Radical Graft Polymerization of Styrene Sulfonate on Poly(ethylene terephthalate) Films for ACL Applications: “Grafting From” and Chemical Characterization

Abstract

The purpose of this study is to develop a reliable method of functionalizing poly(ethylene terephthalate) with bioactive polymers to produce a "biointegrable" artificial anterior cruciate ligament. Radical graft polymerization of the sodium salt of styrene sulfonate (NaSS) onto poly(ethylene terephthalate) (PET) films was performed using the "grafting from" technique. Prior to the grafting, the surfaces of poly(ethylene terephthalate) films were activated by ozonation to generate peroxide and hydroperoxide reactive species on the PET film surfaces. The radical polymerization of NaSS was initiated by thermal decomposition of the hydroperoxides. The grafted PET surfaces were characterized by a toluidin blue colorimetric method, X-ray photoelectron spectroscopy, contact angle measurements, and atomic force microscopy. The influence of ozonation time, monomer concentration, and temperature on NaSS grafting ratios was examined. A total of 30 min of ozonation followed by grafting from a 15% NaSS solution at 70 degrees C for 90 min or more resulted in attachment of poly(NaSS) chains to the PET film surfaces.

Grafting titanium nitride surfaces with sodium styrene sulfonate thin films

“…7,[24][25][26][27] The XPS surface elemental composition of pNaSS grafted surface [ Table I and Fig. 2(c)] showed the presence of sulfur and sodium, which are unique to the NaSS molecules, providing evidence of the successful grafting of pNaSS from the MPS modified surface.…”

“…NaSS was purified by dissolving it in a mixture of water/ethanol (10/90 v/v) at 70 C and then recrystallizing it under vacuum. 25 AIBN was purified by dissolving it in methanol, recrystallizing it at À18 C, and then drying under vacuum. All other chemicals and materials were used as received.…”

“…24,25 Briefly, 7.5 g of toluidine blue was dissolved in 50 ml DI-H 2 O and a buffer solution of 0.2 ml of 2-amino-2-methyl propanol was added. Each polymerized sample was placed in an individual well of a six-well plate with 6 ml of the solution and incubated at 30 C for 6 h. The samples were then soaked in a 5 Â 10 À4 M NaOH solution for 30 min.…”

“…[18][19][20][21][22] It has already been shown that polymers bearing appropriate chemical functions can modulate cell attachment, spreading, and activity on these bioactive polymers. [23][24][25][26] The distributions of ionic groups along with the macromolecular chains create active sites, which can interact with extracellular proteins, such as fibronectin, implicated in cell response. [23][24][25][26][27] Given the benefits of titanium nitride in terms of wear resistance and corrosion protection, grafting of a bioactive polymer from the titanium nitride surface is a potentially useful way to combine the benefits of titanium nitride with the grafted bioactive polymer.…”

Experimental design and analysis of activators regenerated by electron transfer-atom transfer radical polymerization experimental conditions for grafting sodium styrene sulfonate from titanium substrates

“…Interest in NaSS extends to a number of applications, such as an antiflocculating agent, emulsifier, catalyst, and for use in ion-exchange resins and membranes. [18][19][20][21] It has also shown promise as a strategy to increase the osseointegration of titanium [22][23][24][25] and poly(ethylene terephthalate) 26-28 biomedical implants. To investigate possible reasons for the increased osseointegration of these materials, in future studies, the authors intend to test the hypothesis that the NaSS-grafted surfaces preferentially adsorb certain plasma proteins in an orientation and conformation that modulates the foreign body response and promotes formation of new bone.…”