Research Article New Green Polymeric Composites Based on Hemp and Natural Rubber Processed by Electron Beam Irradiation Maria-Daniela Stelescu, 1 Elena Manaila, 2 Gabriela Craciun, 2 and Maria Dumitrascu 2 1 National Research and Development Institute for Textile and Leather-Leather and Footwear Research Institute, 93 Ion Minulescu Street, 031215 Bucharest, Romania 2 National Institute for Lasers, Plasma and Radiation Physics, Accelerators Laboratory, 409 Atomistilor Street, 077125 Magurele, Romania Correspondence should be addressed to Elena Manaila; elena.manaila@inlpr.ro Received 29 August 2013; Accepted 31 October 2013; Published 28 January 2014 Academic Editors: P. Dallas and K. Jayakumar Copyright © 2014 Maria-Daniela Stelescu et al. his is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. A new polymeric composite based on natural rubber reinforced with hemp has been processed by electron beam irradiation and characterized by several methods. he mechanical characteristics: gel fraction, crosslink density, water uptake, swelling parameters, and FTIR of natural rubber/hemp iber composites have been investigated as a function of the hemp content and absorbed dose. Physical and mechanical properties present a signiicant improvement as a result of adding hemp ibres in blends. Our experiments showed that the hemp ibers have a reinforcing efect on natural rubber similar to mineral illers (chalk, carbon black, silica). he crosslinking rates of samples, measured using the Flory-Rehner equation, increase as a result of the amount of hemp in blends and the electron beam irradiation dose increasing. he swelling parameters of samples signiicantly depend on the amount of hemp in blends, because the latter have hydrophilic characteristics. 1. Introduction Green composite combines plant ibers with natural resins to create natural composite materials. Natural ibers such as hemp, kenaf, lax, jute, sisal, and so forth have attracted inter- est, especially as a synthetic ibers substitute in the rubber and plastics industry. he advantages of natural ibers over syn- thetic are low cost, low density, acceptable speciic strength properties, ease of separation, carbon dioxide sequestration, and biodegradability. In ibers-reinforced composites, the ibers serve as reinforcements by giving strength and stifness to the composite structure [1, 2]. In this paper the results of our study on obtaining and characterizating a new green polymeric composite based on hemp and natural rubber, crosslinked by irradiation with electron beam (EB) are presented. here are few studies regarding the use of hemp iber for the achievement of composites based on natural rubber. Osabohien and Egboh [3] conducted a study on the use of bowstring hemp iber as iller in natural rubber compounds, compared with carbon black. he hemp ibers/rubber had lower tensile strength (only 2/3 of the carbon black/rubber), but the hemp iber/rubber showed superior hardness (1.26 times that of carbon black/rubber). So, hemp ibers could replace active illers such as carbon black or silica from natural rubber. Silica is known to have adverse efects on health: silico- sis, cancer (Group 1 according to IARC—the International Agency for Research on Cancer), autoimmune diseases, tuberculosis, kidney disease, and so forth, and in 1995, the IARC rated carbon black as IARC classiication 2B— possibly carcinogenic to humans and deinitely carcinogenic to animals [4–8]. Cho and collaborators [9] specify that an introduction of ecofriendly natural ibers to natural rubber can play a role not only in reinforcing rubber but also in reducing the amount of carbon black used in rubber and tire applications. In the mentioned study [3] the curing of natural rubber/hemp composites has been achieved by the classical method of crosslinking, that is, using sulfur and vulcanization accelerators. In another study [10], elastomer crosslinking was performed using benzoyl peroxide in order to obtain also Hindawi Publishing Corporation e Scientific World Journal Volume 2014, Article ID 684047, 13 pages http://dx.doi.org/10.1155/2014/684047