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Adhesion promoting systems based on 3-aminopropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, N-2-aminoethyl-3-aminopropyltrimethoxysilane, hexamethylenetetramine, m-aminophenol, and silica were added into acrylonitrile-butadiene rubber (NBR) compounds to facilitate improved adhesion to a glass fiber cord. The kinetics of sulfur vulcanization, static and dynamic mechanical properties, surface energy, and adhesion to a glass fiber cord of the rubber compounds were studied. The addition of the adhesion promoters significantly influenced compounds' vulcanization, which resulted in significantly changed mechanical properties of the vulcanizates, while the dynamic properties were impacted only slightly. The surface energy measurement results were not in line with the final adhesion test results, which were most likely caused by the effect of acrylonitrile monomer units of NBR orientation toward the bulk of the compound. In consequence, the results indicated a lowering of the surface energy of the samples containing the adhesion promoters, whereas the pull-out test of the glass cord showed a significant improvement of the compounds' adhesion. The most effective adhesion-promoting system consisted of hexamethylenetetramine, m-aminophenol, and silica resulting in an over 300% increase of the adhesion force in comparison to unmodified NBR. [ABSTRACT FROM AUTHOR]

In modern polymer industry, there still is a room for new generations of fillers capable of enhancing the performance of composite materials. Currently, much effort is being put into a process of improving mechanical properties of elastomer materials. In this work, multiwalled carbon nanotubes (MWCNTs) and graphene nanoplatelets (GnPs) were modified with silane, titanate, or zirconate using plasma treatment, in order to apply them as fillers for styrene/butadiene rubber. Following its modification, filler surface was analyzed: Surface free energy (SFE) was measured with tensiometry, and micromorphology and chemical composition were studied with scanning electron microscopy–energy-dispersive spectroscopy (SEM–EDS), while elemental composition and bonding were assessed with X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS). Low-temperature oxygen plasma activation of MWCNT fillers leads to a significant increase in the SFE polar component, with the same effect being much weaker for GnP fillers. Grafting silanes, zirconates, and titanates on activated filler surface results in a decrease in SFE polar component—surface oxygen-containing active groups react with silane/zirconate/titanate molecules. Fillers modified in this way exhibit different micromorphology and surface chemical composition what is revealed with the SEM–EDS, ToF-SIMS, and XPS techniques. As the ultimate step, either MWCNT or GnP rubber nanocomposites were manufactured using the modified fillers with their mechanical properties and cross-link density being studied. Filler modification resulted in substantial changes both in composite performance, and in its cross-linking density. In the case of modified filler containing composites, improved tensile strength and elongation at break were observed. [ABSTRACT FROM AUTHOR]

The aim of this work is to describe the changes in the properties of ceramifiable silicone rubber-based composites caused by the incorporation of novel alternative minerals in comparison to other popular, widely utilized fillers. TiO2, calcined kaolin and calcium-based minerals mix (CbMix) consisting of CaO (6.26 wt%), CaCO3 (26.18 wt%) and Ca(OH)2 (67.56 wt%) have not been considered as a dispersed phase of ceramifiable silicone composites destined for wire covers yet. Mineral fillers: TiO2 (anatase), mica (phlogopite), CbMix, CaCO3, Al(OH)3, kaolin and calcined kaolin affect the processing and the various properties of silicone rubber-based composites destined for wire covers differently. The properties—flammability, smoke intensity, micromorphology and mechanical durability after ceramification—are assessed by measuring: the kinetics of vulcanization, stress at different levels of elongation, tensile strength and the elongation at break of the materials. Although the curing process of the composites is disturbed by the addition of CbMix, it benefits from an increase in oxygen index value, which reaches 31.4%. What is more, also its flammability parameters measured by cone calorimetry improve, such as the total heat released (THR) reaching 9.3 MJ/m2. Samples containing kaolin and calcined kaolin exhibit the best mechanical properties before ceramification, whereas composites filled with calcium-based powders (CbMix, CaCO3) mechanically display the strongest mineral char after heat treatment, possibly due to a more homogenous micromorphology and the creation of calcium silicates at elevated temperature. Significant amounts of wollastonite, parawollastonite and pseudowollastonite are visible in their structure after ceramification. [ABSTRACT FROM AUTHOR]

The paper presents the test results of the effect of modified graphene and multi-wall carbon nanotubes on the thermal and mechanical properties and flammability of acrylic rubber and styrene-butadiene rubber. The rubbers were cross-linked with the use of organic peroxide. Based on the test results obtained by optic and AFM methods, a relationship between the surface morphology of the nanocomposites obtained was presented. By means of thermal analysis methods (TG, DTG, DTA) and a micro-calorimeter, it has been found that the nanofillers used considerably increase the thermal stability and decrease flammability of the nanocomposites. The mechanical properties of the elastomeric materials obtained depend on the type and content of nanofiller. [ABSTRACT FROM AUTHOR]