scholarly journals Chemical and physico-mechanical characterizations of leather for restoration

2020 ◽  
Author(s):  
Lucretia Miu ◽  
Simona-Maria Paunescu ◽  
Maria-Cristina Micu ◽  
Iulia-Maria Caniola ◽  
Madalina Ignat ◽  
...  
Keyword(s):  
Mechanical Characteristics ◽  
Mechanical Tests ◽  
Shrinkage Temperature ◽  
Physical Chemical ◽  
Physical Examinations ◽  
Multiple Sample ◽  
Historical Leather ◽  
Multiple Chemical ◽  
Standard Tests ◽  
Comprehensive Study

Leather is a complex material mostly consisting of a matrix of collagen, chemically stabilized by various tannins. This matrix, sooner or later undergoes alterations as a consequence of interactions between their structure and environment. A comprehensive study based on multiple chemical and physico-mechanical standard tests regarding leather samples which were artificially aged from 7 to 112 days has been made at 70°C. The behavior in artificial aging of calf leather samples tanned at pilot level with two different vegetal tannins, mimosa and quebracho, were investigated due to its’s similarity to the natural degradation of historical leather samples. Physico-mechanical characteristics of historical leather can be corelated with the high impact of degree of deterioration even though there are no standard regulations. To be able to choose the proper way to achieve compatibility with an appropriate material in the restoration-conservation process, multiple sample characteristic must be known. The condition of historical leather can be assessed by a series of simple visual and physical examinations which determine the flexibility, strength and coherency of the fibers and then correlate these assessments with the condition of leather as determined by various chemical and physical-chemical analyses. Therefore, the following chemical standard tests were made: volatile substances, shrinkage temperature, extractable substances, total soluble substances and the following physico-mechanical tests: tensile strength, elongation at breaking and tear resistance.

Obtaining and Characterisation of Starch-Based Edible Films Incorporating Honey, Propolis and Bee Bread

2019 ◽  
Vol 23 (2) ◽  
pp. 193-198
Author(s):  
Monica Mironescu ◽  
Laura Fratila ◽  
Alexandru Hupert ◽  
Ion Dan Mironescu
Keyword(s):  
Water Activity ◽  
Mechanical Characteristics ◽  
Edible Films ◽  
Ash Content ◽  
Colour Intensity ◽  
Sensorial Analysis ◽  
Physical Chemical ◽  
Control Film ◽  
Bee Bread

Abstract This research investigates the physical-chemical, sensorial and mechanical characteristics of starch-based edible films incorporating three types of bee hive products: honey, propolis and bee bread, in concentrations varying from 1% to 3%, reported to starch. The results indicates an increasing of films moisture, water activity, ash content and acidity, in the order: honey<propolis<bee bread, all values increasing with the increasing of hive products percentage into the control film; aw is remaining at very low values, under 0.4. Sensorial analysis indicated honey as the better suited for improving taste and flavour and bee bread for increasing colour intensity of the films; the sensorial characteristics are maintained during 30 days of films storage, in all cases. Compared with the control starch-based film (which is elastic, brittle and hard), the films containing 2% bee hive products are elasto-plastic and more resistant to penetration, the resistance increasing in the order: bee bread<propolis<honey.

scholarly journals Theoretical and experimental method for determining elastic characteristics of nanomaterials

2019 ◽  
Vol 489 (5) ◽  
pp. 469-472
Author(s):  
V. M. Fomin ◽  
A. A. Filippov
Keyword(s):  
Mechanical Characteristics ◽  
Heterogeneous Material ◽  
Uniaxial Stress ◽  
Analytical Form ◽  
Mechanical Tests ◽  
Stress And Strain ◽  
Binder Phase ◽  
Homogeneous Materials ◽  
Silica Dioxide ◽  
Elastic Characteristics

The method allows determining the mechanical characteristic of nanoobjects was presented. A heterogeneous material consisting of a nanophase and a binder phase was considered, the mass and volume concentrations of components were given. Heterogeneous material is reduced to homogeneous by averaging methods while the mechanical characteristics will be associated with averaged ones. Assuming that the mechanical characteristics of the binder and averaged homogeneous materials are known from mechanical tests, the system of equations allow us to determine the mechanical characteristics of nanoobjects included in this heterogeneous material. It is believed that the mechanical characteristics of bonding and averaged homogeneous materials make it possible to obtain equations of equations that allow one to determine the mechanical characteristics of nano-objects present in this heterogeneous material. Classical mechanical tests were carried out, describing the uniaxial stress and strain states of materials, which made it possible to obtain an analytical form the dependences of the mechanical characteristics of nanophases depending on their size. Specific examples are given for silica dioxide nanoparticles (Aerosil and Tarkosil powders).

Thermoplastique Degradation under Heat and Irradiation

2021 ◽  
Vol 904 ◽  
pp. 196-201
Author(s):  
Sonya Redjala ◽  
Said Azem ◽  
Nourredine Ait Hocine
Keyword(s):  
Mechanical Characteristics ◽  
Low Cost ◽  
Impact Resistance ◽  
Ultra Violet ◽  
Analytical Techniques ◽  
Mechanical Tests ◽  
Ultraviolet Rays ◽  
Technical Material ◽  
Effects Of Temperature ◽  
The Impact

The aim of the article is to highlight the effect of the environment on the properties of a polycarbonate (PC). It consists in aging this material under Ultra-violet (UV) combined with temperature for different periods of time, and to reveal the physicochemical and mechanical changes caused by aging. PC is a highly valued technical material for its various important characteristics and low cost. It finds its application in various fields but mainly in those whose requirements are the transparency and the impact resistance. The physicochemical and mechanicals characterizations of the marketed polycarbonate are necessary in order to highlight its intrinsic properties and to develop strategies that can improve its lifespan. In this work, we highlight the physicochemical and mechanical characteristics of virgin and aged polycarbonate. For this, analytical techniques and mechanical tests were used. A comparison of the characteristics revealed the combined effects of temperature and ultraviolet rays.

scholarly journals Evaluation of Microcrystalline Chitosan and Fibrin Membranes as Platelet-Derived Growth Factor-BB Carriers with Amoxicillin

2015 ◽  
Vol 2015 ◽  
pp. 1-13 ◽  
Author(s):  
Kazimiera H. Bodek ◽  
Karolina M. Nowak ◽  
Marcin Kozakiewicz ◽  
Andrzej Bodek ◽  
Marta Michalska
Keyword(s):  
Growth Factor ◽  
Mechanical Characteristics ◽  
Composite Membranes ◽  
Mechanical Tests ◽  
Platelet Derived Growth Factor ◽  
Sem Images ◽  
Elongation At Break ◽  
Microcrystalline Chitosan ◽  
Kinetics Of

The aim of this study was to describe the mechanical and sorption features of homogeneous and composite membranes which consist of microcrystalline chitosan (MCCh) and fibrin (Fb) in various proportions as well as thein vitrokinetics of platelet-derived growth factor-BB (PDGF-BB) released from ten types of membranes in the presence or absence of amoxicillin (Am). The films were characterized by Fourier transform infrared (FTIR) spectroscopy, mechanical tests: breaking strength (Bs) and elongation at break (Eb), as well as SEM images, and swelling study. The influence of the form of samples (dry or wet) on Young’s modulus (E) was also examined. The homogeneous MCCh (M1) and composite M3 and M4 (MCCh : Fb = 2 : 1 and 1 : 1) membranes were characterized by good sorption properties and higher mechanical strength, when compared with Fb (M2) membrane. Connecting MCCh with Fb decreases release of PDGF-BB and increases release of Am. The most efficient release of PDGF-BB was observed in the case of M4 (the optimum MCCh : Fb ratio was 1 : 1) membrane. It was found that the degree of PDGF-BB release from the membrane is influenced by the physicochemical and mechanical characteristics of the films and by its affinity to growth factor PDGF-BB.

Evaluation of an HDPE geomembrane after 14 years as a leachate lagoon liner

2003 ◽  
Vol 40 (3) ◽  
pp. 536-550 ◽  
Author(s):  
R Kerry Rowe ◽  
Henri P Sangam ◽  
Craig B Lake
Keyword(s):  
Ionic Species ◽  
Mechanical Tests ◽  
Compacted Clay ◽  
Composite Liner ◽  
Physical Chemical ◽  
Significant Difference ◽  
Volatile Organic ◽  
Liner System ◽  
Exposure Levels ◽  
And Diffusion

A geomembrane – compacted clay composite liner system used to contain municipal solid waste (MSW) landfill leachate for 14 years is evaluated. Field observations of the geomembrane revealed many defects, including holes, patches, and cracks. Physical, chemical, and mechanical tests conducted on samples collected from five different locations of the liner suggest that samples continuously exposed to sunlight and high temperatures experienced more degradation compared to samples that were covered by leachate or soil. Sorption and diffusion tests revealed that the permeation coefficients of volatile organic compounds were in the range of 4 × 10–12 to 6 × 10–11 m2/s and that, with respect to these parameters, there was no significant difference between samples with different exposure levels. However, the permeation coefficients were between four and five times lower than values obtained for unaged HDPE geomembranes typical of present day production. Contaminant modelling of the entire lagoon liner suggests that the geomembrane liner most likely stopped being effective as a contaminant barrier to ionic species sometime between 0 and 4 years after the installation.Key words: liquid containment, composite liner, diffusion, HDPE geomembrane, performance.

scholarly journals Enhancing the Thermal Stability of Ionogels: Synthesis and Properties of Triple Ionic Liquid/Halloysite/MCC Ionogels

Molecules ◽  
2021 ◽  
Vol 26 (20) ◽  
pp. 6198
Author(s):  
Olga V. Alekseeva ◽  
Valeriya D. Shibaeva ◽  
Andrew V. Noskov ◽  
Vladimir K. Ivanov ◽  
Alexander V. Agafonov
Keyword(s):  
Thermal Stability ◽  
Ionic Liquid ◽  
Glass Transition ◽  
Mechanical Characteristics ◽  
Interlayer Space ◽  
Xrd Analysis ◽  
Mechanical Tests ◽  
Water Molecules ◽  
Residual Water ◽  
Thermal Stability Of

In this study, an ionic liquid (IL), 1-butyl-3-methylimidazolium acetate, was used to prepare ionogels with microcrystalline cellulose (MCC) and halloysite (Hal). SEM, XRD, TG, DSC, FTIR spectroscopy, conductometry and mechanical tests were used to study the morphology, structure, thermal behaviour and electrophysical and mechanical characteristics of synthesised ionogels. XRD analysis showed a slight decrease in the interlayer space of halloysite in ionogels containing MCC, which may have been associated with the removal of residual water molecules resulting from hydrophilic IL anions and polymer macromolecules. A change in conductivity and glass-transition temperature of the ionic liquid was revealed due to intercalation into halloysite (a confinement effect) and modification with cellulose. For triple IL/Hal/MCC ionogels, the characteristic thermal degradation temperatures were higher than the corresponding values for IL/Hal composites. This indicates that the synthesised IL/Hal/MCC ionogels are characterised by a greater thermal stability than those of IL/Hal systems.

scholarly journals Effect of storage time and chlorhexidine addition on the mechanical properties of glass ionomer cements

2017 ◽  
Vol 16 ◽  
pp. 1-9
Author(s):  
Juliana de Carvalho Machado ◽  
Cristiane Duque ◽  
Josânia Pitzer de Oliveira ◽  
Angela Scarparo Caldo-Teixeira
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Compressive Strength ◽  
Storage Time ◽  
Mechanical Characteristics ◽  
Mechanical Tests ◽  
Glass Ionomer Cements ◽  
Glass Ionomer ◽  
Strength Tests ◽  
Storage Times

Aims: To evaluate the effect of the chlorhexidine (CHX) incorporation and the storage time on the mechanical properties of glass ionomer cements (GICs). Methods: The following GICs were evaluated: Ketac Molar Easymix (KM), Vidrion R (VR) and Vitromolar (VM), containing or not CHX.  GIC liquid was modified by adding 1.25 % CHX digluconate and then manipulated with the power and placed into the stainless steel cylindrical or bar-shaped molds. GICs specimens were stored into water for 1, 7 and 28 days. After these periods, specimens were submitted to flexural, diametral tensile and compressive strength tests, according to ISO standards. Data from mechanical tests were statistically analyzed using 2-way ANOVA and Tukey tests. Results: Overall, the storage time did not influence any of the mechanical properties of the GICs tested. In contrast, the inclusion of CHX reduced significantly these properties for all GICs tested. KM presented the highest values of compressive strength for all storage times. KM + 1.25% CHX had lower compressive strength results than KM, however, it showed similar results when compared to another GICs without CHX. Conclusions: The presence of chlorhexidine, independent of the storage time, interfered on the mechanical characteristics of GIC.

scholarly journals The Behavior of Sheep Leather Parchment to Artificial Ageing

2020 ◽  
Vol 20 (3) ◽  
pp. 313-322
Author(s):  
Lucretia Miu ◽  
Elena Badea ◽  
Claudiu Sendrea ◽  
Maria-Cristina Micu ◽  
Simona Maria Paunescu ◽  
...  
Keyword(s):  
Volatile Matter ◽  
Matter Content ◽  
Fibrillar Structure ◽  
Silver Foil ◽  
Artificial Ageing ◽  
Oxidation Reactions ◽  
Shrinkage Temperature ◽  
Physical Chemical ◽  
Colour Parameters ◽  
Aesthetic Characteristics

Parchment used for restoration, book binding and art requires special performance on physical-chemical, organoleptic and aesthetic characteristics, but also good long-term stability. In this sense, the parchment is ecologically processed, with features that ensure firmness, fullness, light resistance, dimensional stability, thermal stability, malleability, flexural/pressure bending resistance. For a good behaviour in time and to artificial ageing, it is found that in the case of parchments made/obtained from sheepskin, the fat or volatile matter content must be as low as possible. The parchment with these qualities allows for the creation of new covers or historical replicas, complements for the integration of old covers, hot and/or cold stamping modelling, incision, entrainment, deposition of gold and silver foil, colouring and decoration with pigments and dyes. Some niche areas such as book bindings and art require a dedicated craftsmanship that promotes the survival of artisanal forms of production and the perpetuation of local creativity and identity. The parchments have undergone artificial ageing treatments based on the concomitant action of temperature and relative humidity for up to 16 days. Chemical (volatile matter, extractable substances, total ash, total nitrogen, dermal) and physical-chemical (measurement of colour variation and shrinkage temperature) analyses were performed to evaluate colour parameters and collagen hydrostability. The fat content of the parchment leads to oxidation reactions that cause the bathochromic effect, closing the colour, but also the deterioration over time of the fibrillar structure by depreciating the contraction temperature.

Physical, Chemical, and Mechanical Characteristics of Polyphenyl Ether

1967 ◽  
Vol 6 (2) ◽  
pp. 81-88 ◽  
Author(s):  
D. R. Wilson ◽  
W. A. Marshall ◽  
R. E. Dolle ◽  
R. J. Benzing
Keyword(s):  
Mechanical Characteristics ◽  
Polyphenyl Ether ◽  
Physical Chemical
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