Enhancement of carbon-steel peel adhesion to rubber blend using atmospheric pressure plasma

The surface of carbon-steel plates was modified by non-equilibrium plasma of diffuse coplanar surface barrier discharge (DCSBD) in order to improve the adhesive properties to the NR (natural rubber) green rubber compound. The effect of different treatment times as well as different input power and frequency of supplied high voltage was investigated. The samples were characterized using contact angle and surface free energy measurement, measurement of adhesive properties, scanning electron microscopy (SEM) and atomic force microscopy (AFM). Surface chemical composition was studied by energy-dispersive X-ray spectroscopy (EDX). Significant increase in wettability was observed even after 2 s of plasma exposure. The surface modification was confirmed also by peel test, where the best results were obtained for 6 s of plasma treatment. In addition the ageing effect was studied to investigate the durability of modification, which is crucial for the industrial applications

Morphological, Mechanical and Gas Penetration Properties of Elastomer Composites with Hybrid Fillers

Ethylene–propylene–diene monomer (EPDM)-based composites including four different types of graphene nanoplatelets (GnPs) were prepared to evaluate the size effects of GnPs in terms of both specific surface area and lateral size on the morphological, mechanical, and viscoelastic properties, swelling ratio, crosslink density, and oxygen permeability. EPDM-based hybrid composites with GnPs and carbon black (CB) fillers were prepared, with the concentrations of 20 and 50 phr of CB and GnPs up to 7 phr. All samples were prepared using the melt mixing method, followed by compression molding. The specific surface area of GnPs is a more important key factor for mechanical and viscoelastic properties than its lateral size. The presence of GnPs leads to a decrease in the swelling ratio and oxygen permeability of the matrix while an increase in the crosslinking density. For a given specific surface area of GnPs (170 m(2)/g) and the same thickness (5 nm), the optimum lateral size for mechanical properties, swelling ratio, and crosslinking density is about 30 µm. There is a distinct synergic effect on the mentioned properties when hybrid fillers are used. For hybrid composites, the optimum total and each filler concentration are found to be important for achieving the best performance in terms of mechanical properties, swelling ratio, and crosslink density