A Method to Improve the Characteristics of EPDM Rubber Based Eco-Composites with Electron Beam

Abstract

A natural fiber reinforced composite, belonging to the class of eco composites, based on ethylene-propylene-terpolymer rubber (EPDM) and wood wastes were obtained by electron beam irradiation at 75, 150, 300, and 600 kGy in atmospheric conditions and at room temperature using a linear accelerator of 5.5 MeV. The sawdust (S), in amounts of 5 and 15 phr, respectively, was used to act as a natural filler for the improvement of physical and chemical characteristics. The cross-linking effects were evaluated through sol-gel analysis, mechanical tests, and Fourier Transform Infrared FTIR spectroscopy comparatively with the classic method with dibenzoyl peroxide (P) applied on the same types of samples at high temperature. Gel fraction exhibits values over 98% but, in the case of P cross-linking, is necessary to add more sawdust (15 phr) to obtain the same results as in the case of electron beam (EB) cross-linking (5 phr/300 kGy). Even if the EB cross-linking and sawdust addition have a reinforcement effect on EPDM rubber, the medium irradiation dose of 300 kGy looks to be a limit to which or from which the properties of the composite are improved or deteriorated. The absorption behavior of the eco-composites was studied through water uptake tests.

Electron Beam Irradiation: A Method for Degradation of Composites Based on Natural Rubber and Plasticized Starch

“…Samples prepared as above were irradiated at 150, 300, and 450 kGy in atmospheric conditions and at room temperature of 25 • C, using the ALID-7 electron beam accelerator from the National Institute for Laser, Plasma and Radiation Physics, Magurele, Romania. The nominal values of the electron beam (EB) parameters are as follows: energy −5.5 MeV, peak current −130 mA, mean output power −134 W, pulse repetition −3.75 µs, and frequency −50 Hz [15][16][17] The irradiation process performance depends on the rigorous control of the irradiation dose and dose rate [18,19]. In our experiments, the dose rate was of 1.5 kGy/min.…”

“…The sol-gel and cross-link density analysis on samples cross-linked with peroxide and irradiated with EB, were carried out as in our previous works [15][16][17]. In order to determine the gel content in the cross-linked products (gel fraction), the solvent extraction method using toluene was used [15][16][17]. Samples weighed and swollen in toluene for 72 h, were dried in air for 6 days and in a laboratory oven at 80 • C for 12 h in order to completely remove the solvent.…”

“…The water absorption in irradiated NR and NR/PS composites was evaluated as in previous works [15][16][17], in accordance with ISO 20344/2011, by immersion in distilled water until the samples no longer absorbed water.…”

Advances in Wood Composites II

“…In the area of composites, Cracium et al [40] presented a natural-fiber-reinforced eco-composite. This was based on wood wastes (obtained by electron beam irradiation) and on a rubber monomer (ethylene-propylene-diene monomer).…”

Development of elasto-plastic eco-nano-materials for the footwear industry

“…Figures 1-6 present the infrared spectra obtained in the range of 450-3000 cm -1 of the control blend (sample 1), plasticized starch and sample 5. Control sample spectrum (sample 1) includes C-H stretching vibration (2914,53 cm −1 and 2847,59 cm −1 ), CH2 bending and rocking vibrations (1472 cm −1 , 1462 cm −1 and 719-730 cm −1 ), specific bands of EPDM and HDPE (Craciun et al, 2020). Figure 2.…”