Summary: The effectiveness of some thermoplastic elastomers grafted with maleic anhydride (MA) or with glycidyl methacrylate (GMA) as compatibilizer precursors (CPs) for blends of low density polyethylene (LDPE) with polyamide‐6 (PA) has been studied. The CPs were produced by grafting different amounts of MA or GMA onto a styrene‐block‐(ethylene‐co‐1‐butene)‐block‐styrene copolymer (SEBS) (KRATON G 1652), either in the melt or in solution. A commercially available SEBS‐g‐MA copolymer with 1.7 wt.‐% MA (KRATON FG 1901X) was also used. The effect of the MA concentration and of other characteristics of the SEBS‐g‐MA CPs was also studied. The specific interactions between the CPs and the blends components were investigated through characterizations of the binary LDPE/CP and PA/CP blends, in the whole composition range. It was demonstrated that the SEBS‐g‐GMA copolymers display poor compatibilizing effectiveness due to cross‐linking resulting from reactions of the epoxy rings of these CPs with both the amine and the carboxyl end groups of PA. On the contrary, the compatibilizing efficiency of the MA‐grafted elastomers, as revealed by the thermal properties and the morphology of the compatibilized blends, was shown to be excellent. The results of this study confirm that the anhydride functional groups possess considerably higher efficiency, for the reactive compatibilization of LDPE/PA blends, than those of the ethylene‐acrylic acid and ethylene‐glycidyl methacrylate copolymers investigated in previous works.
SEM micrograph of the 75/25 LD08/PA blend (with 2 phr SEBSMA1). 相似文献
In vitro activity of nine cyanobacterial and ten microalgal newly isolated or culture collection strains against eight significant food‐borne pathogens has been evaluated and compared. Water extracts and culture liquids of Gloeocapsa sp. and Synechocystis sp. demonstrated the widest spectrum of activity with minimal inhibitory concentration (MIC) ranging from 1.56 to 12.5 mg mL?1. Culture liquid of Anabaena sp. had the highest activity (MIC = 0.39 mg mL?1) but only to Gram‐positive bacteria. Ethanol extracts and fatty acids from all cyanobacteria and microalgae were active against Streptococcus pyogenes and/or Staphylococcus aureus. The fatty acids of Synechocystis sp. inhibited the growth of Bacillus cereus, Escherichia coli and Candida albicans (MIC values of 2.5–1.25 mg mL?1, respectively). Exopolysaccharides (EPS) of Gloeocapsa sp. were the sample that exhibited activity against all test pathogens with lowest MIC values (0.125–1 mg mL?1). High activity with a narrower range of susceptible targets demonstrated the exopolysaccharides of Synechocystis sp. and Rhodella reticulata. Antimicrobial activity was proven for phycobiliproteins isolated from Synechocystis sp., Arthrospira fusiformis, Porphyridium aerugineum and Porphyridium cruentum, respectively. In conclusion Gloeocapsa sp. and Synechocystis sp. and especially their exopolysaccharides showed the most promising potential against the examined food pathogens. 相似文献
United States regulations require ready-to-eat meat and poultry processors to control Listeria monocytogenes using interventions which may include antimicrobials that reduce post-processing contamination by at least 1 log-cycle; if the treatment achieves ≥2 log reductions, the plant is subject to less frequent microbial testing. Lactic acid (LA) may be useful as a post-lethality intervention and its antimicrobial properties may increase with temperature of application. The aim of this study was to evaluate the effect of LA solution concentration and temperature on L. monocytogenes counts of inoculated frankfurters and to identify parameters (concentration, temperature, and time) that achieve 1 and 2 log-unit immediate reductions. Frankfurters were surface-inoculated with a 10-strain mixture of L. monocytogenes (4.4 ± 0.1 log CFU/cm2) and then immersed in distilled water or LA solutions (0–3%) of 4, 25, 40, or 55 °C for 0–120 s. A regression equation for L. monocytogenes reduction included significant (P < 0.05) effects by the terms of concentration, time, temperature, and the interaction of concentration and temperature; other tested parameters (other interactions, quadratic and cubic terms), within the experimental range examined, did not affect (P ≥ 0.05) the extent of reduction. Results indicated that the effectiveness of LA against L. monocytogenes, in addition to concentration, increased with solution temperature (in the range of 0.6–2.8 log CFU/cm2). The developed equation may allow processors to vary conditions of treatment with LA to achieve a 1 or 2 log-unit reduction of the pathogen and comply with United States regulations. 相似文献
We addressed the issue of C1q autoantigenicity by studying the structural features of the autoepitopes recognized by the polyclonal anti-C1q antibodies present in Lupus Nephritis (LN) sera. We used six fractions of anti-C1q as antigens and selected anti-idiotypic scFv antibodies from the phage library “Griffin.1”. The monoclonal scFv A1 was the most potent inhibitor of the recognition of C1q and its fragments ghA, ghB and ghC, comprising the globular domain gC1q, by the lupus autoantibodies. It was sequenced and in silico folded by molecular dynamics into a 3D structure. The generated 3D model of A1 elucidated CDR similarity to the apical region of gC1q, thus mapping indirectly for the first time a globular autoepitope of C1q. The VH CDR2 of A1 mimicked the ghA sequence GSEAD suggested as a cross-epitope between anti-DNA and anti-C1q antibodies. Other potential inhibitors of the recognition of C1q by the LN autoantibodies among the selected recombinant antibodies were the monoclonal scFv F6, F9 and A12. 相似文献
The Journal of Supercomputing - The holistic analysis and understanding of the latent (that is, not directly observable) variables and patterns buried in large datasets is crucial for data-driven... 相似文献
Two new unsaturated compounds, i. e. triazinyl-2,2,6,6-tetramethylpiperidine derivatives (TTMP), were synthesized under conditions of phase-transfer catalysis and their copolymers with styrene (St) were prepared. The participation of TTMP in the polymerization did not affect the rate of copolymerization, molecular weight and polydispersity of the St polymers. At low concentrations (0.1 wt.-%) a significant stabilizing effect against photodegradation was determined. 相似文献
Doppler broadening of annihilation gamma-line combined with a slow positron beam was used to measure the momentum density distribution of annihilating pair in a set of sintered UO2 samples. The influence of surface polishing, of implantation with 800-keV 136Xe2+ at fluences of 1 × 1015 and 1 × 1016 Xe cm?2, and of annealing were studied by following the changes of the momentum distribution shape by means of S and W parameters. The program used for this purpose was VEPFIT. At the two fluences in the stoichiometric as-implanted UO2, formation of Xe bubbles was not detected. The post-implantation annealing and over-stoichiometry in the as-implanted sample caused Xe precipitation and formation of Xe bubbles. 相似文献