الفهرس 
Silicone Rubber (Silicone or polysiloxane)Only 14 pages are availabe for public view
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Abstract
This thesis deals with the modification of silicone rubber
based hydrogels manifesting the comfort and wearability for use
in contact lenses application. Silicone rubber was modified by
three different techniques to obtain silicone hydrogel (SiH)
biomaterials possessing hydrophilic and antibacterial properties
for contact lenses application.
First technique: Interpenetrating polymer network (INP)
Polydimethylsiloxane (PDMS), a type of silicone rubber
mostly used in biomedical devices, was modified into
ultraviolet-curable PDMS- polyurethane (PDMS-PU)
prepolymer, then INP silicone hydrogels consisting of
ultraviolet- curable PDMS-PU prepolymer, 3-
methacryloxypropyl tris(trimethylsoloxy silane) (TRIS) and
hydrophilic monomers N,N-dimethyl acrylamide (DMA) and
polyethylene glycol methacrylate PEGMA were formed.
Second technique: Graft copolymerization of PDMS
through photo-polymerization
Grafting copolymerization of PDMS, having methacryloxy
side chain, with different concentrations of DMA and N-vinyl
pyrrolidone was done by free radical polymerization.
The chemical groups of these silicone hydrogels formed by
IPN and grafting copolymerization techniques were
characterized by FTIR. Their tensile modulus, protein
adsorption, equilibrium water content and water contact angle
were also measured. It was found that the equilibrium water
content enhanced when the hydrophilic monomer content
increased, while their protein adsorption, tensile modulus and
water contact angle decreased.
Third technique: The impregnation of silver
nanoparticles into the prepared
silicone hydrogel
Nanosilver- silicone hydrogel (NAgSiH) composites were
synthesized by impregnation of the prepared SiH films
(containing PDMS dimthacrylate macromer) in silver nitrate
followed by diffusion and in-situ chemical reduction of silver
ions loaded in SiH film.
The silver nano particles (AgNPS) were identified by UV-Vis
absorption spectroscopy, Energy-dispersive X-ray spectroscopy
(EDX) mapping and EDX spectrum. The physico-mechanical
and chemical properties of NAgSIH films were studied. The
antimicrobial effect of the hydrogels was evaluated. It was
found that UV-Vis absorption spectroscopy and EDX mapping
and spectrum emphasized that AgNPS were in spherical shape.
The light transmittance decreased as the concentration of
AgNPS increased, while the Young’s modulus increased
gradually. NAgSiH composites possessed an excellent
antimicrobial activities.
Key words: silicone rubber, PDMS, SiH, ultraviolet-curable
PDMS-PU prepolymer, IPN, Grafting
copolymerization, NAgSiH composites, AgNPS,
antimicrobial activities.