Radiation Processing and Characterization of Some Ethylene-propylene-diene Terpolymer/Butyl (Halobutyl) Rubber/Nanosilica Composites.

Elena Manaila,Florica Doroftei,Cristian-Dragos Varganici,Laurentia Alexandrescu,Nicusor Fifere,Daniela Pamfil,Anton Airinei,Maria Daniela Stelescu,Adrian Bele,Maria Sonmez,Gabriela Craciun

doi:10.3390/polym12102431

Abstract

Composites based on ethylene–propylene–diene terpolymer (EPDM), butyl/halobutyl rubber and nanosilica were prepared by melt mixing and subjected to different doses of electron beam irradiation. The effect of irradiation dose on the mechanical properties, morphology, glass transition temperature, thermal stability and water uptake was investigated. The efficiency of the crosslinking by electron beam irradiation was analyzed by Charlesby–Pinner parameter evaluation and crosslink density measurements. The scanning electron microscopy data showed a good dispersion of nanosilica in the rubber matrix. An improvement in hardness and 100% modulus was revealed by increasing irradiation dose up to 150 kGy. The interaction between polymer matrix and nanosilica was analyzed using the Kraus equation. Additionally, these results indicated that the mechanical properties, surface characteristics, and water uptake were dependent on crosslink characteristics.

Highlights

Ethylene–propylene–diene terpolymer (EPDM) is a widely used rubber with superior resistance against heat, ozone, chemical ageing, weathering
The different mechanical characteristics of the ethylene–propylene–diene terpolymer (EPDM)/butyl rubber/nanosilica composites including hardness, tensile strength, elongation at break, 100% modulus, 300% modulus, elongation set and elasticity are presented in Figures 1–4 as a function of the irradiation dose
These results demonstrate that electron beam irradiation changes the surface properties of silica, being more compatible with EPDM chains and more uniformly dispersed in the rubber matrix by favoring the polymer/filler physical interaction and reducing the interparticle forces

Summary

Introduction

Ethylene–propylene–diene terpolymer (EPDM) is a widely used rubber with superior resistance against heat, ozone, chemical ageing, weathering. EPDM exhibits excellent electrical properties, good mechanical properties, resistance to various aggressive chemicals (acids, alkalies, phosphate esters or ketones), good adhesion characteristics and good low-temperature properties due to its saturated and stable polymer backbone structure [1,2,3,4]. Some nanofillers can be included in the EPDM rubber matrix to improve the mechanical and processing characteristics as compared to the conventional fillers [8,9]. The incorporation of small amounts of nanosilica in polymers leads to the improvement of mechanical properties, higher resistance to abrasion, corrosion or scratching, superior fatigue resistance

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