Migration of Paraffin Wax to Sulfur Vulcanized Styrene–Butadiene Rubber (SBR) Surface: Effect of Temperature

Torregrosa-Coque, Rafael; Álvarez-García, Sonia; Martı́n-Martı́nez, José Miguel

doi:10.1163/016942411x580027

Cited by 9 publications

(11 citation statements)

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“…Earlier work showed the effect of electric charges formed during repeated deformations on the fatigue resistance of vulcanized rubber [23], but the literature on rubber fatigue is usually silent on electrostatic phenomena [24][25][26][27][28]. Electrostatic charging features are even less understood for rubber than for other dielectric materials.Electrostatic charging is usually dependent on the materials surface properties, and rubber surfaces show great variation and complexity [29] that is further increased by various surface treatments, exudates [30], oxidation [31] thermal damage [32], and aging. Rubber surfaces may change rapidly in response to changes in the outer environment, due to fast molecular motion at polymer surfaces above the glass transition temperature [33].…”

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confidence: 99%

“…Electrostatic charging is usually dependent on the materials surface properties, and rubber surfaces show great variation and complexity [29] that is further increased by various surface treatments, exudates [30], oxidation [31] thermal damage [32], and aging. Rubber surfaces may change rapidly in response to changes in the outer environment, due to fast molecular motion at polymer surfaces above the glass transition temperature [33].…”

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confidence: 99%

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Rubber Surface Change and Static Charging under Periodic Stress

Santos

Campo

Silva

et al. 2018

Colloids and Interfaces

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Rubber materials play an important role in robotics, due to their sensing and actuating abilities, that are exploited in soft smart materials endowed with shape-adaptive and electroadhesive properties. The application of an electric field produces non-linear deformation that has been extensively modelled, but is not understood at the molecular level. The symmetric effect (the production of an electric field due to rubber deformation) was recently discovered and explained as follows: rubber surface chemical composition and adsorptive properties change during rubber deformation, allowing the surface to exchange charge with the atmosphere. The present work describes the complex surface morphology and microchemistry of tubing made from vulcanized natural rubber, showing that it is rough and made from two domain types: stiffer elevations containing Br or Al (depending on the sample used) and O, that rise above an elastic base that is exempt of elements other than C and H. The surface area fraction occupied by the elastic base is higher in the strained rubber than when it is relaxed. Electrostatic potential on rubber surfaces was measured as a function of the stretching frequency, using Kelvin electrodes and showing frequency-dependent potential variation. This is explained considering charge exchange between the atmosphere and rubber surface, mediated by water vapor adsorbed in the stretched rubber and trapped when it relaxes.Colloids Interfaces 2018, 2, 55 2 of 11 of rubber performance in many important situations, but this does not benefit from knowledge on the molecular mechanisms of the observed phenomena.Recent work from this group described a new finding on the electrostatic behavior of elastomers: in short, rubber tube stretching, followed by relaxation, provokes the appearance of transient excess charge that is more pronounced under higher relative humidity [14]. This effect is not related to any existing electrostatic charging phenomenon (piezoelectricity, flexoelectricity, triboelectricity, and contact charging) and a new mechanism was then proposed to explain charge pick-up and dissipation by stretched elastomers, as the result of water adsorption and the partition of water ions (H + and OH − ) in the rubber-air interface, due to periodic rubber surface modification.Other unexpected findings on electrostatic phenomena in dielectrics have been described recently, leading to a revision of widespread ideas on electrostatic charging and its mechanisms [15]. Important aspects of electrostatic phenomena are not well understood [16][17][18], but tribo-and piezoelectricity are important sources of the electrostatic potentials detected in anthropic environments, often reaching many-thousand volts. They are currently used in nanotribogenerators, with great success. This is creating new opportunities for energy scavenging [19][20][21], and it is probably relevant to the prevention of harmful electrostatic discharge.Knowledge of the electrostatic behavior of elastomers is more limited than in the case of semicrystallin...

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confidence: 99%

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confidence: 99%

Rubber Surface Change and Static Charging under Periodic Stress

Santos

Campo

Silva

et al. 2018

Colloids and Interfaces

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“…At lower temperatures, the diffusion process of paraffin is inhibited, and the internal stress can be maintained for a long time, so the initial secretion rate and the decay process are slow, and the paraffin stock and secretion rate remain high in the later stage (Figure S15). − Summarizing the above results, we can regulate the autocrine rate of AWMs by adjusting the ambient temperature and the sample thickness. In addition, we reloaded the used AWM with internal stress and waxiness by reswelling the paraffin in a paraffin bath at 80 °C for 12 h (Figure S16).…”

Section: Resultsmentioning

confidence: 80%

“…The heat source is close to the AWM surface, and heat is transferred into the sample through contact heat transfer, radiation heat transfer, etc., which increases the temperature of the area near the heat source, thereby increasing the diffusion rate of paraffin molecules in this area. 42,48 Figure 3b shows that increasing the temperature increases the wax secretion rate at an early stage. The temperature gradient gradually disappears under the entropy increase rule.…”

Section: Surface Structure Characteristics Of Awms Under Thermal Stim...mentioning

confidence: 98%

Multi-stimulus Response Behavior of Biomimetic Autocrine Waxy Materials for Potential Self-Constructing Surface Microstructures

Yan,

Liu,

Lan

et al. 2023

ACS Appl. Mater. Interfaces

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Many functions of terrestrial plant leaves rely on the regenerable epidermal wax layer. Biomimetic autocrine waxy materials (AWMs) inspired by renewable epidermal waxes are attracting increasing attention. However, the growth properties of the wax layer remain unclear, limiting the development of this promising material. This work focuses on the stimulated growth characteristics and microstructural regulation methods of the waxy layers. It is found that the wax layers exhibit a corresponding behavior of changing their surface micromorphology under force, heat, solvents, and other stimuli during the self-growth process, and as a result of which, various types of fine surface microstructures such as grids, rings, stripes, pattern copying, and printing can be self-built on their surfaces. The composition of the surface autocrine wax layer changes with the autocrine time, and this finding may be useful for the separation and purification of alkane mixtures. In addition, the surface wax layer possesses the ability to self-heal and strengthen itself at the damage site after being stimulated by injury, similar to the damage-response behavior of a bark surface. Such multi-stimulus response behavior described here provides a platform for the discovery of more functional materials and microstructural self-construction techniques and can also serve as a basis for their applications.

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“…Natural rubber (NR) is a type of elastomer known for its low gas diffusion and compression set, high tensile strength, and good flexibility, electrical properties, wet grip, wear and tear resistance, oil resistance, and rolling resistance [1,2]. These properties lead to many industrial applications of rubber in mining, medicine, agriculture, footwear, paper, textile, adhesive, and automobile industries [3,4]. To achieve the physical properties of rubber for a specific application, NR are compounded and cured by vulcanization with cross-linking agents, accelerators, activators, fillers, anti-degradants, processing aids and surfactants [3][4][5][6][7][8][9][10][11][12].…”

Section: Introductionmentioning

confidence: 99%

Ambient Blooming Behavior and Mechanical Properties of Vulcanized Natural Rubber Loaded with Non-Ionic Surfactants

Santiago

Pajarito

Aparre

et al. 2016

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This study investigated the ambient blooming behavior of additives and mechanical properties of vulcanized natural rubber (VNR) loaded with non-ionic surfactants coco diethanolamide (CDEA) and glycerol monostearate (GMS). Taguchi method and analysis of variance (ANOVA) were used to determine the significant main effects of additives on bloom rates and mechanical properties of VNR. Attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) spectra of VNR surface confirm the presence of chemical functional groups of stearic acid, paraffin wax, used oil, CDEA, and GMS. The amount of bloom (MB) versus square root of time (t1/2) plot yields two linear regions corresponding to distinct bloom rates which suggest that the blooming behavior of additives follows a non-Fickian mechanism. High loadings of stearic acid, used oil, and paraffin wax increase the bloom rates due to migration of excess unreacted additives to the surface of VNR. Also, additives easily diffuse out of the VNR due to softening of the rubber matrix. High loadings of sulfur and CDEA consistently decrease the bloom rates because of the increase in crosslink density and increase in filler dispersion, making it difficult for additives to bloom out of rubber matrix. High loading of sulfur significantly improves the tensile and compression moduli of VNR. Meanwhile, high loadings of ZnO and used oil significantly decrease the tensile and compression moduli of VNR. Sulfur as a crosslinking agent increases the crosslink density which resulted to increase mechanical properties. Excess used oil and zinc stearate, reaction product of ZnO and stearic acid, on the VNR matrix resulted to rubber matrix softening and decrease in mechanical properties.

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Migration of Paraffin Wax to Sulfur Vulcanized Styrene–Butadiene Rubber (SBR) Surface: Effect of Temperature

Cited by 9 publications

References 1 publication

Rubber Surface Change and Static Charging under Periodic Stress

Rubber Surface Change and Static Charging under Periodic Stress

Multi-stimulus Response Behavior of Biomimetic Autocrine Waxy Materials for Potential Self-Constructing Surface Microstructures

Ambient Blooming Behavior and Mechanical Properties of Vulcanized Natural Rubber Loaded with Non-Ionic Surfactants

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