Oil Resistance Properties Research Articles

Unique commercial applications of the sol-gel process in Japan

Two unique commercial applications of the sol-gel process in Japan are presented. One application involves alkoxide-derived nanometer-sized silica particles used in the final polishing of silicon wafers for the fabrication of integrated circuits. The particles are cocoon-like in shape and have almost replaced conventional abrasives because of the advantages over spherical particles of similar size in terms of obtaining high polishing efficiency for good surface finish. The other application concerns the treatment of paper with an alkoxide solution for water repellent and oil resistance properties, which leads to new products for disposable tableware or cooking ware for microwave oven use.

Oil resistance and physical properties of in situ epoxidized natural rubber from high ammonia concentrated latex

AbstractEpoxidized natural rubber (ENR) was prepared via in situ epoxidation from high ammonia concentrated natural rubber latex with formic acid and hydrogen peroxide in the presence of a surfactant at 50°C for 4, 8, and 12 h. The obtained ENRs containing 20, 45, and 65 mol % of expoxide groups were denoted ENR20, ENR45, and ENR65, respectively. The differential scanning calorimetric study revealed that they exhibited higher glass transition temperatures than that of natural rubber (−62.4°C), at −38.2°C for ENR20, −27.8°C for ENR45, and −19.7°C for ENR 65. It was clearly seen that their glass transition temperatures increased as the amount of epoxide groups increased. The prepared ENRs were compounded and vulcanized to prepare test specimens for determination of oil resistance and various physical properties. It was found that the swelling of ENRs in oils was substantially less than that of natural rubber. The oil resistance of ENR65 was comparable to that of nitrile rubber, commonly used as oil resistant rubber. ENR65 also showed higher hardness than other ENRs. Contrarily, ENR20 possessed superior tensile strength and compression set when compared with other ENRs. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3948–3955, 2006

Electro-optic materials from co-polymeric elastomer–acrylonitrile butadiene rubber (NBR)

Recently, we demonstrated that conjugated sequences of unsaturated double bonds can be introduced into co-polymers such as styrene butadiene rubber (SBR), which contains isolated double bonds along the polymer backbone through conjugation reactions induced by iodine [Sreeja R. Submitted for publication [1]]. Here, we report for the first time the doping reaction in another notable co-polymer nitrile rubber, a co-polymer of acrylonitrile and butadiene. The conductivity reaches a value of about 0.01 S/cm with the characteristic color change from colorless to dark red upon doping. FT-IR and UV/VIS studies of the polymer film establish the formation of conjugated sequences of the unsaturated double bonds followed by the formation of charge transfer complexes with the dopant ion. The reaction is analogous to the iodine doping of SBR for longer doping period and retained flexibility of the film after doping. However, the band gap evaluated is greater for NBR and this increase can be explained as due to the presence of electron withdrawing –CN groups in place of electron releasing phenyl group in the SBR backbone, which can cause a partial influence on the chemical reaction along the polymer backbone. The excellent oil resistance, abrasion resistance and mechanical properties of NBR combined with the newly developed semi conducting behaviour can be utilized for fabricating various electronic and optical devices based on this elastomer.

Oil and thermal aging resistance in compatibilized and thermally stabilized chlorinated polyethylene/natural rubber blends

Influences of EPDM- g-MA as a compatibilizer and a phenolic antioxidant on oil and thermal aging resistance in 50/50 CPE/NR blends were investigated. It has been found that EPDM- g-MA could decrease phase size of the blend system, indicating compatibilizing effect. The optimal concentration of EPDM- g-MA is 1 phr. Beyond this concentration, phase size starts to increase. The addition of phenolic antioxidant apparently decreases the phase size in blends. This is probably due to the improvement in a thermal stabilization of NR phase in blends provided by the antioxidant, which leads to a reduction in phase coalescence during blending. In addition, the results of oil and thermal aging resistance are in good agreement with the morphological results, indicating that the oil resistance and thermal aging properties based on relative tensile strength in the 50/50 CPE/NR blends are strongly controlled by the size of the NR dispersed phase in CPE matrix. The smaller the dispersed phase size, the higher the resistance to oil and thermal aging.

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.

Oil and thermal aging resistance in compatibilized and thermally stabilized chlorinated polyethylene/natural rubber blends

Influences of EPDM- g -MA as a compatibilizer and a phenolic antioxidant on oil and thermal aging resistance in 50/50 CPE/NR blends were investigated. It has been found that EPDM- g -MA could decrease phase size of the blend system, indicating compatibilizing effect. The optimal concentration of EPDM- g -MA is 1 phr. Beyond this concentration, phase size starts to increase. The addition of phenolic antioxidant apparently decreases the phase size in blends. This is probably due to the improvement in a thermal stabilization of NR phase in blends provided by the antioxidant, which leads to a reduction in phase coalescence during blending. In addition, the results of oil and thermal aging resistance are in good agreement with the morphological results, indicating that the oil resistance and thermal aging properties based on relative tensile strength in the 50/50 CPE/NR blends are strongly controlled by the size of the NR dispersed phase in CPE matrix. The smaller the dispersed phase size, the higher the resistance to oil and thermal aging.

Relationship among phase morphology, oil resistance, and thermal aging properties in CPE/NR blends: effect of blending conditions

AbstractThe CPE/NR blends with blend ratio of 50/50% by weight were prepared with various blending conditions. The resistance to oil and thermal aging of the blends was investigated and correlated with phase morphology. The NR dispersed phase size in blends was found to decrease with increasing rotor speed up to 45 rpm and subsequently level off at higher rotor speeds. With increasing mixing time at a given rotor speed, NR dispersed phase size reached a minimum and increased again with a further increase in mixing time, caused by domain breakup and phase coalescence, respectively. In addition, the results revealed a strong relationship between NR phase size and resistances to oil as well as thermal aging, that is, the smaller the dispersed phase size, the higher the oil resistance and the thermal aging properties. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 4038–4046, 2003

Mechanical properties, oil resistance, and thermal aging properties in chlorinated polyethylene/natural rubber blends

AbstractThe use of natural rubber (NR) for partly substituting elastomeric chlorinated polyethylene (CPE) was determined. Mechanical and thermal aging properties as well as oil resistance of the blends were also investigated. The amount of NR in blends significantly affected the properties of the blends. The blends with NR content up to 50 wt % possessed similar tensile strength to that of pure CPE even after oil immersion or thermal aging. Modulus and hardness of the blends appeared to decrease progressively with increasing NR content. These properties also decreased in blends after thermal aging. After oil immersion, hardness decreased significantly for the blends with high NR content, whereas no change in modulus was observed. The dynamic mechanical properties were determined by dynamic mechanical thermal analysis. NR and CPE showed damping peaks at about −40 and 4 °c, respectively; these values correlate with the glass‐transition temperatures (Tg) of NR and CPE, respectively. The shift in the Tg values was observed after blending, suggesting an interfacial interaction between the two phases probably caused by the co‐vulcanization in CPE/NR blends. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 22–28, 2002; DOI 10.1002/app.10171

Preparation and characterization of butyl/NBR vulcanizates

To obtain rubber compounds with satisfactory thermal and oil resistance properties, blends of butyl rubber (IIR) with nitrile rubber (NBR) were prepared on a laboratory open mill. Cure behaviour of the blends, physico-mechanical properties and ageing and oil resistance properties of the vulcanizates were determined. For electric insulation application, dielectric constant, dielectric loss and tan δ were measured. The results indicate that the vulcanizates of IIR/NBR blends of the ratios (70:30), (30:70) and (20:80), show superior thermal stability upon ageing, compared to individual rubbers and other blend compositions. Blending of IIR with NBR (main component) improves swelling behaviour of NBR in brake fluid and toluene. However, blending of NBR with IIR (main component) improves swelling resistance of IIR in motor oil and gasoline. Thus, the results obtained reveal effective improvement in thermal and oil resistance upon blending.

Internal Treatment of Paper Sheets from Wood and Bagasse Pulps with Polyvinyl Alcohol

Mechanical strength and optical properties of paper sheets prepared from polyvinyl alcohol (PVA)-treated wood and bagasse pulps were investigated. The effects of the percentage of added PVA, the amount and type of polymer precipitant, and the manner of polymer addition (before or after the beating stage) on the properties of prepared sheets were presented. Studies were also carried out to compare the properties of loaded paper sheets produced from PVA-treated pulp and fillers (kaolin, TiO2, talc, and CaCO3), with those produced from conventional rosin-alum-filler loaded paper sheets. The obtained results show that 4% PVA (based on pulp) and 100% borax (based on polymer) were the optimum additives required to attain the maximum improvement in the strength properties of the paper sheets obtained from both pulps. It was found that the pH value of the pulp slurry has a profound effect on the filler retention and strength properties of produced sheets, whereas it has a weak effect on the optical properties of sheets. The optimum strength properties were noticed at pH 7.0. Also, the addition of PVA was more efficient for improving the strength and optical properties of paper sheets loaded with a high percentage of Filler, especially kaolin, compared with conventional rosin-alum addition. However, the reverse trend was noticed in the case of the oil resistance property for ail paper samples under investigation, except the case of paper sheets made from 4% PVA addition to bagasse pulp, as the beating additive, whereas its oil resistance property was nearly the same as the case of rosin addition.

Radiation vulcanization of hydrogenated acrylonitrile butadiene rubber (HNBR)

AbstractRaw polymer and compound of hydrogenated acrylonitrile butadiene rubber (HNBR) were subjected to γ‐ray irradiation. Crosslinking was found to be the main chemical reaction induced by irradiation; the ratio of chain scission to crosslinking as well as the does at which gelation occurred were determined from gel content measurements to be 0.41 and 3.8 Mrad, respectively. The excellent hot‐air and oil‐resistant properties should be retained because no formation of double bonds or changing of the nitrile groups were observed with in the optimum dose range. Desired mechanical properties of the vulcanizate may be conveniently obtained by controlling the radiation dose. © 1994 John Wiley & Sons, Inc.

Effects of Compatibilisers on the Properties of Polyvinyl Chloride/Nonpolar Rubbers Blends

The effects of some commercial polymers used as a third component on the properties of the PVC blends with nonpolar rubbers, such as BR, SBR, EPDM, NR and reclaimed rubber, were studied. It was found that NBR-18 was a very efficient compatibiliser for PVC/nonpolar rubbers blends in a wide range of blend composition, and the mechanical properties of these blends were significantly improved even when the NBR-18 content was as low as 2%. The presence of NBR-18 in PVC/nonpolar rubbers blends promoted better dispersion of PVC particles in rubber matrix, and the interfacial adhesion between PVC and the rubber phases was significantly improved by the co-vulcanisation of NBR-18 and nonpolar rubbers as well as the same compatibility of PVC with NBR-18. The PVC/NBR-l8lnonpolar rubbers ternary blends have not only good mechanical properties but also good oil and low-temperature resistance and excellent electrical insulation property.

Effects of Compatibilisers on the Properties of Polyvinyl Chloride/Nonpolar Rubbers Blends

The effects of some commercial polymers used as a third component on the properties of the PVC blends with nonpolar rubbers, such as BR, SBR, EPDM, NR and reclaimed rubber, were studied. It was found that NBR-18 was a very efficient compatibiliser for PVC/nonpolar rubbers blends in a wide range of blend composition, and the mechanical properties of these blends were significantly improved even when the NBR-18 content was as low as 2%. The presence of NBR-18 in PVC/nonpolar rubbers blends promoted better dispersion of PVC particles in rubber matrix, and the interfacial adhesion between PVC and the rubber phases was significantly improved by the co-vulcanisation of NBR-18 and nonpolar rubbers as well as the same compatibility of PVC with NBR-18. The PVC/NBR-l8lnonpolar rubbers ternary blends have not only good mechanical properties but also good oil and low-temperature resistance and excellent electrical insulation property.

Low-molecular-weight guayule natural rubber as a feedstock for epoxidized natural rubber

The low-molecular-weight fraction of guayule rubber ( M w 2.68 × 10 5) can be modified to yield a low-viscosity analog of epoxidized natural rubber. A hexane or cyclohexane solution of rubber is treated at 23–63°C with peracid formed in situ from hydrogen peroxide and formic acid. The epoxidized polymer enhances the physical properties of cured rubber compositions, particularly abrasion and oil resistance properties. Low-molecular-weight natural rubbers from other temperate zone plants could be similarly modified.

Copolymerization of trialkyl aconitates with butadiene and some vinyl monomers

AbstractReactivity ratios have been determined for the copolymerization of trimethyl aconitate with butadiene, styrene, acrylonitrile, and vinyl chloride, and for triethyl aconitate with butadiene and styrene. The values obtained indicate that trialkyl aconitates are very reactive in free radical initiated copolymerizations. No copolymerizations of aconitic acid were realized. A copolymer of butadiene and trimethyl aconitate has been prepared in a modified Mutual recipe at 50°C. The copolymer shows fair oil resistance and tensile properties but the low‐temperature properties are poor. The temperature rise of trimethyl aconitate copolymer is possibly better than that of standard GR‐S made at 50°C.

Copolymerization of vinylsulfonic acid derivatives with butadiene

AbstractCopolymers of vinylsulfonic acid derivatives with butadiene, isoprene, and styrene have been prepared. The evaluation of butadiene‐vinylsulfonic acid ester copolymers indicates that these rubbers have good low‐temperature characteristics and that the stress‐strain properties of the n‐butyl vinylsulfonate copolymer approach those of the standard GR‐S rubber; however the oil resistance properties are poor. The stress‐strain properties of the butadiene‐n‐hexyl vinylsulfonate copolymer are inferior to those of the n‐butyl analog.

Some new butadiene copolymers

AbstractCopolymers of butadiene with 2‐ethoxyethyl acrylate, 2‐ethoxyethyl methacrylate, tetrahydrofurfuryl acrylate, acrylic acid, and methacrylic acid have been prepared and evaluated as rubbers. The 2‐ethoxyethyl acrylate copolymer has good low temperature properties. The methacrylic acid copolymer has unexpectedly good oil resistance, but the low temperature properties are poor. The acrylic acid copolymers show fair oil resistance and good low temperature properties. Both acrylic acid and methacrylic acid copolymers with butadiene show unexpectedly good tensiles.

A Survey of Resilience and the Development of Resilient Compounds

Abstract A study was made of the methods and machines used in measuring resilience and classified as of the impact, free oscillation, forced oscillation, or other type: A search of the literature revealed that resilience is affected by numerous factors, such as temperature, duration of loading, magnitude of stress, method of applying stress, amplitude, frequency, and energy losses during measurement ; by shape and thickness of the sample, and by the state of cure, amount and type of plasticizer, amount and type of fillers, and the type of elastomer used. A series of Neoprene compounds was compounded, cured, and tested to determine the effect of various classes of carbon black on the resilience of the Neoprene elastomer, which is the most resilient commercially made rubber material. The resilience was found to decrease as the carbon black particle size decreased. A second series of compounds utilizing 15, 25, 35, 45, and 55 parts of medium thermal carbon black based on the Neoprene were tested, and the results show that resilience decreases with increase in loading. A comparison of the physical properties of these compounds with those of the currently used natural-rubber packing shows that the former are superior for replacing the natural rubber in mechanisms. The Neoprene compounds possess better tensile strength, elongation, resilience, aging, and oil resistant properties than the rubber compound, but are slightly inferior in low-temperature flexibility.

The Oil Resistance of Rubber

Abstract The thermal effects of benzene on various rubber films are correlated with the polar and oil-resisting properties of rubber. By means of quantitative experiments on these effects, natural crude rubber was proved to be a non-polar material; purification, vulcanization, mastication, irradiation by ultra-violet rays, and chlorination increase the polarity of rubber. Synthetic films show small thermal effects because of the high polar properties and the compactness of structure of the films.

Oil-Resisting Rubber

Abstract From the mechanical engineer's point of view, rubber has one serious drawback, and that is the behavior toward lubricating oil. By proper compounding and curing, rubber is being used under circumstances which involve contact with oils, but there is still room for improvement. When one considers that oil-resisting rubber is finding and could find still greater application in the engineering, especially the automobile, electrical, petroleum, gas, paint, printing, agricultural, and other industries, it is not astonishing that this problem is one of the most important of the rubber industry. Little work, however, has been published on this subject prior to the present year. The popular belief that glue protects rubber against oil has been shown to be incorrect, and will be dealt with later in the paper. Ishiguro (Rubber Chem. & Tech., 6, 278 (1933)) studied a large number of fillers, soaps, glue, starch, and accelerators, but in view of the fact that the author did not make a preliminary study of the effect of these substances upon cure, the reader of the paper is left with the impression that the results are due as much to the effect of the various substances upon the state of cure as to their intrinsic oil-resisting properties. It is true that a certain amount of correction was made in the case of accelerators. The paper must, however, be welcomed as the first systematic publication based on experimental work on this subject. Karsten (Kautschuk, 9, 73 (1933)) brings out a very important point in his paper to the effect that the best method of obtaining oil-resistance in rubber must depend upon the use to which the finished article will be put: for example, large proportions of reinforcing fillers and glue cannot be used when a flexible rubber is required, and so on.