeric and metallic ligatures when orthodontic...

determination of blood compatibility is an important problem in blood contacting devices. in this study, two classes of materials including polyurethane (based on polyethylene glycol and poly tetrametylene oxide) and polyvinyl alcohol samples, with different hydrophilicity properties were synthesized and their physico-chemical properties were compared. water uptake ratio, ftir spectroscopy, and...

The objective of this research is to develop soy-based polyurethane (PU) foam product reinforced with carbon nanotubes. The shortage of petroleum and the increasing concern on environmental issues have resulted in an interest in using renewable substances as building blocks for polymer applications. Multi-walled carbon nanotube (MWNT) was used in this study to reinforce the soy-based polyuretha...

Background: Water pollution is an important environmental problem, undoubtedly, the presence of toxic heavy metals forms the main source of water contamination. Sorption characteristics of polyurethane foams modified with bis (2-ethylhexyl)phosphoric acid (DEHPA) for the removal of zinc, lead and cadmium ions from contaminated solutions were investigated. Methods: Operating variables, such as ...

Ultraviolet and heat-curable polyurethane acrylate prepolymers were synthesized from 4,4’-diphenyl methane diisocyanate, polyethylene adipate diol, polyhexamethylene carbonate diol, polycaprolactone diol and 1,6hexamethylene diamine , acrylic acid. Effects of nature of the soft segments on the physical properties were investigated. It was found that the thermal stability increased from polycarb...

We report that hydrophilic polyurethane mushroom shaped microfiber arrays possess wet self-cleaning ability using the lotus effect as biologically inspired synthetic fibrillar adhesives. In comparison with a flat surface made of the same polyurethane, the fiber array exhibited almost 100% wet self-cleaning without any degradation of adhesive strength. We attribute this cleaning ability to the m...

Polyurethane-resin doming is currently one of the fastest growing markets in the field of industrial graphics and product identification. Semi-rigid bio-based polyurethanes were prepared deriving from soybean oil as a valuable alternative to fossil materials for digital doming and applied to digital mosaic technology. Bio-resins produced can favorably compete with the analogous fossil polymers,...