scholarly journals Comparative Analysis of Structure and Properties of Stereoscopic Cocoon and Flat Cocoon

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Bin Zhou ◽  
Huiling Wang ◽  
Hongtao Zhou ◽  
Ke Wang ◽  
Shudong Wang ◽  
...  

Abstract Cocoon is a kind of natural biopolymer material with reasonable structure and various functions. However, its structure and functions are often destroyed in practical application. In this study, we took common Bombyx Mori as the research object, and provided different cocooning sites for single or multiple silkworms to construct common stereoscopic cocoons (“normal cocoons” [NC]) and flat cocoons (“single-silkworm flat cocoons” [SFC] and “multi-silkworm flat cocoons” [MFC]), respectively, and compared the morphological structure and basic properties of these cocoons. The study found that the flat cocoons have similar multi-layered variable structure and characteristics compared to those of the common cocoons; also, morphological characteristics and physical and chemical properties of silk fiber from outer layer to inner layer, such as sericin content, fiber fineness, and change rule of basic mechanical properties, are completely consistent with those of the common cocoons. It can be considered that the flat cocoons are constructed by silkworms in the same “procedural” process as that of common cocoons. Due to the expansion of cocooning space, the mechanical properties of fibers are significantly improved. By controlling the size of the cocooning space or the quantity of silkworms cocooning simultaneously, and the time of spinning, a cocoon material with controllable thickness, weight per square meter, porosity, and number of cocoon layers can be obtained as a composite material for direct application.

2021 ◽  
Vol 316 ◽  
pp. 51-55
Author(s):  
Tamara I. Shishelova ◽  
Vadim V. Fedchishin ◽  
Mikhail A. Khramovskih

Rapid expansion of technologies poses higher requirements to structural materials and items made of them. Conventional materials are being replaced by composite materials (composites). Different additives enhancing the properties of initial materials are used as reinforcement fibers of composites. Utilization of micro-and nanosize particles for production of present-day materials is paid much attention to. Whiskers are among such materials. These crystals have high strength, high chemical and temperature resistance. But for rational utilization of whickers of different chemical composition in composite materials one should know their physical and chemical properties. Objectives of the paper: to study physical and chemical properties of whiskers in different compounds, their composition and structure; to prove experimentally the feasibility of utilizing whiskers as a reinforcement fiber of composite materials. Object of study: specimens of whiskers of silicon nitride (Si3N4), aluminum oxide (Al2O3), aluminum nitride (AlN), and mullite (Al6Si2O13). Methods of investigation: thermal study of specimens, study of mechanical properties and chemical strength, and IR-spectroscopy. Results of study: specimens of whiskers have been studied and their mechanical properties have been tabulated for comparison. Extensive thermal investigation was followed by deduction of regularities and identification of chemical properties of whiskers. IR-spectra of whiskers have been studied and conclusions on molecular composition and on presence of impurities in some whiskers have been made.


Author(s):  
Tjokorda Gde Tirta Nindhia ◽  
Zdenek Knejzlík ◽  
Tomáš Ruml ◽  
I Wayan Surata ◽  
Tjokorda Sari Nindhia

Silk can be produced by spider or insect and have prospect as biomaterial for regenerative healing in medical treatment. Silk having physical and chemical properties that support biocompatibility in the living things..In this research, silk that was obtained from Indonesia natural resource of Attacus atlas silkmoth was explored and then will be  developed for biocompatible biomaterial. The treatment with NaOH was developed to separate the fiber from the cocoon. The obtained fiber is investigated its mechanical property by performing tensile test for single fiber. The biocompatibility testing was conducted with human cell (osteosarccoma) cultivation. The result identify that separation by using NaOH yield better better mechanical properties comparing konvenstional method with boiling in hot water. Biocompatibility testing indicate that the the fiber having good biocompatibility.


Holzforschung ◽  
2013 ◽  
Vol 67 (5) ◽  
pp. 549-557 ◽  
Author(s):  
Bernt O. Myrvold

Abstract The solubility of lignosulfonates (LSs) in water is strongly dependent on other ions present in the water phase. The differences in the solubility might strongly influence the measurements of the physical and chemical properties of the LS molecules. A reduced solubility of the LS might also affect its utility in many practical applications. The understanding of the interaction between LSs and various salts is important for both practical and theoretical reasons. Therefore, the effect of salt concentrations on the LS has been investigated for 41 different salts with 14 different cations and 16 different anions. The observations cannot be explained by the common ion effect or the screening effects. On the contrary, it was found that the stability of LS solutions follows the Hofmeister series, with the exception of those ions that will chemically interact with the LS molecule. Moreover, the positions of phosphate (HPO42-) and sulfate (SO42-) ions were reversed.


2014 ◽  
Vol 899 ◽  
pp. 409-414 ◽  
Author(s):  
Alena Struhárová ◽  
Stanislav Unčík ◽  
Svetozár Balkovic ◽  
Mária Hlavinková

Fluidized fly ash has different physical and chemical properties compared to fly ash emerging from classic combustion. It contains amorphous phases resulting from a dehydration of clay minerals as well as unreacted sorbent of CaCO3, free CaO and anhydrite (CaSO4). Work targets the possibilities of production of an autoclaved aerated concrete (AAC) from fluidized fly ash, and its influence on particular physical-mechanical properties of autoclaved aerated concrete.


Polymers ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 94
Author(s):  
Hui Zhao ◽  
Xianzhen Li ◽  
Xi Wang ◽  
Mianwu Meng ◽  
Xiujian Wang ◽  
...  

The purpose of this work is to investigate the effects of copper (II) sulfate on formaldehyde release and the mechanical properties of urea formaldehyde (UF) adhesive. Copper (II) sulfate has been used as a formaldehyde scavenger in UF resin, and its effects on the physical and chemical properties of UF adhesive have been studied. Moreover, the mechanical properties and formaldehyde release of plywood prepared with modified UF resin have been determined. The UF resin has been characterized by Fourier-transform infrared (FTIR) spectroscopy and thermogravimetric analysis (TGA). FTIR spectra showed that the addition of copper (II) sulfate to the UF resin did not affect the infrared (IR) absorptions of its functional groups, implying that the structure of UF was not modified. Further results showed that: the free formaldehyde content of the UF resin by the incorporation of 3% copper (II) sulfate was 0.13 wt.%, around 71% lower than that of the control UF adhesive. With a copper (II) sulfate content of 3%, the formaldehyde release from treated plywood was 0.74 mg·L−1, around 50% lower than that from the control UF adhesive, and the bonding strength reached 1.73 MPa, around 43% higher than that of the control UF adhesive.


Author(s):  
Vuong Van Thanh ◽  
Tran The Quang ◽  
Nguyen Tuan Hung ◽  
Vu Le Huy ◽  
Do Van Truong

Nanowires (NWs) have been used increasingly in practice due to their outstanding mechanical, physical, and chemical properties. In this paper, we use the molecular dynamics (MD) method to investigate the mechanical properties of NWs (Si/Ge, Ge/Si) with a core-shell structure under the axial tensile strain along the <100>/{100} direction. Our results show that the strength and elastic modulus of Ge/Si and Si/Ge NWs depend on the composition and size of the core/shell crosssection. The strength and strain of Ge/Si NW decrease with increasing the size of the core crosssection because of the lattice mismatch between two layers of core/shell materials. The elastic modulus of Ge/Si NWs increases with the increasing the size of the core cross-section, while the elastic modulus of the Si/Ge NW decreases. In addition, the theoretical strength and elastic modulus of Ge/Si NWs reduce with the growth of the temperature. Furthermore, we also investigate the effect of strain rate on the mechanical properties of the Ge/Si NWs. The obtained results of the study provide the intrinsic properties of the core-shell NWs and also help in the design and fabrication of electronic and optical devices based on the Ge/Si NWs.


2005 ◽  
Vol 156 (2) ◽  
pp. 47-51 ◽  
Author(s):  
Fritz Bächle ◽  
Peter Niemz

A range of mechanical, physical and chemical properties were tested on spruce, which had been subjected to diverse thermal treatments. The results of the examination are presented in tables and graphic figures.


Nanomaterials ◽  
2018 ◽  
Vol 8 (7) ◽  
pp. 546 ◽  
Author(s):  
Venkatesh Vijayaraghavan ◽  
Liangchi Zhang

Research in boron nitride nanosheets (BNNS) has evoked significant interest in the field of nano-electronics, nanoelectromechanical (NEMS) devices, and nanocomposites due to its excellent physical and chemical properties. Despite this, there has been no reliable data on the effective mechanical properties of BNNS, with the literature reporting a wide scatter of strength data for the same material. To address this challenge, this article presents a comprehensive analysis on the effect of vital factors which can result in variations of the effective mechanical properties of BNNS. Additionally, the article also presents the computation of the correct wall thickness of BNNS from elastic theory equations, which is an important descriptor for any research to determine the mechanical properties of BNNS. It was predicted that the correct thickness of BNNS should be 0.106 nm and the effective Young’s modulus to be 2.75 TPa. It is anticipated that the findings from this study could provide valuable insights on the true mechanical properties of BNNS that could assist in the design and development of efficient BN-based NEMS devices, nanosensors, and nanocomposites.


RSC Advances ◽  
2017 ◽  
Vol 7 (17) ◽  
pp. 10306-10315 ◽  
Author(s):  
Ning Ding ◽  
Huan Wang ◽  
Xiangfeng Chen ◽  
Chi-Man Lawrence Wu

As a silicon analog of graphene, silicene has attracted considerable attention due to its unique physical and chemical properties.


2021 ◽  
Vol 3 (6) ◽  
Author(s):  
Jamerson Carneiro de Oliveira ◽  
Aissam Airoudj ◽  
Philippe Kunemann ◽  
Florence Bally-Le Gall ◽  
Vincent Roucoules

Abstract Plasma polymers are micro-, or more commonly, nano-sized coatings that can be deposited on a variety of substrates through different approaches. The versatility of these polymers is incremented by the possibility to use other precursors than conventional polymerization reactions and by potential changes in the polymerization mechanisms according to the intrinsic physical and chemical properties of the plasma. That flexibility offers a fruitful ground to a great range of scientific and engineering fields, but it also brings many challenges for universalization of empirical observations. In this review, the use of different precursors, substrates and changes in plasma external parameters were evaluated as common, but not necessarily ideal nor exhaustive, variables for the analysis of mechanical properties of plasma polymer films. The commonly reported trends are complemented with the exceptions, and a variety of hypothesis drawn by the empirical observations are shown. The techniques and methods used for determining the mechanical properties of plasma polymers, the effect of post-treatments on them and some applications are evaluated. Finally, a general conclusion highlighting the challenges of the field is provided. Article highlights The mechanical properties of plasma polymers are evaluated as a function of selected parameters. The techniques of characterization of mechanical properties of plasma polymers are summarized. A discussion of future and current demands for the analysis of mechanical properties of plasma polymers is done.


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