The effects of melt annealing and counterpart's molecular weight on the thermal properties and phase morphology of poly(L-lactide)-based blends

2009 ◽  
Vol 47 (15) ◽  
pp. 1497-1510 ◽  
Author(s):  
Fang-Chyou Chiu ◽  
Chin-Yu Kan ◽  
Jen-Chang Yang
Keyword(s):  
Molecular Weight ◽  
Thermal Properties ◽  
Phase Morphology ◽  
Melt Annealing

scholarly journals Effect of the annealing procedure and the molecular weight on the crystalline phase morphology and thermal properties of polylactide

2019 ◽  
Vol 68 (10) ◽  
pp. 1767-1775 ◽  
Author(s):  
Martí Hortós ◽  
Jon Anakabe ◽  
Alex Arrillaga ◽  
Sebastián Espino ◽  
Jordi J Bou
Keyword(s):  
Molecular Weight ◽  
Thermal Properties ◽  
Crystalline Phase ◽  
Phase Morphology ◽  
Annealing Procedure

Preparation, curing properties, and phase morphology of epoxy-novolac resin/multiepoxy-terminated low-molecular-weight poly(phenylene oxide) blend

2013 ◽  
Vol 54 (11) ◽  
pp. 2595-2604 ◽  
Author(s):  
Huan Wang ◽  
Jingzhao Mo ◽  
Baoqing Shentu ◽  
Zhixue Weng
Keyword(s):  
Molecular Weight ◽  
Phase Morphology ◽  
Low Molecular Weight ◽  
Novolac Resin ◽  
Phenylene Oxide

Graft modification in bamboo cellulose nanofibrils: An effective option to improve compatibility and tunable surface energy

2021 ◽  
Author(s):  
Carlos Alejandro Rodríguez-Ramírez ◽  
Alain Dufresne ◽  
Norma Beatriz D'Accorso ◽  
Nancy Garcia
Keyword(s):  
Molecular Weight ◽  
Thermal Properties ◽  
Cellulose Nanofibrils ◽  
Value Added ◽  
Xrd Analysis ◽  
Low Molecular Weight ◽  
Mechanical And Thermal Properties ◽  
Graft Modification ◽  
Effective Option ◽  
20 Nm

Abstract In this work, from an endemic and non-significant value-added bamboo argentine, nanofibrils (CNFs) of 20 nm in width were obtained. These nanofibrils were chemical modified in surface with three simple steps using a noncommercial low molecular weight polylactic acid. The success of modification was confirmed by FTIR, TGA, DSC and XRD analysis. The modified nanofibrils were taken up for changing surface properties in films based on commercial PLA. The results show that dispersive (γ D/S) component of films increase of 34.7 mN/m to 36.1 mN/m after the addition of modified nanofibrils from 2 to 5% in formulation of the films, comparing with a physical blend. Interesting others result in physical, mechanical, and thermal properties of the nanocomposites, were reported.

Effects of Molecular Weight of Chitosan on the Biodegradability and Thermal Properties of Polybutylene Succinate/Chitosan Composites

2018 ◽  
Vol 775 ◽  
pp. 26-31
Author(s):  
Sukantika Manatsittipan ◽  
Kamonthip Kuttiyawong ◽  
Kazuo Ito ◽  
Sunan Tiptipakorn
Keyword(s):  
Molecular Weight ◽  
Weight Loss ◽  
Thermal Properties ◽  
Water Absorption ◽  
Melting Temperature ◽  
Microbial Degradation ◽  
Decomposition Temperature ◽  
Molecular Weights ◽  
Significant Difference ◽  
Polybutylene Succinate

In this study, the biodegradability and thermal properties the composites of polybutylene succinate (PBS) and chitosan of different molecular weights (Mn = 104,105, and 106 Da) were prepared at chitosan contents of 0-10 wt%. After 10 days of microbial degradation, the results show that the amount of holes from degradation was increased with either decreasing Mn or increasing chitosan contents. However, the size of holes was increased with increasing Mn and chitosan contents. The results from Differential Scanning Calorimeter (DSC) present that the melting temperature (Tm) of PBS was decreased with increasing chitosan contents. Moreover, there was no significant difference between Tm of the composites with different Mn of chitosan. From the TGA thermograms, the decomposition temperature at 10% weight loss (Td10) was decreased with increasing chitosan contents. Moreover, the water absorption of PBS/chitosan composites was increased with increasing Mn and content of chitosan.

Molecular weight and thermal properties of polyhydroxyalkanoates produced from fermented sugar molasses by open mixed cultures

2010 ◽  
Vol 147 (3-4) ◽  
pp. 172-179 ◽  
Author(s):  
Simon Bengtsson ◽  
Ana R. Pisco ◽  
Peter Johansson ◽  
Paulo C. Lemos ◽  
Maria A.M. Reis
Keyword(s):  
Molecular Weight ◽  
Thermal Properties ◽  
Mixed Cultures

Alternating poly(ester amide)s from glutaric anhydride and α,ω-aminoalcohols: synthesis and thermal properties

e-Polymers ◽  
2003 ◽  
Vol 3 (1) ◽  
Author(s):  
Thomas Fey ◽  
Helmut Keul ◽  
Hartwig Höcker
Keyword(s):  
Molecular Weight ◽  
Thermal Properties ◽  
Homologous Series ◽  
Average Molecular Weight ◽  
Number Average Molecular Weight ◽  
Melting Points ◽  
Glutaric Anhydride ◽  
H Nmr ◽  
Activating Agent ◽  
Dimethylformamide Solution

Abstract Alternating poly(ester amide)s 6a - e were prepared by polycondensation of α-carboxyl-ω-hydroxyamides 3a - e which were obtained by aminolysis of glutaric anhydride (1) and α,ω-aminoalcohols, H2N-(CH2)x-OH (x = 2 - 6) 2a - e. The polycondensation was performed in dimethylformamide solution using a carbodiimide as activating agent, or in bulk with Bu2Sn(OMe)2, Ti(OBu)4 and Sn(octoate)2 as a catalyst. For the polycondensation in bulk, the influence of catalyst and of temperature on the number-average molecular weight was studied. 1H NMR analyses of the poly(ester amide)s clearly show the alternating microstructure. The poly(ester amide)s from glutaric anhydride and the homologous series of α,ω-aminoalcohols are semicrystalline materials; their melting points show the odd/even effect observed for other poly(ester amide)s.

Use of hydroxytelechelic cis-1,4-polyisoprene (HTPI) in the synthesis of polyurethanes (PUs). Part 1. Influence of molecular weight and chemical modification of HTPI on the mechanical and thermal properties of PUs

Polymer ◽  
2005 ◽  
Vol 46 (18) ◽  
pp. 6869-6877 ◽  
Author(s):  
Nasreddine Kébir ◽  
Irène Campistron ◽  
Albert Laguerre ◽  
Jean-François Pilard ◽  
Claude Bunel ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Thermal Properties ◽  
Chemical Modification ◽  
Mechanical And Thermal Properties

scholarly journals Solid-State Polymerization of Poly(Ethylene Furanoate) Biobased Polyester, III: Extended Study on Effect of Catalyst Type on Molecular Weight Increase

Polymers ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 438 ◽  
Author(s):  
Yosra Chebbi ◽  
Nejib Kasmi ◽  
Mustapha Majdoub ◽  
George Papageorgiou ◽  
Dimitris Achilias ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Thermal Properties ◽  
Solid State ◽  
Intrinsic Viscosity ◽  
Weight Increase ◽  
Degree Of Crystallinity ◽  
Solid State Polymerization ◽  
End Groups ◽  
Poly Ethylene ◽  
Molecular Weight Increase

In this study, the synthesis of poly(ethylene furanoate) (PEF), catalyzed by five different catalysts—antimony acetate (III) (Sb Ac), zirconium (IV) isopropoxide isopropanal (Zr Is Ip), antimony (III) oxide (Sb Ox), zirconium (IV) 2,4-pentanedionate (Zr Pe) and germanium (IV) oxide (Ge Ox)—via an industrially common combination of melt polymerization and subsequent solid-state polymerization (SSP) is presented. In all reactions, proper amounts of 2,5-dimethylfuran-dicarboxylate (DMFD) and ethylene glycol (EG) in a molar ratio of DMFD/EG= 1/2 and 400 ppm of catalyst were used. Polyester samples were subjected to SSP procedure, under vacuum application, at different reaction times (1, 2, 3.5, and 5 h) and temperatures of 190, 200, and 205 °C. Carboxyl end-groups concentration (–COOH), intrinsic viscosity (IV), and thermal properties, via differential scanning calorimetry (DSC), were measured for all resultant polymers to study the effect of the used catalysts on the molecular weight increase of PEF during SSP process. As was expected, it was found that with increasing the SSP time and temperature, the intrinsic viscosity and the average molecular weight of PEF steadily increased. In contrast, the number of carboxyl end-groups content showed the opposite trend as intrinsic viscosity, that is, gradually decreasing during SSP time and temperature increase. It is worthy to note that thanks to the SSP process an obvious and continuous enhancement in the thermal properties of the prepared PEF samples was attained, in which their melting temperatures (Tm) and degree of crystallinity (Xc) increase progressively with increasing of reaction time and temperature. To predict the time evolution of polymers IV, as well as the hydroxyl and carboxyl content of PEF polyesters during the SSP, a simple kinetic model was developed. From both the theoretical simulation results and the experimental measurements, it was demonstrated that surely the Zr Is Ip catalyst shows the best catalytic characteristics compared to all other used catalysts herein, that is, leading in reducing—in a spectacular way—the activation energy of the involved both transesterification and esterification reactions during SSP.

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