Surface Modification of Polyethylene through Bromination

Abstract

Surface bromination of low-density polyethylene (LDPE) was carried out by brief exposure to gaseous bromine followed by UV irradiation. X-ray photoelectron spectroscopy suggests two different types of C−Br groups. Atomic force microscopy and wetting studies reveal that excessive bromination is accompanied by severe surface roughening. A nucleophilic substitution reaction was used to introduce surface 4-aminobenzenethiolate functionalities. UV spectral analysis indicates a grafting density of 2.9 bromine atoms per 100 Å2 for the first bromination cycle.

UV Assisted Surface Modification of Polystyrene in the Presence of Trialkylsilanes

“…[1] Furthermore, surface modification with UV light in the presence of reactive gases, have been developed over the last decade. [2][3][4] Surface modification with the help of UV light is an easily applicable and low-cost method without any expensive set-up needed in contrast to other surface modification techniques employing radiation and discharges (e À -beam, corona discharge).…”

“…Si-H bond dissociation energies (BDEs) of trialkylsilanes R 3 Si-H and the reactivity of trialkylsilyl radicals R 3 Si . have been studied thoroughly.…”

“…have been studied thoroughly. Hydrogen abstraction by an alkyl radical from the silane R 3 SiH is an exothermic reaction. DH values for the hydrogen abstraction step amount to À27 kJ Á mol À1 for trialkylsilanes and to À80 kJ Á mol À1 for tris(trimethylsilyl)silane (TTMSS).…”

Precision Ethylene/Vinyl Bromide Polymers

“…[7] Additionally, surface bromination of thin PE films with bromine vapor has been described. [8] Another somewhat different approach to these polymers involves reductive debromination of poly(vinyl bromide). [5] Deficiencies in the above techniques can be attributed to the incorporation of structural defects in the polymer precursor (e.g., branching, cyclic defects caused by back-biting) as well as the uncontrolled chemical events that accompany post-polymerization bromination.…”

“…In addition, the EV/B co-polymers could find direct materials applications stemming from the flame retardancy induced in bromine-containing materials, [11] or more generally based on the modified physical properties and their influence on adhesion, wettability, and surface energy. [8] Olefin metathesis offers distinct advantages over previously used methods for the synthesis of EV/B polymers. Acyclic diene metathesis polymerization (ADMET) is now widely accepted as a route to polyolefins having a precisely defined primary structure, for it entails mild chemistry, which does not lead to side reactions involving the reactive bromine functionality.…”