Abstract

Silicone rubber films were modified by the consecutive grafting of 2-(diethylamino)ethyl methacrylate (DEAEMA) and N-vinylcaprolactam (NVCL) using direct method on two steps with gamma-rays. The effect of absorbed dose and monomer concentration on grafting degree was determined. The grafted samples were verified by FTIR-ATR spectroscopy and swelling; thermal properties were analyzed by DSC and TGA. The stimuli-responsive behavior was studied by swelling and/or DSC. Thermo- and pH-sensitive films of (PP-g-DEAEMA)-g-NVCL presented a pH critical at 3.2 and LCST around 63.5℃.

Highlights

  • Treatment of diseases and injuries is focused in synthesis of new drugs or enhancing of existents, and in the development of more and better biomaterials suitable for the manufacture of prostheses and medical devices [1]

  • The radiation grafting yield of NVCL onto SR-g-diethylaminoethyl methacrylate (DEAEMA)(11% graft) as function of irradiation dose and monomer concentration 50 vol%., the effect of the irradiation dose on the grafting yield was examined by two step method at fixed monomer concentrations varying the irradiation dose between 10 and 60 kGy

  • For a 50% monomer concentration, the grafting yield of poly (NVCL) onto SR films is depicted in Figure 2, where it can be observed that there is an increase in grafting percentage as the irradiation dose increases, which is not unexpected given that the number of latent initiating sites is expected to increase with increasing radiation dose, in all cases, copolymers films were homogenous

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Summary

Introduction

Treatment of diseases and injuries is focused in synthesis of new drugs or enhancing of existents, and in the development of more and better biomaterials suitable for the manufacture of prostheses and medical devices [1]. Gamma radiation grafting is an attractive method for obtaining a modified material without chemical initiators or other additives that is applicable to most polymer-monomer combinations [12]. Incorporating monomers with swelling-deswelling capabilities depending on the pH or temperature of the medium, generated synthesis of new materials with various biomedical applications [19] Several polymers such as poly(acrylamide), poly(Nisopropylacrylamide), and their copolymers, can respond to environmental changes, but presents problems with biocompatibility, which makes them unsuitable as materials with biomedical applications. That’s why we sought to exploit the advantages of the NVCL (thermo-sensitive) and DEAEMA (pH-sensitive) to generate a binary graft copolymer on silicone rubber by two-step method with swelling-deswelling capabilities This system retained the mechanical properties of silicone, but with improved biocompatibility by the inclusion of soluble monomers and with fast response to temperature and pH. The optimum grafting conditions and response to temperature and pH was evaluated

Materials
Physical Characterization
Thermo-Responsive Measurement
Results and Discussion
Conclusion
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