scholarly journals Investigations on the general properties of biomass-based aldehyde tanned sheep fur for its selective post-tanning processing

2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Wei Ding ◽  
Ya-nan Wang ◽  
Jianfei Zhou ◽  
Haiteng Liu ◽  
Xiaoyan Pang ◽  
...  
Keyword(s):  
Schiff Base ◽  
Collagen Fiber ◽  
Processing Conditions ◽  
Covalent Bonds ◽  
Acid Sensitivity ◽  
General Properties ◽  
Dyeing Process ◽  
Chrome Tanning ◽  
Ionic Bonds ◽  
Base Structure

Abstract Dialdehyde sodium alginate (DSA) is an alternative chrome-free tanning material for fur production. To obtain satisfactory resultant fur and provide suggestions for the usage of DSA in fur making, the general properties of DSA tanned sheep fur were systematically investigated. The tanning mechanism of DSA was analyzed and it was verified that DSA was mainly combined with collagen fiber by forming Schiff base covalent bonds while supplemented by a small number of hydrogen bonds and ionic bonds. Due to the acid sensitivity of Schiff base structure, DSA tanned fur had poor resistance to acid rinsing but had excellent resistance to washing and good fatliquoring performance. Also, it had good resistances to yellowing and reductant. After being retanned by chrome tanning agent, the fur was capable of enduring a high-temperature dyeing process (68 °C for 8 h). Overall, DSA tanned sheep fur had favorable properties under appropriate post-tanning processing conditions to manufacture light-colored or dark-colored fur products with desirable physical properties. Graphical abstract

Cd(II) coordination polymer of fumaric acid and pyridyl-hydrazide Schiff base: Structure, photoconductivity and theoretical interpretation

2021 ◽  
Vol 518 ◽  
pp. 120253
Author(s):  
Angeera Chandra ◽  
Dhananjoy Das ◽  
Joaquín-Ortega Castro ◽  
Kaushik Naskar ◽  
Srikanta Jana ◽  
...  
Keyword(s):  
Schiff Base ◽  
Coordination Polymer ◽  
Fumaric Acid ◽  
Theoretical Interpretation ◽  
Base Structure

scholarly journals ОЦІНЮВАННЯ ФОРМОСТІЙКОСТІ ШКІРЯНИХ МАТЕРІАЛІВ ДЛЯ ВЕРХУ ВЗУТТЯ

2019 ◽  
Vol 134 (3) ◽  
pp. 62-72
Author(s):  
Н. В. Первая
Keyword(s):  
Processing Conditions ◽  
Chrome Tanning ◽  
Production Conditions

The  influence  of  the  processing  conditions  of  leather  for  upper  to  keep  the  shape  after molding by the example of leather for uppers made from pigs' skins using different (vegetable, dialdehyde, syntan, chrome) tanning methods was studied to simulate the process of molding and process of keep the shape after molding on a last under real production conditions

First-Principles Study of Ag3Sn, AgZn3 and Ag5Zn8 Intermetallic Compounds

2021 ◽  
Vol 871 ◽  
pp. 254-263
Author(s):  
Zhan Cheng ◽  
Guan Xing Zhang ◽  
Wei Min Long ◽  
Svitlana Maksymova ◽  
Jian Xiu Liu
Keyword(s):  
First Principles ◽  
Density Functional ◽  
Elastic Anisotropy ◽  
Constant Density ◽  
Mulliken Population ◽  
Covalent Bonds ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Anisotropy Index ◽  
Ionic Bonds

The first-principles calculations by CASTEP program based on the density functional theory is applied to calculate the cohesive energy, enthalpy of formation, elastic constant, density of states and Mulliken population of Ag3Sn、AgZn3 and Ag5Zn8. Furthermore, the elastic properties, bonding characteristics, and intrinsic connections of different phases are investigated. The results show that Ag3Sn、AgZn3 and Ag5Zn8 have stability structural, plasticity characteristics and different degrees of elastic anisotropy; Ag3Sn is the most stable structural, has the strongest alloying ability and the best plasticity. AgZn3 is the most unstable structure, has the worst plasticity; The strength of Ag5Zn8 is strongest, AgZn3 has the weakest strength, the largest shear resistance, and the highest hardness. Ag5Zn8 has the maximum Anisotropy index and Ag3Sn has the minimum Anisotropy index. Ag3Sn、AgZn3 and Ag5Zn8 are all have covalent bonds and ionic bonds, the ionic bonds decrease in the order Ag3Sn>Ag5Zn8>AgZn3 and covalent bonds decreases in the order Ag5Zn8>Ag3Sn>AgZn3.

The Influence of Nanostructured Metal Oxides and Unsaturated Acids on Peroxide Cross-Linking of Ethylene-Octene Rubber

2012 ◽  
Vol 714 ◽  
pp. 271-276 ◽  
Author(s):  
Martyna Pingot ◽  
Tomasz Pingot ◽  
Magdalena Maciejewska ◽  
Marian Zaborski
Keyword(s):  
Metal Oxides ◽  
Sem Images ◽  
Covalent Bonds ◽  
Dispersion Degree ◽  
Link Density ◽  
Ionic Bonds ◽  
Density Analysis ◽  
Elastomer Composites ◽  
Nanostructured Metal Oxides ◽  
Nanostructured Metal

This paper deals with blends of ethylene-octene rubber (POE) with nanostructured metal oxides: magnesium oxide (MgO), calcium oxide (CaO), zinc oxide (ZnO) and unsaturated acids: itaconic acid (IA), sorbic acid (SA) and crotonic acid (CA), as co-agents. Dicumyl peroxide (DCP) was used as a vulcanizing agent. Elastomer composites were prepared in Brabender measuring mixer N50. Rheometric properties of rubber mixes and crosslink density of vulcanizates were measured. Mechanical properties of the samples were also investigated. Dispersion degree of coagents in elastomer matrix was studied by SEM images. Cross-link density analysis revealed that POE vulcanizates contained both ionic bonds and covalent bonds. The results showed that the nanostructured metal oxides and unsaturated acids used as co-agents can greatly improve the modulus at 100% of elongation and tensile strength of the vulcanizates.

scholarly journals Adsorption Behavior of Divalent Metal Ions onto Surface-functionalized Mesoporous Silicate MCM-41 Having Schiff Base Structure

2020 ◽  
Author(s):  
Syunichi OSHIMA ◽  
Hidekazu OHINATA ◽  
Takushi MATSUNO ◽  
Kenta TAKASAWA ◽  
Yujiro WATANABE ◽  
...  
Keyword(s):  
Schiff Base ◽  
Metal Ions ◽  
Divalent Metal ◽  
Adsorption Behavior ◽  
Divalent Metal Ions ◽  
Mesoporous Silicate ◽  
Mcm 41 ◽  
Base Structure

scholarly journals Enhancement of EPDM Crosslinked Elastic Properties by Association of Both Covalent and Ionic Networks

Polymers ◽  
2021 ◽  
Vol 13 (18) ◽  
pp. 3161
Author(s):  
Chloé Larrue ◽  
Véronique Bounor-Legaré ◽  
Philippe Cassagnau
Keyword(s):  
Metal Salts ◽  
Reversible Systems ◽  
Covalent Bonds ◽  
Long Period ◽  
Compression Set ◽  
Metallic Salts ◽  
Ionic Bonds ◽  
Physical And Chemical ◽  
Ethylene Propylene Diene Terpolymer ◽  
Physical Crosslinking

The objective of this study was to replace elastomer crosslinking based on chemical covalent bonds by reversible systems under processing. One way is based on ionic bonds creation, which allows a physical crosslinking while keeping the process reversibility. However, due to the weak elasticity recovery of such a physical network after a long period of compression, the combination of both physical and chemical networks was studied. In that frame, an ethylene-propylene-diene terpolymer grafted with maleic anhydride (EPDM-g-MA) was crosslinked with metal salts and/or dicumyl peroxide (DCP). Thus, the influence of these two types of crosslinking networks and their combination were studied in detail in terms of compression set. The second part of this work was focused on the influence of different metallic salts (KOH, ZnAc2) and the sensitivity to the water of the physical crosslinking network. Finally, the combination of ionic and covalent network allowed combining the processability and better mechanical properties in terms of recovery elasticity. KAc proved to be the best ionic candidate to avoid water degradation of the ionic network and then to preserve the elasticity recovery properties under aging.

scholarly journals First principle study of occupancy, bonding characteristics and alloying effect of Zr, Nb, V in bulk γ-Fe(C)

2020 ◽  
Vol 213 ◽  
pp. 01019
Author(s):  
Fei Liu ◽  
Shan Cong ◽  
Long Hao
Keyword(s):  
Solid Solution ◽  
Covalent Bond ◽  
Alloy Element ◽  
Chemical Bonds ◽  
Covalent Bonds ◽  
Binding Characteristics ◽  
Crystal Cell ◽  
Ionic Bonds ◽  
Crystal Cells ◽  
Bonding Characteristics

The total energy, binding characteristics, density of states, charge distribution and differential charge density of γ-Fe(C)-M crystal cells formed by solid solution of Zr, Nb and V in γ-Fe(C) were calculated by using the first-principles method. Thus, the mechanism of Zr, Nb, and V with γ-Fe(C) was investigated in this paper. The results show that Zr, Nb and V all preferentially replaced the Fe atoms which are at the top angle in γ-Fe(C). Crystal cell reaches its highest stability after V solid solution. Nb reaches after it, and Zr is relatively weak. In the γ-Fe(C)-Zr cell, Fe-Zr covalent bond and Zr-C ionic bond are the main chemical bonds. In the γ-Fe(C)-Nb and γ-Fe(C)-V cells, Fe-Nb and Fe-V covalent bonds are the main chemical bonds with a number of Nb-C and V-C ionic bonds. After solid solution, the electron cloud density around C atom changed little, while Fe atom changed obviously. The orbital electrons around Fe atoms in γFe(C)-V has maximal distribution, which means that the electrons delocalized most and most of the electrons are bonding. It is the main factor for the increase in the binding energy of crystal cell. The effects of Zr, Nb, V solution on austenitic stability are investigated by studying the influence of alloy element on γFe(C) electronic structure.

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