scholarly journals Stability evaluation of tocopheryl acetate and ascorbyl tetraisopalmitate in isolation and incorporated in cosmetic formulations using thermal analysis

2010 ◽  
Vol 46 (1) ◽  
pp. 129-134 ◽  
Author(s):  
Mariana Mandelli de Almeida ◽  
Cibele Rosana Ribeiro de Castro Lima ◽  
Joyce Santos Quenca-Guillen ◽  
Elder Moscardini Filho ◽  
Lucildes Pita Mercuri ◽  
...  
Keyword(s):  
Thermal Analysis ◽  
Raw Materials ◽  
Skin Aging ◽  
Tocopheryl Acetate ◽  
Stability Evaluation ◽  
Scanning Calorimetry ◽  
Cosmetic Formulations ◽  
Cosmetic Formulation ◽  
Excellent Tool

In view of the increase in the number of cosmetic preparations containing antioxidant vitamins, chiefly, due to their action in preventing the process of skin aging, there is a need to develop pre-formulation studies and to validate analytical methods in order to obtain high quality products. Thus, the objective of this research was to evaluate and compare the thermal behavior of tocopheryl acetate and ascorbyl tetraisopalmitate as raw materials, and incorporated into a base cream. Thermogravimetry (TG / DTG) and differential scanning calorimetry (DSC) were used for this purpose. Both vitamins were found to be stable up to 250ºC. The base cream (placebo) and the sample (base cream containing the vitamins) presented different weight loss. Thermal analysis has shown itself to be an excellent tool for the characterization of these vitamins and can be used in routine analysis for quality control of this type of cosmetic formulation.

Synthesis and Characterization of New Polyurethane Adhesives

2006 ◽  
Vol 514-516 ◽  
pp. 843-847 ◽  
Author(s):  
Cristina Borges Correia ◽  
João C. Bordado
Keyword(s):  
Raw Materials ◽  
Impact Resistance ◽  
Inert Atmosphere ◽  
Stray Field ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Polyurethane Adhesives ◽  
Dimer Acids

Polyurethane adhesives provide excellent flexibility, impact resistance and durability. Polyurethanes are formed through the reaction of an isocyanate component with polyether or polyester polyols or other active hydrogen compounds. This paper refers to polyurethane adhesives made from polyester polyols with long aliphatic chains (up to 36 carbon atoms) and MDI (diphenylmethane-4,4’-diisocyanate). The polyester polyols have been made from dimer acids obtained from renewable sources and short chain diols. The polyols that were used presented different degrees of unsaturation. The influence of the different raw materials in the adhesives performance is studied. The polyurethanes were produced by reaction between quasi-stoichiometric quantities of polyol and MDI, at several temperatures. The reaction was carried under inert atmosphere and at temperatures below 100°C. Performance of the adhesives was tested by carrying adhesion, hardness and water absorption tests. Characterization of both the polyester polyols and polyurethane adhesives was carried by Fourier Transform Infrared Spectroscopy (FTIR), Differential Scanning Calorimetry (DSC), Magnetic Nuclear Resonance (NMR), X-Ray Diffraction (WAXD), Scanning RMN Imaging of 1H of Stray- Field b (MRI) and Brookfield viscometry.

Preparation and Characterization of Silver Myristate/AgBr Composite Particles

2010 ◽  
Vol 663-665 ◽  
pp. 1089-1092
Author(s):  
Ya Ling Li ◽  
Jia Ning Ning ◽  
Yuan Mei Chen ◽  
Guang Fei Liu ◽  
Guo Qing Zhang
Keyword(s):  
Raw Materials ◽  
Layer Structure ◽  
Silver Bromide ◽  
Composite Particles ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Alcohol System ◽  
Average Size ◽  
Water Alcohol

Silver myristate/AgBr composite particles were prepared by using silver nitrate, sodium hydroxide, myristic acid, and sodium bromide as raw materials and PVP as surfactant in water-alcohol system and characterized by scanning electron microscopy (SEM), X-ray powder diffraction (XRD), ultraviolet-visible spectroscopy (UV) and differential scanning calorimetry (DSC). The results showed that silver myristate/AgBr composite particles are composed of rod-like silver myristate grains with a layer structure and small silver bromide particles formed on the surface of silver myristate. Silver bromide can extend the ultraviolet absorbance range of silver myristate. The size of silver myristate is about 260nm and the average size of silver bromide is about 44nm. TG and DSC analysis showed that the reaction was carried out completely. The composite particles start to decompose at about 210oC. Silver bromide of the composite particles melts at 418.2oC.

Characterization of Rattan Waste for Binderless Particleboard (BPB) Production

2015 ◽  
Vol 1115 ◽  
pp. 317-320 ◽  
Author(s):  
Tajuddin Maisarah ◽  
Zuraida Ahmad ◽  
A. Roszalia ◽  
M.A. Luqman
Keyword(s):  
Thermal Analysis ◽  
Moisture Content ◽  
Morphological Study ◽  
Raw Materials ◽  
Lignin Content ◽  
Value Added ◽  
Vascular Bundles ◽  
Endothermic Process ◽  
High Lignin Content

The manufacturing of furniture using rattan is becoming common nowadays, and creates high amount of waste that can be value-added into binderless particleboards (BPB). In order to determine the suitability of the rattan waste for production of BPB, characterization of rattan waste is executed and reported in this paper. The physical properties such as density and moisture content of the rattan waste, together with its morphological study and thermal analysis as well as lignin content are evaluated. It is observed that density and moisture content for rattan waste are in the range of 0.64g/cm3, and 11.3% respectively. On the other hand, the morphology of rattan stem showed that rattan waste has various diameters of vascular bundles along with wide metaxylem vessels as well as thin-walled fibres. Thermal analysis of rattan waste explicated that rattan waste went through endothermic process with peak melting point of 177.80 °C during heating. The greatest weight loss occurred at 257.03 °C. Rattan waste has high lignin content of 21.2% that obtained through Klason lignin test. These promising preliminary results show that the rattan waste is appropriate to be used as raw materials in producing BPB.

scholarly journals Stability and sensory assessment of emulsions containing propolis extract and/or tocopheryl acetate

2011 ◽  
Vol 47 (3) ◽  
pp. 585-592 ◽  
Author(s):  
Gisele Mara Silva Gonçalves ◽  
Silvana Mariana Srebernich ◽  
Jacqueline Alves de Macedo Souza
Keyword(s):  
Antioxidant Properties ◽  
Skin Aging ◽  
Stability Study ◽  
Tocopheryl Acetate ◽  
Cosmetic Products ◽  
Sensory Assessment ◽  
Propolis Extract ◽  
Cosmetic Formulations ◽  
Ph Decrease ◽  
The Stability

The prevention of skin aging has been one of the main aims of cosmetic products. Propolis and tocopheryl acetate can be promising substances because of their antioxidant properties. In this study, propolis extract was obtained and associated with tocopheryl acetate in a cream formulation, which then underwent stability and sensory assessment. The formulation containing propolis extract and tocopheryl acetate proved to be stable in the preliminary stability study, demonstrating gradual darkening and slight pH decrease when subjected to 60ºC for 28 days, but showing stability on rheological study. In the sensory analysis, the formulation containing these two components was preferred by the product testers over the base cream and creams containing propolis extract or tocopheryl acetate alone. In conclusion, given the stability of the formulation and the preference of the product testers for this formulation, this association proved promising for use in cosmetic formulations.

Studies of Elastomer Oxidation via Thermal Analysis

1999 ◽  
Vol 72 (1) ◽  
pp. 165-173 ◽  
Author(s):  
D. J. Burlett
Keyword(s):  
Thermal Analysis ◽  
Differential Scanning Calorimetry ◽  
Oxidation Process ◽  
Industrial Applications ◽  
Scanning Calorimetry ◽  
Thermoanalytical Techniques ◽  
The Stability ◽  
Induction Times ◽  
Oxidation Susceptibility

Abstract Elastomers are used in many industrial applications because of their remarkable toughness and elasticity. However, the source of these properties is also a weakness, in that loss of properties via oxidation is an important factor in their selection. Thermoanalytical techniques, such as differential scanning calorimetry (DSC), provide useful tools for the characterization of the stability of elastomers. DSC can not only be used to determine oxidative induction times under isothermal conditions but can also be used to determine apparent overall activation energies of the oxidation process. An evaluation of these techniques is made and the technique is used to compare the oxidation susceptibility of polybutadienes of different microstructure. The results of these DSC scans are interpreted in terms of the chemistry of the oxidation process using FTIR results.

Preparation and Characterization of Melt-Spun Poly( Acrylonitrile-Methylacrylate) Hollow Fiber

2011 ◽  
Vol 332-334 ◽  
pp. 339-342
Author(s):  
Wei Wei Peng ◽  
Na Han ◽  
Xiao Fen Tang ◽  
Hai Hui Liu ◽  
Xing Xiang Zhang
Keyword(s):  
Hollow Fiber ◽  
Melt Spinning ◽  
Raw Materials ◽  
Thermo Gravimetric Analysis ◽  
Feed Ratio ◽  
Gravimetric Analysis ◽  
Scanning Calorimetry ◽  
Single Screw Extruder ◽  
Heat Preservation

In this study, a 85/15 AN/MA copolymer (acrylonitrile – methylacrylate copolymer with feed ratio of 85/15 mol%) was synthesized by emulsion polymerization at 60 °C, and then the copolymer was used to produce hollow fiber (abbreviated as PAN hollow fiber )by melt spinning using a single screw extruder machine. The PAN hollow fiber was characterized by using Scanning Electron Microscope (SEM), Thermo-gravimetric Analysis (TGA) and Differential Scanning Calorimetry (DSC). The hollow fiber of melt-spinning PAN with high hollow rate of 51.1% has a homogeneous wall and regular section. The hollow fiber is potentially used as raw materials to fabricate heat preservation fabric for comfort clothing.

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