Fast Extrusion Furnace Research Articles

Multiphase modeling of pressure-dependent hydrogen diffusivity in fractal porous structures of acrylonitrile butadiene rubber-carbon black composites with different fillers

The hydrogen diffusivities of acrylonitrile butadiene rubber (NBR) composites with different types and contents of carbon black (CB) fillers were investigated in the exposure pressure range of 0.5–10 MPa using a volumetric analysis system. These measured diffusivities exhibited distinct pressure-dependent behavior. The diffusivities of unfilled NBR and NBR composites containing medium-thermal CB filler decreased from 39.7 × 10−11 m2/s to 9.4 × 10−11 m2/s as the pressure increased. On the other hand, the pressure-dependent diffusivities of NBR composites containing high-abrasion furnace, fast-extrusion furnace and semireinforcing furnace CB fillers revealed left-biased unimodal shaped curves, with peak values ranging from 19.7 × 10−11 m2/s to 5.6 × 10−11 m2/s. To model this observed behavior, the diffusion resistance theory with a heterogeneous NBR–CB composite and a fractal porous structure for H2 was introduced. The theoretical parallel diffusion resistance model was found to coexist independently as the surface, Knudsen, and bulk diffusion phases. This theoretical multiphase modeling was applied to the measured diffusivities, determining diffusion resistance parameters for each phase. The obtained individual parametric characteristics for each diffusion were interpreted by considering the CB filler content and volume fraction of the filler. As a result, the diffusivities calculated by multiphase diffusion modeling were in quite agreement with the measured diffusivities for all investigated specimens, where the determined squared correlation coefficient (R2) by fitting process was in the range from 0.69 to 0.97.

Synergistic effect of fast extrusion furnace (FEF) black on viscosity and rheological properties of ethylene propylene diene monomer vulcanizate

An investigation is made on vulcanizates based Ethylene propylene diene monomer (EPDM) rubber which is prepared by incorporating 30 phr of cellulose short fibres along with different loading levels of fast extrusion furnace black (FEF) at an increment level of 20 phr in two roll mill. EPDM rubber was found as an attractive candidate for the thermal insulation of case-bonded SRM due to the advantages such as low specific gravity, improved ageing properties, and longer shelf life. This research provides theoretical and experimental characterisation for the friction behaviours of EPDM rubber. The effect of FEF on viscosity and rheological properties of various EPDM compounds such as C1–C8 were fairly investigated using the Monsanto moving die Rheometer (MDR 2000), and Mooney viscometer. The curing characteristics like TS2, TS5, ML, MH, cure time (TC90), and viscosity of various EPDM compounds were extensively determined and the results were critically compared. It was fairly observed that the reinforcement of FEF along with cellulose short fibres in the EPDM compounds has made a greater impact on improving the rheological properties and showed the synergistic effect between the fillers and the rubber matrix. The increase in temperature causes a decrease in the friction coefficient.

Coconut shell powder as cost effective filler in copolymer of acrylonitrile and butadiene rubber

Filler is one of the major additives in rubber compounds to enhance the physical properties. Even though numerous benefits obtained from agricultural by products like coconut shell, rice husk etc., still they constitute a large source of environmental pollution. In this investigation, one of the agricultural bye product coconut shell powder (CSP) is used as filler in the compounding KNB rubber. It shows the positive and satisfied result was achieved only by the use of filler Fast Extrusion Furnace (FEF) and coconut shell powder (CSP) which was used 50% in each. The effect of these fillers on the mechanical properties of a rubber material at various loading raging from 0 to 60PHP was studied. Mercaptodibanzothiazole disulphide (MBTS) was used as an accelerator. The result shows that presence of 25% and 50% of the composites has better mechanical properties like Hardness, Tensile strength, Elongation at break and Specific gravity when compared with other two combinations. Even though both 25% and 50% of composites shows good mechanical properties, 50% of CSP have more efficient than 25% of CSP.

STUDIES ON BOUND RUBBER OF CB BEFORE/AFTER VULCANIZATION OF ISOPRENE RUBBER

ABSTRACT The high abrasion furnace (HAF), fast extrusion furnace (FEF), and fine thermal (FT) loadings used in this study were adjusted to keep the carbon black (CB)–specific area of cetyl trimethyl ammonium bromide adsorption to 2490 m2g−1. Their polyisoprene (IR) compounds and vulcanizates were investigated. Regarding the dependence of the CB gel fraction (FCB gel) on the IR gel/CB weight ratio (WRIR/CB), the amount of CB in the CB gel increased with a larger CB aggregate size, whereas the amount of the IR gel decreased. With regard to the dependence of the activation energy (ΔE(T2)) of the spin–spin relaxation time (T2) on the CB aggregate size, an immobilized rubber layer around CB formed more easily in the order of FT < FEF < HAF. Moreover, it became clear from the relationship between WRIR/CB and ΔE(T2) that the amount of the IR gel in the CB gel increased with decreasing ΔE(T2). The unique ratio of the surface area to the volume of CB aggregates (SCB/VCB) was obtained from results of three-dimensional transmission electron microscopy observation. The dependence of the amount of dibutyl phthalate (DBP) adsorption and compressed DBP adsorption on SCB/VCB was approximately linear, which suggested that SCB/VCB was closely related to CB aggregates and CB agglomerates. The linear relationship seen between SCB/VCB and ΔE(T2) revealed that an immobilized rubber layer was present around CB. The dependence of (qCB/qIR)(WRIR/CB) on SCB/VCB was also investigated using the densities (ρIR and ρCB) of IR and CB. The slope (tirl) of their approximately linear relationship was about 3.9 nm, which almost agreed with the bound rubber thickness reported in the literature to date. It is also inferred that because the intercept (α), which reflects the change in the IR gel weight fraction, was about 0.04 (4%), the IR gel weight fraction changed very little between before and after vulcanization.

Mechanical and swelling properties of thermoplastic elastomer blends

The mechanical behavior, microhardness and abrasion resistance of acrylonitrile butadiene rubber (NBR) vulcanizate loaded with 40 phr fast extrusion furnace (FEF) carbon black nanopowder and different concentrations of suspension polymerization polyvinyl chloride (PVC) were studied. The measured parameters (i.e., the Young’s modulus, tensile strength, and elongation at break) varied with the concentration of PVC. Both the elastic modulus and the tensile strength increased with increasing PVC loadings while the elongation at brake recorded a linear decrease. The hardness degree and the abraded mass increased as the concentration of PVC increased. The classical theory of rubber elasticity was used to calculate the rubbery modulus, the number of effective chains per unit volume and the average molecular weight. Swelling measurements were done on the mentioned samples. Addition of PVC was found to decrease the maximum degree of swelling, the penetration rate and the average diffusion coefficient. Swelling was found to slightly affect the degree of hardness and elastic modulus.

Butadiene acrylonitrile rubber loaded fast extrusion furnace black as a compressive strain and pressure sensors

Electrically conductive acrylonitrile butadiene rubber (NBR) compounds filled with different concentrations of fast extrusion furnace black (FEF) were experimentally investigated. The percolation concentration of the investigated composites was found to be 65 phr. Of all composites examined, sample N70, which apparently belonged to the region of percolation phase transition, was found most sensitive to compressive strain. The electrical conductivity of this sample was changed by more than 50% upon a 16% compression. Sample N70 showed a good reproducibility after preconditioning rather than before preconditioning. The piezo-resistive effects practically are thermally stable within the interval of 297–308 K. The working range of load pressure, for sample N70, from 5 to 25 kg and the working voltage from 30 to 150 V.

The effect of heating–cooling cycles on PTCC and NTCC made of FEF/NBR composites

AbstractElectrically conductive acrylonitrile butadiene rubber compounds filled with different concentrations of fast extrusion furnace black were experimentally investigated. The percolation concentration of the investigated composites was found to be 65 phr. Samples below percolation concentration are PTCC and above percolation concentration are NTCC. Sample N70 that belongs to the percolation concentration exhibits NTCC and PTCC. The effect of heating–cooling cycles shows that samples with high concentration have small hysteresis compared with low concentrations. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2837–2842, 2007

The mechanical behaviour of NBR/FEF under compressive cyclic stress–strain

Acrylonitrile butadiene rubber compounds filled with different concentrations of fast extrusion furnace (FEF) carbon black were experimentally investigated. The stress–strain curves of the composites were studied, which suggest good filler–matrix adhesion. The large reinforcement effect of the filler followed the Guth model for non-spherical particles. The effect of FEF carbon black on the cyclic fatigue and hysteresis was also examined. The loading and unloading stress–strain relationships for any cycle were described by applying Ogden's model for rubber samples. The dissipation energy that indicates the vibration damping capacity for all samples was determined. A simple model was proposed, to investigate the relation between maximum stress and the number of cyclic fatigue.

Studies of electrical and mechanical properties of poly(vinyl chloride) mixed with electrically conductive additives

AbstractDifferent samples of poly(vinyl chloride) (PVC) compositions were formulated from PVC, a polar plasticizer such as dioctylphthalate (DOP), and variable proportions of electrically conductive additives such as fast extrusion furnace (FEF) carbon black (CB), poly(vinylpyridine) (PVP), or polyacrylonitrile (PAN). Epoxidized soybean oil was added as a heat stabilizer. Samples of the PVC–CB system were also prepared by dispersing different concentrations of CB into the PVC matrix. The electrical studies showed that the addition of CB to the PVC–DOP system produces a plasticized PVC with high electrical conductivity whereas the compounding of PVC with CB produces a sample with much higher electrical conductivity. The effect of the structure of PVP and PAN on the electrical and mechanical properties of the PVC–DOP system was also studied to obtain a semiconductive plasticized PVC with good mechanical properties. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1590–1598, 2004

Mechanical and dielectric properties of styrene-butadiene rubber polyester short-fiber composites, part III: Composites loaded with fast extrusion furnace carbon black

The present article aims to study the mechanical and dielectric properties of styrene butadiene rubber (SBR) reinforced with polyester (PE) short-fiber loaded with fast extrusion furnace carbon black (FEF) in increasing quantities. The effect of carbon particle size on the mentioned properties is also reported. From the results obtained in this article and others, it was found that, the tensile strength and Young's modulus of FEF and HAF carbon black increase with the increase of carbon content whereas elongation at break was decreased. The retaining ability of the tensile strength and Young's modulus of the composites loaded with either FEF or HAF carbon black has been increased with the increase of aging time and decreased by increasing carbon content in the vulcanizates. At certain concentration of carbon black in the rubber matrix, there was an abrupt increase in the dielectric permittively l ' and the dielectric loss l ". The concentration at which l ' and k " shows a sharp increase is in line with the increase of carbon black particle size. The mechanical and dielectric properties for vulcanizates loaded with smaller carbon black particle size are higher than those loaded with larger ones. The dielectric permittivity l ' has been increased by increasing the temperature whereas the dielectric loss was decreased. The results are discussed and Interpreted.

Strain energy density of carbon-black-loaded rubber vulcanizates

The strain energy density behaviour is studied at room temperature,for 100 phr (parts per 100 parts of rubber by weight) FEF carbon-black-loadedstyrene-butadiene rubber (SBR), natural rubber (NR), butadiene-acryle nitrialrubber (NBR), butyl rubber (IIR) and butadiene rubber (BR). This behaviour isalso studied for 100 phr of different types of carbon-black, (intermediatesuper abrasion furnace) (ISAF), high abrasion furnace (HAF), fast extrusionfurnace (FEF), semi-reinforcing furnace (SRF) and easy processing channel(EPC)-)loaded SBR rubber vulcanizates and for different concentrations of FEFcarbon-black-loaded SBR rubber vulcanizates.The shear modulus for allcomposites is also obtained and discussed. These data are used to calculatethe strain energy density using the equation proposed by Blatz et al (1974 Trans. Soc. Rheol. 18 145-61), based onthe n-measure of Sethe.It is found that the n-measure is still a material constant, even after theaddition of carbon black, but with higher values than that for unloadedrubber.

Studies on Epdm/Nr Blends. I. Dielectric and Mechanical Properties

Ethylene-propylene-diene terpolymer rubberlnatural rubber blends (EPDM/NR) in different proportions (100 : 0, 75 : 25, 50 : 50, 25 : 75, and 0 : 100) reinforced with 20 phr semireinforcing furnace carbon black have been studied. The permittivity ε' and dielectric loss ε″ for these samples were determined in the frequency range 102–107 Hz. Also, their physico-mechanical properties were investigated. The EPDM/NR blend (75 : 25) possessed the best mechanical properties and stability against aging. Thus, it was chosen to explore the effect of adding carbon black in different quantities up to 50 phr on its electrical and mechanical properties. Three different types of carbon black. namely high-abrasion furnace black, fast-extrusion furnace black, and medium thermal black, were used. At a certain concentration of carbon black, referred to as the threshold percolation concentration, an abrupt increase in ε′ and ε″, which depends on its type, was detected. This could be attributed to some sort of interaction between the blend and the carbon black at higher concentrations.

Percolation concept and the electrical conductivity of carbon black-polymer composites 3: Crystallisable chloroprene rubber mixed with FEF carbon black

The filler concentration and temperature dependence of the electrical conductivity (σ) of the crystallisable chloroprene rubber CR(Butaclor 41H) mixed with fast extrusion furnace (FEF) carbon black was investigated. It was found that the percolation concept holds true for these composites where σ shows a nearly sharp increase when the mass fraction of FEF carbon black in the mixture exceeds 20%. The estimated values of the filling factor (ƒ) and the occupation number ( Z) were found to be 0.82 and 8.2 respectively. The scaling law of the percolation clusters [ σ = σ 0( P − P c) β ] was valid within the range P c ⩽ P ⩽ 0.34 and the estimated value of β is 6.8. The temperature dependence of σ is thermally activated below and at the percolation threshold with the same activation energy. The decrease in σ with temperature followed by a subsequent increase above certain temperature was attributed to the phase transition of CR(41H) and the change in the size of carbon black clusters from infinite to finite with temperature. In the highly loaded compounds the temperature dependence of σ is controlled by the break-down and re-formation of carbon clusters with temperature.

The Percolation Concept and the Electrical Conductivity of Carbon Black-Polymer Composites. 3. Crystalline Chloroprene Rubber Mixed with FEF Carbon Black

The filler concentration and temperature dependence of the electrical conductivity (a) of crystalline chloroprene rubber CR (Butaclor 41H) mixed with fast extrusion furnace (FEF) carbon black was investigated. It was found that the percolation concept held true for these composites, where σ shows a fairly sharp increase when the mass fraction of FEF carbon black in the mixture exceeds 20%. The estimated values of the filling factor (f) and the occupation number (Z) were found to be 0.82 and 8.2 respectively. The scaling law for percolation clusters [σ = σo (P - Pc)β] was valid within the range Pc ≤ P ≤ 0.34 and the estimated value of the exponent β was 6.8, where P = concentration of filler and Pc = the critical concentration. The conductivity was thermally activated below and at the percolation threshold, with the same activation energy. The decrease in c with temperature (followed by a subsequent increase above a certain temperature) was attributed to the phase transition of CR (41H) and to the change in size of the carbon black clusters from infinite to finite with temperature. In the more highly loaded compounds, the temperature dependence of σ was controlled by the breakdown and reformation of carbon clusters with temperature.

Thermal and thermoelastic properties of fast extrusion furnace (FEF) carbon black loaded SBR vulcanizates

AbstractThe effect of FEF carbon black as filler on the thermal capacity c, diffusivity a, and thermal conductivity λ, of styrene butadiene rubber (SBR) composites in the temperature range 300–420 K was studied. The filler strongly increases the thermal diffusivity, whilst strongly decreasing the thermal capacity and the thermal conductivity (except at high FEF content ≥80 phr).The influence of the filler on the thermoelastic behaviour of the same composites was also investigated. It was found that the thermoelastic temperature change (ΔT) increased with carbon black concentration as well as the entropy change per unit extension.

Influence of dynamic cyclic extension on the electrical conductivity of fast extrusion furnace (FEF) black loaded rubber vulcanizates

AbstractThe influence of dynamic cyclic extension on the electrcal conductivity (σ) of 100 parts FEF carbon black loaded rubber (NR and SBR) vulcanizates was studied. The conductivity showed an initial rapid decrease with increasing cyclic strain amplitude, indicating a probable breakdown of the carbon black structure, owing to the masking of carbon particles by insulating rubber layers.The conduction mechanisms in these composites in terms of both the number of strain cycles and the strain amplitude were also studied. In addition, the temperature coefficient of conductivity was calculated for different amplitudes. It was greatly affected by the magnitude of the strain amplitude.

Thermoelasticity in carbon black-filled styrene-butadiene rubber

Temperature changes resulting from application of periodic strain (deformation) with strain amplitudes up to 60% are reported for vulcanized styrene-butadiene rubber loaded with different parts of fast extrusion furnace carbon black at room temperature. The method used involves determination of the thermoelastic coefficient, change in entropy, enthalpy per unit length and Gruneisen constant. Thermal effects were found to be dependent on the strain amplitude and carbon concentration. An empirical formula is suggested to account for the obtained results.

DC conduction in butyl rubber (IIR) loaded with carbon black

AbstractCurrent–voltage characteristics of samples of butyl rubber loaded with two different types of carbon black have been studied at different temperatures in the voltage range 10–3 KV. The conduction mechanism was found to follow the conventional band approach followed by the hopping model for isobutylene isoprene rubber (IIR) mixed with 40 phr of fast‐extrusion furnace black (FEF) carbon black and the hopping model for IIR mixed with 50 phr of semireinforcing furnace black (SRF) carbon black. © 1992 John Wiley & Sons, Inc.

Effect of concentration and temperature on the electrical conductivity of butyl rubber loaded with different types of carbon black

AbstractIn this study we are interested in the effect of concentration and temperature on the electrical resistivity of butyl rubber (IIR) loaded with two types of carbon black, (namely, high abrasion furnace black (HAF), and fast extrusion furnace black (FEF)). It was found that the conductivity at low carbon black concentrations is mainly achieved by thermal activation of carriers. Tunneling mechanism at low termperature followed by thermal activation at relatively high temperature is found to be predominant for moderate concentrations for both carbon blacks. The metal‐like behaviour which was observed in highly loaded compounds was attributed to both, the thermal expansion of the tunneling paths between carbon‐carbon agglomerates and the breakdown of carbon agglomerates with temperature.

Effect of hydrostatic pressure on the electrical conductivity of FEF carbon black‐loaded sbr vulcanizates

AbstractThe electrical conduction was investigated in styrene butadiene rubber (SBR‐1502) loaded with different concentrations of fast extrusion furnace (FEF) black (70, 80, 90, and 100 phr). On the bases of Holm's model, a qualitative description for the electrical conduction through these composites was sought. The pressure coefficient K was calculated and found to be strongly dependent on the carbon black concentrations.