1. Abstract Phase separation in segmented polyurethanes is an important phenomenon, which affects on characteristic properties of polyurethanes. Morphology, formation and distribution of micro-domains (hard segments and soft segments) are effective parameters on interfacial interaction and adhesion of polyurethane system. In this work segmented polyurethanes based on 4,4 -diphenylmethane diisoc...

The polymer most often used for the coagulation process is polyurethane. Nearly all leather substitutes sold in the world consist partially or totally of polyurethanes. Therefore a whole chapter is dedicated to the coagulation of polyurethanes. In 1951 a coagulation process for a polyurethane was published for the first time [1]. Since 1954 [36] additional process steps have been developed to p...

Biodegradable porous polyurethanes scaffold have themselves opportunities in service, including controlled degradation rate, no-toxic degradation products. However, polyurethanes are lack of bioactive groups, which limits their application. This review gives the common modification methods, surface functionalization and blending modification. In finally, the review puts forward to the bulk modi...

During blood-material interaction, the enzymes factor XII fragment (factor XIIf) and kallikrein are generated (contact activation). In this study, the enzymatic activities of factor XIIf and kallikrein were examined with an assay based on the conversion of tripeptide-p-nitroanilide substrate. With the use of aprotinin to inhibit kallikrein, the proteolytic activities of factor XIIf and kallikre...

Citation Payne, Josh et al. " Wireless power transmission for medical applications. Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. The MIT Faculty has made this article openly available. Please share how this access benefits you. Your story matters. We studied the wireless power t...

The thermal stability of aqueous polyurethanes has been measured applying the thermogravimetric analysis. The aqueous polyurethanes (aqPUR) with catalysts of different selectivity have been studied by use of the dynamic method. To obtain degradations of 0.025, 0.05, and 0.10, employing the dynamic method, the heating rates of 0.5, 1, 2, 5, and 10 °C min have been used in the range of 30-500 oC....

Polyurethanes are the only class of polymers that display thermoplastic, elastomeric, and thermoset behavior depending on their chemical and morphological makeup. In addition to compact polyurethanes, foamed variations in particular are very widespread, and they achieve their targeted properties at very low weights. The simple production of sandwich structures and material composites in a singl...

Polyurethanes are widely used in the manufacturing of biomedical catheters and other blood-contacting devices; however, thrombus formation still occurs, which renders these catheters ineffective unless systemic anticlotting agents are used. Nitric oxide (NO) is a well-known inhibitor of platelet activity. In the current study, two commercially available medical polyurethanes (Pellethane and Tec...

New thermoplastic segmented polyurethanes were obtained by a one-step melt polyaddition using 40, 50 and 60 mol% poly(hexane-1,6-diyl carbonate) diol of [Formula: see text] g mol-1, 1,1'-methanediylbis(4-isocyanatobenzene) and 2,2'-[sulfanediylbis(benzene-1,4-diyloxy)]diethanol, 2,2'-[oxybis(benzene-1,4-diylsulfanediyl)]diethanol or 2,2'-[sulfanediylbis(benzene-1,4-diylsulfanediyl)]diethanol as...

Nitric oxide (NO)-releasing polyurethanes capable of releasing up to 0.20 μmol NO cm(-2) were synthesized by incorporating active S-nitrosothiol functionalities into hard and soft segment domains using thiol group protection and post-polymerization modifications, respectively. The nitrosothiol position within the hard and soft segment domains of the polyurethanes impacted both the total NO rele...