Influence of annealing, thermal history, and solvent treatments on the degree of crystallinity and glass transition temperature of normal and low temperature-polymerized PVC

1981 ◽  
Vol 19 (2) ◽  
pp. 177-203 ◽  
Author(s):  
Paramjit Singh ◽  
J. Lyngaae-Jøsrgensen
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Low Temperature ◽  
Thermal History ◽  
Degree Of Crystallinity ◽  
The Degree Of Crystallinity

The Influence of the Degree of Crystallinity on the Glass Transition Temperature of Polymers

2013 ◽  
Vol 864-867 ◽  
pp. 751-754 ◽  
Author(s):  
Andrey Askadskii ◽  
Marina Popova ◽  
Tatyana Matseevich ◽  
Elena Kurskaya
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Degree Of Crystallinity ◽  
Low Degrees ◽  
The Degree Of Crystallinity

The influence of the degree of crystallinity of polymers on the glass transition temperature Tg of their amorphous domains is quantitatively analyzed. The analysis is made based on the Mandelkerns ideas [ concerning the restrictive effect of crystallization on the mobility of macromolecules within the amorphous domains. At low degrees of crystallinity, Tg of amorphous domains slowly increases, and then increases much faster at high degrees of crystallinity.

The Effect of Methylene Diphenyl Diisocyanate on the Nonisothermal Properties of Polylactic Acid/Elaeis guineensis Fibres Biocomposites

2013 ◽  
Vol 594-595 ◽  
pp. 823-827
Author(s):  
Luqman Hakim Ahmad Subri ◽  
Sakinah Mohd Alauddin ◽  
Senawi Rosman
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Polylactic Acid ◽  
Elaeis Guineensis ◽  
Fibre Surface ◽  
Degree Of Crystallinity ◽  
Chain Mobility ◽  
Methylene Diphenyl Diisocyanate ◽  
The Degree Of Crystallinity

Biocomposites demands are significantly rising due to environmental regulations and concerns. However, incompatibility between the fibre and matrix is a major setback that diminishes the biocompostie properties. Therefore in this work, methylene diphenyl diisocynate (MDI) compatibilizers were used together with fibre surface treatment in order to increase compatibility between polylactic acid (PLA) and Elaeis Guineensis Fibres (EGF) biocomposite. Nonisothermal properties were investigated and it was found that, MDI increased compatibility of the PLA and EGF which led to the restriction of chain movements in the biocomposite. This restriction in chain mobility caused an increase the glass transition temperature and crystallization temperature and also reduced the degree of crystallinity.

Citric acid grafting onto polyurethane for the control of molecular interactions and water compatibility

2016 ◽  
Vol 48 (8) ◽  
pp. 691-710
Author(s):  
Yong-Chan Chung ◽  
Hyeryoung Yoon ◽  
Jae Won Choi ◽  
Byoung Chul Chun
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Citric Acid ◽  
Low Temperature ◽  
Molecular Interactions ◽  
Water Permeability ◽  
Enthalpy Change ◽  
Low Temperature Flexibility ◽  
Grafting Onto

Citric acid (CA) was used as a grafted group onto polyurethane (PU) to form a CA-grafted PU series, with a control PU series containing free CA prepared for comparison. With an increase in the CA content, the enthalpy change during the melting increased for the PU and CPU series, and the glass transition temperature increased with the increase in CA content for the PU series but not for the CPU series. The tensile strengths of the PU series sharply increased with the CA content, whereas those of the CPU series did not. The PU series demonstrated better low-temperature flexibility and water permeability than the unmodified PU.

Cryomicroscopy of Latex and Latex Films

2000 ◽  
Vol 6 (S2) ◽  
pp. 316-317
Author(s):  
O. L. Shaffer ◽  
M. S. El-Aasser
Keyword(s):  
Electron Microscopy ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Low Temperature ◽  
Protective Coatings ◽  
Continuous Film ◽  
The Core ◽  
Film Forming ◽  
Water Uses

Latexes are dispersions of homopolymers and copolymers, usually in water. Uses of these latexes are many such as protective coatings and adhesives. In order to form a continuous film the polymer must have film forming properties such as a low glass transition temperature (Tg). Latexes are being designed such as one polymer in the core of the particle and a shell of another polymer or perhaps a series of shell layers. Microscopy has become a powerful tool in the examination of the morphology of the latex particles. Because of the use of low Tg polymers, sample preparation and examination by electron microscopy at temperatures above the Tg of the polymer causes the particles to become distorted and no longer representative of their true morphology. Low temperature methods therefore have become crucial in the field of latex microscopy.

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