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We examine the effects of high fullerene nanoparticle (f-NP) concentrations, ?f-NP ∼ (10–20) mass% on polystyrene (PS)/polybutadiene (PB) blend thin film stability. Dewetting of the polymer blend around spinodally clustered f-NPs in this high concentration limit leads to a spinodal like dewetting morphology. This is in contrast to our previously observed results on the stabilization effects of f-NPs on PS/PB blend thin films in the intermediate f-NP concentration range of 7–10 mass%, wherein, after saturating the polymer–blend interface, the NPs stabilize the film by segregating to the blend–substrate interface. We determine three regimes of polymer blend film stability as a function of filler concentration: a) ?f-NP < 7 mass% where preferential segregation of the f-NPs to the polymer–polymer interface leads to macroscopic dewetting, b) ?f-NP ∼ (7–10) mass% where PS/PB blend films exhibit complete film stability, and c) ?f-NP ∼ (11–20) mass%, where spinodal clustering of the f-NPs gives rise to polymer–NP phase exclusion and subsequent dewetting. 相似文献
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A study was done of jute composite using a polymer matrix of epoxidized Novolac resin (ENR), diglycidyl ether of bisphenol A (DGEBA)–based epoxy, and their blends with different weight percentages of the resins. It was found that on blending ENR with DGEBA, the storage modulii at room temperature are enhanced by about 100% or more in the case of 30 and 40% ENR‐containing matrices, whereas the enhancement in the case of 20 and 12% ENR‐containing matrices is only 50% that of the pure matrix. It was also observed that the tan δ peak heights of the composites containing 30 and 40% ENR are closer to that of 20% ENR‐containing composite. The probable explanation drawn on the basis of experimental findings of DMA and mechanical analysis is that by blending ENR with DGEBA epoxy it is possible to manufacture jute composites with increased stiffness without sacrificing their ductility. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 2800–2807, 2002 相似文献
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Septic complications represent frequent causes of morbidity in liver diseases and following hepatic operations. Most infections are caused by the individual own intestinal microflora. The intestinal microflora composition is important in physiological and pathophysiological processes in the human gastrointestinal tract, but their influence on liver in different situations is unclear. We therefore studied the effect of different Lactobacillus strains and a Bifidobacterium strain on the extent of liver injury, bacterial translocation and intestinal microflora in an acute liver injury model.Sprague–Dawley rats were divided into five groups: acute liver injury control, acute liver injury+B. animalis NM2, acute liver injury+L. acidophilus NM1, acute liver injury+L. rhamnosus ATCC 53103, and acute liver injury+L. rhamnosus DSM 6594 and L. plantarum DSM 9843. The bacteria were administered rectally daily for 8 days. Liver injury was induced on the 8th day by intraperitoneal injection of
-galactosamine (1.1 g/kg BW). Samples were collected 24 h after the liver injury. Liver enzymes and bilirubin serum levels, bacterial translocation (to arterial and portal blood, liver and mesenteric lymph nodes (MLNs)), and intestinal microflora were evaluated.L. acidophilus NM1; L. rhamnosus ATCC 53103, and L. rhamnosus DSM 6594+L. plantarum DSM 9843 decreased bacterial translocation compared to the liver injury control group. B. animalis NM2 increased bacterial translocation to the mesenteric lymph nodes. The levels of alanine aminotransferase (ALAT) were significantly lower in the L. acidophilus, L. rhamnosus ATCC 53103, L. rhamnosus DSM 6594+L. plantarum DSM 9843 groups compared to the liver injury group. The L. rhamnosus and L. rhamnosus+L. plantarum groups significantly reduced ALAT levels compared to the B. animalis group. All administered bacteria decreased the Enterobacteriaceae count in the cecum and colon.Administration of different lactobacilli and a Bifidobacterium strain in an acute liver injury rat model, has shown different effects on bacterial translocation and hepatocellular damage. L. acidophilus, L. rhamnosus, and L. rhamnosus+L. plantarum reduced bacterial translocation and hepatocellular damage. B. animalis NM2 increased bacterial translocation to the mesenteric lymph nodes and did not affect hepatocellular damage. 相似文献
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Epoxy [50:50 mixture of Di‐Glycidyl Ether of Bis‐Phenol A (DGEBA) and Epoxidized Novolac (EPN)] was solution blended with Vinyl Acetate‐2‐ Ethylhexylacrylate (VAc‐EHA) resin in aqueous medium, in varying weight fractions, with Hexamethoxymethylmelamine (HMMM) as a crosslinker and data was compared with a control. The present work was aimed to optimize the tensile strength, dynamic mechanical strength, impact strength, and toughness by preparing a blend followed by jute composites of a semi‐ and full interpenetrating network (IPN). In control experiments epoxy alone was crosslinked (semi‐IPN), whereas the DGEBA‐EPN and VAc‐EHA/HMMM were crosslinked separately (full‐IPN), using jute as the substrate for making composites. Composites of full‐IPN systems of epoxy/VAc‐EHA system had higher moduli and UTS than the semi‐IPN systems. Dynamic mechanical study showed that full‐IPN systems have higher Tg values than semi‐IPN systems. The impact strength increases with increasing proportions of VAc‐EHA copolymer. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 958–963, 2004 相似文献
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The mechanical properties such as the tenacity, breaking extension, initial modulus, elastic and work recovery, and stress relaxation behavior of methyl methacrylate (MMA) grafted silk fibers prepared under different conditions were measured and explained in terms of the relative dominance of the stress concentration, reduction in the interchain cohesion, and fiber matrix stiffening at different grafting percentages. The moisture regain characteristics of fibers grafted in the presence of different solvents were also studied and compared. The grafting of MMA on silk was found to improve the recovery properties significantly without affecting the stress relaxation behavior. The moisture regain studies indicate that moisture regain is reduced with increasing length of the grafted poly(MMA) chains. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 969–974, 2002; DOI 10.1002/app.10202 相似文献
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A.M. Adawi A. Cadby L.G. Connolly W.‐C. Hung R. Dean A. Tahraoui A.M. Fox A.G. Cullis D. Sanvitto M.S. Skolnick D.G. Lidzey 《Advanced materials (Deerfield Beach, Fla.)》2006,18(6)
The cover depicts a micropillar microcavity containing a fluorescent organic dye, Lumogen Red, the fabrication of which is described on p. 742 by Lidzey and co‐workers. The optical confinement resulting from the low‐dimensionality of the pillar results in a number of effects, including an enhancement in spontaneous‐emission rate. This process is confirmed using time‐resolved scanning near‐field optical microscopy. Such structures are of interest in the development of new types of low‐threshold lasers and single‐photon light sources for quantum cryptography. 相似文献
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Both specific polycolonal antibody and monoclonal antibody against the microsomal antigen of adult S. mansoni were used to detect antigenaemia and antigenuria by antigen-capture sandwich ELISA in the sera and urine of patients infected with S. mansoni and other parasites. Antigenaemia was detected in 22 sera out of 100 of patients infected with S. mansoni but no antigenuria was detected. None of the sera of S. mansoni free patients were positive for microsomal antigen. More standardization of the technique and more refining of the reagents used is required to improve the sensitivity of the test. 相似文献