Synthesis and Thermal Properties of Etherified Konjac Glucomannan

2009 ◽  
Vol 620-622 ◽  
pp. 197-200 ◽  
Author(s):  
Qiang Wu ◽  
Xiao Yan Lin ◽  
Xue Gang Luo ◽  
Yan Chen
Keyword(s):  
Glass Transition ◽  
Thermal Properties ◽  
Transition Temperature ◽  
Decomposition Temperature ◽  
Konjac Glucomannan ◽  
Vibration Band ◽  
Hydrophobic Polymer ◽  
Stretching Vibration ◽  
Ft Ir ◽  
Dsc Thermograms

A novel etherified KGM (EKGM) was synthesized with Konjac glucomannan (KGM) and 1-bromopropane in Lithium chloride/dimethyl sulfoxide (LiCl/DMSO). The EKGM was characterized by FT-IR, DSC and TG. The IR of EKGM showed that –OH stretching vibration band decreased and the C–H and C–O–C stretching vibration bands increased comparing with the unmodified KGM, which was indicating that KGM had been etherified. The DSC thermograms showed that an obvious glass transition of EKGM appeared and its glass transition temperature (Tg) decreased with the increasing of Pr/OH ratio. And it was also found that the EKGM had a higher decomposition temperature than unmodified. Meanwhile, it was proved that the EKGM was a good hydrophobic polymer and dissolved in some organic solvent easily.

Study on the Reaction of Acetylated Konjac Glucomannan and EVA during Processing

2011 ◽  
Vol 695 ◽  
pp. 61-64 ◽  
Author(s):  
Xian Hong Li ◽  
Xiao Yan Lin ◽  
Xue Gang Luo ◽  
Ji Wei Li
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Vinyl Acetate ◽  
Ethylene Vinyl Acetate ◽  
Konjac Glucomannan ◽  
Ft Ir

The transesterification in acetylated konjac glucomannan/ethylene vinyl acetate (AKGM/EVA) melting blend system with the presence of dibutyltin oxide (DBTO) catalyst was investigated by means of a torque rheometer during compounding. The characteristics of the products were evaluated by DSC and FT-IR. The glass transition temperature at about 179.4 °C was found in the DSC curve of AKGM-EVA, the equilibrium torque of AKGM/EVA with 0.25 wt% DBTO was lower than that without DBTO. The results showed that the transesterification took place in the AKGM/EVA blend system.

scholarly journals Mechanical & Thermal Properties of Epoxy Based Hybrid Composites Reinforced with Jute/Sansevieria cylindrica Fibres

2014 ◽  
Vol 38 ◽  
pp. 191-197 ◽  
Author(s):  
M. Ashok Kumar ◽  
G. Ramachandra Reddy
Keyword(s):  
Glass Transition ◽  
Thermal Properties ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Room Temperature ◽  
Hybrid Composites ◽  
Fibre Length ◽  
Decomposition Temperature ◽  
Weight Room ◽  
Tga And Dsc

Tensile properties are studied to assess the influence of fiber weight. Room temperature cured epoxy was impregnated with jute/Scin order to evaluate the performance of hybrid composites. Jute/Scfibers are taken in the 1:1 weight ratios to suspend on epoxy resin with different fiber lengths such as 1, 2, 3 and 4 cm. The variations of aforementioned properties on hybrid composites with different fiber lengths have been studied. Significant improvement in tensile strengths of the jute/Schybrid composites has been observed by the alkali treatments. Thermal properties such as TGA and DSC are studied to investigate the influence of change in fibre length on treated and untreated hybrid composites in which 4 °C rise in decomposition temperature, 3 °C rise for glass transition temperature respectively

Thermal Properties of Silicon-Containing Polyimide Filled with Carbon Black of Low Structure

2014 ◽  
Vol 968 ◽  
pp. 21-24 ◽  
Author(s):  
Sunan Tiptipakorn ◽  
Sarawut Rimdusit ◽  
Sarote Phromdee ◽  
Kasinee Hemvichian
Keyword(s):  
Glass Transition ◽  
Thermal Properties ◽  
Transition Temperature ◽  
Carbon Black ◽  
Thermo Gravimetric ◽  
Electrically Conductive ◽  
Degradation Temperature ◽  
Thermo Gravimetric Analyzer ◽  
High Structure ◽  
Dsc Thermograms

The nanocomposites between silicon-containing polyimide (SPI) and electrically conductive carbon black (CB) of low structure (Conductex K Ultra) were prepared. The contents of the conductive nanofillers were varied from 0 to 40 phr. The thermal properties of the nanocomposites were determined via Differential Scanning Calorimeter (DSC) and Thermo-gravimetric Analyzer (TGA). DSC thermograms revealed that the glass transition temperature (Tg) and degradation temperature (Td) of the nanocomposites increased with increasing the amount of fillers. The Tg and Td values of the composites filled with high structure were higher than those of the ones filled with low structure.

scholarly journals Core/Clad Phosphate Glass Fibres Containing Iron and/or Titanium

2015 ◽  
Vol 1 (1) ◽  
Author(s):  
Ifty Ahmed ◽  
S. S. Shaharuddin ◽  
N. Sharmin ◽  
D. Furniss ◽  
C. Rudd
Keyword(s):  
Thermal Expansion ◽  
Glass Transition ◽  
Thermal Properties ◽  
Transition Temperature ◽  
Tensile Modulus ◽  
Average Diameter ◽  
Phosphate Glasses ◽  
Dissolution Medium ◽  
The Core ◽  
Controllable Degradation

AbstractPhosphate glasses are novel amorphous biomaterials due to their fully resorbable characteristics, with controllable degradation profiles. In this study, phosphate glasses containing titanium and/or iron were identified to exhibit sufficiently matched thermal properties (glass transition temperature, thermal expansion coefficient and viscosity) which enabled successful co-extrusion of glass billets to form a core/clad preform. The cladding composition for the core/clad preforms were also reversed. Fe clad and Ti clad fibres were successfully drawn with an average diameter of between 30~50 μm. The average cladding annular thickness was estimated to be less than 2 μm. Annealed core/clad fibres were degraded in PBS for a period of 27 days. The strength of the Fe clad fibres appeared to increase from 303 ± 73 MPa to 386 ± 45 MPa after nearly 2 weeks in the dissolution medium (phosphate buffered solution) before decreasing by day 27. The strength of the Ti clad fibres revealed an increase from 236 ± 53 MPa to 295 ± 61 MPa when compared at week 3. The tensile modulus measured for both core/clad fibres ranged between 51 GPa to 60 GPa. During the dissolution study, Fe clad fibres showed a peeling mechanism compared to the Ti clad fibres.

scholarly journals Melt Stable Functionalized Organosolv and Kraft Lignin Thermoplastic

Processes ◽  
2020 ◽  
Vol 8 (9) ◽  
pp. 1108
Author(s):  
Shubhankar Bhattacharyya ◽  
Leonidas Matsakas ◽  
Ulrika Rova ◽  
Paul Christakopoulos
Keyword(s):  
Thermal Stability ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Kraft Lignin ◽  
Added Value ◽  
Lignin Valorization ◽  
1H Nuclear Magnetic Resonance ◽  
Ft Ir ◽  
Viable Biomass

A shift towards an economically viable biomass biorefinery concept requires the use of all biomass fractions (cellulose, hemicellulose, and lignin) for the production of high added-value products. As lignin is often underutilized, the establishment of lignin valorization routes is highly important. In-house produced organosolv as well as commercial Kraft lignin were used in this study. The aim of the current work was to make a comparative study of thermoplastic biomaterials from two different types of lignins. Native lignins were alkylate with two different alkyl iodides to produce ether-functionalized lignins. Successful etherification was verified by FT-IR spectroscopy, changes in the molecular weight of lignin, as well as 13C and 1H Nuclear Magnetic Resonance (NMR). The thermal stability of etherified lignin samples was considerably improved with the T2% of organosolv to increase from 143 °C to up to 213 °C and of Kraft lignin from 133 °C to up to 168 °C, and glass transition temperature was observed. The present study shows that etherification of both organosolv and Kraft lignin with alkyl halides can produce lignin thermoplastic biomaterials with low glass transition temperature. The length of the alkyl chain affects thermal stability as well as other thermal properties.

Thermal Properties of Bi2O3-B2O3-ZnO Glass System

2006 ◽  
Vol 510-511 ◽  
pp. 578-581 ◽  
Author(s):  
Yu Jin Kim ◽  
Seong Jin Hwang ◽  
Hyung Sun Kim
Keyword(s):  
Glass Transition ◽  
Thermal Properties ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Lead Oxide ◽  
Lead Free ◽  
Oxide Glasses ◽  
Glass Formation Region ◽  
Formation Region ◽  
Lower Glass Transition Temperature

Oxide glasses having lower glass transition temperature are widely used in electric devices. The oxide glasses usually contain lead oxide. Recently, lead oxide glasses have been replaced with lead-free oxide glasses because of the environmental pollution. We investigated the thermal properties and the glass formation region in the Bi2O3-B2O3-ZnO ternary system. The results showed that the ratio of Tg/Tl of the bismate glasses is around 0.55, which is lower than the value of ratio 0.67, the two-third rule (Tg/ Tl=2/3)

Synthesis and Properties of Cellulose Stearate

2011 ◽  
Vol 228-229 ◽  
pp. 919-924 ◽  
Author(s):  
Feng Yuan Huang
Keyword(s):  
Thermal Analysis ◽  
Thermal Decomposition ◽  
Glass Transition ◽  
Transition Temperature ◽  
1H Nmr ◽  
Homogeneous System ◽  
Molar Ratio ◽  
Maximum Temperature ◽  
Key Factor ◽  
Ft Ir

Cellulose Stearate (CS) was synthesized by acylating microcrystalline cellulose (MCC) in homogeneous system with p-toluenesulfonyl chloride (Tos-Cl) and stearic acid (SA). The reactive conditions were discussed. The molar ratio of AGU:SA:Tos-Cl was the key factor which affected the degree of substitution (DS) of CS. In the present paper, CSs with DS ranging from 0.64 to 2.35 were prepared under mild condition. The structure of CS was characterized by FT-IR and 1H-NMR, and DS of CS was determined by traditional saponification method and 1H-NMR, respectively. The solubility of CS was also investigated; the results showed that the higher DS of CS was, the easier CS dissolved in organic solvents. The thermal analysis was measured with DSC, and the results indicated that the glass transition temperature (Tg) and the maximum temperature of thermal decomposition (Tmax) of CS were dependent on DS.

Influence of PCBM on the Glass Transition Temperature (Tg) of Poly(N-Vinylcarbazole)-Based Photorefractive Composite

2017 ◽  
Vol 896 ◽  
pp. 62-71 ◽  
Author(s):  
Bai Li Chen ◽  
Chuan Qun Huang ◽  
Rui Zhuang Yang ◽  
Yu Fang ◽  
Qing Jun Zhang ◽  
...  
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Acid Methyl Ester ◽  
Differential Scanning Calorimetric ◽  
H Nmr ◽  
Composite Polymers ◽  
Vis Spectroscopy ◽  
Ft Ir ◽  
Dsc Method

2,5-dimethyl-(4-p-nitrophenylazo) phenetole (DMNPAPE) was synthesized. And its structure was confirmed with ultraviolet-visible (UV-vis) spectroscopy, Fourier transform infrared (FT-IR) spectra and 1H Nuclear Magnetic Resonance (1H NMR) spectroscopy. The photorefractive composite consist of 33 wt % poly (N-vinycarbazole) (PVK), 50 wt % 2, 5-dimethyl-(4-p-nitrophenylazo) phenetole (DMNPAPE) and 16 wt % ethyl carbazole (ECZ) doped with x wt % (≤1 wt%) [6, 6]-phenyl C61 butyric acid methyl ester (PCBM) was fabricated. The influence of PCBM on the glass transition temperature (Tg) of the photorefractive composite was studied using a differential scanning calorimetric (DSC) method. The active energy of glass transition (Eg) was evaluated by Kissinger’s and Moynihan’s relation. The analysis results indicate that the transition region shifts to higher temperatures with the increasing heating rate, and PCBM content (≤1.0 wt %) can influence Tg of PVK - based PR composite polymers. The Tg first increase and then went down with the PCBM content (below 1.0 wt %) increasing. The possible cause of the influence of PCBM on Tg was proposed.

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