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.

Spatial control of the topography of photo-sensitive block copolymer thin films

2019 ◽  
Vol 10 (23) ◽  
pp. 3135-3145 ◽  
Author(s):  
Lewis C. Chambers ◽  
Yun Huang ◽  
Kevin S. Jack ◽  
Idriss Blakey
Keyword(s):  
Thin Films ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Block Copolymer ◽  
Molecular Interactions ◽  
Self Assembly ◽  
Spatial Control

Spatially controlling self-assembly of block copolymer thin films through photoinduced molecular interactions that significantly impact on the glass transition temperature.

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