50 research outputs found
Functionalization of different polymers with sulfonic groups as a way to coat them with a biomimetic apatite layer
Covalent coupling of sulfonic group (–SO3H)
was attempted on different polymers to evaluate efficacy of
this functional group in inducing nucleation of apatite in
body environment, and thereupon to design a simple biomimetic
process for preparing bonelike apatite-polymer
composites. Substrates of polyethylene terephthalate
(PET), polycaprolactam (Nylon 6), high molecular weight
polyethylene (HMWPE) and ethylene-vinyl alcohol copolymer
(EVOH) were subjected to sulfonation by being
soaked in sulfuric acid (H2SO4) or chlorosulfonic acid
(ClSO3H) with different concentrations. In order to incorporate
calcium ions, the sulfonated substrates were soaked
in saturated solution of calcium hydroxide (Ca(OH)2). The
treated substrates were soaked in a simulated body fluid
(SBF). Fourier transformed infrared spectroscopy, thin-film
X-ray diffraction, and scanning electron microscopy
showed that the sulfonation and subsequent Ca(OH)2
treatments allowed formation of –SO3H groups binding
Ca2+ ions on the surface of HMWPE and EVOH, but not on
PET and Nylon 6. The HMWPE and EVOH could thus
form bonelike apatite layer on their surfaces in SBF within
7 d. These results indicate that the –SO3H groups are
effective for inducing apatite nucleation, and thereby that
surface sulfonation of polymers are effective pre-treatment
method for preparing biomimetic apatite on their surfaces