Rhodanine‐chitosan hydrogel as a novel antioxidant for acrylonitrile‐butadiene rubber composites

Abstract

Rhodanine‐chitosan (RC) hydrogel is examined as a novel antioxidant for acrylonitrile‐butadiene rubber (NBR) composites. RC is added to NBR with different proportions (1, 2 phr) and compared to the commercial 2,2,4‐trimethyl‐1,2‐dihydroquinoline polymer (TMQ) antioxidant. Physico‐mechanical properties including tensile strength, elongation, and modulus are also studied. It is found that NBR composite containing 2 phr of RC has the most favorable mechanical properties. The formed composites were subjected to thermo‐oxidative aging at 90°C for 1, 3, and 5 days. It is noticed that NBR composite containing 2 phr of RC is the most resistant to aging. Swelling properties and crosslink density are also determined. Composite containing 2 phr of RC has also higher crosslink density than the other prepared composites. The formed NBR composites containing both TMQ and RC are characterized by Fourier transforms infrared (FTIR), thermogravimetric analysis (TGA), and field emission scanning electron microscope (FESEM). The effect of aging on chemical structure of the composite and on surface morphology are also studied. It is found that the chemical structure of the composites containing 2 phr of RC is not affected by aging.Highlights Rhodanine‐chitosan (RC) is assessed as a new antioxidant for acrylonitrile‐butadiene rubber (NBR). RC is incorporated into NBR at two different concentrations: 1 and 2 phr. Mechanical, thermo‐oxidative aging, and swelling properties are evaluated. Thermal stability, Fourier transforms infrared and field emission scanning electron microscope are studied. Vulcanizates with 2 phr of RC show the most superior properties.

Investigation of novel polyanilines as new antioxidants for ethylene propylene diene monomer rubber composites

“…Swelling of the prepared EPDM composites before and after aging was done in toluene for 24 h according to ASTM D573-2007. Molecular weight between two crosslinks (Mc) was determined using swelling data by applying Flory-Rehner equation according to the following relation 19 :…”

Preparation of chitosan‐based macromolecular synergistic antioxidants containing hindered phenolic and secondary amine structures and its effects on thermo‐oxidative aging of styrene‐butadiene rubber/silica composites

“…For example, Xie et al 22 synthesized a macromolecular antioxidant CS‐UC‐GA containing amide, carbon–carbon double bond, and phenolic hydroxyl group by grafting 10‐undecylenoyl chloride (UC) and gallic acid (GA) into chitosan (CS), and found that CS‐UC‐GA with superior extraction resistance could endow styrene‐butadiene rubber (SBR)/SiO 2 composites with better thermo‐oxidative aging resistance. The utilization of CS as a matrix and its chemical modification as a macromolecular antioxidant can broaden the application of CS and promote the development of the rubber industry, as well as help to make full use of resources and protect the environment 23 …”