Performance Evaluation of Dimethyl Silicone Oil as Archaeological Dry Leather Lubricant

2020 ◽  
Vol 115 (4) ◽  
pp. 140-144
Author(s):  
Alireza Koochakzaei ◽  
Hossein Ahmadi ◽  
Mohsen Mohammadi Achachlouei
Keyword(s):  
Differential Scanning Calorimetry ◽  
Performance Evaluation ◽  
Treatment Effect ◽  
Silicone Oil ◽  
Accelerated Aging ◽  
Scanning Calorimetry ◽  
Shrinkage Temperature ◽  
Before And After ◽  
Dimethyl Silicone ◽  
Efficacy Of Treatment

This study aimed to investigate?the treatment effect?of dimethyl silicone oil on archaeological dried leather. Leather samples, without treatment and treated in a vacuum, were submitted to an accelerated aging at 100°C for 72 hours. In order to evaluate the efficacy of treatment, leather characteristics were examined before and after treatment with dimethyl silicone oil and after accelerated aging. Colorimetry, ATR-FTIR spectroscopy, shrinkage temperature measurement and differential scanning calorimetry were used to examine the leather characteristics and the effectiveness and stability of treatment. The results revealed that the dimethyl silicone oil has a suitable performance in the treatment of dry leather. The results also showed that the use of dimethyl silicone oil significantly reduces the changes in leather during accelerated aging. In other words, dimethyl silicone oil treatment improves the leather stability against deterioration.  

Assessment of Color Stability of Treated Leathers with Silicone Oil and Polyethylene Glycol

2014 ◽  
Vol 1 (1) ◽  
pp. 24-34
Author(s):  
Alireza K. ◽  
Hossein Ahmadi ◽  
Mohsen Mohammadi
Keyword(s):  
Ascorbic Acid ◽  
Polyethylene Glycol ◽  
Treatment Process ◽  
Color Change ◽  
Silicone Oil ◽  
Accelerated Aging ◽  
Color Stability ◽  
Antioxidant Additive ◽  
Before And After ◽  
Aesthetic Values

Lubricants and leather dressings are the most common treatments of dry and water logged historical leathers. Color change has a great importance during the time and treatment process, due to visual and aesthetic values of historic leather relics. Polyethylene glycol (PEG) and silicone oil (SiO) are frequently used leather dressings in the conservation procedures. Therefore, color stability of treated leathers with PEG and SiO were investigated before and after heat accelerated aging. Moreover, application of ascorbic acid was evaluated as an antioxidant additive for PEG (PEG+AA).Color change after treatment and aging were studied by colorimetry technique in the CIE *L*a*b system. Results indicated to severe color alteration in PEG treated and aged leathers with or without ascorbic acid. Whereas, SiO treated samples showed better stability and minimum color shift after aging. Silicone oil was characterized as the best dressing for historical leathers with compared to PEG and PEG+AA, due to its high stability and aesthetical properties.

Chemical Exchange Reactions in Blends of the Biodegradable Polyester with poly(hydroxy ether of bisphenol-A)

2014 ◽  
Vol 953-954 ◽  
pp. 1246-1249 ◽  
Author(s):  
Chean Cheng Su ◽  
Chern Hwa Chen ◽  
Neng Lang Shih ◽  
Yin Shuo Li
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Differential Scanning Calorimetry ◽  
Bisphenol A ◽  
Chemical Exchange ◽  
Exchange Reactions ◽  
Scanning Calorimetry ◽  
Butylene Succinate ◽  
Butylene Terephthalate ◽  
Before And After ◽  
Hydroxy Ether

Compatibilization via transreactions in blends of poly (butylene succinate-co-butylene terephthalate) [P(BS-co-BT)] with poly (hydroxy ether of bisphenol-A) (phenoxy) were investigated. Analyses were based on characterization using differential scanning calorimetry (DSC) and solid-state nuclear magnetic resonance (NMR). They revealed that the P(BS-co-BT)/phenoxy blend had a phase morphology that could be homogenized only following annealing at high temperatures. As-blended P(BS-co-BT)/phenoxy (50/50 composition) exhibited immiscible phases with two distinct Tgs, but the initially phase separated blends finally merged to form a homogeneous phase with a single Tgupon heating and annealing for 60 min at 280 °C. Chemical exchange reactions upon heat-annealing were likely to have caused the phase homogenization in the P(BS-co-BT)/phenoxy blend. NMR was performed on blend samples before and after they were heated to 280 °C, but the similarity of bonds made obtaining straight results difficult. Results of this study demonstrate phase homogenization can be brought only upon heat-annealing in the P(BS-co-BT)/phenoxy blend.

Potential solvent for reconditioning polyolefin waste materials

2012 ◽  
Vol 32 (8-9) ◽  
pp. 585-591 ◽  
Author(s):  
Arkan J. Hadi ◽  
Ghazi Faisal Najmuldeen ◽  
Iqbal Ahmed
Keyword(s):  
Mechanical Properties ◽  
Differential Scanning Calorimetry ◽  
Fourier Transform ◽  
High Density Polyethylene ◽  
Waste Materials ◽  
Scanning Calorimetry ◽  
Polymer Recycling ◽  
Significant Difference ◽  
Before And After ◽  
Waste Polymer

Abstract Waste polymer reconditioning was examined by a method of dissolution/reprecipitation on low- and high-density polyethylene (PE) and polypropylene (PP). Toluene and petroleum ether, in different proportions, were used as solvents, and n-hexane was used as a non-solvent. Commercial polymer products used on an everyday basis were used with a virgin polymer, to optimize the qualities of the final product, and 98% polymer was recovered in each case. Fourier transform infrared spectroscopy (FTIR) images and tensile mechanical properties of the samples, before and after recycling, were analyzed. The potential recycling-based degradation of the polymer was further investigated by measuring the thermal properties (melting point and crystallinity) before and after recycling, using differential scanning calorimetry (DSC). High reconditioning was observed in most recycled samples, with no significant difference from the virgin materials. The studied technique seems to be viable for waste polyolefin polymer recycling.

scholarly journals Low-pickle Processing of Leather: Assessment of Leather Tanning Quality by Methods of Thermal Analysis

2020 ◽  
Vol 26 (3) ◽  
pp. 333-336
Author(s):  
Virgilijus VALEIKA
Keyword(s):  
Thermal Stability ◽  
Differential Scanning Calorimetry ◽  
Oxalic Acid Solution ◽  
Additional Treatment ◽  
High Tensile Strength ◽  
Scanning Calorimetry ◽  
Shrinkage Temperature ◽  
Thermogravimetric Analyses ◽  
Thermal Stability Of

Pelt obtained by deliming with peracetic acid can be chromed after additional treatment with sodium chloride or oxalic acid solution, or directly tanned using synthetic tannins. The results of differential scanning calorimetry and thermogravimetric analyses have suggested that any tanning increases thermal stability of leather collagen. The produced chrome-free leather, despite its high tensile strength, is not characterized by high shrinkage temperature what indicates insufficient thermal stability of such leather. This fact contradicts the results of differential scanning calorimetry and thermogravimetric analyses results which show the high thermal stability of the chrome-free leather. It has been concluded that scanning calorimetry and thermogravimetric analyses are not sufficient for the appropriate assessment of leather obtained by the methods of various tanning, and the conclusions about changes in leather structure and quality of leather can not be drawn only upon results of the mentioned analyses.

Effect of polyphosphate binding on the chain dynamic of caseins: investigation by differential scanning calorimetry and thermally stimulated currents

1988 ◽  
Vol 55 (3) ◽  
pp. 401-412 ◽  
Author(s):  
Alain Lamure ◽  
Jean-François Pommert ◽  
Alain Klaebe ◽  
Colette Lacabanne ◽  
Jean-Jacques Perie
Keyword(s):  
Differential Scanning Calorimetry ◽  
Structural Changes ◽  
Water Molecules ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Thermally Stimulated Currents ◽  
Transmission Electron ◽  
Different Types ◽  
Before And After ◽  
Chain Dynamic

SummarySamples of caseins having different Ca contents as used in cheese processing were analysed by techniques using differential scanning calorimetry and thermally stimulated currents (TSC) before and after treatment with Na poly-phosphate, a food additive used in the manufacture of processed cheese. These techniques revealed structural changes induced by the salt, and the different types of water molecules associated with the protein are evident. This characterization is in agreement with results obtained by other techniques, particularly X-ray diffraction of proteins. Transmission electron microscopy of the same samples confirmed that the changes observed by TSC were associated with an unravelling of the protein.

The Glass Transition of Wool: An Improved Determination Using DSC

1997 ◽  
Vol 67 (1) ◽  
pp. 18-22 ◽  
Author(s):  
Julie M. Kure ◽  
Anthony P. Pierlot ◽  
Ian M. Russell ◽  
Robert A. Shanks
Keyword(s):  
Differential Scanning Calorimetry ◽  
Heat Capacity ◽  
Glass Transition ◽  
Transition Temperature ◽  
Water Content ◽  
Weight Fraction ◽  
Glass Transition Region ◽  
Scanning Calorimetry ◽  
Large Variability ◽  
Before And After

The glass transition temperature ( Tg) of wool and its dependence on water content is reinvestigated using differential scanning calorimetry (dsc). Previous studies with dsc have not accounted for the influence of thermal history, which may introduce a large variability in Tg measurements. Because the Tg of wool is an important parameter affecting textile performance and properties, it needs to be clearly defined. When the finite volume of the water-impenetrable phase is taken into account, an important correction of the Fox equation is obtained, describing the dependence of Tg on water content. On melting of the water-impenetrable crystalline regions, a reduction in the temperature range of the glass transition region is apparent, suggesting that the crystalline regions behave in a manner analogous to filler particles in rubber. The ratio of the change in heat capacity at the glass transition, before and after melting, may provide a way to estimate the crystalline weight fraction in native wool.

Accelerated aging and characterization of HDPE pin type insulators (15 kV)

2021 ◽  
pp. 096739112110476
Author(s):  
Cynthia DC Erbetta ◽  
Maria Elisa SR Silva ◽  
Roberto FS Freitas ◽  
Ricardo G Sousa
Keyword(s):  
Differential Scanning Calorimetry ◽  
Fourier Transform ◽  
High Density Polyethylene ◽  
Accelerated Aging ◽  
Natural Aging ◽  
Accelerated Weathering ◽  
Electrical System ◽  
Scanning Calorimetry ◽  
Aging Conditions

The study of the behavior of polymeric material used for insulators in the electrical system is extremely important in order to evaluate their lifetime as well as their performance when exposed to different environmental conditions. In the present work, the behavior of high-density polyethylene (HDPE) pin type insulators (15 kV), under accelerated aging conditions, was studied. Samples were exposed to aging, for 200 h, 1000 h, and 2000 h, in accelerated weathering chambers, according to two different methods. In Method 1, the parameters were established based on natural aging in location conditions, and in Method 2, ASTM G155 standard parameters were used. All samples were characterized by rheometry, Fourier-transform infrared spectroscopy (FTIR), and differential scanning calorimetry (DSC). The accelerated aging conditions, used in Methods 1 and 2, affected the aging of HDPE pin type insulators samples differently, the changes being more intense in Method 1.

Reevaluation of Antimicrobial and Antioxidant Activity of Thymus spp. Extracts before and after Encapsulation in Liposomes

2006 ◽  
Vol 69 (12) ◽  
pp. 2998-3005 ◽  
Author(s):  
OLGA GORTZI ◽  
STAVROS LALAS ◽  
IOANNA CHINOU ◽  
JOHN TSAKNIS
Keyword(s):  
Differential Scanning Calorimetry ◽  
Antioxidant Activity ◽  
High Performance ◽  
Antimicrobial Activities ◽  
Butylated Hydroxytoluene ◽  
Antioxidant Action ◽  
Scanning Calorimetry ◽  
Lipid Mixture ◽  
Before And After ◽  
Antimicrobial And Antioxidant Activity

The antioxidant and antimicrobial activity of four Thymus species (boissieri, longicaulis, leucospermus, and ocheus) extracts were determined. Two methods (Rancimat and malondialdehyde by high-performance liquid chromatography) were used to measure the antioxidant action in comparison with common commercial antioxidants, including butylated hydroxytoluene and α-tocopherol. The extracts that presented high antioxidant activity were encapsulated in liposomes and their antioxidant action was again estimated. Thermal-oxidative decomposition of the samples (pure liposomes and encapsulating extracts) was studied using the differential scanning calorimetry method. The modification of the main transition temperature for the lipid mixture and the splitting of the calorimetric peak in the presence of the antioxidants were also demonstrated by differential scanning calorimetry. All extracts showed antioxidant and antimicrobial activities. Some extracts showed superior or equal antioxidant activity to α-tocopherol. When the extracts were encapsulated in liposomes, their antioxidant as well as antimicrobial activities proved to be superior from the same extracts in pure form.

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