scholarly journals Production, characterization, and mechanical properties of starch modified by Ophiostoma spp.

BioResources ◽  
2006 ◽  
Vol 1 (2) ◽  
pp. 257-269 ◽  
Author(s):  
Chun Bei Huang ◽  
Robert Jeng ◽  
Mohini Sain ◽  
Bradley A. Saville ◽  
Martin Hubbes
Keyword(s):  
Mechanical Properties ◽  
Raw Materials ◽  
Potato Starch ◽  
Peak Stress ◽  
Tensile Tests ◽  
Microbial Conversion ◽  
Ft Ir ◽  
Pharmaceutical Industries ◽  
Relationship Of

Microbial modification of starch with Ophiostoma spp . was investigated, with the purpose of developing a novel packaging material for the food or pharmaceutical industries. Various starch sources, such as tapioca, potato, corn, rice and amylopectin were tested as raw materials. The initial screening demonstrated that tapioca and potato starch had better performance for biopolymer production. The yield was about 85%. Preliminary characterization of the modified biopolymer was also conducted. Following microbial conversion, the percentage of molecules with at least a Mw of 10M Daltons increased from 25% to 89% after 3 days, confirming that the modification increased the weight of the starch polymer. Fourier Transform Infrared (FT-IR) revealed changes in the chemical structure of the starch after the modification. Both pure starches and the modified biopolymers were cast into films and tested for mechanical properties. The tensile tests showed that after treatment with the fungus, the peak stress and modulus of the films increased about 10 and 40 times, respectively. Also, the water barrier property was improved. Therefore, microbial modification positively impacted proper-ties relevant to the proposed applications . Although the role of the fungus in the modification and the function-property relationship of the biopolymer are not yet completely clear, the results of this study show promise for development of a novel biopolymer that competes with existing packaging materials.

Development of green nanocomposites reinforced by cellulose nanofibers extracted from paper sludge

2015 ◽  
Vol 29 (06n07) ◽  
pp. 1540025 ◽  
Author(s):  
Hitoshi Takagi ◽  
Antonio N. Nakagaito ◽  
Kazuya Kusaka ◽  
Yuya Muneta
Keyword(s):  
Mechanical Properties ◽  
Composite Materials ◽  
Mechanical Treatment ◽  
Raw Materials ◽  
Cellulose Nanofibers ◽  
Tensile Tests ◽  
Cellulose Nanofiber ◽  
Paper Sludge ◽  
Reinforcing Effect ◽  
Mechanical And Physical Properties

Cellulose nanofibers have been showing much greater potential to enhance the mechanical and physical properties of polymer-based composite materials. The purpose of this study is to extract the cellulose nanofibers from waste bio-resources; such as waste newspaper and paper sludge. The cellulosic raw materials were treated chemically and physically in order to extract individualized cellulose nanofiber. The combination of acid hydrolysis and following mechanical treatment resulted in the extraction of cellulose nanofibers having diameter of about 40 nm. In order to examine the reinforcing effect of the extracted cellulose nanofibers, fully biodegradable green nanocomposites were fabricated by composing polyvinyl alcohol (PVA) resin with the extracted cellulose nanofibers, and then the tensile tests were conducted. The results showed that the enhancement in mechanical properties was successfully obtained in the cellulose nanofiber/PVA green nanocomposites.

Preparation of Melamine Formaldehyde Resin Modified with Pentaerythritol and its Flame Retardant Effect in Polypropylene

2020 ◽  
Vol 1003 ◽  
pp. 205-212
Author(s):  
Fu Long Zhou ◽  
Hong Zhi Wu ◽  
Ming Mei Sun ◽  
Xin Zhu ◽  
Lin Sheng Tang
Keyword(s):  
Flame Retardant ◽  
Flame Retardancy ◽  
Raw Materials ◽  
Formaldehyde Resin ◽  
Melamine Formaldehyde ◽  
Cone Calorimetry ◽  
Melamine Formaldehyde Resin ◽  
Ft Ir ◽  
C Nmr

A new triazine charring agent, melamine formaldehyde resin modified with pentaerythritol (named as MF-MPOL), was synthesized through hydroxymethylation, condensation and etherification by using melamine, paraformaldehyde and pentaerythritol as raw materials, and characterized by solid-state 13C NMR and FT-IR. The intumescent flame retardant (IFR) consisting of MF-MPOL with ammonium polyphosphate has good flame retardancy in polypropylene (PP). The analysis of the residues obtained in cone calorimetry test showed that the IFR played a role of flame retardancy mainly in condensed phase. In other words, the porous and dense - continuous intumescent char layer formed during the burning process results in flame retardant effect by insulation of heat, oxygen and preventing the underlying PP from degradation and volatilization of pyrolytic products.

scholarly journals The Role of Net Working Capital in the Financing of the Operating Activities of Mining Companies

2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Maria SIERPIŃSKA ◽  
Małgorzata KOWALIK
Keyword(s):  
Raw Materials ◽  
Working Capital ◽  
Short Term ◽  
Excess Liquidity ◽  
Current Asset ◽  
Relationship Of ◽  
High Degree ◽  
Operating Activities

The paper examines how companies’ net working capital is used to finance their operating activities. Net working capital is a source oflong-term financing (equity and long-term external capital) and is more expensive than financing through short-term sources, henceits rational use has a significant impact on the efficiency of companies’ operations. The computed level of net working capital is usedto calculate ratios enabling companies to control this capital. The ratios indicate the relationship of net working capital to currentassets, to the sum of accounts receivable and short-term investments, to cash and cash equivalents, and sales revenues. Based on thesecalculations of the relationships, an assessment was made of net working capital engagement in the financing of operating activities inmining companies. These companies maintain a high degree of current asset financing through long-term capital. In mining companieswith diverse mining activities, the level of current assets financing through long-term capital is higher than in coal mining companies.This is due to the maintenance of a higher level of inventories of extracted raw materials, the distance of outlets from the place ofextraction and the method of transport used. Based on the ratio of net working capital to cash and cash equivalents, it was found thatsome companies were overly liquid. Cash balances significantly exceed the value of this capital over a period of three to four years. Asurplus of cash over net working capital in the short term cannot be treated as excess liquidity, as it is the due to flexible managementof this capital.

scholarly journals Almidones de Cáscara de Yuca (Manihot Esculenta) y Papa (Solanum Tuberosum) para Producción de Bioplásticos: Propiedades Mecánicas y Efecto Gelatinizante

2021 ◽  
Vol 6 (2) ◽  
pp. 137
Author(s):  
Carla Virginia Vélez Martinez ◽  
Xiomara Soledad Zambrano Murillo ◽  
María Hipatia Delgado Demera ◽  
Gabriel Alfonso Burgos Briones ◽  
Carlos Alfredo Cedeño Palacios
Keyword(s):  
Mechanical Properties ◽  
Solanum Tuberosum ◽  
Manihot Esculenta ◽  
Raw Materials ◽  
Amylose Content ◽  
Potato Starch ◽  
Molecular Structures ◽  
Large Space ◽  
Potato Peels ◽  
High Amylose

  Los productos biodegradables basados en materias primas agrícolas ocupan un gran espacio en las investigaciones para el desarrollo y mejoramiento de bioplástico a base de almidón que presentan propiedades similares a los plásticos convencionales. El objetivo de este trabajo consistió en describir la gelatinización y propiedades mecánicas de bioplásticos extraídos de almidones tanto de cáscaras de yuca (Manihot esculenta) como de cáscaras de papa (Solanum tuberosum). A partir de una revisión bibliográfica literaria complementada con aproximadamente 86 artículos científicos se logró comprobar que la gelatinización de estos residuos en función de sus propiedades fisicoquímicas y funcionales, mejoran sus propiedades mecánicas, además la adición de sustancias poliméricas sintéticas y naturales, plastificantes, materiales de relleno, aditivos, agentes acoplantes, agentes desestructurantes y agua otorgaron las propiedades mecánicas necesarias para trabajar como un termoplástico. Si bien ambos almidones presentan propiedades mecánicas viables para la elaboración de biopolímeros, se logra concluir que el almidón de cáscara de papa puede alcanzar un bioplástico con mejores propiedades mecánicas debido a que presenta gránulos más esféricos y regulares, los cuales pueden formar estructuras moleculares más estables, así como su alto contenido de amilosa favorece en la gelatinización y logra que la fuerza de tensión presente un incremento en comparación al almidón de cáscara de yuca.   Palabra clave: Almidón, gelatinización, papa, propiedades mecánicas, yuca.   Abstract Biodegradable products based on agricultural raw materials occupy a large space in research for the development and improvement of starch-based bioplastics that have properties similar to conventional plastics. The objective of this work was to describe the gelatinization and mechanical properties of bioplastics extracted from starches both from cassava peels (Manihot esculenta) and potato peels (Solanum tuberosum). From a literary bibliographic review complemented with approximately 86 scientific articles. it was possible to verify that the gelatinization of these residues based on their physicochemical and functional properties, improves their mechanical properties. Moreover, the addition of synthetic and natural polymeric substances, plasticizers, fillers, additives, coupling agents, destructuring agents, and water will give the necessary mechanical properties to work as a thermoplastic. Although both starches have viable mechanical properties for the production of biopolymers, it is possible to conclude that potato peel starch can achieve a bioplastic with better mechanical properties due to the fact that it presents more spherical and regular granules, which can form more stable molecular structures; as well as, its high amylose content favors gelatinization and achieves an increase in the tensile strength compared to cassava shell starch.  Keywords: Gelatinization, mechanical properties, yucca, potato, starch.

Physical and mechanical properties of polyurethane thermoset matrices reinforced with green coconut fibres

2020 ◽  
Vol 54 (30) ◽  
pp. 4841-4852 ◽  
Author(s):  
Douglas Lamounier Faria ◽  
Laércio Mesquita Júnior ◽  
Ana Angélica Resende ◽  
Daiane Erika Lopes ◽  
Lourival Marin Mendes ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Bulk Density ◽  
Raw Materials ◽  
Chemical Constituents ◽  
Low Cost ◽  
Physical And Mechanical Properties ◽  
Tensile Tests ◽  
Sem Images ◽  
The Matrix ◽  
Coconut Fibre

Currently, the use of composites to replace parts made only with plastics has been gradually employed. The advantages of these composites are low cost, high availability of raw materials and good physical and mechanical properties. Thus, this work aimed at producing and characterizing composites produced with coconut fibre reinforced polyurethane matrices. The coconut fibres were studied as to their chemical constituents, aspect ratio, bulk density, pH, tensile properties, and surface SEM images. The composites were prepared using the hand lay-up process and four different concentrations of coconut fibre were evaluated: 30, 40, 50, and 60%. The composites were assessed as for water absorption after 20 days of immersion, bulk density, impact IZOD, tensile tests, and visualize the matrix-reinforcement interface using SEM. The electron micrographs showed a great deal of impurities on the surface of coconut fibres, such as greases, waxes, and gums, due to the high amount of extraction material (19.78%), which damages the adherence of the polymer onto the coconut fibre and, as observed, cause detachment between the reinforcement and the matrix. The tensile strength of the composites tended to increase as greater amounts of coconut fibres were added to the matrix. The averages were around 6.51 to 6.72 MPa for composites with 30 and 60% fibres, respectively. Therefore, coconut fibres can be considered as an alternative to synthetic fibres commonly used in composites, and they can be used at a ratio of 60% without prejudicing the properties of the composites, making them lighter and cheaper.

scholarly journals Building ceramics based on composition of low-quality clay and slurry

2018 ◽  
Vol 143 ◽  
pp. 02014 ◽  
Author(s):  
Viktoriya Guryeva ◽  
Alexander Doroshin ◽  
Yuliya Andreeva
Keyword(s):  
Mechanical Properties ◽  
Industrial Waste ◽  
Raw Materials ◽  
Physical And Mechanical Properties ◽  
Ceramic Materials ◽  
Methodological Framework ◽  
Structure And Properties ◽  
Increasing Demand ◽  
As Effects

At present, there is a trend towards increasing demand for ceramic products with enhanced physical and mechanical properties. This study is aimed at developing scientifically grounded compositions of ceramic products that maximize the use of local low-quality aluminosilicate raw materials and secondary raw materials in brick-making technology. Characteristics of local low-melting clays and industrial waste in the form of drilling slurry with minimum percentage of petroleum product were studied and presented in this paper. Standard methods for determining physical and mechanical properties of bricks, physicochemical and statistical methods of research are used as a methodological framework. The paper shows effects of drilling slurry with an increased content of calcium oxide on the composition, physical and mechanical properties of wall ceramics, as well as effects of composition of low-quality local clays and slurries on the structure and properties of ceramic materials. The modifying role of container glass and its effects on properties of a synthesized ceramic piece were studied and presented.

Effect of Fiber Surface Modification with Different Functional Groups Silane Agents on Mechanical Properties of Hemps/Polypropylene Composites

2013 ◽  
Vol 470 ◽  
pp. 23-26 ◽  
Author(s):  
Hong Chang Han ◽  
X. Lu Gong
Keyword(s):  
Mechanical Properties ◽  
Fracture Strain ◽  
Fiber Surface ◽  
Covalent Bond ◽  
Tensile Tests ◽  
Hemp Fiber ◽  
Polypropylene Composites ◽  
Propyl Methacrylate ◽  
Ft Ir ◽  
Sem Morphology

In this paper, we firstly treated the hemp fiber with alkali solution, followed by chemical modification with silane agents: 3-(Trimethoxysilyl) propyl methacrylate (MPS), N-[3-(Trimethoxysilyl) propyaniline (PAPS) and (3-Aminopropyl) triethoxysilane (APS), respectively. These treated fibers were then blended with polypropylene (PP). SEM morphology and FT-IR spectra confirmed the successful modifications of MPS, PAPS and APS with hemp fiber. The tensile tests results showed that APS improved the mechanical properties of composite, due to the amino of APS could react with maleic anhydride forming amide covalent bond which is benefit in the stress transferring from PP matrix to fiber. In contrast, since the incompatibility of aniline with propylene, PAPS modification decreased the fracture stress composites. The existences of ester and vinyl groups in MPS contributed to the increase of composite fracture strain caused by chain slips.

Effect of Aging on Microstructure and Performance after Superplastic Deformation of Fine Grained 1420 Al-Li Alloy

2014 ◽  
Vol 936 ◽  
pp. 1647-1652
Author(s):  
Yan Ling Zhang ◽  
Hong Liang Hou ◽  
Yao Qi Wang
Keyword(s):  
Mechanical Properties ◽  
Artificial Aging ◽  
Superplastic Forming ◽  
Tensile Tests ◽  
Strengthening Mechanism ◽  
Fine Grained ◽  
And Performance ◽  
Relationship Of ◽  
Microstructure And Performance ◽  
Strength And Ductility

Superplastic forming (SPF) is an important process for forming fine grained 1420 Al-Li alloy. However, the mechanical properties will be decreased after deforming at high temperature. How to obtain the optimize relationship of strength and ductility after SPF is one of the key problems for the process. In this paper, a set of artificial aging tests including single and two-step aging were carried out, which are the typical strengthening process for Al-Li alloy. Based on experimental results, strength and elongation were studied by means of tensile tests at room temperature, and the effect of aging processes on mechanical properties was analyzed. Finally, the microstructures fore and after aging were examined by OM and TEM, and the strengthening mechanism of 1420 Al-Li alloy was further studied. It is found that artificial aging especially two-step aging can increase mechanical properties of post-SPF material obviously, and δ (Al3Li) is the primary strengthening phase.

scholarly journals Surface Modification of Flax Yarns by Enzymatic Treatment and Their Interfacial Adhesion with Thermoset Matrices

2020 ◽  
Vol 10 (8) ◽  
pp. 2910
Author(s):  
Maria Carolina Seghini ◽  
Jacopo Tirillò ◽  
Maria Paola Bracciale ◽  
Fabienne Touchard ◽  
Laurence Chocinski-Arnault ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Surface Modification ◽  
Interfacial Adhesion ◽  
Tensile Tests ◽  
Enzymatic Treatment ◽  
Enzyme Preparations ◽  
Effective Removal ◽  
Ft Ir ◽  
Single Yarn

The aim of this study was to assess the effects of commercially available and relatively inexpensive enzyme preparations based on endo 1,4-β-xylanase, pectinase and xyloglucanase on the thermal (TGA), morphological (SEM), chemical (FT-IR) and mechanical (single yarn tensile tests) properties of flax yarns. The preparation based on pectinase and xyloglucanase provided the best results, resulting in the effective removal of hydrophilic components such as hemicellulose and pectin, the individualization of yarns and increased thermal stability at the expense of a reduction in mechanical properties, depending on the treatment parameters. Single yarn fragmentation tests pointed out an improved interfacial adhesion after enzymatic treatment, with reduced debonding length values of 18% for an epoxy matrix and up to 36% for a vinylester resin compared to untreated flax yarns.

scholarly journals Development and Multiscale Characterization of 3D Warp Interlock Flax Fabrics with Different Woven Architectures for Composite Applications

Fibers ◽  
2020 ◽  
Vol 8 (2) ◽  
pp. 15 ◽  
Author(s):  
Henri Lansiaux ◽  
Damien Soulat ◽  
François Boussu ◽  
Ahmad Rashed Labanieh
Keyword(s):  
Mechanical Properties ◽  
Natural Fibers ◽  
Three Dimensional ◽  
Tensile Tests ◽  
Woven Fabrics ◽  
Flax Fiber ◽  
Raw Material ◽  
Mechanical Tensile

Multiscale characterization of the textile preform made of natural fibers is an indispensable way to understand and assess the mechanical properties and behavior of composite. In this study, a multiscale experimental characterization is performed on three-dimensional (3D) warp interlock woven fabrics made of flax fiber on the fiber (micro), roving (meso), and fabric (macro) scales. The mechanical tensile properties of the flax fiber were determined by using the impregnated fiber bundle test. The effect of the twist was considered in the back-calculation of the fiber stiffness to reveal the calculation limits of the rule of mixture. Tensile tests on dry rovings were carried out while considering different twist levels to determine the optimal amount of twist required to weave the flax roving into a 3D warp interlock. Finally, at fabric-scale, six different 3D warp interlock architectures were woven to understand the role of the architecture of binding rovings on the mechanical properties of the dry 3D fabric. The results reveal the importance of considering the properties of the fiber and roving at these scales to determine the more adequate raw material for weaving. Further, the characterization of the 3D woven structures shows the preponderant role of the binding roving on their structural and mechanical properties.

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