A new magnetic functionalized derivative of chitosan is synthesized and characterized for the sorption of metal ions (environmental applications and metal valorization). The chemical modification of the glycine derivative of chitosan consists of: activation of the magnetic support with epichlorohydrin, followed by reaction with either glycine to produce the reference material (i.e., Gly sorbent) or glycine ester hydrochloride, followed by hydrazinolysis to synthesize the hydrazide functionalized sorbent (i.e., HGly sorbent). The materials are characterized by titration, elemental analysis, FTIR analysis (Fourrier-transform infrared spectrometry), TGA analysis (thermogravimetric analysis) and with SEM-EDX (scanning electron microscopy coupled to energy dispersive X-ray analysis). The sorption performances for U(VI), Cu(II), and Zn(II) are tested in batch systems. The sorption performances are compared for Gly and HGly taking into account the effect of pH, the uptake kinetics (fitted by the pseudo-second order rate equation), and the sorption isotherms (described by the Langmuir and the Sips equations). The sorption capacities of the modified sorbent reach up to 1.14 mmol U g−1, 1.69 mmol Cu g−1, and 0.85 mmol Zn g−1. In multi-metal solutions of equimolar concentration, the chemical modification changes the preferences for given metal ions. Metal ions are desorbed using 0.2 M HCl solutions and the sorbents are re-used for five cycles of sorption/desorption without significant loss in performances.

The effect of using gamma radiation on the prepared activated carbon (AC) from carbon black using dose 500 kGy was studied. Moreover, AC powder were blended in internal mixer to prepare thermoplastic elastomer with percentage (75/25/10) wt% based on waste polyethylene and waste rubber which irradiated before mixing at dose100 kGy separately and AC. Chemical activity of composites was improved as a result of using gamma radiation which was examined by electron spin resonance estimations. Composites were studied by different techniques, such as FTIR, mechanical, thermal, morphology, and X-ray diffraction. The results indicated that optimistic effect of using gamma rays with improving the properties of the composites. J. VINYL ADDIT.

Waste tire rubber was comparatively devulcanized by using two-roll mill mechano-chemical and microwave techniques at room temperature. The former technique was performed utilizing tetramethylthiuram disulfide and mercaptobenzothiazole disulfide. The developed devulcanized elastomer was characterized by scanning electron microscopy, chemical soluble fraction indication, and cross-link density determination. The blend was mixed in two roll mills by replacing a portion of virgin styrene-butadiene rubber (SBR) in a common formulation with the devulcanized waste rubber (DWR) product at various ratios, namely 10, 20 and 50 wt%. The morphological micrographs confirmed marked improvement in compatibility between both rubbery materials. The tensile strength and elastic modulus examinations of the fabricated blends ensured successful substitution of the virgin SBR with DWR. The abrasion resistance of SBR proved unaffected by blending with DWR. The compounded blends were subjected to γ rays at different radiation doses elevated up to 200 kGy and comparatively mechanically investigated.

No abstract

Replacement of virgin polymer with its waste become one of the special technique that capture the efforts of many researchers and industrialists alike. In this context, this work discussed the partial replacement of waste tire rubber (WR) and microwave devulcanized rubber (DWR) at different ratios on the properties of virgin styrene butadiene rubber (SBR) as one of the most essential components of synthetic rubber in the tire production. Fixed percent of tetramethylthiuram disulfide and spindle oil were added at the first, then the WR mixture was exposed to different microwave times. Microwave devulcanization value at time 6 min gave the highest devulcanization percent. The prepared blends were exposed in an electron beam accelerator (EB) at 50 and 100 kGy. FTIR, different mechanical parameters, thermal stability (TGA) and scanning electron microscopy of the fabricated specimens have been explained. Effect of automotive oil and thermal aging at different temperature, 70oC and 100oC on the tensile strength and elongation at break (E%) of the unirradiated and irradiated prepared blends have been estimated. Mechanical measurements of all examined specimens after thermal aging and oil immersion were least affected. Moreover, these factors before and after oil dipping and thermal aging revealed that unirradiated and irradiated SBR/DWR blends have superior properties than SBR/WR.