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381.
Resilient metal spring silicone-matrix conducting composites for separable interconnections in electronics were fabricated
by the impregnation of silicone into a preform comprising randomly oriented C-shaped Cu-Be springs and a small proportion
of Sn-Pb solder, which served to connect the springs at some of their intersections. Composites containing 6.1-9.8 vol.% total
filler exhibited volume electrical resistivity 0.5-1.0 mΩ.cm and contact resistivity (with copper) 11-17 mΩ.cm2. A compressive stress of about 30 kPa was needed for the low contact resistivity to be reached. The volume 17-26% and the
contact resistivity increased by 5% after heating in air at 130-150°C for seven days. Composites containing <9 vol.% total
filler showed no stress relaxation for seven days at 6.0% strain. 相似文献
382.
383.
Zhiyong Xia Douglas B. Trigg Timothy J. Montalbano Daniel Rose 《Journal of Macromolecular Science: Physics》2020,59(6):390-398
AbstractFour natural rubber-based phase changing materials (PCMs) were synthesized and evaluated with the goal of achieving controlled stiffness modulation at elevated temperatures (~100-120?°C). The phase changing was achieved through either the glass transition or melt transition of one of four phase changing fillers: polystyrene, poly(methyl methacrylate), low density polyethylene, and indium tin alloy. The PCM stiffness was analyzed using dynamic mechanical analysis and the results showed that all four PCMs exhibited two thermal transitions: a low temperature transition at ?58?°C due to the glass transition of the natural rubber matrix and a high temperature transition at ~100-120?°C due to the thermal transitions in the four filler materials. The degree of stiffness change of all PCMs at 100-120?°C was found to be strongly influenced by the type of the phase changing filler as well as the type of thermal transition (glass transition versus melt transition). The compatibilities of the phase changing materials were analyzed using the Flory-Huggins interaction parameter and it was shown that natural rubber and low density polyethylene had the best compatibility. All systems exhibited effective stiffness modulation with the change in temperature, enabling them to be used for applications requiring variable stiffness control. 相似文献
384.
Yuko Ikeda Kazutoshi Kodama Kanji Kajiwara Shinzo Kohjiya 《Journal of Polymer Science.Polymer Physics》1995,33(3):387-394
Poly(ethylene oxide)-grafted butyl rubbers (IIR-g-PEOs), which were synthesized from potassium salt of polyethylene glycol monomethyl ether (PEGM) and chlorinated butyl rubber, were found to behave like thermoplastic elastomers. The poly(ethylene oxide) (PEO) content of these amphiphilic polymers was ca. 10 wt %, and their PEO lengths were 750, 2000, and 5000, respectively. The grafted segments of PEO in butyl rubber (IIR) aggregated to form the PEO domains in IIR matrix. At constant PEO content, the longer the PEO segment length, the larger the size and the crystallinity of PEO domains became. This PEO domain worked as a cross-linking site and a reinforcing filler. The degree of swelling in water of IIR-g-PEO film that was prepared from PEGM-5000 was largest, but its emulsification ability was smallest among them. © 1995 John Wiley & Sons, Inc. 相似文献
385.
Based on the van der Waals-equation of state a characterization of the elastic properties of molecular networks in the total range of strain is presented by the use of Mooney-Rivlin plots. This discussion elucidates the importance of finite chain extensibility as well as global interactions for a quantitative interpretation of the deformation properties of molecular networks. An interpretation of the so-called Mooney-Rivlin coefficients in terms of the van der Waals-parameters delivers at least a novel, yet very consistent understanding of simple extension of swollen networks. 相似文献
386.
387.
The objective of this paper is to show an easy and rapid way to determine qualitatively and quantitatively the type of polymer
or polymer blend used in a rubber formulation. The most common polymers used manufacturing rubber products were tested and
characterized by both their decomposition temperature and the curve profile. Thermogravimetric analysis, which is considered
to be used mainly for quantitative purposes, turned out to be a rather useful analytical tool to obtain qualitative information
of such elastomeric mixtures.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
388.
C. Mao A. P. Zhu Y. Z. Qiu J. Shen S. C. Lin 《Colloids and surfaces. B, Biointerfaces》2003,30(4):299-306
Based on an in vitro test for an improvement of the blood compatibility of silicone rubber (SR) films by grafting O-butyrylchitosan (OBCS), OBCS was covalently immobilized onto SR film surface using the photosensitive hetero-bifunctional crosslinking reagent, 4-azidobenzoic acid, which was previously bonded to OBCS by reaction between an acid group of the crosslinking reagent and a free amino group of OBCS. Surface properties of SR film were investigated by attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), electron spectroscopy for chemical analysis (ESCA) and the water contact angle measurements. The blood compatibility of SR film was evaluated by platelet rich plasma (PRP) contacting experiments and the results were observed by scanning electron microscopy (SEM). The state of platelet adhesion was described. The suitable modifications could be carried out to tailor SR films biomaterial to meet the specific needs of different biomedical applications. These results suggest that the blood compatible of SR films/OBCS films show their suitability as potential biomaterials. 相似文献
389.
Curing and mechanical behavior of carboxylated NBR containing hygrothermally decomposed polyurethane
C.Radhesh KumarJ Karger-Kocsis 《European Polymer Journal》2002,38(11):2231-2237
Hygrothermally decomposed polyester-urethane (HD-PUR) has been added as modifier (up to 20 phr) to sulfur crosslinked carboxylated nitrile rubber (XNBR). The curing and mechanical characteristics of the XNBR have been investigated as a function of the HD-PUR loading in presence and absence of carbon black (CB). The addition of HD-PUR increased the cure rate of both unfilled and CB filled XNBR but resulted in compounds of lower crosslink density and thus of lower stiffness and strength. Based on infrared spectroscopic results it was speculated that the amine functionality of HD-PUR affected the formation of the ionic clusters formed by the reaction between the -COOH groups of XNBR and ZnO. This occurred likely via a coordination complex. Evidence was also found for the formation of -CONH- linkages. Both coordination complexing and chemical reaction between -COOH and -NH2 resulted in a lower overall “crosslinking degree” and as a consequence HD-PUR acted as plasticizer in XNBR. 相似文献
390.
《Surface and interface analysis : SIA》2003,35(12):953-959
Direct adhesion between Ni–P‐plated iron and acrylonitrile–butadiene rubber, hydrogenated acrylonitrile–butadiene rubber and ethylene–propylene rubber was successful using 1,3,5‐triazine‐2,4,6‐trithiol monosodium salt (TTN) without any adhesive. Peel strength in the adherends was influenced by the amount of TTN employed. The interfacial structure between Ni–P‐plated iron and curing rubbers has been investigated with x‐ray microanalysis, x‐ray photoelectron spectroscopy and scanning electron microscopy. The TTN derivatives gathered locally at the interface between the Ni–P‐plated iron and curing rubber adherends. The TTN layer located near the interface is referred to as a reinforcement layer. This layer was in general ~70 nm thick and consisted of composites of the Ni salt of TTN. The TTN is thought to work as a binder that bonds between Ni–P‐plated iron and rubber chains. The single bonds between both Ni–P‐plated iron and rubber TTN was confirmed from Kraus plots and model experiments using TTN. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献