Effect of different types of filler and filler loadings on the properties of carboxylated acrylonitrile-butadiene rubber latex films

Novel slag/natural rubber composite as flexible material for protecting workers against radiation hazards

This work is an attempt to employ the electric arc furnace (EAF) slag as a by-product material to develop an alternative and environmentally friendly material for gamma-radiation protection applications such as in medical and industrial areas. For this purpose, different concentrations of micro-sized EAF slag (0, 20, 40, 60, 80, 100, 500, and 800 phr) were incorporated as fillers in the natural rubber (NR) matrix to produce the shielding composites. In addition, nano-sized EAF slag particles were prepared by using a high-energy ball milling technique to investigate the effect of particle size on the gamma-radiation shielding properties. The synthesized micro and nano EAF/NR composites were tested as protective materials against gamma-radiation by employing NaI(Tl) scintillation detector and standard radioactive point sources (152Eu, 137Cs, 133Ba, and 60Co). Different shielding parameters such as linear and mass attenuation coefficient, half value layer (HVL), tenth value layer, mean free path, effective atomic number (Zeff), and effective electron density (Neff) were determined to assess the radiation shielding capability of the EAF/NR composites. Furthermore, equivalent atomic number (Zeq) and the exposure buildup factor values for photon energy in the range from 0.015 to 15 MeV were also computed by Geometric Progression method. The experimental results of micro EAF/NR composites showed that at 121.78 keV, EAF0 composite (without EAF slag content) had the lowest μ value of 0.1695 cm-1, while the EAF800 composite (which was loaded with 800 phr of micro EAF slag) had the highest μ value of 0.2939 cm-1 at the same energy, which in turn decreases the HVL from 4.09 to 2.36 cm, respectively. Therefore, increasing the filler weight fractions of EAF slag in the NR matrix, increases the shielding properties of the composites. Moreover, the NR composite reinforced with 800 phr of nano EAF slag has better gamma-radiation shielding efficiency compared to that filled with 800 phr of micro EAF slag. The success of this work was to prepare a flexible, lightweight, low-cost, and lead-free material with better shielding capability.

Effect of Fillers on the Recovery of Rubber Foam: From Theory to Applications

Natural rubber foam (NRF) can be prepared from concentrated natural latex, providing specific characteristics such as density, compression strength, compression set, and so on, suitable for making shape-memory products. However, many customers require NRF products with a low compression set. This study aims to develop and prepare NRF to investigate its recoverability and other related characteristics by the addition of charcoal and silica fillers. The results showed that increasing filler loading increases physical and mechanical properties. The recoverability of NRF improves as silica increases, contrary to charcoal loading, due to the higher specific surface area of silica. Thermodynamic aspects showed that increasing filler loading increases the compression force (F) as well as the proportion of internal energy to the compression force (F_u/F). The entropy (S) also increases with increasing filler loading, which is favorable for thermodynamic systems. The activation enthalpy (∆H_a) of the NRF with silica is higher than the control NRF, which is due to rubber–filler interactions created within the NRF. A thermodynamic concept of crosslinked rubber foam with filler is proposed. From theory to application, in this study, the NRF has better recoverability with silica loading.

Use of carbon and aluminosilicate nanofillers in XNBR composites designed for protective materials against oils

The objective of the work was to investigate the possibility of application of carbon and bentonite nanoparticles in carboxylated acrylonitrile-butadiene rubber (XNBR) and the related effects of the nanofillers on the structure, as well as mechanical and barrier properties, of the resulting composites. The composites were designed for use in protective clothing and gloves. XNBR compounds were modified with 2 phr of graphene flakes, graphene oxide, or modified bentonite, and crosslinked with sulfur-accelerator system. Rubber compounds were prepared using a conventional method with a laboratory rolling mill. The composites were studied in terms of structure (WAXS), surface morphology (AFM), the presence of functional groups (ATR-FTIR) barrier properties against chemical substances (mineral oil) and swelling properties, as well as mechanical properties (abrasion resistance and tensile strength). The composites were characterized by very high resistance to oil permeation (breakthrough time >480 min). The type of nanofiller added to the XNBR blend in the amount of 2 phr did not significantly affect mechanical parameters.

Gloves against mineral oils and mechanical hazards: composites of carboxylated acrylonitrile-butadiene rubber latex

Resistance to permeation of noxious chemical substances should be accompanied by resistance to mechanical factors because the glove material may be torn, cut or punctured in the workplace. This study reports on glove materials, protecting against mineral oils and mechanical hazards, made of carboxylated acrylonitrile-butadiene rubber (XNBR) latex. The obtained materials were characterized by a very high resistance of the produced materials to oil permeation (breakthrough time > 480 min). The mechanical properties, and especially tear resistance, of the studied materials were improved after the addition of modified bentonite (nanofiller) to the XNBR latex mixture. The nanocomposite meets the requirements in terms of parameters characterizing tear, abrasion, cut and puncture resistance. Therefore, the developed material may be used for the production of multifunctional protective gloves.