A simple and green approach to the preparation of super tough IIR/SWCNTs nanocomposites with tunable and strain responsive electrical conductivity

Nanocomposites of single-wall carbon nanotubes in isobutylene isoprene rubber (IIR/SWCNTs) were successfully prepared by a simple and green wet process. The traditional melt mixing process and organic solvent dissolution suffered from unable to effectively disperse the SWCNTs of tangled structure, and degradation of polymer molecules, respectively. Our process very well avoided these two problems. The SWCNTs aqueous solutions emulsified by polyoxyethylene octyl phenol ether (OP-10) were firstly mixed and compounded with IIR rubber at a relatively high temperature, followed by the second step of melt compounding process with the addition of cross-linking agent and accelerators. The SWCNTs were dispersed uniformly, and a fine network was constructed in the matrix of the obtained IIR/SWCNTs nanocomposite with a low percolation threshold. With the concentration of SWCNTs as low as 2 phr, the IIR/SWCNTs nanocomposite received an electrical conductivity of 10−6∼10−3 S/cm, and a 71% improvement of tensile strength. By varying the loadings of SWCNTs in a certain range, the tensile strength, electrical conductivity, and dielectric property were found tunable. Besides, the nanocomposites also presented strain responsive specific resistance, excellent elongation (600–740%), and better heat resistance.

Kinetic Modelling and Determination of Octyl Phenol Ethoxylate (OPE) and Bisphenol A (BPA) (used as plastic additives) Inhibition Constants for Nitrogen Conversion

<p>Conversion of ammonia to nitrate is sensitive to a number of inhibitors. There is limited information on the nitrification inhibition coefficient and kinetic model in the current literature. Octyl Phenol Ethoxylate (OPE) and Bisphenol A (BPA) inhibition constants were found in nitrogen removal using an activated sludge system. Firstly, OPE and BPA free wastewater was used to determine the optimum operating conditions. The effect of OPE and BPA concentration on system performance was investigated. The ammonium removal rate was less affected by lower OPE and BPA concentrations. When the BPA and OPE concentrations were increased from 0 mg/L to 30 mg/L, the outlet ammonium nitrogen concentrations were increased respectively from 2.8 mg/L to 49.8 mg/L and from 2.6 mg/L to 20.40 mg/L. Due to the inhibition created by these compounds on Nitrobacter, nitrite nitrogen increased in the medium. As the OPE and BPA concentrations increased, the conversion rate of the ammonium nitrogen into nitrate decreased. Based on the experimental results, a kinetic model was developed, and the OPE and BPA inhibition constants (KOPE and KBPA) were found to be 40.7 mg/L and 11.76 mg/L, respectively. In nitrogen removal, BPA created a higher inhibition effect in comparison to OPE.</p>

APPLICATION OF THE RESIN DERIVED FROM THE NATIVE EUPHORBIA CADUCIFOLIA HAINES AS MULTIFUNCTIONAL ADDITIVE IN FILLED NATURAL RUBBER COMPOUNDS

ABSTRACT The whole coagulum (Cog) and its toluene-soluble fraction [toluene extract (TE)] obtained via the coagulation of the latex of Euphorbia caducifolia Haines was used as a green, multifunctional additive in a filled NR compound. The actions of Cog and TE were compared with two commercial resins, non-heat-reactive octyl phenol-formaldehyde (PF) and coumarone-indene (CI), at equal doses and also with conventional aromatic oil (through replacement). Both Cog and TE exhibited comparable tack strength with CI, but lower tack strength with PF. In addition, TE improved the cure rate index, unlike Cog and the commercial resins. When the aromatic oil was replaced with TE and Cog at different levels, we observed that TE could replace 100% of the original oil content, whereas Cog could only replace 33% of the original oil content from the recipe without deterioration of physico-mechanical properties. Both forms of natural resins decreased the intrinsic elasticity of the compounds and improved the aging resistance of the vulcanizates.