Novel antimicrobial polyethylene composites prepared by metallocenic in situ polymerization with TiO₂‐based nanoparticles

Abstract

Polyethylene (PE) composites with titanium oxide (TiO2) nanoparticles were produced via in situ polymerization representing a novel route to obtain antimicrobial polymeric materials. The TiO2 nanoparticles synthesized by the sol–gel method were used either as‐synthesized or modified organically with hexadecyltrimethoxysilane (Mod‐TiO2). These particles were added, together with the catalytic system (formed by a metallocenic catalyst and methylaluminoxane as cocatalyst), directly to the reactor, yielding in situ PE composites with 2 and 8 wt % content of nanofiller. The catalytic polymerization activity presented a slight decrease with the incorporation of the TiO2 and Mod‐TiO2 nanoparticles compared to polymerization without filler. Regarding the properties of the composites, crystallinity increased slightly when the different nanofillers were added, and the elastic modulus increased around 15% compared to neat PE. PE/TiO2 nanocomposites containing 8 wt % of TiO2 exposed to UVA irradiations presented antimicrobial activity against Escherichia coli. The PE/Mod‐TiO2 nanocomposite with 8 wt % filler killed 99.99% of E. coli, regardless of light and time irradiation. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012

FTIR and Raman Characterization of TiO2 Nanoparticles Coated with Polyethylene Glycol as Carrier for 2-Methoxyestradiol

“…The reagents used in the synthesis of the nanoparticles and in their organic modifications were titanium isopropoxide (TTIP; Aldrich, reagent grade, 99%), isopropanol, nitric acid (HNO 3 ), distilled water, and hexadecyl trimethoxysilane (Mod-TiO 2 ) (Aldrich, reagent grade, 98%) was used for the modification of TiO 2 nanoparticles [24].…”

Effect of hydrothermally synthesized titanium nanotubes on the behaviour of polypropylene for antimicrobial applications

“…According to the E g = 1239.6/ λ g equation, the calculated band gap ( E g ) energies were ca 3.38 eV for TiO 2 ‐Ntbs and 3.31 eV for Mod‐TiO 2 ‐Ntbs. The E g values of our TiO 2 nanotubes were slightly higher than the value reported for the anatase phase ( E g = 3.1 eV) with spherical morphology . It is probable that the change in the morphology from nanospheres to nanotubes resulted in an increase of the band gap in the anatase crystalline structure.…”

“…In order to improve the thermal and mechanical properties, and to add biocidal characteristics, TiO 2 nanoparticles with quasi‐spherical or spherical morphology have been incorporated into different polyolefin matrices such as high density PE, low density PE, polystyrene and PP …”

FURTHER STUDIES ON HOMO- AND COPOLYMERIZATION OF STYRENE THROUGH CpTICl3-MAO INITIATOR SYSTEM

“…In the last two years our Group has been working on nanocomposites through in-situ metallocenic polymerization. 19,20,21 More recently exploratory research has been under way, and exploratory studies on the synthesis of nanocomposites obtained through in-situ copolymerization including styrene, p-methylstyrene and SiO 2 nanoparticles using CpTiCl3-MAO initiator system have been performed. Table 3 reports the results of the styrene/p-methylstyrene copolymers and of those in which 5% of SiO 2 nanoparticles, Nps, were included in the initial feed, and of a third situation where hexadecytrimethylsilane-modified nanoparticules, modified-Nps, were included at the initial feed of the polymerization reaction.…”