New Method for Optimization of Polymer Powder Plasma Treatment for Composite Materials

Abstract

This paper describes a newly developed testing method for determination of the adhesivity of a film sintered from thermoplastic powder. This method is based on the modified EN 15337 standard. Application of this method enables an effective development of thermoplastic composites with enhanced adhesion between reinforcement and matrix and/or high-quality joints between plastics and dissimilar materials. The proposed method was successfully tested on a series of polyethylene powders treated in the oxygen atmosphere for 0–1200 s. Adhesion to metal and glass substrates in dependence on treatment conditions is described along with powder wettability and X-ray photoelectron spectroscopy analysis. The results show an increase in adhesion to metal by 580% and to glass by 1670% for the longest treatment time, compared to a nontreated powder. Sintering of treated powders revealed a strong influence of treatment time on the melting process. The XPS analysis confirmed the formation of new oxygen groups (C–O, C=O, O–C=O). The method reveals a specific behavior of powders based on treatment conditions, which is crucial for the optimization of plasma treatment for the improved adhesion, applicability of polymer powders, and a development of composite materials.

The Effect of Plasma Treatment of Polyethylene Powder and Glass Fibers on Selected Properties of Their Composites Prepared via Rotational Molding

“…The images show that there are no gaps between the fibers and PE matrix, and there is an increase in the amount of polyethylene residue left on the fiber surface after breaking; this indicates good adhesion between the fiber and the matrix. These images are consistent with those of Zuzana et al [42]. on the adhesion between treated material and glass rods.…”

“…This indicates that a longer heating time is needed to prepare composites using powder treated for a longer time. These results correspond with the results obtained by Z. Weberova et al, on the sintering of plasma-treated polyethylene on glass rods in an oven which showed that plasma treatment time of the polyethylene powder affected their sintering behavior and longer time is needed to obtain a proper sintering of the powder [42]. The tensile strength of the composites prepared using treated and untreat fibers is presented in Figure 12.…”

“…This behavior can be explained by the fact that the powders treated for a longer time need longer sintering times to achieve a uniform and proper even layer [42]. In the first step of the experiment, the holding time at the maximum oven temperature 250 • C was only 5 min, and this could not be sufficient for proper sintering of the mixture of glass fiber and powder treated for a longer time.…”

Wettability and Adhesion of Polyethylene Powder Treated with Non-Equilibrium Various Gaseous Plasma in Semi-Industrial Equipment

“…Adhesion was characterized by shear strength, measured using a modified pin-collar test, a method adapted for the measurement of the adhesion of polymer powders to solid substrates. The same procedure as that described by Weberova et al [22] was used. Rods made from chrome-plated steel C35 with a fine smooth surface (Ra max = 0.2 µm, average Ra = 0.13 µm) with d = 12 mm, l = 45 mm (Hydraulics s.r.o., Slopné, Czech Republic), were used as a metal substrate.…”

Experimental Studies on the Influence of Plasma Treatment of Polyethylene in Carbon Fiber Composites: Mechanical and Morphological Studies

“…This method is an eco-friendly approach creating a wide range of reactive species in the polymers, such as amine, hydroxyl, carboxyl, ether, peroxide and carbonyl groups, depending on the surrounding medium. Plasma treatment enhances the surface roughness and hardness properties of the composites [ 5 , 6 , 7 ].…”