Showing papers on "Nitrile rubber published in 1998"

Performance Improvement of Rubber-Modified Polybenzoxazine

Abstract: Polybenzoxazine as a noble phenolic resin was modified with amine-terminated butadiene acrylronitrile rubber (ATBN) and with carboxyl-terminated butadiene acrylronitrile rubber (CTBN) in order to improve its mechanical properties. The fracture toughness, flexural modulus, and flexural strength of rubber-modified polybenzoxazine were measured to investigate the effect of rubber modification. In fracture toughness, ATBN is more effective than CTBN. ATBN-modified polybenzoxazine showed better distribution of rubber particles in matrix phase than did CTBN-modified polybenzoxazine. The cure rates in these systems were monitored by differential scanning calorimetry to investigate the effect of cure rate on rubber size. The change of glass transition temperatures of rubber-modified polybenzoxazine was measured with a dynamic mechanical thermal analyzer to explain the variation of mechanical properties. In addition, the relationship between mechanical properties and the morphology of rubber-modified polybenzoxazines was also undertaken. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 67: 1–10, 1998

Blends of natural rubber : novel techniques for blending with speciality polymers

Abstract: Introduction. Estimating crosslinked densities in vulcanized blends. Characterization of blends by microscopy. NR/Nitrile rubber blends - basic problems and solutions. Improving the morphology and properties of NR/nitrile rubber blends with graft copolymers. Improving the morphology and properties of NR/nitrile rubber blends with polychloroprene as a compatibilizer. NR/nitrile rubber blends - compounding for food contact applications. Novel NR/EPM blends. Estimation of crosslink density by solid-state NMR spectroscopy. Combining high damping with good physical properties without low temperature dependence. Partition coefficients for ester plasticizers in black-filled blends. Improving resistance to low temperature crystallization. Compounding NR/epoxided natural rubber blends for engineering applications. Solutions to the basic problems of poor physical properties of NR/EPDM blends. Compounding NR/EPDM blends for tyre sidewalls. Compounding NR/EPDM blends for light-coloured applications. Compounding NR/EPDM blends for extruded profiles. NR/EPDM blends: formulation development and processing. An assessment of the CFC-funded project.

Reactive compatibilization of a nitrile rubber/phenolic resin blend: Effect on adhesive and composite properties

Abstract: Resole phenolic resins containing various p-cresol (PC) to phenol (P) mol ratios were prepared and characterized. These phenolic resins were blended with nitrile rubber (NBR) and the measurements of adhesive joint strength, stress–strain properties, DSC, TGA, DMA, TEM, and SEM were performed using a 50 : 50 NBR/phenolic resin blend. It was observed that the adhesive joint strength and the mechanical properties of the blend enhanced significantly on incorporation of p-cresol into the phenolic resin, and the optimum p-cresol/phenol mol ratio was in the vicinity of 2 : 1. Observation of a more continuous phase and the increase in Tg of the rubber region in the blend indicated increased reactivity and compatibilization of NBR with phenolic resin as p-cresol was incorporated. The effect of silica filler on the properties of the nitrile rubber/phenolic resin blend was also studied without and with p-cresol modification and the results suggest that silica filler take not only the role of a reinforcing filler in the nitrile–phenolic–silica composite, but also a role as surface compatibilizer of the blend components. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 69: 1187–1201, 1998

Electrical and mechanical properties of polyethylene–rubber blends

Abstract: A systematic electrical and mechanical study was carried out on styrene butadiene rubber (SBR), as a nonpolar rubber, and nitrile rubber (NBR), as a polar one blended with pure and waste polyethylene (PE), low and high density. The compatibility investigations, which were carried out by the dielectric method and confirmed by the calculated heat of mixing, indicate that SBR–PE blends (either low or high density) are compatible, while NBR–PE blends are incompatible. From the electrical and mechanical results, it is found that the addition of waste PE to either polar or nonpolar rubber leads to better electrical and mechanical properties when compared with those for the blends having pure PE. The values of permittivity e′ are found to increase pronouncely, while the values of dielectric loss e′ slightly decrease. Shore hardness was also measured for all the investigated systems and found to vary linearly with the permittivity e′. © 1998 John Wiley & Sons, Inc. J Appl Polm Sci 69: 775–783, 1998

Thermoplastic compositions containing elastomers and fluorine containing thermoplastics

Abstract: A thermoplastic vulcanizate prepared by dynamically vulcanizing a rubber within a blend that comprises the rubber, a fluorine containing thermoplastic, and a vulcanizing agent; wherein the rubber is selected from nitrile rubber, hydrogenated nitrile rubber, amino-functionalized nitrile rubber, acrylonitrile-isoprene rubber, and mixtures thereof.

Processed fiber which is bondable to a rubber composition and a power transmission belt incorporating the processed fiber

Abstract: Processed fiber for bonding to a rubber composition. The processed fiber consists of unprocessed fiber treated with a) a first processing liquid having at least one of an isocyanate compound and an epoxy compound, b) a second processing liquid having RFL that includes at least one rubber latex selected from acrylonitrile-butadiene rubber latex and hydrogenated nitrile rubber latex, and c) a third processing liquid having rubber paste including acrylonitrile-butadiene rubber composition dissolved in a solvent and an isocyanate compound. The weight ratio of the isocyanate compound to the acrylonitrile-butadiene rubber composition is from 1/1 to 1/3. The third processing liquid has a solid content of from 3-7%.

Electrical and mechanical properties of grafted and ungrafted polyacrylamide–rubber blends

Abstract: A systematic dielectric and mechanical study was carried out on an ethylene propylene diene monomer (EPDM) and a nitrile rubber (NBR) blended with polyacrylamide (PAM). From the compatibility investigations, it was found that EPDM/PAM is incompatible while NBR/PAM is semicompatible. To overcome the problem of phase separation between rubber and PAM, PAM was grafted with two different monomers, acrylonitrile (AN) and acrylic acid (AA), and added with 10 phr to both EPDM and NBR. Poly(vinyl chloride) (PVC) was also added as a compatiblizing agent to both types of blend. It was concluded that the addition of either a grafted polymer or PVC to the rubber–plastic blend could improve to some extent the compatibility of such blends. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 70: 2053–2059, 1998

Thermoplastic vulcanizates of carboxylated nitrile rubber and polyester thermoplastics

Abstract: Low oil swell, processable carboxylated nitrile rubber thermoplastic vulcanizate compositions having high melting points are made utilizing a processing aid, for example, maleated polyethylene, and addition type curing agents such as bisoxazolines or bisimidazolines. The compositions generally contain polar thermoplastic high melting point crystalline polymers such as polyester as a continuous phase with the carboxylated nitrile rubber being dispersed therein.

Intensification of interfacial interaction in dynamic vulcanization

Abstract: The mechanical properties of dynamic vulcanizates depend very much on the attractive forces between the thermoplastic and rubber phases. Both in situ and separately formed block and graft copolymers were successfully used to intensify these inter facial interactions in a polymer system of polypropylene and nitrile rubber to gain a thermoplastic rubber with both excellent mechanical properties and oil resistance.

Heat conductive material

Abstract: thermally conductive material having excellent flexibility high thermal conductivity, providing no possibility of heat-conducting material which leads to electrical contacts disorder. A heat conductive material of the present invention, the synthetic resin material as a base material, adding hydrate of metal compound as the thermally conductive filler is a mixture. Thermally conductive filler, Aluminum hydroxide, magnesium hydroxide, zinc hydroxide, calcium hydroxide, tin hydroxide, and the like other metal hydrate. The substrate is a synthetic rubber, EPDM, butyl rubber, chloroprene rubber, acrylic rubber, nitrile rubber, fluorocarbon rubber, chlorosulfonated polyethylene rubber, styrene - butadiene rubbers are preferred. Also, oil may be added to increase flexibility. The oil, process oil, liquid paraffin, fatty oil, chlorinated paraffin, ester plasticizers, liquid rubbers, Liquid butadiene, and hydrocarbon-based synthetic lubricating oils are preferred.

Polyvinyl chloride elastomers

Abstract: Thermoplastic elastomers including a polyvinyl chloride and a nitrile rubber additive are disclosed. The nitrile rubber additive can be cross-linked and/or essentially free of plasticizer. The thermoplastic elastomers can include additional materials, such as copolyester and/or a plasticizer. The thermoplastic elastomers can be soft, elastomeric and/or oil resistant. The thermoplastic elastomers can have good low temperature properties. The thermoplastic elastomers can have good flame retardant, smoke suppressant and/or char forming properties.

Rubber laminated metal panel

Abstract: PROBLEM TO BE SOLVED: To provide a rubber laminated metal panel satisfying a long-term air heating aging test, for example, at a high temp. of 175°C and also excellent in anti-freeze resistance. SOLUTION: A rubber laminated metal panel is obtained by laminating a vulcanizate layer of a nitrile rubber or hydrogenated nitrile rubber containing a liquid plasticizer on the single surface or both surfaces of a metal panel subjected to the surface treatment with a composite chromate treatment agent through an adhesive containing a bisphenol A type epoxy resin and a resole type phenol resin. In this case, one of or both of a novolac type phenol resin and (hydrogenated) nitrile rubber compd. containing the liquid plasticizer can be further added to this adhesive. COPYRIGHT: (C)1999,JPO

Synergism in properties of ionomeric polyblends based on zinc salts of maleated high‐density polyethylene and carboxylated nitrile rubber

Abstract: An ionic thermoplastic elastomer (ITPE) was prepared by melt blending zinc salts of carboxylated nitrile rubber (Zn–XNBR) and maleated high-density polyethylene (Zn–mHDPE). The synergism in physical properties of the ITPE is due to the formation of strong intermolecular ionic crosslinks, which act as a compatibilizer. Infrared studies revealed that ionic interactions are stronger in the ionomeric polyblends as compared to the neat ionomers. The ionomeric polyblend of Zn–XNBR/Zn–mHDPE shows higher physical properties than those of the corresponding nonionomeric polyblend of XNBR/mHDPE. Dynamic mechanical thermal analyses showed the occurrence of a high-temperature transition in the neat ionomers and the ionomeric polyblend, due to the relaxation of the restricted mobility region in the ionic cluster region, but it is absent in the nonionomeric polyblend. Reprocessability studies and measurements of physical properties show the thermoplastic elastomeric nature of the ionomeric polyblend. © 1998 John Wiley & Sons, Inc. J. Appl. Polym. Sci. 70: 483–492, 1998

Sequential interpenetrating polymer network based on nitrile–phenolic blend and poly(alkyl methacrylate)

Abstract: Interpenetrating polymer networks (IPNs) based on a nitrile rubber (NBR)–phenolic resin (PH) blend and poly(alkyl methacrylates) were synthesized by a sequential method. The cured blends were swollen in a methacrylate monomer containing a crosslinker and initiator. The swollen rubber sheets were cured at 60°C. From the swelling study of the monomer, it was found that IPN formation in the blend is in between the rubber and poly(alkyl methacrylate) phases only. The IPNs thus formed were characterized for their tensile, dynamic mechanical, and solvent-resistance characteristics. The tensile strength of the IPNs are dependent on the PH content; at a lower content of PH (up to 20 parts), IPNs have a higher strength compared to their corresponding blends, whereas at a higher content of PH (beyond 30 parts), the strength decreases. But for every NBR/PH-fixed composition, the strength of IPNs was found to be increasing in the order of PBuMA < PEMA < PMMA. The dynamic property results showed that NBR/PH blends are incompatible. The storage modulus of IPNs are always higher than their corresponding blends at all temperatures. The tan δ peaks of IPNs are broad, indicating the presence of microphase-separated domains. The IPNs show superior solvent-resistance characteristics compared to the blends. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 68:255–262, 1998

Ionic elastomer Blends of zinc salts of maleated EPDM rubber and carboxylated nitrile rubber

Abstract: Blends of zinc salts of maleic anhydride-grafted EPDM rubber and carboxylated nitrile rubber behave as ionic elastomers. Measurement of physical properties suggest that the blend is compatible. It is proposed that the compatibility arises presumably due to formation of interfacial ionic aggregates. Dynamic mechanical and infrared spectroscopic studies reveal that the ionic aggregates can be solvated by ammonia. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 69: 153–160, 1998

High shock absorbing rubber compositions

Abstract: A high shock absorbing rubber composition comprises a cured blend of a conjugated diene rubber such as natural rubber or nitrile rubber with an EPDM rubber, and significant amounts of silica and optionally clay. The cured composition has low pendulum rebound properties of 20% or less, and is suitable for use as sport grips such as tennis rackets or golf grips, hand tools, lawn equipment, and the like.

Rubber-plastic elastomer material and its preparation

Abstract: The elastomer material is prepared through plastication of polypropylene grafted by maleic anhydride, nitrile rubber aminated by amine initiator, chlorinated polyethylene, plasticizer, stearic acid, antioxidant 1010 and stannous chloride in certain proportion The said product is processed and formed through the method for thermoplastic plastic rather than the complicated sulphurization process for rubber product, and this can save power, reduce cost and raise productivity The said material may be used for heat and oil resisting product, such as sealing part, pipe, etc and its performance may reach that of similar rubber product

Aging of vulcanizates of formulations for rubber seals

Abstract: Typical formulations based on NBR (acrylonitrile butadiene rubber), EPDM (ethylene propylene diene monomer rubber), and a NBR–CR (polychloroprene rubber) blend were studied for various properties under accelerated air aging conditions. The trend in tensile properties indicated the propensity of these formulations to oxidative degradation. The derivatives of these properties, such as their retention indices, strain energy, and Mooney–Rivlin constants also showed similar trends. Some of the observations correlate to shelf-aging data, but the time to rupture data derived from ultimate elongation values did not provide tangible conclusions. © 1998 John Wiley & Sons, Inc. J. Appl. Polym. Sci. 70: 985–994, 1998

Thermoset adhesive and flexible printed circuit board material by using the same

Abstract: PROBLEM TO BE SOLVED: To obtain the subject adhesive, capable of sustaining heat resistance for a long time and hardly causing the decrease in peel strength even if the adhesive is heated and treated at a high temperature for a long time by including an epoxy resin, a specific rubber mixture, a hardener and a specified hardening accelerator. SOLUTION: The objective composition comprises (A) 100 pts.wt. epoxy resin, (B) 30-150 pts.wt. mixture of a nitrile rubber obtained by mixing (i) the nitrile rubber having 20-50 wt.% acrylonitrile content, 0.005-5% end carboxyl group content and 200-350 iodine number, with (ii) the nitrile rubber having 20-50 wt.% acrylonitrile content, 0-60 iodine number and no functional group at the end, and regulated so that the mixing weight ratio of components (i)/(ii) may be (40/60)-(85/15), (C) 2-20 pts.wt. hardener and (D) 0.1-3 pts.wt. hardening accelerator selected from imidazole compound, a borofluoride material and an octylic acid salt.