Decoupling Temperature–Volume Effects on Poly[2-Methoxy-5-(2′-Ethylhexyloxy)-1,4-Phenylene-Vinylene] Films at the β-Relaxation Temperature

2020 ◽  
Vol 124 (26) ◽  
pp. 5496-5501
Author(s):  
Silésia de Fátima Curcino da Silva ◽  
Maurício Foschini ◽  
José Roberto Tozoni ◽  
Osvaldo N. Oliveira ◽  
Patricia Targon Campana ◽  
...  
Keyword(s):  
Phenylene Vinylene ◽  
Relaxation Temperature ◽  
Β Relaxation ◽  
Volume Effects

Glass Transition Temperature and β Relaxation Temperature around Chain End of Polystyrene Determined by Site Specific Spin Labeling

2012 ◽  
Vol 116 (4) ◽  
pp. 1282-1288 ◽  
Author(s):  
Yohei Miwa ◽  
Osamu Urakawa ◽  
Akinari Doi ◽  
Katsuhiro Yamamoto ◽  
Shogo Nobukawa
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Spin Labeling ◽  
Site Specific ◽  
Relaxation Temperature ◽  
Β Relaxation

Thermoplastics Modified with Nanoscale Inorganic Macromers

1998 ◽  
Vol 519 ◽  
Author(s):  
Timothy S. Haddad ◽  
Patrick T. Mather ◽  
Hong G. Jeont ◽  
Angel Romo-Uribe ◽  
Amy R. Farrist ◽  
...  
Keyword(s):  
Storage Modulus ◽  
Mole Fraction ◽  
Inorganic Materials ◽  
Mechanical Relaxation ◽  
Hybrid Copolymers ◽  
Polymer Properties ◽  
Relaxation Temperature ◽  
Unique Approach ◽  
Β Relaxation ◽  
Oligomeric Silsesquioxane

AbstractWe have taken a unique approach to the synthesis and study of hybrid organic/inorganic materials. Our method involves synthesizing nano-size inorganic P1R7Si8O12 clusters which contain seven inert “R” groups for solubility and only one functional “P” group for polymerization. This strategy permits the synthesis of melt processable, linear hybrid polymers containing pendent inorganic clusters and allows us to study the effect these clusters have on chain motions and polymer properties. The synthesis of norbomenyl-based polyhedral oligomeric silsesquioxane (POSS) macromers, their ring opening metathesis copolymerizations with varying amounts of norbornene, and analysis of the effect of the pendent POSS group is presented. The mechanical relaxation behavior and microstructure of norbornyl-POSS hybrid copolymers have been examined for their dependencies on the mole fraction of POSS-norbornyl monomer, as well as for potential sensitivity to the seven inert “R” groups present in each POSS macromer. POSS copolymerization is observed to enhance the α-relaxation temperature, Tα, in proportion to the mole fraction of POSS-norbornyl comonomer. Interestingly, however, the magnitude of this dependence is larger for POSS-norbornyl comonomer possessing cyclohexyl groups (CyPOSS) than for cyclopentyl groups (CpPOSS). While POSS copolymerization yields only slight enhancement of the tensile storage modulus measured near room temperature, at temperatures lower than a strong mechanical relaxation (β-relaxation near T = -75 °C), there is a significant POSS-reinforcement of the storage modulus.

scholarly journals β phase instability in poly(vinylidene fluoride/trifluoroethylene) thin films near β relaxation temperature

2015 ◽  
Vol 106 (9) ◽  
pp. 092902 ◽  
Author(s):  
B. B. Tian ◽  
X. F. Bai ◽  
Y. Liu ◽  
P. Gemeiner ◽  
X. L. Zhao ◽  
...  
Keyword(s):  
Thin Films ◽  
Vinylidene Fluoride ◽  
Phase Instability ◽  
Β Phase ◽  
Relaxation Temperature ◽  
Poly Vinylidene Fluoride ◽  
Β Relaxation

scholarly journals Thermal Properties of Plasticized Cellulose Acetate and Its β-Relaxation Phenomenon

Polymers ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1356
Author(s):  
Rafael Erdmann ◽  
Stephan Kabasci ◽  
Hans-Peter Heim
Keyword(s):  
Mechanical Properties ◽  
Activation Energy ◽  
Cellulose Acetate ◽  
Theoretical Models ◽  
Thermomechanical Properties ◽  
Plasticizer Content ◽  
Relaxation Temperature ◽  
Triethyl Citrate ◽  
Β Relaxation ◽  
Work Done

Cellulose acetate (CA), an organic ester, is a biobased polymer which exhibits good mechanical properties (e.g., high Young’s modulus and tensile strength). In recent decades, there has been significant work done to verify the thermal and thermomechanical behaviors of raw and plasticized cellulose acetate. In this study, the thermomechanical properties of plasticized cellulose acetate—especially its ββ-relaxation and activation energy—were investigated. The general thermal behavior was analyzed and compared with theoretical models. The study’s findings could be of special interest, due to the known ββ-relaxation dependency of some polymers regarding mechanical properties—which could also be the case for cellulose acetate. However, this would require further investigation. The concentration of the plasticizers—glycerol triacetate (GTA) and triethyl citrate (TEC)—used in CA ranged from 15 to 40 wt%. DMTA measurements at varying frequencies were performed, and the activation energies of each relaxation were assessed. Increasing plasticizer content first led to a shift in ββ-relaxation temperature to highervalues, then reached a maximum before declining again at higher concentrations. Furthermore, the activation energy of the ββ-relaxation constantly rose with increases in plasticizer content. The trend in the ββ-relaxation temperature of the plasticized CA could be interpreted as a change in the predominant phase of the overlapping ββ-relaxation of the CA itself and the αα′-relaxation of the plasticizer—which appears in the same temperature range. The plasticizer used (GTA) demonstrated a higher plasticization efficiency than TEC. The efficiencies of both plasticizers declined with increasing plasticizer content. Additionally, both plasticizers hit the saturation point (in CA) at the lowest studied concentration (15 wt%).

Photooxidation effects on the electroluminescent properties in poly(p-phenylene vinylene) derivative

2002 ◽  
Vol 122 (4) ◽  
pp. 409-414
Author(s):  
Kazuya Tada ◽  
Mitsuyoshi Onoda
Keyword(s):  
Phenylene Vinylene

Functional Poly(p-Xylylene)s via Chemical Reduction of Poly(p-Phenylene Vinylene)s

2019 ◽  
Author(s):  
Ain Uddin ◽  
Weifan Sang ◽  
Yong Gao ◽  
Kyle Plunkett
Keyword(s):  
Film Formation ◽  
Chemical Reduction ◽  
Water Soluble ◽  
Phenylene Vinylene ◽  
Polymer Modification ◽  
Polymer Backbone ◽  
Crosslinking Process ◽  
Conducting Membranes ◽  
In Situ Crosslinking

The synthesis of poly(p-xylylene)s (PPXs) with sidechains containing alkyl bromide functionality, and their post-polymer modification, is described. The PPXs were prepared by a diimide hydrogenation of poly(p-phenylene vinylene)s (PPVs) that were originally synthesized by a Gilch polymerization. The polymer backbone reduction was carried out with hydrazine hydrate in toluene at 80 °C to provide polymers with the sidechain-containing bromide functionality intact. To demonstrate post-polymer modification of the sidechains, the resulting PPX polymers were modified with trimethylamine to form tetraalkylammonium ion functionality and were evaluated as anion conducting membranes. While PPX homopolymers containing tetralkylammonium ions were completely water soluble and not able to form valuable films, PPX copolymers containing mixed tetraalkylammonium ions and hydrophobic chains were capable of film formation and alkaline stability. In addition, an in situ crosslinking process that used N,N,N',N'-tetramethyl-1,6-hexanediamine during the tetraalkylammonium formation of brominated PPX polymers was also evaluated and gave reasonable films with conductivities of ~10 mS-cm-1.

Functional Poly(p-Xylylene)s via Chemical Reduction of Poly(p-Phenylene Vinylene)s

2019 ◽  
Author(s):  
Ain Uddin ◽  
Weifan Sang ◽  
Yong Gao ◽  
Kyle Plunkett
Keyword(s):  
Film Formation ◽  
Chemical Reduction ◽  
Water Soluble ◽  
Phenylene Vinylene ◽  
Polymer Modification ◽  
Polymer Backbone ◽  
Crosslinking Process ◽  
Conducting Membranes ◽  
In Situ Crosslinking

The synthesis of poly(p-xylylene)s (PPXs) with sidechains containing alkyl bromide functionality, and their post-polymer modification, is described. The PPXs were prepared by a diimide hydrogenation of poly(p-phenylene vinylene)s (PPVs) that were originally synthesized by a Gilch polymerization. The polymer backbone reduction was carried out with hydrazine hydrate in toluene at 80 °C to provide polymers with the sidechain-containing bromide functionality intact. To demonstrate post-polymer modification of the sidechains, the resulting PPX polymers were modified with trimethylamine to form tetraalkylammonium ion functionality and were evaluated as anion conducting membranes. While PPX homopolymers containing tetralkylammonium ions were completely water soluble and not able to form valuable films, PPX copolymers containing mixed tetraalkylammonium ions and hydrophobic chains were capable of film formation and alkaline stability. In addition, an in situ crosslinking process that used N,N,N',N'-tetramethyl-1,6-hexanediamine during the tetraalkylammonium formation of brominated PPX polymers was also evaluated and gave reasonable films with conductivities of ~10 mS-cm-1.

Features of radiothermoluminescence of polypropylene and ethylene propylenediene elastomer SKEPT-4044 compositions with nanoscale metal-containing fillers

2020 ◽  
pp. 66-73
Author(s):  
A.M. Magerramov ◽  
◽  
N.I. Kurbanova ◽  
M.N. Bayramov ◽  
N.A. Alimirzoyeva ◽  
...  
Keyword(s):  
Transition Temperature ◽  
Molecular Mobility ◽  
Fe3o4 Nanoparticles ◽  
Low Temperatures ◽  
Frost Resistance ◽  
Relaxation Processes ◽  
Ethylene Propylene ◽  
Temperature Range ◽  
Β Relaxation

Using radiothermoluminescence (RTL), the molecular mobility features in the temperature range of 77-300 K were studied for the polypropylene (PP)/ethylene propylene diene elastomer SKEPT-4044 with NiO, Cu2O and Fe3O4 nanoparticles (NPs) based on ABS-acrylonitrile butadiene or SCS-divinyl styrene matrices. It has been shown that the introduction of nanofillers in PP significantly affects the nature and temperature of γ- and β-relaxation processes, while the region of manifestation of the β-process noticeably shifts to the region of low temperatures. Composites with Cu2O NPs have a higher β-transition temperature Tβ than composites with other NPs. It was found that PP/SKEPT-4044 composites with Cu2O NPs with a dispersion of 11-15 nm and acrylonitrile butadiene thermoplastics have optimal frost resistance compared to other compositions.

Sampling Volume Effects on Determining Salt in a Soil Profile1

1983 ◽  
Vol 47 (6) ◽  
pp. 1265 ◽  
Author(s):  
H. M. Hassan ◽  
A. W. Warrick ◽  
A. Amoozegar-Fard
Keyword(s):  
Sampling Volume ◽  
Volume Effects

Float Capitalization Index Weights in Dow Jones STOXX Price and Volume Effects

2002 ◽  
Author(s):  
Torben Voetmann ◽  
Robert Neumann
Keyword(s):  
Volume Effects
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