Laser confocal microscopical characterization of toughened epoxy resins: Correlations between structural features and mechanical properties

2017 ◽  
Vol 135 (14) ◽  
pp. 46094 ◽  
Author(s):  
Laura Hader-Kregl ◽  
Gernot M. Wallner ◽  
Reinhold W. Lang ◽  
Bernhard Strauß
Keyword(s):  
Mechanical Properties ◽  
Epoxy Resins ◽  
Structural Features ◽  
Toughened Epoxy

scholarly journals Mechanical characterization of different epoxy resins enhanced with carbon nanofibers

2020 ◽  
Vol 15 (55) ◽  
pp. 198-212
Author(s):  
Paulo Sérgio Pina dos Santos ◽  
A. Maceiras ◽  
S. Valvez ◽  
P.N.B. Reis
Keyword(s):  
Mechanical Properties ◽  
Stress Relaxation ◽  
Strain Rate ◽  
Carbon Nanofibers ◽  
Viscoelastic Properties ◽  
Epoxy Resins ◽  
Mechanical Characterization ◽  
Low Cost ◽  
International Standards

Epoxy with carbon nanofibers (CNFs) are effective nano enhanced materials that can be prepared by easy and low-cost method. The present paper compares the improvements, in terms of flexural and viscoelastic properties, of two epoxy resins reinforced with different weight percentages (wt.%) of CNFs. These epoxy resins have different viscosities, and weight contents between 0% and 1% of CNFs were used to achieve the maximum mechanical properties. Subsequently, for the best configurations obtained, the sensitivity to the strain rate and the viscoelastic behaviour (stress relaxation and creep) were analysed based on international standards. It was possible to conclude that, for both resins, carbon CNFs promote significant improvements in all the studied mechanical properties, even for different contents by weight.    

scholarly journals Epoxy Composites Based on Resins Having High Flexibility Reinforced with Functionalized Carbon Nanotubes

2017 ◽  
Vol 54 (1) ◽  
pp. 125-128
Author(s):  
Magdalena Adriana Ladaniuc ◽  
Gheorghe Hubca ◽  
Raluca Gabor ◽  
Cristian Andi Nicolae ◽  
Elvira Alexandrescu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Epoxy Resins ◽  
Hydroxyl Groups ◽  
Reinforced Composites ◽  
Functionalized Carbon Nanotubes ◽  
Weight Concentration ◽  
High Flexibility ◽  
Functionalized Mwcnts

The present paper was aimed at achieving a study on carbon nanotubes-reinforced composites and involved obtaining and characterization of composites based on epoxy compounds modified with hydroxyl groups-containing compounds (glycols). In order to obtain high flexibility epoxy resins-based composites, carboxyl- functionalized MWCNTs were used as filler at a concentration of 0.5 %. The influence of the weight concentration in CNTs on the mechanical and thermo -mechanical properties of the epoxy compounds was evaluated in comparison to mechanical properties of the DGEBA standard composites reinforced with 0.5 % MWCNT.

scholarly journals Production and Characterization of Animal Waste Reinforced Composite Materials By Powder Metallurgy

2021 ◽  
Author(s):  
Assoc. Prof. Dr. Ahmet YONETKEN ◽  
Ayhan EROL ◽  
Gunnur Pesmen
Keyword(s):  
Mechanical Properties ◽  
Composite Materials ◽  
Boron Carbide ◽  
Structural Features ◽  
Industrial Applications ◽  
Sintering Process ◽  
Reinforced Composite ◽  
Powder Samples ◽  
Composite Production

Abstract Boron carbide is a product used for reinforcement in composite production and frequently used in the defense industry. The fact that boron carbide behaves similarly to the mechanical properties of bone and that titanium is strengthened with boron carbide, which is used as a biomaterial, causes it to be preferred among composite materials. It also makes it attractive to use in industrial applications at high temperatures. It is known that Fe-B4C composites are used together with Fe matrix materials to improve the properties of the group in addition to elements such as Cr, especially Ti, Co, Mo and Fe in various application areas. This makes it frequently used in the sintering process. In this study, 98,33%Fe-1,66%B4C, 96.66%Fe-1,66%B4C-1,66%eggshell powders, 95%Fe-1,66%B4C-3,32%eggshell powders, 93,33%Fe-1,66%B4C-5%eggshell powders and 91,66%Fe-1,66%B4C-6,66% eggshell powder samples were prepared using the compositions of. It is formed in a single axis press under 400bar pressure. When the mechanical and metallographic properties of the samples produced after sintering at 1400 ᵒC were examined, the effects of eggshell powders on composite samples produced by adding Fe-B4C composite and eggshell powders in different compositions were observed. 1,66% to 6,66% eggshell powders additive was used in the compositions and mechanical properties were determined in the produced samples. Structural features were tried to be determined by looking at metallographic analyses. The densities of the produced samples were calculated and their hardness and strength were determined. According to the analysis results, 3,33% Egshelters composition and 3,71 gr/cm3 density and 285,5 HV hardness values ​​at 1400 °C were obtained.

Skeletal elements of crinoid echinoderms: High-resolution structural and microanalytical results

1983 ◽  
Vol 41 ◽  
pp. 194-195
Author(s):  
D. F. Blake ◽  
L. F. Allard ◽  
D. R. Peacor
Keyword(s):  
High Resolution ◽  
Marine Invertebrates ◽  
Sea Urchins ◽  
Structural Features ◽  
Sea Stars ◽  
High Resolution Tem ◽  
Relationship Of ◽  
The Relationship ◽  
Insight Into

Echinodermata is a phylum of marine invertebrates which has been extant since Cambrian time (c.a. 500 m.y. before the present). Modern examples of echinoderms include sea urchins, sea stars, and sea lilies (crinoids). The endoskeletons of echinoderms are composed of plates or ossicles (Fig. 1) which are with few exceptions, porous, single crystals of high-magnesian calcite. Despite their single crystal nature, fracture surfaces do not exhibit the near-perfect {10.4} cleavage characteristic of inorganic calcite. This paradoxical mix of biogenic and inorganic features has prompted much recent work on echinoderm skeletal crystallography. Furthermore, fossil echinoderm hard parts comprise a volumetrically significant portion of some marine limestones sequences. The ultrastructural and microchemical characterization of modern skeletal material should lend insight into: 1). The nature of the biogenic processes involved, for example, the relationship of Mg heterogeneity to morphological and structural features in modern echinoderm material, and 2). The nature of the diagenetic changes undergone by their ancient, fossilized counterparts. In this study, high resolution TEM (HRTEM), high voltage TEM (HVTEM), and STEM microanalysis are used to characterize tha ultrastructural and microchemical composition of skeletal elements of the modern crinoid Neocrinus blakei.

Ultrastructural identification of three types of sensory setae on copepod antennae

1995 ◽  
Vol 53 ◽  
pp. 956-957
Author(s):  
T. M. Weatherby ◽  
P.H. Lenz
Keyword(s):  
Phase Locking ◽  
Membrane Surface ◽  
Reaction Times ◽  
High Sensitivity ◽  
Structural Features ◽  
Calanoid Copepods ◽  
Marine Food Webs ◽  
Dendritic Membrane ◽  
Ultrastructural Characterization

Crustaceans, as well as other arthropods, are covered with sensory setae and hairs, including mechanoand chemosensory sensillae with a ciliary origin. Calanoid copepods are small planktonic crustaceans forming a major link in marine food webs. In conjunction with behavioral and physiological studies of the antennae of calanoids, we undertook the ultrastructural characterization of sensory setae on the antennae of Pleuromamma xiphias.Distal mechanoreceptive setae exhibit exceptional behavioral and physiological performance characteristics: high sensitivity (<10 nm displacements), fast reaction times (<1 msec latency) and phase locking to high frequencies (1-2 kHz). Unusual structural features of the mechanoreceptors are likely to be related to their physiological sensitivity. These features include a large number (up to 3000) of microtubules in each sensory cell dendrite, arising from or anchored to electron dense rods associated with the ciliary basal body microtubule doublets. The microtubules are arranged in a regular array, with bridges between and within rows. These bundles of microtubules extend far into each mechanoreceptive seta and terminate in a staggered fashion along the dendritic membrane, contacting a large membrane surface area and providing a large potential site of mechanotransduction.

Quantitative nano-characterization of heterogeneous catalysts

1995 ◽  
Vol 53 ◽  
pp. 398-399
Author(s):  
P.A. Crozier ◽  
M. Pan
Keyword(s):  
Heterogeneous Catalysts ◽  
Low Dose ◽  
Imaging Techniques ◽  
Structural Features ◽  
Catalyst Characterization ◽  
New Developments ◽  
Double Phase ◽  
Phase Systems ◽  
Dose Imaging

Heterogeneous catalysts can be of varying complexity ranging from single or double phase systems to complicated mixtures of metals and oxides with additives to help promote chemical reactions, extend the life of the catalysts, prevent poisoning etc. Although catalysis occurs on the surface of most systems, detailed descriptions of the microstructure and chemistry of catalysts can be helpful for developing an understanding of the mechanism by which a catalyst facilitates a reaction. Recent years have seen continued development and improvement of various TEM, STEM and AEM techniques for yielding information on the structure and chemistry of catalysts on the nanometer scale. Here we review some quantitative approaches to catalyst characterization that have resulted from new developments in instrumentation.HREM has been used to examine structural features of catalysts often by employing profile imaging techniques to study atomic details on the surface. Digital recording techniques employing slow-scan CCD cameras have facilitated the use of low-dose imaging in zeolite structure analysis and electron crystallography. Fig. la shows a low-dose image from SSZ-33 zeolite revealing the presence of a stacking fault.

Microstructural and fractographic characterization of B4C-Al cermets tested under dynamic and static loading

1989 ◽  
Vol 47 ◽  
pp. 562-563
Author(s):  
Gyeung Ho Kim ◽  
Mehmet Sarikaya ◽  
D. L. Milius ◽  
I. A. Aksay
Keyword(s):  
Thin Film ◽  
Mechanical Properties ◽  
Fracture Toughness ◽  
Static Loading ◽  
Carbon Deposition ◽  
Full Density ◽  
Unique Combination ◽  
Strong Component ◽  
Reaction Products

Cermets are designed to optimize the mechanical properties of ceramics (hard and strong component) and metals (ductile and tough component) into one system. However, the processing of such systems is a problem in obtaining fully dense composite without deleterious reaction products. In the lightweight (2.65 g/cc) B4C-Al cermet, many of the processing problems have been circumvented. It is now possible to process fully dense B4C-Al cermet with tailored microstructures and achieve unique combination of mechanical properties (fracture strength of over 600 MPa and fracture toughness of 12 MPa-m1/2). In this paper, microstructure and fractography of B4C-Al cermets, tested under dynamic and static loading conditions, are described.The cermet is prepared by infiltration of Al at 1150°C into partially sintered B4C compact under vacuum to full density. Fracture surface replicas were prepared by using cellulose acetate and thin-film carbon deposition. Samples were observed with a Philips 3000 at 100 kV.

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