Hydrophilic polymers biomedical applications

Polyvinyl alcohol (PVA), which is a water soluble polyhidroxy polymer, is one of the widely used synthetic polymers for a variety of medical applications [197] because of easy preparation, excellent chemical resistance, and physical properties. [198] But it has poor stability in water because of its highly hydrophilic character. Therefore, to overcome this problem PVA should be insolubilized by copolymerization [43], grafting [199], crosslinking [200], and blending [201], These processes may lead a decrease in the hydrophilic character of PVA. Because of this reason these processes should be carried out in the presence of hydrophilic polymers. Polyfyinyl pyrrolidone), PVP, is one of the hydrophilic, biocompatible polymer and it is used in many biomedical applications [202] and separation processes to increase the hydrophilic character of the blended polymeric materials [203,204], An important factor in the development of new materials based on polymeric blends is the miscibility between the polymers in the mixture, because the degree of miscibility is directly related to the final properties of polymeric blends [205],... 

From the results presented in this chapter we can conclude that it is feasible to prepare sugar-based polymers analogous to the more qualified technological polymers - polyamides, polyesters, polyurethanes - with an enhanced hydrophilicity and degradability. However, in most cases, the high costs associated with the preparation of the monomers restrict the application of these polymers to biomedical applications and other specialized fields. More readily available monomers and simpler polymerization processes have to be found if sugar-derived polymers should compete with petrochemical-based polymers that are used in domestic applications. 

The production of polymeric materials is one of the world s major industries. Polymers are utilized in many applications because of their processability, ease of manufacture, and diverse range of properties. Many of the commonest polymers such as polyethylene, polystyrene, and polytetrafluoroethylene (PTFE) are highly hydrophobic materials rendering them unsuitable for many biomedical applications. For applications that require contact with body fluids such as blood or urine, it is necessary for the materials to be hydrophilic and to be capable of maintaining intimate contact with the fluid in question for prolonged periods of time without significant loss of functional performance. 

Polyt2-hydroxyethyl methacrylate) Cp-HEMA) is a hydrophilic methacrylate polymer which was first prepared by Wichterle and Lim (.1). This polymer, and many other synthetic hydrogels, has been extensively examined for potential biomedical applications (2 ). Although many studies have focused on the physicochemical nature of these hydrogels, many questions remain unanswered. 

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