Improvement In Tear Strength Research Articles

The effect of silane‐modified carbon black and nano‐silica, individually and in combination, on the performance of ethylene–propylene–diene monomer rubber

AbstractThis study assesses the effectiveness of a specially developed surface‐modified carbon black, both on its own and in combination with nano‐silica, as a hybrid filler for ethylene–propylene–diene monomer (EPDM) rubber compounds. The modification process, which included treatment with a silane coupling agent, resulted in enhanced curing characteristics. The ∆Torque values for compounds incorporating the modified carbon black exceeded those of other formulations by 25.85%. Scanning electron microscopy (SEM) analysis demonstrated improved filler dispersion and better compatibility between rubber and filler due to the surface modification. The silane‐modified carbon black showed considerable enhancements in mechanical properties, particularly in tear resistance, with increases in tensile and tear strength of 22.46% and 34.86%, respectively, following surface treatment. Dynamic mechanical analysis (DMA) indicated the influence of both surface modification and filler type, revealing that the combination of modified carbon black and nano‐silica achieved a reduction in rolling resistance of 20.41% and enhanced ice and wet grip performance by 7.95%. Additionally, modified carbon black displayed varying effects on the glass transition temperature. Thermal gravimetric analysis (TGA) confirmed that the thermal stability of the compounds was consistent, while solvent resistance improved with surface modification, as shown by swelling ratios. Thermodynamic analysis indicated that the surface modification of carbon black positively influences the elasticity and chain mobility of the rubber compounds studied. In conclusion, the careful selection and optimization of filler materials and their modifications are essential for customizing the properties of rubber compounds to satisfy specific performance criteria and applications.Highlights Promising EPDM compounds were prepared with Silane‐Modified CB and Nano‐Silica. Silane‐modified CB effectively improved the curing properties of the EPDM compound. The ΔTorque and cross‐link density of modified CB/EPDM show the highest value. Modified CB/Nano‐Silica/EPDM exhibited significant improvement in tear strength. Modified CB/Nano‐silica/EPDM have lower rolling resistance and higher wet grip.

Nylon 66 short fiber reinforcement in EPDM power transmission belting: A path to enhanced mechanical performance

AbstractV‐belts are commonly used to transmit power between two distant pulleys. Therefore, a strong reinforcement for dimensional stability and thermomechanical properties are essential in power transmission belts. The influence of resorcinol formaldehyde resin (RFL) treated nylon short fibers in EPDM peroxide‐cured formulations was investigated, with concentrations ranging from 0 to 30 parts per hundred rubber (phr) in increments of five. The incorporation of nylon short fibers resulted in improved tensile and mechanical properties in EPDM vulcanizates. Specifically, the tensile stress at 100% elongation increased by 177% to (10.8 MPa), and the improvement in tear strength to 16.2% (75.7 N/mm) was observed. Among other functional requirements in a weak rubber like EPDM, enhanced tear strength is significant for its application in power transmission. Substantial reinforcement between the fiber‐elastomer matrix was confirmed via scanning electron microscopy, as evidenced by increased storage modulus (E′). Notably, there were no considerable effects on the curing rate or low‐temperature properties. Significant improvement in heat stability is observed through thermogravimetric analysis. These enhancements in mechanical and thermal properties might play a role in increased durability and performance in actual V‐ribbed belt applications.Highlights This manuscript describes the effect of treated nylon 66 short fiber on EPDM V‐belt compound. A significant increase in storage modulus, tear strength, and thermal stability. A belt is made using the experimental formulation and it meets the performance requirement. Low fiber content (<15 phr) compounds are unsuitable for dimensional stability. High fiber content (>25 phr) compounds pose processing challenges.

Synergistic effect of Tween 20 and TESPT compatibilizers on the performance characteristics of latex imprinted silica-reinforced green tyre tread formulation

The present study has a prime goal to develop a green tyre tread formulation with enhanced performance characteristics including low rolling resistance, improved wet grip, low heat build-up and enhanced mechanical properties which are essential for a high-performance tyre tread compound. A base formulation of natural rubber/polybutadiene (NR/BR) blend with minimum carbon filler was formulated initially without compromising the physical properties much by balancing the properties by incorporating precipitated silica. Enhanced surface area for silica was obtained through the latex imprinting method which had an ultimate effect on the interaction between the matrix macromolecules and filler particles positively. Further, ENR was used as a compatibilizing agent to upgrade physical properties in terms of 20% improvement in tensile and around 10% improvement in tear strength. Additional improvement in physical as well as rolling resistance performance was achieved via the incorporation of coupling agents including TESPT and polyoxyethylene(20) sorbitan monolaurate (Tween 20). Apart from the improvement in mechanical properties, rolling resistance and heat build-up properties are promising for the final tyre tread formulation as both the values tend to reduce considerably by 35% and 63% respectively concerning the base formulation.

Achieving ultra-tear resistant high-performance natural rubber nanocomposite via bio-inspired lignocellulosic compatibilization

Elastomers which are strong, tough, and resistant to tearing, are highly attractive for engineering applications such as conveyer belts, high-performance seals, tires, and soft robotics. Enhancing these properties for natural rubber materials is possible by utilizing nanoscale fillers, however the nanocomposite approach remains challenging because (a) nanofillers can impede latex molecular crosslinking, and (b) reduce the material’s inherent elasticity and compliance. This study demonstrates an approach to prepare ultra-strong, tear-resistant natural rubber nanocomposites using cellulose nanofibers decorated with nanoscale lignin. The reinforcement of latex with 0.1 wt% cellulose nanofibre compatibilized with 0.5 wt% lignin resulted in a 256% improvement in tear strength, 95% in tensile strength, and 50% in toughness, while retaining the elongation at break. Such a simultaneous improvement in tensile and tear properties has not been previously achieved through the latex casting method with any other fillers, and herein it is attributed to the nanoscale reinforcement efficiency of nanofibre coupled with enhanced interfacial adhesion between nanofibers and NR latex with the introduction of nanoscale lignin. This compatibilization approach has also resulted in improved resilience in the nanocomposites, as evidenced by the cycling loading and unloading analysis.

Evaluation of mechanical properties and cytotoxicity of maxillofacial silicone material after incorporation of zirconia nanopowder

Abstract Resilient polymeric materials such as silicone elastomers are currently used for maxillofacial prostheses construction but the strength of these materials and their clinical performance need to be optimized with the addition of reinforcing fillers. This study investigates the effect of zirconia nanopowder addition on tear strength, tensile strength, elongation at break, Shore A hardness, surface roughness and cytotoxicity of VST-50 maxillofacial silicone. Silicone base was mixed with different amounts (1%, 2% and 3%) of zirconia nanopowder using a vacuum mixer. Silicone without filler was used as control for comparison. Scanning Electron Microscopy and Atomic Force Microscopy were utilized to assess the efficiency of high-shear vacuum mixing as filler dispersion method and the surface topography, respectively. Both SEM and AFM images showed that the zirconia nanopowder were distributed fairly well within the polymer. Statistically, highly significant increase in tear strength, tensile strength and hardness with non-significant decrease in elongation at break and non-significant increase in surface roughness were seen with 1% and 2% groups. Whereas with 3% group, there was significant improvement in tear strength, tensile strength and hardness but there was significant undesirable decrease in elongation and increase in roughness. Cytotoxicity test revealed that the addition of zirconia nanopowder was nontoxic to Rat Embryonic Fibroblast (REF) cells and there was non-significant change in the cell viability of all study groups after 24- and 72-hours incubation periods. In conclusion, the addition of 2% by weight nano zirconia to VST-50 maxillofacial silicone could be beneficial in enhancing its performance.

Impact of soft segment size on physicochemical and antimicrobial properties of waterborne polyurethane dispersions for textile applications

The waterborne polyurethane dispersions (WPUDs) have substituted solvent borne systems due to strong environmental concerns. In this study, a series of WPUDs synthesized to evaluate the impact of size of soft segment (Polyethylene glycol; PEG) on their properties. The Fourier Transform Infrared spectroscopy (FTIR), dynamic light scattering, rheometer and gravimetric determination of total solid content were used to assess the physicochemical properties of dispersions. The appearance of characteristic NH and CO urethane bands in FTIR spectra demonstrated the proposed synthesis of WPUDs. An increase in the molecular weight of hydrophilic soft segment ensued a decrease in average particle size of dispersions along with a parallel increase in viscosity and total solid content of dispersions. The textile testing and SEM analyses supported the finishing of cotton fabric with slight improvement in tear strength. However, no significant correlation was observed between tear strength and size of soft segment. Furthermore, the dispersions showed antimicrobial activity against gram −ve and +ve bacteria though the effect was diminishing with increase in the molecular weight of soft segment.

Structural variation in soft segment of waterborne polyurethane acrylate nanoemulsions

ABSTRACTHigh solid content waterborne polyurethane acrylate (WPUA) nanoemulsions are prepared as textile finishes. Two structurally different soft segments, that is, polyether and polyester are used with isophorone diisocyanate, 2‐hydroxyethyl methacrylate, and butyl acrylate. Structural variations are investigated in features of nanoemulsions and their coatings. Physical properties of nanoemulsions, such as average particle size, stability, solid content, and viscosity, are investigated. Nanoemulsions with high solid content, that is, 40–47% are produced without any internal emulsifier. Average nanoparticle size, that is, <100 nm is confirmed by dynamic light scattering and atomic force microscopy (AFM). Fourier transform infrared spectroscopy proved synthesis of proposed WPUA products. Synergistic effect of polyurethane and acrylate is observed in chemical and water resistance of WPUA. Differential scanning calorimetry (DSC) and thermogravimetric analysis indicate stable uniformly cross‐linked network of WPUA. Application of nanoemulsions on 100% cotton fabric shows a significant improvement in tear strength, which is more pronounced for polyester‐based WPUA. Scanning electron microscope images of treated fabric samples show good adhesion of nanoemulsions on cotton surface. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41706.

Nanoclay Reinforcement of Liquid Silicone Rubber

Siloxane modified montmorillonite clay was prepared from sodium montmorillonite and quaternary ammonium-containing siloxane surfactant. X-ray diffraction and Fourier transform infrared analyses indicated that the polysiloxane oligomer chains were successfully grafted onto the surface of the montmorillonite clay platelets. The siloxane modified montmorillonite clay and commercial organo-modified montmorillonite and bentonite clays were incorporated into a rapid-cure liquid silicone rubber (LSR) matrix. The morphologies of the LSR/nanoclay composites were analyzed by SEM and TEM, and partial exfoliation of the silicate nanolayers of the clay platelets was observed. Up to a 20% reduction in water vapor permeability was achieved as well as a 24% improvement in tear strength and a 40% improvement in the compression set.

Alloying of poly(vinyl chloride) to reduce plasticizer migration

AbstractConcern over the migration of low molecular weight plasticizer from flexible poly(vinyl chloride) (PVC) used in toys and medical products has spearheaded the commercialization of a number of plasticizing polymers. In this study the plasticizing behavior of an ethylene/vinyl acetate/carbon monoxide terpolymer (Elvaloy® from DuPont) was investigated. Blends of PVC, Elvaloy 742, and dioctyl phthalate (DOP) were processed on a twin‐roll mill and compression molded into plaques. These materials were characterized in terms of their hardness, glass‐transition temperature (Tg), clarity, mechanical properties, and plasticizer migration behavior. The ratios of PVC/DOP/Elvaloy investigated were determined by experimental design. Using this approach it was possible to model the results and produce contour plots to map out the properties of a wide range of formulations. It was confirmed that Elvaloy 742 is compatible with PVC and has a plasticizing effect: this was demonstrated both in terms of a reduction in Shore A hardness and a reduction in Tg. Plasticizer migration was reduced in proportion to the amount of liquid plasticizer replaced. Plasticizing with Elvaloy gave an improvement in tear strength. However, at constant hardness there was no improvement in tensile strength from replacing DOP with Elvaloy. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 2022–2031, 2004

Characterization of Immiscible Elastomer Blends

Abstract Considerable improvements have been made in the analysis of elastomer blends for composition, morphology and filler inter-phase distribution. GC, IR, NMR and thermal analysis (DTG, DSC, TG) techniques can provide quantitative information on composition. The latter three methods, along with SAXS, SANS, DMTA and microscopy (LM phase contrast, TEM, SEM, AFM) are also useful for resolving differences in blend homogeneity. The microscopical techniques are the most useful for characterizing morphology. TEM, in conjunction with cryosectioning and staining techniques, has provided the best means of resolving filler distribution to date. However, new AFM scanning modes may provide improved analyses in the future. Carbon black inter-phase distribution in blends of NR, SBR and BR can be controlled reasonably well by blending Banbury mixed masterbatches containing the desired carbon black loading in each polymer. Transfer of carbon black from one elastomer to another is favored by low unsaturation for the polymer originally containing the black, or a low heat history (e.g. solution and latex mixing) during preparation of the masterbatch. The overall polymer interaction with carbon black increases in the order: IIR, EPDM, NR, BR, SBR, the latter two being fairly close. Commercial carbon blacks will transfer extensively from an IIR Banbury masterbatch to NR, but not from EPDM to NR. Significant transfer to SBR occurs from both IIR and EPDM. Inert (partially graphitized) carbon blacks tend to distribute more evenly between the blend components regardless of which polymer contained them initially. Carbon black phase distributional variations can cause significant changes in unvulcanized and vulcanized rubber properties. For NR/BR and NR/SBR blends, reduced hysteresis generally occurs with a higher carbon black loading in the NR phase. Tear strength and cut growth tend to be maximized with higher carbon black in the continuous polymer phase, particularly when that phase is the higher strength polymer. The smaller the carbon black particle size, the greater the improvement in tear strength as a function of phase distribution. NR/BR fatigue life was maximized with about an equal distribution of carbon black in each polymer. This type of carbon black distribution also produced the greatest resistance to ozone cracking for NR/EPDM blends, which were further improved with very small domain size for the EPDM (disperse) phase. The abrasion resistance of NR/BR blends has indicated some improvement in the direction of higher carbon black in the BR. These results have been variable, however, and further study is needed for clarification.