Laws of growth of the prefracture zone at the edge of a macrocrack in a polymeric material

1988 ◽  
Vol 24 (2) ◽  
pp. 163-169
Author(s):  
A. A. Kaminskii
Keyword(s):  
Polymeric Material ◽  
Prefracture Zone ◽  
Laws Of Growth

Organic Syntheses During the Impact of a Comet with a Gaseous Planet

1997 ◽  
Vol 161 ◽  
pp. 189-195
Author(s):  
Cesare Guaita ◽  
Roberto Crippa ◽  
Federico Manzini
Keyword(s):  
Polymeric Material ◽  
Molecular Form ◽  
Parent Compound ◽  
Blue Filter ◽  
Organic Syntheses ◽  
The Impact

AbstractA large amount of CO has been detected above many SL9/Jupiter impacts. This gas was never detected before the collision. So, in our opinion, CO was released from a parent compound during the collision. We identify this compound as POM (polyoxymethylene), a formaldehyde (HCHO) polymer that, when suddenly heated, reformes monomeric HCHO. At temperatures higher than 1200°K HCHO cannot exist in molecular form and the most probable result of its decomposition is the formation of CO. At lower temperatures, HCHO can react with NH3 and/or HCN to form high UV-absorbing polymeric material. In our opinion, this kind of material has also to be taken in to account to explain the complex evolution of some SL9 impacts that we observed in CCD images taken with a blue filter.

Making Graphene-type Material via Polymerization of Porphyrin

2020 ◽  
Author(s):  
SANJIB KAR ◽  
Sruti Mondal ◽  
Kasturi Sahu ◽  
Dilruba Hasina ◽  
Tapobrata Som ◽  
...  
Keyword(s):  
Layer Thickness ◽  
Polymeric Material ◽  
Single Layer ◽  
Type Material ◽  
Synthetic Pathway ◽  
Simple Chemical ◽  
Doped Graphene ◽  
Ring Nitrogen ◽  
2D Structure ◽  
Porphyrin Macrocycles

<p>The synthesis of new graphene-type materials (<i>via</i> polymerization of porphyrin macrocycles) through a simple chemical synthetic pathway (at RT) has been demonstrated. This newly synthesized material can be dispersed in water with an average sheet size of few microns and with single layer thickness. As the porphyrin contains four inner ring nitrogen atoms thus the presented polymeric material will be close analogous of N-doped graphene. Porphyrin as the key component to synthesize layered graphene type continuous 2D structure has never been attempted before. </p> <p> </p>

Review: Polyaniline—A novel polymeric material

Talanta ◽  
1991 ◽  
Vol 38 (8) ◽  
pp. 815-837 ◽  
Author(s):  
Akheel A. Syed ◽  
Maravattickal K. Dinesan
Keyword(s):  
Polymeric Material

scholarly journals Osteoblast cell response to a CO2 laser modified polymeric material

2012 ◽  
Vol 50 (2) ◽  
pp. 236-247 ◽  
Author(s):  
D.G. Waugh ◽  
J. Lawrence ◽  
E.M. Brown
Keyword(s):  
Polymeric Material ◽  
Co2 Laser ◽  
Cell Response ◽  
Osteoblast Cell

The Influence of Factors of a Biological and Physical Nature on the Biodegradation and Physicochemical Properties of Composites Based on Polyvinyl Chloride and Natural Polymers

2018 ◽  
Vol 45 (6) ◽  
pp. 283-288
Author(s):  
V.F. Smirnov ◽  
A.A. Glagoleva ◽  
A.E. Mochalova ◽  
L.A. Smirnova ◽  
N.A. Anikina
Keyword(s):  
Physicochemical Properties ◽  
Polyvinyl Chloride ◽  
Polymeric Material ◽  
Starch Content ◽  
Physical Nature ◽  
Physical Factors ◽  
Microscopic Fungi ◽  
Natural Polymers ◽  
Properties Of Composites

It has been established that the degree of biodegradation of composites based on polyvinyl chloride and natural polymers by microscopic fungi changes as a function of the chitosan and starch content in the composites. Biodegradation of polymeric material is accompanied with change in its physicochemical properties. A number of physical factors result in an increase in the degree of biodegradation of the materials investigated.

Polydeckerkomplexe mit μ,η5-2,3-Dihydro-1,3-diborolylnickel-Fragmenten als Stapeleinheiten / Polydecker Complexes with μ,η5-2,3-Dihydro-1,3-diborolylnickel Fragments as Stacking Units

1993 ◽  
Vol 48 (11) ◽  
pp. 1512-1518 ◽  
Author(s):  
Ulrich Fenner ◽  
Thomas Kuhlmann ◽  
Gregor Brodt ◽  
Jacques Roziére ◽  
Walter Siebert
Keyword(s):  
Mass Loss ◽  
Polymeric Material ◽  
Slow Heating ◽  
Sensitive Material ◽  
Reduced Pressure ◽  
Endothermic Process ◽  
Ring Atom

Reactions of 2,3-dihydro-1,3-diboroles 6a–h with (C3H5)2Νi lead to µ,η5-2,3-dihydro-1,3-diborolylnickel triple-decker complexes 7a –h. By slow heating these oily, diamagnetic complexes in a rotating flask polycondensation with formation of black 8a–h as well as of bis(allyl)nickel and hexadiene occurs. The latter can be removed under reduced pressure. The constitution of the polymeric material follows from EXAFS studies. The Ni–Ni distance is 3,35 A, the ring atom Ni bonds are in the range of 2,13 to 2,15 A. Thermogravimetric measurements between 200 and 400°C show a mass loss of 20-40%, depending of the alkyl substituents of the heterocycle. In dynamic difference calorimetry an endothermic process occurs near 420°C. The powder conductivity of the amorphous, air-sensitive material is in the range of 10-2 S • cm-1. Doping with iodine or oxygen causes a decrease in the conductivity of these semi-conductors.

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