Effects of curing agents and modified graphene oxide on the properties of XNBR composites. (March 2020)

• Record Type: Journal Article
• Authors: Krzemińska, Sylwia M.; Smejda-Krzewicka, Aleksandra A.; Leniart, Andrzej; Lipińska, Ludwika; Woluntarski, Michał
• Is Part Of: Polymer testing. Volume 83(2020)
• Publication Date: 2020-03
• Subjects: Polymer composites -- Graphene oxide GO -- Barrier properties -- Mechanical properties -- Structure (SEM, AFM, FTIR, DSC) -- Employee protection in the work environment; Polymers -- Testing -- Periodicals; Polymères -- Tests -- Périodiques; 620.1920287
• DOI: 10.1016/j.polymertesting.2020.106368
• Languages: English
• ISSNs: 0142-9418

Abstract

Abstract: This paper investigates the effects of crosslinking methods on the incorporation of graphene oxide (GO) in carboxylated nitrile butadiene rubber (XNBR) in the process of producing nanocomposites for chemical-resistant protective clothing and gloves. The novel aspect of the study is a comprehensive approach involving both unmodified GO as well as GO that was carboxylated to increase its affinity to XNBR and to facilitate its application. The nanostructure of XNBR composites was characterized by scanning electron microscopy (SEM) and atomic force microscopy (AFM). Fourier transform infrared spectroscopy (FTIR) was used to elucidate the chemical structure of the composites. Thermal stability studies were performed using differential scanning calorimetry (DSC). The barrier properties of the composites were determined based on swelling, crosslinking density, and permeation by mineral oils. The mechanical tests included resistance to puncture and abrasion, stress at strain, and tensile strength. Contact angle was measured to determine the degree of hydrophobicity of the obtained composites. AFM and SEM images revealed the effects of different curing agents (sulfur, magnesium oxide, or a hybrid system) as well as GO type on the surface morphology of XNBR composites. The type of curing agent was found to affect the kind of crosslinks formed and their spatial network structure, as confirmed by FTIR. The DSC curves showed that the crosslinking methods of XNBR did not affect glass transition temperature, but led to large changes observed in the temperature range of 130–220 °C. The type of crosslinking method affected the degree of swelling. It was found that the incorporation of carbon nanofillers led to an improvement in the abrasion and puncture resistance as well as tensile strength of XNBR composites. The water contact angle of the composites indicated hydrophobicity. The properties of XNBR composites containing GO revealed their substantial application potential in protective clothing. Highlights: Hybrid crosslinking of XNBR leads to the creation of a dualistic network structure with sulfide bridges and ionic bonds. Unfilled XNBR cured with sulfur only is the most hydrophobic material. Incorporation of GO modified with carboxylic groups to XNBR led to an improvement in mechanical properties. Crosslinking density shows a correlation with degree of swelling and tensile tests. Application of graphene oxide promote surface uniformity of composites.