Poly(Dimethylsiloxane) Elastomers from Aqueous Emulsions: III. Effects of Blended Silica Fillers and γ-Radiation-Induced Crosslinking

1998 ◽  
Vol 71 (5) ◽  
pp. 941-948 ◽  
Author(s):  
D. W. McCarthy ◽  
J. E. Mark
Keyword(s):  
Colloidal Silica ◽  
Film Formation ◽  
Continuous Phase ◽  
Γ Radiation ◽  
Silica Fillers ◽  
Radiation Induced ◽  
Different Shapes ◽  
Morphological Differences ◽  
Silica Phases

Abstract The morphologies of the reinforced elastomers prepared from emulsions were found to depend greatly on how the silica phases were introduced. More specifically, blending colloidal silica into the elastomer prior to film formation was found to yield a highly unusual elastomer in which the continuous phase was the silica and the dispersed phase the elastomer. This is the opposite of the usual case in which, for example, the silica is generated in-situ within the continuous elastomeric phase. These morphological differences were used to explain the different shapes of the stress—strain isotherms of these materials in simple elongation. Results on the crosslinking effects of gamma radiation demonstrated that this treatment represents another useful technique for optimizing the properties of these emulsion-derived materials.

In situ TEM studies of irradiation effects for materials improvement

1991 ◽  
Vol 49 ◽  
pp. 452-453
Author(s):  
Charles W. Allen
Keyword(s):  
Nuclear Reactor ◽  
Austenitic Stainless Steels ◽  
High Energy ◽  
Point Of View ◽  
In Situ Tem ◽  
Irradiation Effects ◽  
Tem Analysis ◽  
Radiation Induced ◽  
Analytical Tools

Irradiation effects studies employing TEMs as analytical tools have been conducted for almost as many years as materials people have done TEM, motivated largely by materials needs for nuclear reactor development. Such studies have focussed on the behavior both of nuclear fuels and of materials for other reactor components which are subjected to radiation-induced degradation. Especially in the 1950s and 60s, post-irradiation TEM analysis may have been coupled to in situ (in reactor or in pile) experiments (e.g., irradiation-induced creep experiments of austenitic stainless steels). Although necessary from a technological point of view, such experiments are difficult to instrument (measure strain dynamically, e.g.) and control (temperature, e.g.) and require months or even years to perform in a nuclear reactor or in a spallation neutron source. Consequently, methods were sought for simulation of neutroninduced radiation damage of materials, the simulations employing other forms of radiation; in the case of metals and alloys, high energy electrons and high energy ions.

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.

scholarly journals Excavation unloading‐induced fracturing of hard rock containing different shapes of central holes affected by unloading rates and in situ stresses

2019 ◽  
Vol 8 (1) ◽  
pp. 4-27 ◽  
Author(s):  
Fan Feng ◽  
Shaojie Chen ◽  
Diyuan Li ◽  
Wanpeng Huang ◽  
Kang Peng ◽  
...  
Keyword(s):  
Hard Rock ◽  
In Situ Stresses ◽  
Different Shapes

scholarly journals Inhibition of γ-Radiation Induced DNA Damage in Plasmid pBR322 by TMG, a Water-soluble Derivative of Vitamin E

2002 ◽  
Vol 43 (2) ◽  
pp. 153-153 ◽  
Author(s):  
REMA RAJAGOPALAN ◽  
KHALIDA WANI ◽  
NAGARAJ G. HUILGOL ◽  
TSUTOMU V. KAGIYA ◽  
CHERUPALLY K. KRISHNAN NAIR
Keyword(s):  
Dna Damage ◽  
Vitamin E ◽  
Water Soluble ◽  
Plasmid Pbr322 ◽  
Γ Radiation ◽  
Radiation Induced
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