Medical applications polymeric surfaces

In dentistry, silicones are primarily used as dental-impression materials where chemical- and bioinertness are critical, and, thus, thoroughly evaluated.546 The development of a method for the detection of antibodies to silicones has been reviewed,547 as the search for novel silicone biomaterials continues. Thus, aromatic polyamide-silicone resins have been reviewed as a new class of biomaterials.548 In a short review, the comparison of silicones with their major competitor in biomaterials, polyurethanes, has been conducted.549 But silicones are also used in the modification of polyurethanes and other polymers via co-polymerization, formation of IPNs, blending, or functionalization by grafting, affecting both bulk and surface characteristics of the materials, as discussed in the recent reviews.550-552 A number of papers deal specifically with surface modification of silicones for medical applications, as described in a recent reference.555 The role of silicones in biodegradable polyurethane co-polymers,554 and in other hydrolytically degradable co-polymers,555 was recently studied. 

Applications to polymer chemistry have also been proposed. Interestingly. the adhesion toward itself. Al or stainless steel, of polythene or TeHon with epoxyresins adhesives is considerably improved by a glow discharge polymerization of methane (or etheiie. ethyne) on the polymer surface, CH4 giving the best results (33). Such a modification of polymer surfaces has also received attention within the scope of modifying poly mer membrane compatibility with blood for medical applications. Various o nic compounds (even CH4 > have been studied in this context, where an ultrathin layer (< 1000 is sufficient to alter blood compatibility 134). 

Composites utilizing cellulose fibers have been prepared with many different materials, especially polymers. It has been well demonstrated that these fibers help to alter and in general enhance the physical properties of polymeric composites [140, 149-157]. Additionally, their bio-degradability and biocompatibility enables cellulose-reinforced materials to be suitable for bio-scaffolding in medical applications, if the polymeric component is also biocompatible [140, 158]. Some surface modifications have been performed on cellulose to add selected characteristics, such as antimicrobial properties to polymeric matrixes [140,159]. 

Abstract Surface properties are a critical aspect of textiles for medical applications. This chapter discusses some popular surface modification techniques plasma activation, plasma polymerization, chemical grafting, and polymer encapsulation of nanoparticles. 

Polymeric materials are used in a wide range of medical applications, because of their unique physical properties such as strength, elasticity, and pliability. A potential application could include small diameter vascular implants if one of the major problems of polymeric biomaterials in contact with blood, thrombus formation, could be overcome. Although the underlying processes are not completely understood, an initial step in the thrombogenic sequence is the adsorption of plasma proteins to the surface of a material followed by adhesion of platelets and/or leukocytes.2 3 The extent of thrombosis, in turn, is related to the... 

In the medical industry, porous thermoplastic or thermoset membranes can be used to remove extremely small particles. They are used in applications requiring surface filtration where the particles are trapped on the surface of the media. Although the polymeric membranes are able to remove particles ranging in size from the smallest ions (<0.001 pm) up to approximately one miaon particles, they tend to be expensive and fragile. By coating the membrane on a textile substrate or lamination of a polymeric membrane with a textile fabric, it is possible to combine the physical strength of the textile materials with the filtration properties of membrane materials, hi this sense. 

Graft copolymers combine the properties of their polymeric constituents and as such are polymer alloys, which open a vast field of new polymeric species. This is why active research along these lines is performed in many academic and industrial research laboratories all over the world. However, only few applications have reached a commercial level today. They involve the production of specific polymeric adhesives, perm-selective membranes, bio-medical devices and the surface modification of certain products. 

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