Epichlorohydrin Rubber Research Articles

Synthesis and properties of amphiphilic poly(methacrylic acid) copolymers possessing uniform polystyrene side-chains

Poly(methacrylic acid) (PMAA) copolymers with uniform polystyrene (PS) side-chains were synthesized through the macromer technique. The graft copolymers (PMAA- g-PS) were purified by extraction with water and hot cyclohexane, and were then characterized by gel permeation chromatography, infra-red spectrophotometry and 1H nuclear magnetic resonance spectroscopy. The average grafting number was determined to be 3–7, and decreases with increasing conversion. The graft copolymers showed good emulsifying properties and high water absorbency, and can be used as a good compatibilizer for blending polystyrene with epichlorohydrin rubber (CHR). Only 2–3 wt% of the graft copolymer based on the blend was needed to enhance the mechanical properties of the blends, and the blends with weight ratio of PS CHR = 3 7 to 5/5 behave as good thermoplastic elastomers. When PMAA- g-PS was mixed with polyoxyethylene (PEO) grafted with PS in molar ratio of PEO PMAA = 1 , a thermoplastic intermolecular complex membrane was formed. This behaved as a chemical valve, as its permeability can be controlled reversibly by changing the pH value.

Aluminium-Aluminium Bonding by Rubber Blend Based on Epichlorohydrin Rubber and Carboxylated Nitrile Rubber

Abstract Rubber blends based on epichlorohydrin rubber and carboxylated nitrile rubber can be used as adhesives for aluminium-aluminium bonding. The bond strength depends on blend composition and moulding conditions, such as time, temperature and pressure. Lewis acid/base type interaction is responsible for this type of adhesion. The failure mechanism of the composites was studied by SEM.

Durability studies of aluminium/ aluminium joints bonded by chlorobutyl rubber-carboxylated nitrile rubber and epichlorohydrin rubber-carboxylated nitrile rubber blends

Two novel rubber blends based on chlorobutyl rubber ( ciir)-carboxylate nitrile rubber ( xnbr) and epichlorohydrin rubber (ECO)-carboxylated nitrile rubber ( xnbr) can be used as adhesives for aluminium/aluminium bonding. Incorporation of silica filler in the ciir-xnbr blend and carbon black in the eco-xnbr blend improves joint strength. The adhesives show remarkable water and salt water resistance. The adhesives based on eco-xnbr show remarkable heat and water resistance. Heat stability of the adhesives based on ciir-xnbr is not satisfactory but can be improved by the application of silane primer on the aluminium surface. Silane primer also improves the paraffin oil resistance. The increase in joint strength resulting from the application of silane primer is due to the formation of Si-O-Al linkages at the aluminium/primer interface.

Synthesis and Properties of Poly(acrylic Acid) with Uniform Poly(methyl Methacrylate) Side Chains

Abstract Copolymerization of the poly(methyl methacrylate) (PMMA) macromer with acrylic acid in dimethylformamide solution was studied using AIBN as initiator. The copolymers were purified by extractions with toluene and methanol successively and characterized with IR, 1H NMR, and TEM. The graft copolymers exhibit good emulsifying properties which change with pH and behave as a good compatibilizer for the blending of epichlorohydrin rubber with poly(vinyl chloride) or PMMA. The addition of approximately 3% graft copolymer to the blends evidently improves their mechanical properties and causes the two Tg's to become closer. The blends of PMMA with epichlorohydrin rubber at a weight ratio of 6/4 with the addition of 2–4% graft copolymer show the mechanical properties of a thermoplastic elastomer.

Dynamic mechanical studies on the adhesion between aluminium and rubber

Dynamic mechanical studies can provide useful information on aluminium-rubber adhesion. This study deals with aluminium (Al) and five types of rubber: (i) carboxylated nitrile rubber (XNBR), (ii) chlorobutyl rubber (CIIR), (iii) epichlorohydrin rubber (ECO), (iv) a CIIR-XNBR blend, and (v) an ECO-XNBR blend. In contrast to the single rubbers, the blends are known to be good adhesives for aluminium. While the storage modulus, loss modulus, and loss tangent of the single rubbers (CIIR, XNBR, and ECO) were found to be unaffected by the attachment of Al foil to the rubber surfaces, the dynamic mechanical properties of the blends ( CIIR-XNBR and ECO-XNBR) were greatly altered by the attachment of Al foil. It was observed that the greater the adhesion between Al and rubber, the greater are the changes in the dynamic mechanical properties of the rubber blend due to attachment of Al to its surface.

Synthesis and properties of multiblock copolymers of styrene and propylene oxide

AbstractMultiblock copolymers of styrene and propylene oxide were synthesized by coupling together poly(propylene glycol) and telechelic dihydroxy‐polystyrene with 2, 4‐toluene diisocyanate(TDI) as the coupling agent. The results showed that it was better to terminate the telechelic dihydroxy polystyrene with TDI first, then react with poly(propylene glycol). The copolymer obtained in this two‐step method contains less homopolymers than that obtained when all the three reagents reacted together in one step. The crude product can be purified by extractions with absolute ethyl alcohol and decalin in order to remove the unreacted poly(propylene glycol) and polystyrene, respectively. The purified products were characterized by IR, TH NMR, GPC, membrane osmometry, elemental analysis and shown to be multiblock copolymers of styrene and propylene oxide. The multiblock copolymer exhibits two transition temperatures(Tg's) and behaves like a thermoplastic elastomer at 20–30% polystyrene content. Addition or 2% of the copolymers to the blends of polystyrene and epichlorohydrin rubber improves evidently their mechanical properties and causes the two Tg's to become closer.

Synthesis and Properties of Multiblock Copolymers of Styrene and Propylene Oxide

Multiblock copolymers of styrene and propylene oxide were synthesized by coupling together polypropylene glycol and telechelic dihydroxyl polystyrene with 2,4-toluene diisocyanate (TDI) as the coupling agent. The results showed that it was better to terminate the telechelic dihydroxyl polystyrene with TDI first, then react with polypropylene glycol. The copolymer obtained in this two-step method possesses less homopolymers than that obtained when all the three reagents reacted together in one step. The crude product can be purified by extractions with absolute ethyl alcohol and decalin in order to remove the unreacted polypropylene glycol and polystyrene respectively. The purified products were characterized by IR, 1H NMR, GPC, membrane osmometry, elemental analysis, and shown to be multiblock copolymers of styrene and propylene oxide. The multiblock copolymer exhibits two glass transition temperatures (Tg) and behaves like a thermoplastic elastomer at 20—30% polystyrene content. Addition of 2% of the copolymers to the blends of polystyrene and epichlorohydrin rubber improves evidently their mechanical properties and causes the two Tg’s become closer.

金型汚染とその対策 各種ゴムと汚染対策 Ｖ ヒドリンゴム及びアクリルゴム

金型汚染とその対策 各種ゴムと汚染対策 Ｖ ヒドリンゴム及びアクリルゴム

Improvement of Sour Gasoline Resistance for Epichlorohydrin Rubber

Abstract The resistance to sour gasoline of epichlorohydrin-ethylene oxide terpolymers with allyl groups was studied for various curing systems, antioxidants, and allyl contents. A rubber with 5% of allyl content, cured by a triazine trithiol-MgO-CaCO3 system, showed the best resistance, probably due to the presence of thiol groups in the crosslinks.

High Performance Nitrile Rubber Automotive Fuel Hose

Abstract The GM-6165M specification represents a significant upgrading of the performance of nitrile rubber based automotive fuel hose. Industry acceptance of this specification could lead to consolidation of hose types, and a cost saving if it displaces epichlorohydrin rubber. Compounding to meet the GM hose specification requires a departure from traditional carbon black formulations. A specific selection of each compound ingredient for its contribution to the total performance of the hose is necessary. Bound antioxidant nitrile rubbers are recognized by those who have seriously worked with them as superior performance polymers. Their service performance is unmatched by any other nitrile rubber in the applications which have developed for them in the Automotive Industry. They have consistently performed better than suggested by laboratory testing. This report demonstrates how to compound the 28% acrylonitrile Chemigum HR-765 to meet the severe requirements of GM-6165M.

Evaluation of 2-R-4,6-Dithiol-s-Triazine for Neoprene Vulcanization

Abstract The most useful accelerator for neoprene (CR) vulcanization with magnesia and zinc oxide has been 2-mercaptoimidazoline (NA-22). However, an alternative accelerator or crosslinking agent that is almost completely devoid of toxic effects is required since toxicity investigation has indicated the danger of carcinogenicity arising from NA-22. Although thiol-s-triazine compounds have already been patented as accelerators in CR vulcanization, these must be reexamined with regard to the vulcanizing effect, since nontoxic dithiol-s-triazine compounds (Table I) have recently been produced on a commercial scale. Curing systems for poly (vinyl chloride) (PVC) or epichlorohydrin rubber (CO) with 2-R-4,6-dithiol-s-triazine (1, R: NHC6H5 or N(C4H9)2) have been found to give crosslinked products with excellent aging resistance; and thus a similar crosslinking effect might be observed in CR vulcanized with 1. The present studies were undertaken to confirm the crosslinking effect of 1 in CR vulcanization and then to show the antioxidative effects which remain after solvent extraction of CR vulcanized with 1 containing antioxidant substituent R.

Synthesis and Photosensitive Properties of Photocrosslinkable Poly(glicidyl cinnamate)

Poly(glicidyl cinnamate)(PGC), a new photosensitive polymer was prepared by the condensqtion reactibrf of epichlorohydrin rubber with potassium cinnamate in aprotic polar solvents such as hexamethylp. hosphoramide(HMPA), dimethylsulfoxide(DMSO) and dimethylformamide(DMF).The effects of temperatures, solvents and catalyst on the reaction were investigated. lt was observed that the condensation reaction proceeded more readily in HMPA than in DMSO and DMF, and the degree of esterification of PGC obtained in HMPA was higher than that in the others. The degradation of polymer was found to occur as a side reaction during the condensation reaction.PGC was also prepared by the Schotten-Baumann reaction from cinnamoyl chloride and polyglycidol which was obtained by the cationic polymerization of glycidol.Some properties of PGC prepared from epichlerohydrin rubber (PECH) with potassium cinnamate were measured. The relative sensitivity of PGC containing 5-nitroacenaphthene as a sensitizer was ca, 8 times higher than that of KPR; observation for the hange of infrared absorption of C C at 1640 cmin i in PGC caused by ultraviolet irradiation suggested that PGC crosslinks more rapidly than polyvinylcinnamate. The glass transition temperature of PGC was found to be 3

Rheological Behavior of Elastomers. I. Melt Viscosity Characteristics of Uncured Epichlorohydrin Rubber

Abstract The data presented indicates that: Mooney viscosity does not give an accurate indication of the viscosity or heat build-up for the polymers under the shear rates and temperatures experienced in factory operations. A new ane more reliable test is needed. The Brabender plasticorder as well as the Instron have the potential of filling this need. Hydrin 200, a 100 Mooney polymer, has a viscosity similar to Neoprene W and lower than or equal to Hycar 1052 under the conditions of shear and temperature found in usual elastomer processing operations. Hydrin 100, a 56 Mooney polymer, has a viscosity which is lower than either Hycar 1052 or Neoprene W. Both Hydrin 100 and Hydrin 200 exhibit lower heat build-up due to shear induced heating than either Hycar 1052 or Neoprene W. This lower shear heat build-up reduces the danger of scorching during processing. Basic rheological data has been presented for four elastomers: Hycar 1052, Hydrin 100, Hydrin 200 and Neoprene W. This data can be used to obtain a better understanding of the processing characteristics of elastomers.