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41.
Kar Tean Tan Christopher C. White Donald Hunston Justin M. Gorham Michael J. Imburgia Aaron M. Forster Bryan D. Vogt 《Polymer Engineering and Science》2016,56(1):18-26
Joints held by polymeric adhesives are commonplace in many engineered products, but normal service can require exposure to environmental conditions that present a significant challenge for maintaining the structural integrity of the interface. In particular, aqueous environments can wreak havoc on the joint strength. Here, a mechanistic approach is used to understand the difference in the debonding behavior of an epoxy/aluminum (oxide) interface when exposed to deionized (DI) water and aqueous sodium chloride by correlating macroscopic failure with the sorption of salt and water into the adhesive and its nanoscale distribution. For the epoxy‐aluminum system examined here, the presence of sodium chloride increases the resistance to crack growth in comparison to DI water. The debonding appears to be controlled by water near the buried interface. Salt water decreases the solubility of water in the epoxy and decreases the concentration of water near the buried interface, but the concentration of salt that enters the epoxy is below the detection limit. Thus, even if ions cannot penetrate or sorb into the adhesive, the presence of salt can significantly alter the water distribution within the adhesive and ultimately the strength of the joint. POLYM. ENG. SCI., 56:18–26, 2016. © 2015 Society of Plastics Engineers 相似文献
42.
Reduction of the elongation at break of thermoplastic polyolefins through melt blending with polylactide and the influence of the amount of compatibilizers and the viscosity ratios of the blend components on phase morphology and mechanics 下载免费PDF全文
Carolin Vogt Hans‐Josef Endres Jürgen Bühring Henning Menzel 《Polymer Engineering and Science》2016,56(8):905-913
The objective of this work is the synthesis of a polypropylene/ethylene‐propylene‐rubber (TPO)/polylactide (PLA)/compatibilizer (PVM) blend to reduce the elongation at break of TPO by blending TPO with brittle PLA. Three TPO types with different viscosities were melt blended with PLA and an ethylene/n‐butylacrylate/glycidyl methacrylate terpolymer (PVM) as reactive compatibilizer. All blends had a constant PLA amount of 30 wt%. Two parameters were varied in the experiments, viscosity of the TPO types, and amount of PVM used in the blends. Both parameters played important roles in reducing the nominal elongation at break compared to pure TPO foils and influencing the phase morphology of extruded blend foils. The nominal elongation at break could be reduced by 100‐150% through blending TPO with PLA and PVM. Characterization regarding the blend morphology, especially the size and shape of the dispersed PLA phase in the TPO matrix was done by Environmental Scanning Electron Microscopy (ESEM) images. Investigations of the morphology showed that size and shape of dispersed PLA phases are dependent on the viscosity ratios of the blend components and on the amount of compatibilizer in the blend. AFM images of the polymer blends reveal soft rubbery layers around the dispersed PLA phases. POLYM. ENG. SCI., 56:905–913, 2016. © 2016 Society of Plastics Engineers 相似文献
43.
Seven novel high refractive index (HRI) acrylic monomers, comprising the quinolinone structural motive, have been synthesized and characterized. Cross-linked homo- as well as copolymers were prepared by photochemical bulk polymerization. The homopolymers show refractive indices at 589 nm (n 589) ranging from 1.60 up to 1.68, glass transition temperatures (T g) from 52 to 76 °C, and Abbe numbers (ν Abbe) of 19 to 25. Due to these parameters, the homopolymers are not suitable to be used directly for intraocular lens (IOL) manufacture, but the quinolinone monomers may be used as high refractive index components in copolymers. Potential mixtures were calculated theoretically and one example, a copolymer with PEA and PEGPEA, was prepared and characterized. The experimentally found values were T g?=?24 °C, n 589?=?1.593, and ν Abbe?=?28.3. Interestingly, the quinolinone compound which does not have any spacer between the polymerizable group and the high refractive index group appears to be the most useful one. The lightfastness of the new material fulfills the demands for IOLs. Quinolinone derivatives are promising new comonomers for high refractive index copolymers. 相似文献
44.
Dr.‐Ing. Andrea Ohle Michael Obst Prof. Dr.‐Ing. Norbert Mollekopf Prof. Dr.‐Ing. Leon Urbas 《化学,工程师,技术》2014,86(5):640-648
Modularization has been identified as one of the research fields of the ?50 % idea”?. A development methodology for modules must consider both the economies of scale for investment costs and costs of operation and maintenance. In this paper, the impact of an absorber module, which is offered as discretized diameter scaling, on the total process is investigated at the example of the CO2 separation from biogas. The simulation shows the effect of this approach to the stripper diameter and the energy demand of the process. The calculations form the basis for applying cost models. 相似文献
45.
Christian Monsé Christian Monz Dirk Dahmann Christof Asbach Burkhard Stahlmecke Norbert Lichtenstein 《Aerosol science and technology》2014,48(4):418-426
In the EU there is an increasing need for regulatory agencies to derive health based threshold limits based on human inhalation studies with airborne particles. A necessary prerequisite for such projects is the development of a suitable generator system to produce nanoparticle test aerosols for human whole-body inhalation studies. We decided to use a generator with flame-based heating of aqueous precursor solutions. Validation of the test system was done by generating zinc oxide (ZnO) nanoparticles with minimal contamination of trace gases, i.e., nitric oxides or carbon monoxide that could confound the effects seen in exposed subjects. ZnO was selected based on the uncertainties surrounding its health effects after exposure at the workplace. The generation process of the developed flame generator yields ZnO nanoparticles with monomodal size distribution and very good temporal stability. The maximum target exposure mass concentration of 2 mg/m3 ZnO, with a resulting median particle diameter of 57 nm, is attainable in our human exposure laboratory. The morphological examination shows typical agglomerates and aggregates formed by high temperature processes. Overall, the performed experiments confirm that a constant exposure can be provided for all subjects at all times.
Copyright 2014 American Association for Aerosol Research 相似文献
46.
Gerhard Heise Andreas Brner Marcel Dickmann Marina Englmaier Andreas Heiss Matthias Kemnitzer Jan Konrad Regina Moser Jrg Palm Helmut Vogt Heinz P. Huber 《Progress in Photovoltaics: Research and Applications》2015,23(10):1291-1304
In this paper, we present the selective structuring of all three patterns (P1, P2 and P3) of a monolithic interconnection of CIS (Cu(In,Ga)(S,Se)2) thin film solar cells by picosecond laser pulses at a wavelength of 1064 nm. We show results for single pulse ablation threshold values and line scribing of molybdenum films on glass (P1), CIS on molybdenum (P2) and zinc oxide on CIS (P3). The purposes of these processes are the p‐type isolation (P1), cell interconnect (P2) and n‐type isolation (P3), which are required for complete cell architecture. The half micron thick molybdenum back electrode can be structured with a process speed of more than 15 m/s at about 15 W average power without detectable residues and damage by direct induced laser ablation from the back side (P1). The CIS layer can be structured selectively down to the molybdenum at process speeds up to 1 m/s at about 15 W average power, due to the precision of direct laser ablation in the ultrashort pulse regime (P2). The ZnO front electrode layer is separated by clean trenches with straight side walls at process speeds of up to 15 m/s at about 10 W average power, as a result of indirect induced laser ablation (P3). A validation of functionality of all processes is demonstrated on CIS solar cell modules (30 × 30 cm2). By replacing one state‐of‐the‐art process by a picosecond laser process at a time, solar efficiencies could be increased for P1 and P2 and stayed on a similar level for P3. After an optimization of the patterning processes in the R&D pilot line of AVANCIS, we achieved a new record efficiency for an all‐laser‐patterned CIS solar module: 14.7% as best value for the aperture area efficiency of a 30 × 30 cm2 sized CIS module was reached. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
47.
Norbert J. M. Kuipers Antonie A. C. M. Beenackers 《Polymer Engineering and Science》1996,36(16):2108-2118
A mathematical model is presented for non-Fickian diffusion of a penetrant A into a granular glassy polymer containing a reactive group B, resulting in the desired product P. Further, both a consecutive reaction between A and P (producing X) and a parallel reaction between A and C (producing Y) are incorporated, with C initially present in the particle. The swelling of the polymer, induced by the penetrant, is described by power-law kinetics for the velocity of the swelling front. Kinetics are considered to be first order in each of the two reactants. Concentration profiles in the particle and selectivity to desired product are calculated as function of the swelling behavior of the polymer grain. In case of a consecutive reaction the local concentration of P reaches a maximum value independent of the swelling rate. However, the position of the maximal concentration of P moves towards the center of the grain with a rate depending on the kinetics of swelling. For Case II diffusion this velocity equals the velocity of the advancing front between glassy and rubbery polymer. The selectivity of the desired reaction decreases with decreasing swelling rate. A low swelling rate also results in an inhomogeneous product distribution within the granule. A criterion is derived predicting under what conditions the consecutive reaction can be neglected and a pure product is obtained. The analysis further reveals that both a more homogeneous product and a higher selectivity toward a desired product can be obtained by realizing preswelling of the polymer with an inert swelling agent. For Case II diffusion the concentration profiles of the side product of the parallel reaction, Y, are flat in the rubbery part of the polymer. This is caused by the relatively low swelling rate allowing Y to redistribute in the swollen polymer. If additional C is continuously supplied from the gas phase, then the selectivity decreases continuously with increasing conversion of B. 相似文献
48.
Investigations on the Amylose Determination in High Protein Starch Source Materials, Especially Peas. The proposed utilization of amylose rich starches requires different methods of amylose determination. In addition to laboratory methods also simple tests are important to that. Because the discussed legume starches are hardly investigated, first of all the suitability of the amperometric iodine titration had to be checked. Then a more easier work was described. In the case of routine analyses a modified test procedure was compared with the method of iodine titration. 相似文献
49.
50.
Akylbek Sydykov Himal Luitel Argen Mamazhakypov Malgorzata Wygrecka Kabita Pradhan Oleg Pak Aleksandar Petrovic Baktybek Kojonazarov Norbert Weissmann Werner Seeger Friedrich Grimminger Hossein Ardeschir Ghofrani Djuro Kosanovic Ralph Theo Schermuly 《International journal of molecular sciences》2020,21(23)
Although the response of the right ventricle (RV) to the increased afterload is an important determinant of the patient outcome, very little is known about the underlying mechanisms. Mast cells have been implicated in the pathogenesis of left ventricular maladaptive remodeling and failure. However, the role of mast cells in RV remodeling remains unexplored. We subjected mast cell-deficient WBB6F1-KitW/W-v (KitW/KitW-v) mice and their mast cell-sufficient littermate controls (MC+/+) to pulmonary artery banding (PAB). PAB led to RV dilatation, extensive myocardial fibrosis, and RV dysfunction in MC+/+ mice. In PAB KitW/KitW-v mice, RV remodeling was characterized by minimal RV chamber dilatation and preserved RV function. We further administered to C57Bl/6J mice either placebo or cromolyn treatment starting from day 1 or 7 days after PAB surgery to test whether mast cells stabilizing drugs can prevent or reverse maladaptive RV remodeling. Both preventive and therapeutic cromolyn applications significantly attenuated RV dilatation and improved RV function. Our study establishes a previously undescribed role of mast cells in pressure overload-induced adverse RV remodeling. Mast cells may thus represent an interesting target for the development of a new therapeutic approach directed specifically at the heart. 相似文献