scholarly journals Microstructure and Mechanical/Hydrophilic Features of Agar-Based Films Incorporated with Konjac Glucomannan

Polymers ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 1952 ◽  
Author(s):  
Dongling Qiao ◽  
Wenyao Tu ◽  
Lei Zhong ◽  
Zhong Wang ◽  
Binjia Zhang ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Chemical Structure ◽  
Structural Changes ◽  
Konjac Glucomannan ◽  
Preparation Temperature ◽  
Phase Separations ◽  
Characterization Methods ◽  
Multi Scale ◽  
Changing Trend ◽  
Scale Structures

Different characterization methods spanning length scales from molecular to micron scale were applied to inspect the microstructures and mechanical/hydrophilic features of agar/konjac glucomannan (KGM) films prepared under different drying temperatures (40 and 60 °C). Note that the lower preparation temperature (40 °C) could increase the strength and elongation of agar/KGM films at high KGM levels (18:82 wt/wt KGM-agar, or higher). This was related to the variations in the film multi-scale structures with the increment of KGM content: the reduced crystallinity, the increased perfection of nanoscale orders at some KGM amounts, and the negligibly-changed morphology and molecular chemical structure under 40 °C preparation temperature. These structural changes initially decreased the film tensile strength, and subsequently increased the film strength and elongation with increasing KGM content. Moreover, under the higher drying temperature (60 °C), the increased KGM content could concurrently reduce the strength and elongation for the films, associated with probable phase separations on nano and smaller scales. In addition, the increased KGM amount tended to make the film more hydrophilic, whereas the changes in the film structures did not dominantly affect the changing trend of hydrophilicity.

scholarly journals Tailoring Multi-Level Structural and Practical Features of Gelatin Films by Varying Konjac Glucomannan Content and Drying Temperature

Polymers ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 385
Author(s):  
Dongling Qiao ◽  
Zhong Wang ◽  
Chi Cai ◽  
Song Yin ◽  
Hong Qian ◽  
...  
Keyword(s):  
Structural Changes ◽  
Structural Features ◽  
Konjac Glucomannan ◽  
Multi Scale ◽  
Gelatin Films ◽  
Film Forming ◽  
Changing Trend ◽  
Higher Temperature ◽  
Multi Level ◽  
Lower Temperature

Here, we tailored the multi-level structural and practical (mechanical/hydrophilic) features of gelatin films by varying the konjac glucomannan (KGM) content and the film-forming temperatures (25 and 40 °C). The addition of KGM apparently improved the mechanical properties and properly increased the hydrophilicity. With the lower temperature (25 °C), the increase in KGM reduced the gelatin crystallites of films, with detectable KGM–gelatin interactions, nanostructures, and micron-scale cracks. These structural features, with increased KGM and negligibly-occurred derivatizations, caused initially an insignificant decrease and then an increase in the strength, with a generally-increased elongation. The higher temperature (40 °C) could reduce the strength and slightly increase the elongation, related to the reduced crystallites of especially gelatin. With this higher temperature, the increase in KGM concurrently increased the strength and the elongation, mainly associated with the increased KGM and crystallites. Additionally, the increase in KGM made the film more hydrophilic; the multi-scale structural changes of films did not dominantly affect the changing trend of hydrophilicity.

Digestibility and supramolecular structural changes of maize starch by non-covalent interactions with gallic acid

2017 ◽  
Vol 8 (2) ◽  
pp. 720-730 ◽  
Author(s):  
Chengdeng Chi ◽  
Xiaoxi Li ◽  
Yiping Zhang ◽  
Ling Chen ◽  
Lin Li ◽  
...  
Keyword(s):  
Synergistic Effect ◽  
Gallic Acid ◽  
Structural Changes ◽  
Maize Starch ◽  
Enzymatic Digestibility ◽  
Multi Scale ◽  
Non Covalent Interactions ◽  
Scale Structures ◽  
Covalent Interactions

The synergistic effect of starch–GA complexes with more ordered multi-scale structures and the released GA inhibition decrease starch enzymatic digestibility.

scholarly journals Dynamic Single-Fiber Pull-Out of Polypropylene Fibers Produced with Different Mechanical and Surface Properties for Concrete Reinforcement

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 722
Author(s):  
Enrico Wölfel ◽  
Harald Brünig ◽  
Iurie Curosu ◽  
Viktor Mechtcherine ◽  
Christina Scheffler
Keyword(s):  
Tensile Strength ◽  
Dynamic Loading ◽  
Melt Spinning ◽  
Structural Changes ◽  
High Surface ◽  
Single Fiber ◽  
Scanning Calorimetry ◽  
Matrix Interaction ◽  
Pull Out ◽  
Fiber Matrix

In strain-hardening cement-based composites (SHCC), polypropylene (PP) fibers are often used to provide ductility through micro crack-bridging, in particular when subjected to high loading rates. For the purposeful material design of SHCC, fundamental research is required to understand the failure mechanisms depending on the mechanical properties of the fibers and the fiber–matrix interaction. Hence, PP fibers with diameters between 10 and 30 µm, differing tensile strength levels and Young’s moduli, but also circular and trilobal cross-sections were produced using melt-spinning equipment. The structural changes induced by the drawing parameters during the spinning process and surface modification by sizing were assessed in single-fiber tensile experiments and differential scanning calorimetry (DSC) of the fiber material. Scanning electron microscopy (SEM), atomic force microscopy (AFM) and contact angle measurements were applied to determine the topographical and wetting properties of the fiber surface. The fiber–matrix interaction under quasi-static and dynamic loading was studied in single-fiber pull-out experiments (SFPO). The main findings of microscale characterization showed that increased fiber tensile strength in combination with enhanced mechanical interlocking caused by high surface roughness led to improved energy absorption under dynamic loading. Further enhancement could be observed in the change from a circular to a trilobal fiber cross-section.

scholarly journals Principles of seed banks and the emergence of complexity from dormancy

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Jay T. Lennon ◽  
Frank den Hollander ◽  
Maite Wilke-Berenguer ◽  
Jochen Blath
Keyword(s):  
Global Change ◽  
Metabolic Activity ◽  
Cancer Biology ◽  
Life Sciences ◽  
Seed Banks ◽  
Tree Of Life ◽  
Multi Scale ◽  
Emergent Phenomena ◽  
Scale Structures ◽  
Emergence Of Complexity

AbstractAcross the tree of life, populations have evolved the capacity to contend with suboptimal conditions by engaging in dormancy, whereby individuals enter a reversible state of reduced metabolic activity. The resulting seed banks are complex, storing information and imparting memory that gives rise to multi-scale structures and networks spanning collections of cells to entire ecosystems. We outline the fundamental attributes and emergent phenomena associated with dormancy and seed banks, with the vision for a unifying and mathematically based framework that can address problems in the life sciences, ranging from global change to cancer biology.

Microstructure and Phase Analyses on the Corrosion of SAC305 Solder in NaСl Solution

2018 ◽  
Vol 273 ◽  
pp. 91-94 ◽  
Author(s):  
Nurwahida Mohd Zaini ◽  
Mukridz Md Mohtar ◽  
Ahmad Azmin Mohamad ◽  
Muhammad Firdaus Mohd Nazeri
Keyword(s):  
Corrosion Product ◽  
Potentiodynamic Polarization ◽  
Structural Changes ◽  
Corrosion Performance ◽  
Sac305 Solder ◽  
Characterization Methods

Utilization of Sn-3.0Ag-0.5Cu to replace toxic lead-based solder was only feasible if the corrosion performance of this solder was assured. To obtain this information, potentiodynamic polarization was implement in 3.5 wt. % NaCl. The morphological and structural changes were investigated via crucial characterization methods (SEM and XRD). Collective evidences verified that the needle-like corrosion product confirmed to be made ofSnO, SnO2and SnCl-and responsible to passivation behavior of this solder.

scholarly journals Monitoring the degradation of partly decomposable plastic foils

2014 ◽  
Vol 6 (1) ◽  
pp. 39-44
Author(s):  
Gabriella Rétháti ◽  
Krisztina Pogácsás ◽  
Tamás Heffner ◽  
Barbara Simon ◽  
Imre Czinkota ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Molecular Mass ◽  
Structural Changes ◽  
Thermoplastic Starch ◽  
Medium Density ◽  
Insulating Layer ◽  
Elongation At Break ◽  
One Year ◽  
The One

Abstract We have monitored the behaviour of different polyethylene foils including virgin medium density polyethylene (MDPE), MDPE containing pro-oxydative additives (238, 242) and MDPE with pro-oxydative additives and thermoplastic starch (297) in the soil for a period of one year. A foil based on a blend of polyester and polylactic acid (BASF Ecovio) served as degradable control. The experiment was carried out by weekly measurements of conductivity and capacity of the soil, since the setup was analogous to a condenser, of which the insulating layer was the foil itself. The twelve replications allowed monthly sampling; the specimen taken out from the soil each month were tested visually for thickness, mechanical properties, morphological and structural changes, and molecular mass. Based on the obtained capacity values, we found that among the polyethylene foils, the one that contained thermoplastic starch extenuated the most. This foil had the greatest decrease in tensile strength and elongation at break due to the presence of thermoplastic starch. The starch can completely degrade in the soil; thus, the foil had cracks and pores. The polyethylene foils that contained pro-oxydant additives showed smaller external change compared to the virgin foil, since there was no available UV radiation and oxygen for their degradation. The smallest change occurred in the virgin polyethylene foil. Among the five examined samples, the commercially available BASF foil showed the largest extenuation and external change, and it deteriorated the most in the soil.

Metallography and Biomimetics – Or New Surfaces Without Chemistry?

2021 ◽  
Vol 58 (7) ◽  
pp. 446-459
Author(s):  
T. Fox ◽  
S. M. Lößlein ◽  
D. W. Müller ◽  
F. Mücklich
Keyword(s):  
Economic Cost ◽  
Electrical Contacts ◽  
Structured Surfaces ◽  
Multi Scale ◽  
Direct Laser ◽  
One Step ◽  
Fine Structures ◽  
Scale Structures ◽  
Processing Techniques ◽  
Direct Laser Interference Patterning

Abstract Fingerprints, a butterfly’s wings, or a lotus leaf: when it comes to surfaces, there is no such thing as coincidence in animated nature. Based on their surfaces, animals and plants control their wettability, their swimming resistance, their appearance, and much more. Evolution has optimized these surfaces and developed a microstructure that fits every need. It is all the more astonishing that, with regard to technical surfaces, man confines himself to random roughnesses or “smooth” surfaces. It is surely not a problem of a lack of incentives: structured surfaces have already provided evidence of optimizing friction and wear [1, 2, 3, 4], improving electrical contacts [5, 6], making implants biocompatible [7, 8], keeping away harmful bacteria [9], and much more. How come we continue counting on grinding, polishing, sandblasting, or etching? As so often, the problem can be found in economic cost effectiveness. It is possible to produce interesting structures such as those of the feather in Fig. 1. However, generating fine structures in the micro and nanometer range usually requires precise processing techniques. This is complex, time-consuming, and cannot readily be integrated into a manufacturing process. Things are different with Direct Laser Interference Patterning, DLIP) [10, 11]. This method makes use of the strong interference pattern of overlapped laser beams as a “stamp” to provide an entire surface area with dots, lines, or other patterns – in one shot. It thus saves time, allows for patterning speeds of up to 1 m2/min and does it without an elaborate pre- or post-treatment [10, 12]. The following article intends to outline how the method works, which structures can be generated, and how the complex multi-scale structures that nature developed over millions of years can be replicated in only one step.

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