ASTM Oil Research Articles

Characterization of Blends of Virgin Nitrile Rubber and Compounded Nitrile Rubber Latex Waste Reclaimed with Urea: Part II - Physico-Mechanical Properties

Recycling of rubber waste materials in order to convert these to usable products is one of the main challenges in the rubber industry. Reclaiming of rubber waste and blending it with virgin rubber have increased during the past due to the growing concern on the environment and increase in the prices of synthetic rubbers. Hence, the aim of this study is to partially replace virgin nitrile rubber (NBR) with reclaimed compounded NBR latex waste to develop new rubber blends suitable for special applications. In this study, physico-mechanical properties, ageing performance and swelling behaviour of virgin NBR / reclaimed NBR blend vulcanizates were evaluated and compared with those of the control vulcanizate produced solely with virgin NBR. Results showed that replacement of 50% virgin NBR with reclaimed NBR retained 71-86% of tensile strength, elongation at break and resilience. Hardness and modulus of this blend vulcanizate increased by less than 18%, whereas abrasion volume loss and compression set increased by 27%. Ageing resistance is similar to that of the control vulcanizate. Interestingly, resistance to swelling in toluene and ASTM oil No.3 increased by 14% and 32%, respectively. Hence, the 50:50 virgin NBR / reclaimed NBR vulcanizate would be suitable for oil resistant applications.

Comparative evaluation of oil resistance, dielectric properties, AC conductivity, and transport properties of nitrile rubber and chlorinated nitrile rubber

Nitrile rubber (NBR) has been extensively used in high oil resistance application such as in automotive seals and gaskets. Due to the poor mechanical strength of NBR, the performance of these products undergoes deterioration when it is in contact with hot oils and solvents. The aim of the present work is to investigate the molecular transport of petroleum fuels and oil through chlorinated NBR (Cl-NBR) with respect to different contents of chlorine. It also focuses on the effect of chlorine content on the alternating current (AC) conductivity and dielectric properties of Cl-NBR for flexible electronic applications. The transport characteristics of petroleum fuels through the NBR and Cl-NBR membranes have been studied by a simple sorption gravimetric analysis in the temperature range 27–50°C. The diffusion results have been explained in terms of the size of liquid molecules and the diffusion mechanism was found to follow the anomalous trend. The diffusion, sorption, solvent uptake, and permeation constants were investigated and were found to decrease with increase in the level of chlorine content in NBR matrix. The activation energy for diffusion and permeation processes were increased and reached maximum value for Cl-NBR (22% Cl content). The oil resistance property of Cl-NBR was significantly higher than pure NBR. The swelling of Cl-NBR in ASTM oil was three times lower than NBR. The electrical conductivity and dielectric properties of NBR was found to be increased with the increase in chlorine content of NBR. NBR showed the AC conductivity value of 7.24 S cm−1 at 106 Hz, while the Cl-NBR with 24% chlorine showed the conductivity value of 4.69 S cm−1. The higher AC conductivity and dielectric properties, solvent, and oil resistance of Cl-NBR than that of NBR suggests that the Cl-NBR can be used as multifunctional materials for flexible nano-electronic devices and high-performance oil-resistant applications.

Magnetorheological elastomers berbasis lateks cair sebagai matriks utama

Kajian ini membahas MRE Isotropic bermatriks lateks dengan variasi fraksi massa CI particle (wt%) dan mengevaluasi karakteristik yang ditentukan, meliputi densitas, kekerasan, tegangan putus, perpanjangan putus dan swelling dari MRE yang dibuat dengan matrik lateks pekat yang berbeda-beda nilai perbandingan massa antara CI particle dan lateks pekat pada saat pencampuran. Komposisi MRE yang dibuat yaitu 0, 30, 40, 50, 60, 70 wt%, dilakukan di Laboratorium Pusat Penelitan Karet Indonesia yang memiliki alat uji karet yang sudah terstandarisasi untuk pengujian nilai tarik, keras dan swelling di Indonesia. Lateks murni dengan massa jenis 0,94 gr/cm3, terjadi peningkatan lebih dari 100% dengan penambahan CI particle 40%. Peningkatan jumlah CI particle juga meningkatan nilai keras yang semula nilai keras 35 point meningkat 15 point saat penambahan CI particle 70%. Penambahan CI particle menyebabkan penurunan hasil pengujian Tarik, terlihat saat lateks murni memperoleh hasil tegangan tarik 14,5 MPa dan perpanjangan putus mencapai 760%. Saat ditambahkan CI particle 70% tegangan putus menjadi turun mencapai 2 MPa dan perpanjangan putus 610%. Perubahan volume pada saat perendaman dengan larutan ASTM OIL 3 terlihat pada lateks murni yang mengalami penambahan volume 167,94% dan meningkat hampir 100% saat ditambahkan CI particle 70% menjadi 305,97%.

Superior heat-resistant and oil-resistant blends based on dynamically vulcanized hydrogenated acrylonitrile butadiene rubber and polyamide 12

High-performance thermoplastic vulcanizates (TPVs) are the new generation of TPVs that provide superior heat and oil aging behavior. TPVs based on hydrogenated acrylonitrile butadiene rubber and polyamide 12 (PA12) have been first developed by the dynamic vulcanization process, in which selective cross-linking of the elastomer phase during melt mixing with the thermoplastic phase (PA12) was carried out simultaneously. In this present investigation, hydrogenated acrylonitrile butadiene rubber (HNBR)/PA12 and partially hydrogenated carboxylated acrylonitrile butadiene rubber (XHNBR)/PA12 with blend ratio of 50:50, 60:40, and 70:30 wt% were prepared at 185°C at a rotor speed of 80 rpm for 5 min. Di-(2-tert-butyl peroxy isopropyl) benzene was chosen as the suitable cross-linking peroxide to pursue the dynamic vulcanization. TPV based on 50:50 HNBR/PA12 and XHNBR/PA12 show better physico-mechanical properties, rheological behavior, thermal stability, dynamic mechanical analysis, and creep behavior among all the TPVs. Morphology study reveals that dispersed phase morphology has been formed with an average dimension of the rubber particles in the range of 0.8–1.5 µm. For aging test, TPVs were exposed to air and ASTM oil 3, respectively. Air aging tests were carried out in hot air oven for 72 hr at 125°C, while the oil aging tests were carried out after immersion of the samples into the oils in an aging oven. After aging, there is only slight deterioration in the physico-mechanical properties of the TPVs. In case of 50:50 blends of HNBR/PA12 and XHNBR/PA12, the retention of the properties upon after aging was found excellent. These TPVs are designed to find potential application in automotive sector especially for under-hood-application, where high-temperature resistance as well as high oil resistance is of prime importance. Copyright © 2016 John Wiley & Sons, Ltd.

Tailored Nanostructured Thermoplastic Elastomers from Polypropylene and Fluoroelastomer: Morphology and Functional Properties

Conventional thermoplastic elastomer from rubber–plastic blends has rubber domains of a few micrometers dispersed in a plastic matrix. Nanotailoring of novel thermoplastic elastomeric blends from polypropylene (PP) and fluoroelastomer (FKM) by a special green technique generated a unique morphology in which FKM was dispersed in the nanometer range (50–70 nm) into the continuous PP matrix. The evolution of the unique nanostructure morphology was explained with the help of a viscoelastic drop breakup mechanism. The nanostructured blends exhibited superior physical properties and outstanding oil swelling resistance and thermal stability, which increased upon vulcanization of the rubber phase in situ. For example, volume swell of nanostructured PP/FKM blends was 8–10% in ASTM oil #3 at 100 °C for 72 h, which was the lowest in this type of thermoplastic elastomer. Insights into how the unique morphology influenced the functional properties of thermoplastic elastomers was provided. These new thermoplastic elastomers can be used in the automotive industry, particularly as a liner material for car hoses where superior flexibility, oil resistance, and heat resistance are desirable properties.

Development of novel polar thermoplastic vulcanizates based on ethylene acrylic elastomer and polyamide 12 with special reference to heat and oil aging

ABSTRACTThermoplastic vulcanizates (TPVs) based on ethylene acrylic elastomer (AEM) and polyamide 12 (PA12) have been developed by the dynamic vulcanization process, in which selective cross‐linking of the elastomer phase (AEM) during melt mixing with the thermoplastic phase (PA12) has been carried out simultaneously. TPVs at varied blend ratios (50 : 50, 60 : 40, 70 : 30) of AEM/PA12 were prepared at 185°C at a rotor speed of 80 rpm up to 5 min of mixing. Di‐(2‐tert‐butyl peroxy isopropyl) benzene (DTBPIB) was chosen as the suitable cross‐linking peroxide to carry out the dynamic vulcanization. Morphology study reveals the development of continuous agglomerate of rubber network in case of all the TPVs took place and the average dimension of the rubber particles are in the range of 30–40 nm. TPV based on 50 : 50 AEM/PA12 shows better physicomechanical properties, thermal stability, and dynamic mechanical behavior among all the TPVs. For aging test, TPVs were exposed to air, ASTM oil 2 and 3. Air aging tests were carried out in hot air oven for 72 h at 125°C, while the oil aging tests were carried out after immersion of the samples into the oils in an aging oven. After aging, there are only slight deterioration of physicomechanical properties of the TPVs. Particularly in case of 50 : 50 blend of AEM/PA12, the retention of the properties even after aging was found excellent. The recyclability of these new TPVs is also found to be excellent leading to find potential application in automotives. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42655.

Effect of fly ash on thermal stability, flammability, oil resistance and transport properties of chlorinated styrene butadiene rubber composites

Fly ash (FA) can be used as a filler in rubber vulcanizates to get rid off their waste. Polymer composite based on chlorinated styrene butadiene rubber (CSBR)/containing varying amount of FA composites has been developed by melt compounding followed by dicumyl peroxide vulcanization. The influence of increased loading of FA on the cure characteristics, mechanical properties, thermal stability, flame and oil resistance has been investigated. The increase in FA loading in CSBR matrices has been found to accelerate the curing process up to 37% compared to unfilled sample. The uniform distribution of FA in CSBR has been confirmed by scanning electron microscopy, which also explained the improved mechanical properties, flame and oil resistance of the composites. The diffusion rate of aromatic hydrocarbon solvents through the composite film is minimum for composites with 30 phr of filler and the rate is increased with increasing the filler content. Activation parameters are estimated and the molecular mass is calculated using Flory–Rehner theory. The sorption data are used to estimate the enthalpy, entropy and free energy of mixing. Mechanical properties such as tensile strength, modulus and hardness of the samples decreased after immersion in ASTM oil and the decreasing trend is lower for 30 phr FA-filled samples.

The Effect of Silane Treatment on Processing Characteristic and Swelling Behavior of Polypropylene/Recycled Acrylonitrile Butadiene Rubber/Rice Husk Powder Composites

The effect of silane treatment on processing characteristic and swelling behavior of recycled acrylonitrile butadiene rubber (NBRr)/polypropylene (PP)/rice husk powder (RHP) composites has been studied. Polypropylene/recycled acrylonitrile butadiene rubber/rice husk powder (PP/NBRr/RHP) composite were prepared by melt mixing technique at 180º C for 9 minutes and 50rpm rotor speed using an internal mixer. Five different composites compositions (70/30/0, 7030/5, 70/30/10, 70/30/15 and 70/30/30), with silane treated RHP (treated) and without silane treatment RHP (untreated) was studied. The specimens were analyzed for swelling behavior with ASTM oil No.3 and processing torque of composites was obtained during composite preparation. The results showed that swelling percentage for both composites increased with NBRr content. However the treated composites exhibited lower swelling characteristics. Processing torque of both composites also showed higher torque reading with increasing NBRr content. However the treated composite with silane exhibited much higher torque value for similar composition composites. Better interaction between RHP filler and PP/NBRr matrixs was obtained with treated composites.

Thermogravimetric analysis, flammability and oil resistance properties in natural rubber and dichlorocarbene modified styrene butadiene rubber blends

Thermogravimetric analysis (TGA), flammability and oil resistance in natural rubber (NR) and dichlorocarbene modified styrene butadiene rubber (DCSBR) blends were investigated as a function of different composition. TGA plot confirms the better thermal stability and flame resistance of DCSBR as well as its blends with NR. The simultaneous difference temperature plot showed the energy requirement for the degradation pattern of the blends. The flammability of the blend was monitored by the limiting oxygen index (LOI) measurement of the rubber vulcanizate. The amount of DCSBR in the blend significantly affected the properties of blends. The mechanical properties investigated after the immersion in ASTM oil was tensile strength, modulus, tear strength and hardness. It was found that these properties were decreases progressively with increasing NR content in the blends.

Effects of Filler Loading on Properties of Polypropylene–Natural Rubber–Recycle Rubber Powder (PP–NR–RRP) Composites

Carbon black, silica and calcium carbonate were used as fillers in polypropylene–natural rubber–recycle rubber powder (PP–NR–RRP) composites. The effects of filler loading on processability, tensile properties, swelling behavior and morphology of PP–NR–RRP composites at a fixed weight ratio of 70/15/15 were studied. The blends were melt mixed using a Brabender Plasticorder torque rheometer at 190°C and 50 rpm. Filler contents were steadily increased from 0 to 30 (wt.%). The results indicated that the tensile strength and Young’s modulus increase with increasing carbon black and silica content in PP–NR–RRP composites whereas calcium carbonate exhibit opposite trend except Young’s modulus. Carbon black filled PP–NR–RRP composites exhibit lowest resistance toward swelling in ASTM oil No.3 than calcium carbonate and silica filled PP–NR–RRP composites. In terms of processability, incorporation of silica in PP–NR–RRP composites give more processing difficulties than carbon black and calcium carbonate filled PP–NR–RRP composites.

A Comparative Study of the Effect of Degradation on the Properties of PP/NR and PP/RR Blends

The effect of various degradations on the tensile and morphological properties of polypropylene (PP)/natural rubber (NR) and PP/recycle rubber (RR) blends at different rubber content were studied. The blends were melt mixed using a Brabender Plasticorder torque rheometer at 190°C and 50 rpm. All blends were exposed at three different conditions, i.e., heated in oven (100°C) for 24 hrs, immersed in distilled water (90°C) for 24 hrs, and immersed in ASTM oil No. 3 for 70 hrs. The results indicated that at a similar rubber content and degradation condition, PP/RR blends exhibit a higher percentage of retention of tensile strength and Young's modulus but a lower elongation at break than PP/NR blends. Scanning electron microscopy (SEM) examination of the tensile fracture surface of PP/NR blends indicates a smooth fracture surface than PP/RR blends after thermo-oxidative aging. This observation supports the higher retention of tensile strength after thermo-oxidative aging of PP/RR blends than PP/NR blends. Thermogravimetric analysis of both blends show that the thermal stability of PP/RR blends is higher than that of PP/NR blends.

Effect of filler loading on cure time and swelling behaviour of SMR L/ENR 25 and SMR L/SBR blends

AbstractThe effect of filler loading on the cure time (t90) and swelling behaviour of SMR L/ENR 25 and SMR L/SBR blends has been studied. Carbon black (N330), silica (Vulcasil C) and calcium carbonate were used as fillers and the loading range was from 0 to 40 phr. Results show that for SMR L/ENR 25 blends the cure time decreases with increasing carbon black loading, whereas silica shows an increasing trend, and calcium carbonate does not show significant changes. For SMR L/SBR blends, the cure time of carbon black, silica and calcium carbonate generally decreases with increasing filler loading. The percentage swelling in toluene and ASTM oil no 3 decreases for both blends with increasing filler loading, with calcium carbonate giving the highest value, followed by silica‐ and carbon black‐filled blends. At a fixed filler loading, SMR L/ENR 25 blend shows a lower percentage swelling than SMR L/SBR blends.© 2003 Society of Chemical Industry

THE EFFECTS OF A MULTIFUNCTIONAL ADDITIVE ON CURING CHARACTERISTICS, MECHANICAL PROPERTIES, AND SWELLING BEHAVIOR OF NATURAL RUBBER/POLYCHLOROPRENE RUBBER BLENDS

The effects of a diamine salt of fatty acid of general structure [RNH2 +[CH2)3NH+] [R′COO−]2 referred to as a multifunctional additive (MFA) on curing characteristics and mechanical properties and swelling behavior of natural rubber (SMR L) and polychloroprene (CR) rubber blends were studied. Compared to SMR L/CR blends without MFA, the incorporation of 2 phr (parts per hundred parts of rubber) of MFA in the blends increased mechanical properties, i.e., tensile strength, tensile modulus and hardness, and improved swelling resistance toward toluene and ASTM oil No. 1. However the scorch time, t 5 and cure index, Δt L decrease with incorporation of MFA into the blends.

The Effect of Several Kinds of Oils on the Oil Resistance Behavior of Polystyrene Thermoplastic Vulcanizate

The oil resistance behavior of polystyrene thermoplastic vulcanizates (TPVs) such as polypropylene (PP)/polystyrene block copolymer (SBC) systems were investigated using a dynamic mechanical spectrometer (DMS) and transmission electron microscopy (TEM). Testing oils used were paraffinic oil, ASTM oil #3, an automobile grease and petrol, into which all specimens were immersed at 1 000C for 72 hrs. Dynamic mechanical spectra showed that non-crosslinking segments of SBC were subjected to damage by testing oil properties. Particularly their segments seemed to be more soluble and swelled by paraffinic oil or ASTM oil #3. TEM photomicrographs of immersed specimens showed similar results.

Influence of Lubricating Oil Additives on Swell-Resistant Elastomers

Abstract In the last few decades the demands made on lubricating oils have become increasingly severe; corresponding improvements in the quality of oils have been achieved primarily by adding additives of widely different composition and function. These substances, however, may severely attack elastomers which come into contact with lubricating oils, possibly making the elastomers useless within a short time. The influences of chemically defined lubricating oil additives on nitrile-butadiene, chloroprene, silicone, and acrylic rubbers are investigated at 140° C, ASTM Oil No. 1 being used as the medium. The various substances are found to have strong influences on the condition of the elastomers, depending on the structure of the polymer. See Figure 16. Sulfonated and chlorosulfonated fatty oils and hydrocarbons cause surface hardening in nitrile rubber, which results in crack formation under flexure or elongation. However, after pronounced initial deterioration of the mechanical properties, further penetration of the additive is prevented by the protective layer thus formed. Chloroprene rubber also takes part in a crosslinking reaction with these additives, though without undergoing surface hardening. Silicone and acrylic rubber, which have no double bonds in the polymer chain, are not attacked by these additives. Owing to a crosslinking reaction compounds which release hydrogen chloride, e.g., chlorinated paraffin, cause severe surface hardening in nitrile and chloroprene rubber vulcanizates, which is not restricted to the surfaces. In the case of nitrile rubber, hydrogen chloride combines with the vulcanizate. In the presence of chlorinated paraffin, acrylic rubber first softens but this is afterwards obscured by hardening. Chlorinated paraffin does not attack silicone rubber. Lead naphthenate damages acrylic and silicone rubber but stabilizes nitrile and chloroprene rubber. With reference to nitrile rubber, as an example, it is shown that the resistance of the elastomers greatly depends on the temperature and concentration of the additive and that both synergistic and antagonistic effects are possible when additives are used in conjunction with one another. The purposes of this study have been, firstly, to show that the differences in the behavior of elastomers in technical lubricating oils are usually due to the influence exerted by additives, and, secondly, to encourage the lubricating oils industry to consider and make allowances for the problems of the rubber industry.