Preparation and Thermal Properties Characterization of Cholesterol-Modified Amphiphilic Chitosan

2012 ◽  
Vol 528 ◽  
pp. 197-201
Author(s):  
Feng Hong Li ◽  
Wen Jing Zhang ◽  
San Xi Li ◽  
Yong Sun ◽  
Tao Jiang
Keyword(s):  
Thermal Properties ◽  
Liquid Crystal ◽  
Biological Material ◽  
Polarized Light ◽  
Weight Ratio ◽  
Coupling Reaction ◽  
Differential Scanning Calorimetric ◽  
Low Molecular Weight Chitosan ◽  
Liquid Crystal Property

In this article, cholesterol 3-hemisuccinate (CHS) was synthesized through the functionalization of the end group of liquid crystal monomer cholesterol with succinic anhydride. Hydrophobic cholesterol modified low molecular weight chitosan (CS-CH) was synthesized by 1-Ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC)-mediated coupling reaction. Chemical structure, crystalline morphology, and thermal properties of the biological material were characterized by Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetric (DSC), and polarized light microscopy (POM). The results of POM showed that CHS was a kind of crystalline material with liquid crystal property of cholesterol. DSC showed that the melting point and the crystalline temperature of CHS were 188 °C and 145 °C respectively. DSC also showed that CS-CH was a kind of thermoplastic biological material. The max melting temperature decreased from 120 °C to 110 °C with increasing the weight ratio of EDC/CHS to chitosan.

Synthesis and Properties of Functionalized Sulfur-Containing Hexa-Peri-Hexabenzocoronene

2015 ◽  
Vol 1088 ◽  
pp. 290-294
Author(s):  
Ying Wang ◽  
Wen Guang Wang ◽  
Rui Cheng ◽  
Jia Ling Pu
Keyword(s):  
Thermal Properties ◽  
Liquid Crystal ◽  
Absorption Spectra ◽  
Synthesis And Characterization ◽  
Discotic Liquid Crystal ◽  
Matrix Surface ◽  
Sulfur Containing ◽  
Columnar Spacing

Synthesis and characterization of a novel hexabenzocoronene (HBC) derivative attached with four alkyl swallow-tailed chains and two sulfur-containing chains are described. The designed peripheral decoration with dove tails as solubilizer and sulfur-containing groups as functionalizer is expected to improve the solubility of molecules, change the columnar spacing stacks and make for its orientation on matrix surface. Its UV−vis absorption spectra appeared in 350-400 nm region as same as typical that of this kind of compounds. The thermal properties as discotic liquid crystal and its orientation on matrix are being studied.

Synthesis and Characterization of Novel Polyfluorene Derivatives

2013 ◽  
Vol 815 ◽  
pp. 443-447
Author(s):  
Li Di Zhou ◽  
Xiao Dan Hu ◽  
Shao Hong Wang ◽  
Zhao Xia Hou ◽  
Mei Han Wang
Keyword(s):  
Glass Transition ◽  
Thermal Properties ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Solid State ◽  
Coupling Reaction ◽  
Synthesis And Characterization ◽  
Sonogashira Coupling ◽  
Sonogashira Coupling Reaction

A novel series of copolymers containing fluorene units are synthesized by Sonogashira coupling reaction in mild condition. Benzene, naphthalene and anthracene are co-polymerized with ethynylfluorene, respectively. The structures are confirmed by NMR, Mass, Elemental analysis and GPC. The polymers have good thermal properties with glass-transition temperature of 90-155°C(Tg), and they have bandgaps from 2.21-2.77 eV. The results of photoluminescence in solid state show that introduction of huge chromophore could effectively suppress the formation of aggregates and excimers which typically cause red-shifted or new emission.

Thermal Characterization of Neodymium-Barium-Copper Ceramic (NBCo Ceramic) Synthesized from Barium Carbonate

2016 ◽  
Vol 869 ◽  
pp. 74-78
Author(s):  
José Passos Fernandes ◽  
A. Tibola ◽  
M. Lorensetti ◽  
G.W. Duarte ◽  
M.R. Rocha ◽  
...  
Keyword(s):  
Thermal Properties ◽  
Barium Carbonate ◽  
Thermal Characterization ◽  
Neodymium Oxide ◽  
Differential Scanning Calorimetric ◽  
X Ray Diffraction ◽  
X Ray ◽  
Treatment Conditions ◽  
Barium Copper

This work presents a study about thermal properties of a ceramic material based on NdBaCu system sintered with barium carbonate. These specialized ceramics are manufactured under special conditions and due to its unique electrical and thermal properties are frequently used by the electronic industry. Ceramics containing neodymium-barium-copper (NdBaCu) exhibit high conductivity at low temperatures. In this work, the ceramic samples were sintered with different percentage of barium carbonate, cupric and neodymium oxide and were characterized with Termogravimetric Analysis (TGA), Differential Scanning Calorimetric (DSC), Thermal Dilatometric Analysis (TDA) and X-Ray Diffraction Analysis (DRX). The results showed that the electrical conductivity of NdBaCu system is dependent on the calcination temperature. In turn, the complete calcination is dependent on the barium percentage and the thermal treatment conditions.

Rheological characterization of tack and viscoelasticity of compositions of crepe coating used in the Yankee dryer

TAPPI Journal ◽  
2019 ◽  
Vol 18 (11) ◽  
pp. 641-649
Author(s):  
JOSHUA OMAMBALA ◽  
CARL MCINTYRE
Keyword(s):  
Normal Force ◽  
Weight Ratio ◽  
Good Combination ◽  
Rheological Characterization ◽  
Nonlinear Viscoelastic ◽  
Coating Composition ◽  
Linear And Nonlinear ◽  
Work Done ◽  
Tissue Production

The vast majority of tissue production uses creping to achieve the required set of properties on the base sheet. The Yankee coating helps to develop the desired crepe that in turn determines properties such as bulk and softness. The adhesion of the sheet to the Yankee surface is a very important characteristic to consider in achieving the desired crepe. The coating mix usually consists of the adhesive, modifier, and release. A good combination of these components is essential to achieving the desired properties of the tissue or towel, which often are determined by trials on the machine that can be time consuming and lead to costly rejects. In this paper, five compositions of an industrial Yankee coating adhesive, modifier, and release were examined rheologically. The weight ratio of the adhesive was kept constant at 30% in all five compositions and the modifier and release ratios were varied. The normal force and work done by the different compositions have been shown at various temperatures simulating that of the Yankee surface, and the oscillatory test was carried out to explain the linear and nonlinear viscoelastic characteristic of the optimal coating composition.

Mechanical and thermal characterization of grafted PP-NCC nanocomposites

2019 ◽  
pp. 089270571987822
Author(s):  
Saud Aldajah ◽  
Mohammad Y Al-Haik ◽  
Waseem Siddique ◽  
Mohammad M Kabir ◽  
Yousef Haik
Keyword(s):  
Thermal Properties ◽  
Interfacial Adhesion ◽  
Thermal Characterization ◽  
Mechanical And Thermal Properties ◽  
Screw Extruder ◽  
Scanning Calorimetry ◽  
Three Point Bending ◽  
Twin Screw ◽  
Thermal Stability Of

This study reveals the enhancement of mechanical and thermal properties of maleic anhydride-grafted polypropylene (PP- g-MA) with the addition of nanocrystalline cellulose (NCC). A nanocomposite was manufactured by blending various percentages of PP, MA, and NCC nanoparticles by means of a twin-screw extruder. The influence of varying the percentages of NCC on the mechanical and thermal behavior of the nanocomposite was studied by performing three-point bending, nanoindentation, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and Fourier-transform infrared (FTIR) spectroscopy tests. The novelty of this study stems on the NCC nanoparticles and their ability to enhance the mechanical and thermal properties of PP. Three-point bending and nanoindentation tests revealed improvement in the mechanical properties in terms of strength, modulus, and hardness of the PP- g-MA nanocomposites as the addition of NCC increased. SEM showed homogeneity between the mixtures which proved the presence of interfacial adhesion between the PP- g-MA incorporated with NCC nanoparticles that was confirmed by the FTIR results. DSC and TGA measurements showed that the thermal stability of the nanocomposites was not compromised due to the addition of the coupling agent and reinforced nanoparticles.

scholarly journals Fabrication and Characterization of Electrospun Poly(acrylonitrile-co-Methyl Acrylate)/Lignin Nanofibers: Effects of Lignin Type and Total Polymer Concentration

Polymers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 992
Author(s):  
Suchitha Devadas ◽  
Saja M. Nabat Al-Ajrash ◽  
Donald A. Klosterman ◽  
Kenya M. Crosson ◽  
Garry S. Crosson ◽  
...  
Keyword(s):  
Methyl Acrylate ◽  
Lignin Content ◽  
Polymer Concentration ◽  
Weight Ratio ◽  
Electrospun Nanofibers ◽  
Polymer Content ◽  
Blend Ratio ◽  
Blend Ratios ◽  
Poly Acrylonitrile

Lignin macromolecules are potential precursor materials for producing electrospun nanofibers for composite applications. However, little is known about the effect of lignin type and blend ratios with synthetic polymers. This study analyzed blends of poly(acrylonitrile-co-methyl acrylate) (PAN-MA) with two types of commercially available lignin, low sulfonate (LSL) and alkali, kraft lignin (AL), in DMF solvent. The electrospinning and polymer blend solution conditions were optimized to produce thermally stable, smooth lignin-based nanofibers with total polymer content of up to 20 wt % in solution and a 50/50 blend weight ratio. Microscopy studies revealed that AL blends possess good solubility, miscibility, and dispersibility compared to LSL blends. Despite the lignin content or type, rheological studies demonstrated that PAN-MA concentration in solution dictated the blend’s viscosity. Smooth electrospun nanofibers were fabricated using AL depending upon the total polymer content and blend ratio. AL’s addition to PAN-MA did not affect the glass transition or degradation temperatures of the nanofibers compared to neat PAN-MA. We confirmed the presence of each lignin type within PAN-MA nanofibers through infrared spectroscopy. PAN-MA/AL nanofibers possessed similar morphological and thermal properties as PAN-MA; thus, these lignin-based nanofibers can replace PAN in future applications, including production of carbon fibers and supercapacitors.

Sign in / Sign up

Export Citation Format

Share Document