Surface modification of polyethylene and polypropylene in atmospheric pressure glow discharge

Abstract

An atmospheric pressure glow discharge (APGD) was used for surface modification of polyethylene (PE) and polypropylene (PP). The discharge was generated between two planar metal electrodes, with the top electrode covered by a glass and the bottom electrode covered by the treated polymer sample. The discharge burned in pure nitrogen or in nitrogen-hydrogen or nitrogen-ammonia mixtures. The surface properties of both treated and untreated polymers were characterized by scanning electron microscopy, atomic force microscopy, surface free energy measurements and x-ray photoelectron spectroscopy. The influence of treatment time and power input to the discharge on the surface properties of the polymers was studied. The ageing of the treated samples was investigated as well. The surface of polymers treated in an APGD was homogeneous and it had less roughness in comparison with polymer surfaces treated in a filamentary discharge. The surface free energy of treated PE obtained under optimum conditions was 54 mJ m −2 and the corresponding contact angle of water was 40˚; the surface free energy of treated PP obtained under optimum conditions was 53 mJ m −2 and the contact angle of water 42˚. The maximum decrease in the surface free energy during the ageing was about 10%.

Polypropylene-based graft copolymers via CuAAC click chemistry

“…The surface properties of graft copolymers and initial PP-Cl sample were investigated by water contact angle (WCA) analysis at room temperature ( Figure 8). While, the average WCA of a droplet of positioned on PP-Cl coated substrate was in the range of 90±1°t hat was in good agreement with the literature values [66][67][68]. By introduction of either hydrophilic PCL-alkyne (determined as 65±1.5°) [69][70][71], or PEG-alkyne (determined as 42±1.9°) units on the PP-Cl backbone, the WCA values of corresponding graft copolymers were decreased down to 83±2.1° and 78±1.8°, respectively.…”

Charging of moving surfaces by corona discharges sustained in air

“…One such application is improvement in wettability of surfaces. [1][2][3][4][5] By creating new surface functional groups on commodity polymer sheets, metallic foils, and paper, surface tension (or surface energy, dyne/cm) can be increased to improve the bonding abilities with adhesives, coatings, and solvents. As a result, the printing quality and lamination strength can be improved.…”

Reel-to-Reel Atmospheric Pressure Dielectric Barrier Discharge (DBD) Plasma Treatment of Polypropylene Films

“…Oxygen was detected on the treated samples despite the fact that the chamber was evacuated and backfilled with the process gases, which should only have contained oxygen in extremely low traces. However, comparison with the findings of other research groups indicates that their polypropylene films treated in pure nitrogen also contained oxygen [31,32,42,43]. This is usually attributed to the much higher reactivity of oxygen species in the plasma than nitrogen species.…”

“…Ten contact angles measurements were conducted for each sample for each testing liquid. The three test liquids chosen for this project, distilled water, diiodomethane and ethylene glycol, were selected because they have been used previously by other researchers to investigate the surface energy of polypropylene [31,32]. A total of 5 µL of HPLC grade water or diiodomethane or ethylene glycol were dropped onto a horizontal sample using a syringe.…”