Synthesis and characterization of temperature-sensitive hydrogels

e-Polymers ◽  
2015 ◽  
Vol 15 (5) ◽  
pp. 353-360 ◽  
Author(s):  
Xiangming Hu ◽  
Weimin Cheng ◽  
Zhenlu Shao ◽  
Lin Xin
Keyword(s):  
Raw Materials ◽  
Solution Concentration ◽  
Ammonium Persulfate ◽  
Temperature Sensitive ◽  
Scanning Calorimetry ◽  
Sem Images ◽  
Structures And Properties ◽  
Cross Linker ◽  
Analytical Tools

AbstractA series of fire-resistant, temperature-sensitive hydrogels were synthesized via free radical polymerization using N-isopropylacrylamide as a temperature-sensitive monomer, N,N′-methylenebisacrylamide as a cross-linker, ammonium persulfate (APS) as an initiator, and other raw materials including acrylic acid, 2-acrylamido-2-methyl propane sulfonic acid (AMPS), and attapulgite clay (APT). The structures and properties of superabsorbent hydrogels were studied using different analytical tools such as Fourier transform infrared spectroscopy, scanning electron microscopy (SEM), and thermogravimetric analysis (TGA)/differential scanning calorimetry. The effects of the monomer, cross-linker, and other reactants (AMPS and APT) on the water absorption ability of the hydrogels were analyzed; moreover, the effect of valence of metal ions was also examined. SEM images revealed the surface of the hydrogels as uneven and corrugated. The surface toughness increased with increasing APT. The addition of APT and AMPS increased the thermal resistance of the hydrogels but decreased the temperature sensitivity. Furthermore, the swelling ratio of the hydrogels decreased with the increase in salt solution concentration and valency of metal cation present in the salt solutions.

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.

scholarly journals Effect of Magnesium Borates on the Fire-Retarding Properties of Zinc Borates

2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
Azmi Seyhun Kipcak ◽  
Nil Baran Acarali ◽  
Emek Moroydor Derun ◽  
Nurcan Tugrul ◽  
Sabriye Piskin
Keyword(s):  
Raw Materials ◽  
High Strength ◽  
High Heat ◽  
Zinc Borate ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Magnesium Borate ◽  
Sem Images ◽  
Ir And Raman Spectroscopies ◽  
Coefficient Of Elasticity

Magnesium borate (MB) is a technical ceramic exhibiting high heat resistance, corrosion resistance, great mechanical strength, great insulation properties, lightweightness, high strength, and a high coefficient of elasticity. Zinc borate (ZB) can be used as a multifunctional synergistic additive in addition to flame retardant additives in polymers. In this study, the raw materials of zinc oxide (ZnO), magnesium oxide (MgO), and boric acid (H3BO3) were used in the mole ratio of 1 : 1 : 9, which was obtained from preexperiments. Using the starting materials, hydrothermal synthesis was applied, and characterisation of the products was performed using X-Ray diffraction (XRD) and Fourier transform infrared (FT-IR) and Raman spectroscopies. The forms of Zn3B6O12·3.5H2O, MgO(B2O3)3·7(H2O), and Mg2(B6O7(OH)6)2·9(H2O) were synthesised successfully. Moreover, the surface morphology was investigated using scanning electron microscopy (SEM), and the B2O3content was determined. In addition, the reaction yields were calculated. The results of the B2O3content analysis were in compliance with the literature values. Examination of the SEM images indicated that the obtained nanoscale minerals had a reaction efficiency ranging between 63–74% for MB and 87–98% for ZB. Finally, the fire-retarding properties of the synthesised pure MBs, pure ZBs, and mixtures of MB and ZB were determined using differential thermal analysis and thermal gravimetry (DTA-TG) and differential scanning calorimetry (DSC).

Preparation and Characterization of Hyperbranched Silicone Oil by Hydrosilylation Reaction

2013 ◽  
Vol 395-396 ◽  
pp. 363-366
Author(s):  
Zhu Liu ◽  
Hua Shi Liu ◽  
Rui Fang Guan ◽  
Chuan Jian Zhou
Keyword(s):  
Dynamic Viscosity ◽  
High Performance ◽  
Silicone Oil ◽  
Raw Materials ◽  
Molar Ratio ◽  
Straight Chain ◽  
Hydrosilylation Reaction ◽  
H Nmr ◽  
Structures And Properties

Hyperbranched silicone oil was prepared using low-polyhydrosiloxane and vinyl terminated methylphenyl silicone oil as the raw materials through hydrosilylation reaction. The structures and properties of hyperbranched silicone oil were characterized through 1H NMR, TG and dynamic viscosity. The influence on synthesis of hyperbranched silicone oil was discussed, which was caused by ratio of different raw materials. When molar ratio of Si-H bond and Si-Vi bond of raw materials was 3.5:1 (mol), the reaction degree of hyperbranched silicone oils double bond was as high as 80%. At room temperature and 100°C, comparing the dynamic viscosity of hyperbranched silicone oil and straight chain silicone oil, we found that viscosity decrease rate of hyperbranched silicone oil was obviously lower. TG curve of hyperbranched silicone oil and straight chain silicone oil also certified that the hyperbranched silicone oil has higher thermal stability than the straight chain phenyl silicone oil. Therefore hyperbranched silicone oil is more suitable for the preparation of high-performance elastic clay than straight chain silicone oil.

Synthesis and Characterization of Red Mud and Sawdust Based Geopolymer Composites as Potential Construction Material

2018 ◽  
Vol 923 ◽  
pp. 130-134 ◽  
Author(s):  
Ing Kong ◽  
Kay Min Khoo ◽  
Oliver Buddrick ◽  
Abdul Aziz Baharuddin ◽  
Pooria Khalili
Keyword(s):  
Compressive Strength ◽  
Red Mud ◽  
Raw Materials ◽  
Construction Material ◽  
Testing Machine ◽  
Industrial Wastes ◽  
Sem Images ◽  
Universal Testing ◽  
Geopolymer Composites

The aim of this study was to synthesize the geopolymer composites formed by two industrial wastes, namely red mud (RM) and saw dust (SD). SD was chemically treated with alkali for the removal of lignin and subsequently bleached, before forming composite with acid-modified RM. The composites were then characterized by using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), thermogravimetic analysis (TGA) and universal testing machine to study the morphology, chemical, thermal and mechanical properties. The FTIR spectrum showed that Si and Al from the raw materials played the major role in forming aluminosilicate geopolymer composites. The SEM images revealed that SD and RM particles aggregated to form fully condensed geopolymer matrices with high compressive strength of 8.3-138 MPa, which were comparable to Portland cement (compressive strength of 9-20.7 MPa).

Obtention and Characterization of Collagen and Chitosan Based Cements for Bone Regerneration. Part 1: Extraction and Characterization of Collagen

2014 ◽  
Vol 775-776 ◽  
pp. 29-33 ◽  
Author(s):  
Karine Cappucio de Castro ◽  
Ivan Silva Prado ◽  
Moacyr Clemente Júnior ◽  
Sylma Carvalho Maestrelli ◽  
Neide Aparecida Mariano ◽  
...  
Keyword(s):  
Cross Linking ◽  
Infrared Analysis ◽  
Fiber Structure ◽  
Cross Link ◽  
Scanning Calorimetry ◽  
High Mechanical Strength ◽  
Structure Characteristics ◽  
Cross Linker ◽  
High Degree

Several cements are used as biomaterials. Biopolymers such as chitosan and collagen exhibit excellent biocompatibility and can be used in the remodeling of bone tissue. The cement must have high mechanical strength and compatibility with original tissue. In this context, the objective of this study was to extract, characterize and cross-link collagen from bovine tendon, forlater associate it with chitosan and calcium phosphate to obtain cements for bone regeneration. Glutaraldehyde was used as cross-linker in 0.1, 0.5, 1.0 and 10% concentration. Infrared analysis confirmed the presence of functional groups characteristic of collagen, whereas the capacity of water absorption decreased with the increasing of cross-linking degree. Denaturation temperatures of collagen samples were obtained by Differential Scanning Calorimetry and Scanning Electron Microscopy showed the fiber structure characteristics of collagen, which were more organized for high degree of cross-linking samples.

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.

Preparation and Characterization of Hydrogels Based on Chitsoan/Polyvinyl Alcohol Blends

2015 ◽  
Vol 1105 ◽  
pp. 203-207
Author(s):  
Mohammed Amine Zitouni ◽  
Sofia Borsali Kara Slimane
Keyword(s):  
Weight Ratio ◽  
Poly Vinyl Alcohol ◽  
Cross Linking ◽  
Scanning Calorimetry ◽  
Intermolecular Hydrogen Bonds ◽  
Sem Images ◽  
Structure Morphology ◽  
Ft Ir ◽  
Scanning Electron

In this study, a series of poly (vinyl alcohol) (PVA)/chitosan (CS) hydrogels with different weight ratio of PVA to CS were prepared by freezing-thawing (F-T) method. The structure, morphology, and crystallinity of hydrogels were investigated by Fourier Transform Infrared (FT-IR), scanning electron microscopy (SEM) and differential scanning calorimetry (DSC). FTIR demonstrated the presence of strong intermolecular hydrogen bonds between CS and PVA molecules. SEM images showed that the higher the chitosan, the greater the porous size of the hydrogel and DSC confirmed that crystallinity is higher when PVA is more in hydrogel. The mechanical properties of these hydrogels were studied by rheometry. The study of swelling ability demonstrated that the hydrogel developed with PVA and Cs was more swellable than that with PVA only because of its cross-linking interaction with PVA.

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.

Preparation and Characterization of Dioxanone and Poly(dioxanone)

2013 ◽  
Vol 711 ◽  
pp. 22-25
Author(s):  
Kui Lin Deng ◽  
Wen Hui Jin ◽  
Fu Chen Zhang ◽  
Chun Xiu Li ◽  
Hui Juan Shen ◽  
...  
Keyword(s):  
Ring Opening ◽  
Raw Materials ◽  
Copper Chromite ◽  
Copper Nitrate ◽  
Ring Opening Polymerization ◽  
Scanning Calorimetry ◽  
H Nmr ◽  
Dsc Measurements ◽  
Ammonium Dichromate

In this paper, the ammonium dichromate and copper nitrate were used as raw materials to prepare the copper chromite, and nanocopper chromite as a catalyst was used to synthesize the monomer dioxanone in diethylene glycol dehydrogenation. Under the strict conditions of no water and no oxygen, the stannous octoate was selected to catalyze ring-opening polymerization of the dioxanone to prepare the polydioxanone. And dioxanone and its polymers were characterized with IR spectroscopy,1H NMR spectroscopy, thermogravimetric analysis (TG) and differential scanning calorimetry (DSC ) measurements.

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