Silicone rubber/hydrogels

Silicone rubber-hydrogel composite is a two-phase system that is capable of swelling in water. The hydrogels prepared have different chemical compositions, size and shape of particles, and correspondingly different specific surfaces. It was found that the mechanical properties of silicone rubber-hydrogel composites depend mostly on the magnitude of the contact surface of both phases. ... 

Lednicky et studied the structure of silicone rubber-hydrogel based on poly(HEMA) by... 

Lopour P, Plichta Z, Volfova Z, Hron P, and Vondracek P. Silicone rubber-hydrogel composites as polymeric biomaterials. Biomaterials, 1993, 14(14), 1051-1055. 

Lednicky F, Janatova V, and Lopour P. Silicone rubber-hydrogel composite as polymeric biomaterials [J]. Biomaterials, 1991, 12, 848. 

Processing requirements for thermoset composites, with specific examples of silicones, were recently reported.514 Composites based on the low molecular weight polysiloxanes for medical applications have been reviewed (in Russian).515 Silicone rubber/hydrogel composites have been evaluated for medical applications.516... 

Chetoni, P., Di-Colo, G., Grandi, M., Morelli, M., Saettone, M.F., and Darougar, S., Silicone rubber/hydrogel composite ophthalmic inserts preparation and preliminary in vitro/in vivo evaluation, Eur. J. Pharm. Biopharm., 46 125-132 (1998). 

Hron P et al. (1997) Silicone rubber-hydrogel composites as polymeric biomaterials. IX Composites containing powdery polyacrylamide hydrogel. Biomaterials 18( 15) 1069— 1073... 

Blending of polymers provides a convenient way of combining the different properties of individual polymers. Hydrophilization of the silicone mbber can be obtained by blending silicone rubber with hydrogels. These kinds of composites combine the good mechanical properties with the hydrophilicity. 

Thermal and pH sensitive heterogeneous copolymer hydrogels which contain silicone rubber domains within a temperature and pH sensitive copolymer of NIPA and acrylic acid have been synthesized by Dong et al. [60]. These materials contained macropores when swollen and collapsed much faster than homopolymers of iV-isopropylacrylamide. Biocatalyst immobilization using copolymers of NIPA and NN - dimethylaminopropylmethacrylamide have also been studied [61]. 

Membrane-reservoir systems based on solution-diffusion mechanism have been utilized in different forms for the controlled delivery of therapeutic agents. These systems including membrane devices, microcapsules, liposomes, and hollow fibres have been applied to a number of areas ranging from birth control, transdermal delivery, to cancer therapy. Various polymeric materials including silicone rubber, ethylene vinylacetate copolymers, polyurethanes, and hydrogels have been employed in the fabrication of such membrane-reservoir systems (13). 

As listed in Table 1, many PSAs fulfilling the above requirements have been applied for the TDS. Rubber, acrylic, silicone, and hydrogel adhesives are discussed separately in the following sections. 

Seifert, L.M. and R.T. Greer, Evaluation of in vivo adsorption of blood elements onto hydrogel-coated silicone rubber by scanning electron microscopy and Fourier transform infrared spectroscopy. Journal of Biomedical Materials Research, 1985, 19, 1043-1071. 

In our experiments the donors were selected to be excitable with a S43 nm HeNe laser. The donors and acceptor were dissolved at concentrations listed in Figure 4 in a 40 mM NaHCOs solution and mixed with a polyHEMA hydrogel (66). The equilibrated hydrogels were sandwiched between silicone rubber membranes, and sealed to retain the indicator solutions. 

Hron, R, and Slechtova, J. 1999. Shape memory of composites based on silicone rubber and polyacrylamide hydrogel. Die Angewandte Makromolekulare Chemie 268 29-35. 

P. Li, S. Jiang, Y. Yu, J. Yang, Z. Yang, Biomaterial characteristics and application of silicone rubber and PVA hydrogels mimicked in organ groups for prostate brachyther-... 

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