Surface-modified polyurethanes

Table 3. Desorption of fibrinogen from surface modified polyurethane...

Morral-Rufz G, Melgar-Lesmes P, Garcfa ML, Solans C, Garcfa-Cehna MJ. Design of biocompatible surface-modified polyurethane and polyurea nanoparticles. Polymer 2012 53(26) 6072-80. 

Melgar-Lesmes P, Morral-Rmz G, Solans C, Garcia-Cehna MJ. Quantifying the bioadhesive properties of surface-modified polyurethane-urea nanoparticles in the vascular network. Colloids SurfB Biointerfaces 2014 118 280-8. 

B. D. Bauman, "Novel Polyurethane Composites with Surface-Modified Polymer Particles," paper presented at SPI 32nddnnual Technical Marketing Conference, 1989. 

Composite Particles, Inc. reported the use of surface-modified rubber particles in formulations of thermoset systems, such as polyurethanes, polysulfides, and epoxies [95], The surface of the mbber was oxidized by a proprietary gas atmosphere, which leads to the formation of polar functional groups like —COOH and —OH, which in turn enhanced the dispersibility and bonding characteristics of mbber particles to other polar polymers. A composite containing 15% treated mbber particles per 85% polyurethane has physical properties similar to those of the pure polyurethane. Inclusion of surface-modified waste mbber in polyurethane matrix increases the coefficient of friction. This finds application in polyurethane tires and shoe soles. The treated mbber particles enhance the flexibility and impact resistance of polyester-based constmction materials [95]. Inclusion of treated waste mbber along with carboxyl terminated nitrile mbber (CTBN) in epoxy formulations increases the fracture toughness of the epoxy resins [96]. 

Coal tar-modified polyurethane is a cold-applied liquid waterproofing system. The system by Sonneborn is an example of this approach to waterproofing. It is applied as a liquid at the rate of 10-15 mils/coat. The coating dries hard, but has some elasticity. This material may be attacked by acids in groundwater but can be defended by a protection board. The performance of any liquid-applied waterproofing systems is limited by the capabilities of the applicator (it is difficult to achieve even coats on vertical surfaces). 

Polymer-modified asphalt is a cold-applied liquid waterproofing system. As with the Sonneborn system mentioned above, the quality of the installation depends on the applicator (it is difficult to achieve an even coating on a vertical surface). High-grade polymer-modified asphalt is superior to coal tar-modified polyurethane in elasticity, crack-spanning ability, and resealability, but inferior in its resistance to chemicals. 

Imanishi et al. [33] pointed out that there was an optimum point at which the tethering density of PEO chains makes a polybutadiene urethane surface biocompatible. They also reported that bovine plasma FGN and bovine y-globulin adsorbed on the PEO-modified polyurethane were completely denatured, in comparison with 4-38% denaturation of BSA adsorbed. 

Ernsting, M.J., Labow, R.S., and Santerre, J.P. "Human monocyte adhesion onto RGD and PHSRN peptides delivered to the surface of a polycarbonate polyurethane using bioactive fluorinated surface modifiers". ] Biomed. Mater. Res. A 83A(3), 759-769 (2007). Ewbank, P.C., Nuding, G., Suenaga, H., McCullough, R.D., and Shinkai, S. "Amine functionalized polythiophenes Synthesis and formation of chiral, ordered structures on DNA substrates". Tetrahedron Lett 42(2), 155-157 (2001). 

Fabrication methods have overwhelmingly focused on improving nanotube dispersion because better nanotube dispersion in polyurethane matrix has been found to improve the properties of the nanocomposites. The dispersion extent of CNTs in the polyurethane matrix plays an important role in the properties of the polymer nanocomposites. Similar to the case of nanotube/solvent suspensions, pristine nanotubes have not yet been shown to be soluble in polymers, illustrating the extreme difficulty of overcoming the inherent thermodynamic drive of nanotubes to bundle. Therefore, CNTs need to be surface modified before the composite fabrication process to improve the load transfer from the polyurethane matrix to the nanotubes. Usually, the polyurethane/CNT nanocomposites can be fabricated by using four techniques melt-mixing (15), solution casting (16-18), in-situ polymerization (19-21), and sol gel process (22). 

Modified polyurethanes as shown in Fig. 4.6 are used for valuable hand variations and as additives for cellulose crosslinkers. Their flexible and elastic films on the fibre surface improve elastic resilience, which is, for example, important for pile fabrics. The principle of their elasticity is, as in elastan fibres, the molecular combination of so-called weak and hard segments. The large weak... 

Tphe surface activity of block copolymers containing dimethylsiloxane units as one component has received considerable attention. Silicone-poly ether block copolymers (1,2,3) have found commercial application, especially as surfactants in polyurethane foam manufacture. Silicone-polycarbonate (4, 5), -polystyrene (6, 7), -polyamide (8), -polymethyl methacrylate (9), and -polyphenylene ether (10) block copolymers all have surface-modifying effects, especially as additives in other polymeric systems. The behavior of several dimethylsiloxane-bisphenol A carbonate block copolymers spread at the air—water interface was described in a previous report from this laboratory (11). Noll et al. (12) have described the characteristics of spread films of some polyether—siloxane block co-... 

A new approach to modification of thermosetting epoxy or polyurethane systems (Plastics Technology, p. 14 (April 1994)) involves surface modified rubber or UHMW-PE particles. These particles after reaction with Cl, 0 or F allows for improved properties (toughness, tear resistance, abrasion resistance, modified coefficient of friction) in the noted thermosets. 

The cell-binding properties of chitosan have led to numerous studies where chitosan is used as a surface coating. Chitosan was employed as a surface modification of poly(e-caprolactone) scaffolds and in vitro studies with fibroblasts showed significantly improved cell attachment and proliferation when chitosan was present. In another study, polyurethane scaffolds were prepared and surface-modified with chitosan for the same reason. This study showed that on the modified scaffold a monolayer of endothelial intima was formed. The incorporation of collagen with chitosan as a chi-tosan-collagen scaffold enhanced the resultant scaffold s ability to support cell attachment and is a strategy similar to the incorporation of peptide sequences. ... 

Zhu, Y, Gao, C., He, T., Shen, J. Endothelium regeneration on luminal surface of polyurethane vascular scaffold modified with diamine and covalently grafted with gelatin. Biomaterials. 2004, 25, 423-430. 

Influence of the Molecular Size of the Filler Surface Modifier on the Strength of Adhesive Bonds with Solid Substrates and the Molecular Mobility of the Filled Polyurethane... 

There are numerous possibilities for the synthesis of polyurethanes, which provides a distinct advantage for tuning the polymer properties to specific applications. Table 4 overviews some possibilities. In addition, the use of surface-modifying additives (typically 1% or less by weight) in polyurethanes can enhance their biostability, or add other functionality to the polymers. ... 

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