Methanol Absorption in Ethylene−Vinyl Alcohol Copolymers:  Relation between Solvent Diffusion and Changes in Glass Transition Temperature in Glassy Polymeric Materials

1996 ◽  
Vol 29 (6) ◽  
pp. 2275-2288 ◽  
Author(s):  
Marsha A. Samus ◽  
Giuseppe Rossi
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Vinyl Alcohol ◽  
Polymeric Materials ◽  
Ethylene Vinyl Alcohol ◽  
Solvent Diffusion ◽  
Methanol Absorption

Polymeric materials for Solar Sail: The combined effects of polymer thickness, radiation, and temperature

2004 ◽  
Vol 851 ◽  
Author(s):  
David L. Edwards ◽  
Mircea Chipara
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Film Thickness ◽  
Polymeric Materials ◽  
Solar Sail ◽  
Polymeric Films ◽  
Space Environment ◽  
Combined Effects ◽  
Polymer Thickness

ABSTRACTThe feasibility and the performance of solar sail depend critically on the availability of light materials and extremely thin polymeric films. The main requirements imposed on solar sail materials are analyzed in depth. The potential effects of the space environment are discussed in detail, with emphasis on the radiation-temperature-polymeric film thickness relationships. It is shown that the radiation component of the space environment triggers two competing degradation processes (erosion and depolymerization) and that both processes act towards the decrease in the glass transition temperature.

scholarly journals The Scissors Effect in Action: The Fox-Flory Relationship between the Glass Transition Temperature of Crosslinked Poly(Methyl Methacrylate) and Mc in Nanophase Separated Poly(Methyl Methacrylate)-l-Polyisobutylene Conetworks

Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 4822
Author(s):  
Szabolcs Pásztor ◽  
Bálint Becsei ◽  
Györgyi Szarka ◽  
Yi Thomann ◽  
Ralf Thomann ◽  
...  
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Methyl Methacrylate ◽  
Single Case ◽  
Average Molecular Weight ◽  
Polymeric Materials ◽  
Poly Methyl Methacrylate ◽  
Margin Of Error ◽  
20 Nm

The glass transition temperature (Tg) is one of the most important properties of polymeric materials. In order to reveal whether the scissors effect, i.e., the Fox–Flory relationship between Tg and the average molecular weight between crosslinking points (Mc), reported only in one case for polymer conetworks so far, is more generally effective or valid only for a single case, a series of poly(methyl methacrylate)-l-polyisobutylene (PMMA-l-PIB) conetworks was prepared and investigated. Two Tgs were found for the conetworks by DSC. Fox–Flory type dependence between Tg and Mc of the PMMA component (Tg = Tg,∞ − K/Mc) was observed. The K constants for the PMMA homopolymer and for the PMMA in the conetworks were the same in the margin of error. AFM images indicated disordered bicontinuous, mutually nanoconfined morphology with average domain sizes of 5–20 nm, but the correlation between Tg and domain sizes was not found. These new results indicate that the macrocrosslinkers act like molecular scissors (scissors effect), and the Tg of PMMA depend exclusively on the Mc in the conetworks. Consequently, these findings mean that the scissors effect is presumably a general phenomenon in nanophase-separated polymer conetworks, and this finding could be utilized in designing, processing, and applications of these novel materials.

Electrical Properties of Poly(Vinyl Alcohol) Complexed with Phosphoric Acid

1988 ◽  
Vol 135 ◽  
Author(s):  
Ke-Cheng Gong ◽  
Huang Shou-Cai
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Electrical Properties ◽  
Phosphoric Acid ◽  
Vinyl Alcohol ◽  
Impedance Measurement ◽  
Poly Vinyl Alcohol ◽  
Promising Candidate ◽  
Polarization Experiment

AbstractThe electrical properties of poly(vinyl alcohol) complexed with phosphoric acid have been studied. It is found that the conductivity increases with the concentration of the acid, and also increases with time if the sample is exposed to the air, which is interpreted in terms of glass transition temperature. A.C. impedance measurement and polarization experiment show that this proton-conducting polymer is a promising candidate for electrochromic display. It is also found that some plasticizers, such as glycerol and ethylene-glycol are effective for improving its conductivity.

Chemical structure and physical properties of cyclic olefin copolymers (IUPAC Technical Report)

2005 ◽  
Vol 77 (5) ◽  
pp. 801-814 ◽  
Author(s):  
Ju Young Shin ◽  
Ji Yong Park ◽  
Chenyang Liu ◽  
Jiasong He ◽  
Sung Chul Kim
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Chemical Structure ◽  
Moisture Absorption ◽  
High Surface ◽  
Polymeric Materials ◽  
Surface Characteristics ◽  
Cyclic Olefin ◽  
Cyclic Olefin Copolymers

Cyclic olefin copolymers comprise a new class of polymeric materials showing properties of high glass-transition temperature, optical clarity, low shrinkage, low moisture absorption, and low birefringence. There are several types of cyclic olefin copolymers based on different types of cyclic monomers and polymerization methods. In this work, we have analyzed the chemical structure of the currently commercialized cyclic olefin copolymers by 13C NMR, and investigated their glass-transition temperatures and surface characteristics. It was observed that the glass-transition temperature, Tg, of cyclic olefin copolymers depended on the bulkiness of the main chain, and the number of rings had an important role in increasing the bulkiness of cyclic olefin copolymers. Cyclic olefin copolymers with polar substituents such as ester or ether groups showed high surface energy per area and peel strength.

Morphology and Long Term Behavior of Polymer Cement Concrete

1989 ◽  
Vol 179 ◽  
Author(s):  
K. P. Grosskurth
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Polymeric Materials ◽  
Heterogeneous Material ◽  
Cement Concrete ◽  
Temperature Dependent ◽  
Dependent Behavior ◽  
Long Term Behavior

AbstractPolymer-modified cement concrete represents a heterogeneous material whose properties are influenced more by the properties of the polymers than by the properties of the cement component. Typical of polymeric materials are their temperature dependent behavior. This temperature dependence can be related to the glass transition temperature of the polymer. In cases where the temperature is higher than the glass transition temperature, strength decreases while deformability simultaneously increases. Polymeric films are formed in the dispersed polymer systems as a result of reactions occurring at the glass transition temperature. A styrene/acrylic modified concrete was studied at different polymer loadings. The tensile and compressive strengths of this system were studied as a function of temperature. Increasing deformability temperatures principally at higher polymer loadings near the glass transition temperature and decreasing strength occurred.

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