scholarly journals Thermal stability of aliphatic hyperbranched polyesters

2002 ◽  
Vol 56 (11) ◽  
pp. 473-477
Author(s):  
Jasna Vukovic ◽  
Branislav Bozic ◽  
Manfred Lechner ◽  
Slobodan Jovanovic
Keyword(s):  
Thermal Stability ◽  
Stearic Acid ◽  
Molar Mass ◽  
Nitrogen Atmosphere ◽  
Fourth Generation ◽  
Mass Generation ◽  
Hyperbranched Polyesters ◽  
Mass Losses ◽  
End Groups ◽  
Thermal Stability Of

The influence of the molar mass (generation), number and type of end groups on the thermal stability of aliphatic hyperbranched polyesters are presented in this study. Different end groups were obtained by modification of the samples with chlorides of propionic acid and stearic acid. The thermal stability of the hyperbranched polyesters was determined by thermogravimetry using a NET-ZSCH TG 209 instrument in nitrogen atmosphere at a heating rate of 10?C/min. A comparison of the temperatures obtained for mass losses of 5 20 and 40 wt% for unmodified samples showed that the thermal stability increased up to the fourth generation and then remained practically constant. An increase in the thermal stability of modified samples of the second, third and fourth generation was observed.

Non-Isothermal Decomposition Kinetic of Polypropylene/Hydrotalcite Composite

2019 ◽  
Vol 19 (11) ◽  
pp. 7493-7501 ◽  
Author(s):  
Sheng Xu ◽  
Min Zhang ◽  
Siyu Li ◽  
Moyu Yi ◽  
Shigen Shen ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Thermal Decomposition ◽  
Nitrogen Atmosphere ◽  
Heating Rates ◽  
Decomposition Reactions ◽  
Kinetic And Thermodynamic Parameters ◽  
Málek Method ◽  
Boundary Reaction ◽  
Phase Boundary Reaction ◽  
Thermal Stability Of

P3O5-10 pillared Mg/Al hydrotalcite (HTs) as a functional fire-retarding filler was successfully prepared by impregnation-reconstruction, where the HTs was used to prepare polypropylene (PP) and HTs composite (PP/HTs). Thermal decomposition was crucial for correctly identifying the thermal behavior for the PP/HTs, and studied using thermogravimetry (TG) at different heating rates. Based on single TG curves and Málek method, as well as 41 mechanism functions, the thermal decompositions of the PP/HTs composite and PP in nitrogen atmosphere were studied under non-isothermal conditions. The mechanism functions of the thermal decomposition reactions for the PP/HTs composite and PP were separately “chemical reaction F3” and “phase boundary reaction R2,” which were also in good agreement with corresponding experimental data. It was found that the addition of the HTs increased the apparent activation energy Ea of the PP/HTs comparing to the PP, which improved the thermal stability of the polypropylene. A difference in the set of kinetic and thermodynamic parameters was also observed between the PP/HTs and PP, particularly with respect to lower ΔS≠ value assigned to higher thermal stability of the PP/HTs composite.

Organic solvent-free synthesis of phosphorus-containing polymers

2007 ◽  
Vol 79 (11) ◽  
pp. 1879-1884 ◽  
Author(s):  
Smaranda Iliescu ◽  
Gheorghe Ilia ◽  
Aurelia Pascariu ◽  
Adriana Popa ◽  
Nicoleta Plesu
Keyword(s):  
Thermal Stability ◽  
Thermal Analysis ◽  
Bisphenol A ◽  
Organic Solvent ◽  
Molar Mass ◽  
Interfacial Polycondensation ◽  
H Nmr ◽  
Phosphorus Containing ◽  
Solvent Free Synthesis ◽  
Thermal Stability Of

Direct, efficient, organic solvent- and catalyst-free synthesis of a series of polyphosphates was accomplished. The reaction involved a gas-liquid interfacial polycondensation between arylphosphoric dichlorides and bisphenol A. The polyphosphates were characterized by IR, 1H NMR, 31P NMR, inherent viscosity, thermal analysis, and molar mass. Yields in the range 70-90 % and inherent viscosities in the range 0.30-0.40 dl/g were obtained. The thermal stability of the polyphosphates was investigated by using thermogravimetry.

Thermal Stability of Soybean Protein Isolate-Based Oleic Acid/Stearic Acid Blend Edible Films

2013 ◽  
Vol 469 ◽  
pp. 171-174 ◽  
Author(s):  
Ning Zhang ◽  
Si Yao Sui ◽  
Zhe Wang ◽  
Zhong Su Ma
Keyword(s):  
Thermal Stability ◽  
Oleic Acid ◽  
Stearic Acid ◽  
Soybean Protein ◽  
Soy Protein Isolate ◽  
Edible Films ◽  
Protein Isolate ◽  
Soybean Protein Isolate ◽  
The Matrix ◽  
Thermal Stability Of

Edible films were prepared using soy protein isolate (4g/100g), oleic acid (0-2g/100g) and stearic acid (0-2g/100g). Effects of the type and ratio of fatty acids (oleic acid and stearic acid) on the thermal properties of soybean protein isolate-based films were investigated. The results indicated that the addition of oleic acid and stearic acid take a significant effect on the thermal stability of soybean protein isolate-based films, as may attribute to that oleic acid is an amphiphilic substance that interacts with both polar and hydrophobic sites on proteins, thus it could improve the functional properties of the films. Besides, the solid state and hydrophobic nature of stearic acid could help limit water diffusion in the matrix more efficiently when it is well-integrated in the matrix through the surfactant action of oleic acid.

Thermal Degradation Study of Functionalized MWNT Reinforced Segmented Polyurethane Membrane

2006 ◽  
Vol 38 (3) ◽  
pp. 261-271 ◽  
Author(s):  
S. Mondal ◽  
J. L. Hu
Keyword(s):  
Thermal Stability ◽  
Thermal Degradation ◽  
Nitrogen Atmosphere ◽  
Segmented Polyurethane ◽  
Degradation Study ◽  
Heat Treated ◽  
Different Temperatures ◽  
Increasing Temperature ◽  
Thermal Stability Of ◽  
Mwnt Content

The thermal degradation of polytetramethylene glycol (PTMG, Mn 1/42900) based polyurethane (PU), along with four different weight contents (such as 0.25, 0.50, 1.0, and 2.5 wt%) of functionalized multiwalled nanotube (MWNT) reinforced PUs are studied in air as well as in nitrogen atmosphere. The degradation results are reported in 10 and 50% weight loss and derivative of thermogravimetry (DTG). As expected, PUs are thermally more stable in nitrogen than in air. However, the influence of MWNT content on thermal stability is unclear. At 0.25 and 0.50 wt% of MWNT content, thermal stability declined and a further increase of MWNT improved the thermal stability of PU. Fourier-transform infrared (FTIR) analysis is also performed for untreated and heat treated films in order to understand the degradation at different temperatures. Free C1/4O stretching neck dimension increases with increasing temperature which signifies breaking of H-bonding detected by FTIR measure ments.

Increased thermal stability of a poled electro-optic polymer using high-molar-mass fractions

2004 ◽  
Vol 70 (4) ◽  
Author(s):  
Ralph P. Bertram ◽  
Nils Benter ◽  
Dirk Apitz ◽  
Elisabeth Soergel ◽  
Karsten Buse ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Molar Mass ◽  
High Molar Mass ◽  
Electro Optic ◽  
Mass Fractions ◽  
Thermal Stability Of

The Thermal Stability of Monosulfidic Crosslinks in Natural Rubber

1983 ◽  
Vol 56 (2) ◽  
pp. 337-343 ◽  
Author(s):  
G. P. McSwkeeney ◽  
N. J. Morrison
Keyword(s):  
Thermal Stability ◽  
Stearic Acid ◽  
Natural Rubber ◽  
High Temperatures ◽  
Zinc Stearate ◽  
Thermally Stable ◽  
Thermal Stability Of

Abstract (1) Networks containing mainly monosuifidic crosslinks at methylene sites in the polyisoprene chains of natural rubber are expected to be more thermally stable than existing efficiently vulcanized networks. (2) Certain zinc-accelerator species promote the decomposition of crosslinks at high temperatures, but may be deactivated by complexation with zinc stearate (which is formed from stearic acid during vulcanization).

Molar mass and composition effects on the thermal stability of functional P(S-r-MMA) random copolymers for nanolithographic applications

2017 ◽  
Vol 2 (5) ◽  
pp. 581-588 ◽  
Author(s):  
Diego Antonioli ◽  
Valentina Gianotti ◽  
Katia Sparnacci ◽  
Michele Laus ◽  
Marco Clericuzio ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Molar Mass ◽  
Random Copolymers ◽  
Composition Effects ◽  
Thermal Stability Of

The thermal stability of P(S-r-MMA) random copolymers for BCP-based nanolithography is discussed with reference to molar mass and composition.

Effect of layered silicates on rheological and mechanical properties and thermal stability of high-molar mass polydimethylsiloxane matrix

e-Polymers ◽  
2011 ◽  
Vol 11 (1) ◽  
Author(s):  
Veronika Rabova ◽  
Petr Hron
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Tensile Strength ◽  
Silicone Rubber ◽  
Molar Mass ◽  
Strength Increase ◽  
Weight Decay ◽  
High Molar Mass ◽  
Surface Modified ◽  
Thermal Stability Of

AbstractThe effect of surface modified fillers based on montmorillonite on rheological and mechanical properties and thermal stability of high-molar mass polydimethylsiloxane matrix was evaluated. Silicone rubber/clay composites were prepared via homogenisation on open two roll-mill followed by torque measurement at two different temperatures. At 30 °C and 100 °C the torque did not extremely differ excepting the mixtures containing Cloisite 15A where it achieved the maximum at 3 phr montmorillonite content, but the tensile strength reached the similar values in all mixtures. Thermogravimetric analysis was utilized to find out the differences in weight decay of composites in silicone rubber/montmorillonite mixtures and in unfilled silicone rubber. Synergism of fillers was also studied and led to tensile strength increase.

Effects of chemical structure and chain end groups on the thermal stability of new silsesquioxanes with methacrylate and/or vinyl units

2013 ◽  
Vol 139 (2-3) ◽  
pp. 719-733 ◽  
Author(s):  
Bogdan C. Simionescu ◽  
Irina-Elena Bordianu ◽  
Nita Tudorachi ◽  
Corneliu Cotofana ◽  
Laura Ursu ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Chemical Structure ◽  
End Groups ◽  
Thermal Stability Of
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