The Chemical Structure of the “Popcorn” Polymer of Butadiene

1958 ◽  
Vol 31 (3) ◽  
pp. 581-587
Author(s):  
A. I. Yakubchik ◽  
A. I. Spasskova
Keyword(s):  
Chemical Structure ◽  
Relative Content ◽  
Double Bonds ◽  
Soluble Polymer ◽  
Degree Of Unsaturation ◽  
Rubbery Polymers

Abstract 1. The chemical structure of spongy butadiene polymer, obtained at 15–20° was examined by the ozonolysis method. 2. The per cent of chains with external double bonds in the spongy polymer was found to be 22.8%. 3. The spongy polymer of butadiene is composed, like the rubbery polymers, of chains with external and internal double bonds. 4. It was established that parts of the molecule of spongy polymer have the same structure as the rubbery butadiene polymers: -1,4-1,4-; -1,4-1,2-1,4-; -1,4-1,2-1,2-1,4-. 5. A chloroform-soluble rubberlike polymer was separated from the butadiene autopolymer. The degree of unsaturation of the chloroform-soluble polymer was determined (86.7%), also the relative content of internal and external double bonds.

The Influence of Structure on the Chemical Activity and Vulcanizability of Butadiene Polymers

1958 ◽  
Vol 31 (3) ◽  
pp. 569-580 ◽  
Author(s):  
B. A. Dogadkin ◽  
A. V. Dobromyslova ◽  
F. S. Tolstukhina ◽  
N. G. Samsonova
Keyword(s):  
Linear Function ◽  
Relative Content ◽  
Double Bonds ◽  
Initial Region ◽  
Linear Region ◽  
Kinetic Curves ◽  
Perbenzoic Acid ◽  
Ordinate Axis ◽  
Sulfur Addition ◽  
Iodine Chloride

Abstract 1. Differences between the chemical reactivities of 1,4- and 1,2-structures of butadiene are found in the reactions with perbenzoic acid, iodine chloride, and sulfur. 2. The interaction of perbenzoic acid with solutions of butadiene polymers is represented by kinetic curves with an initial region of a high rate, mainly corresponding to the reaction of the double bonds of 1,4-structure, and a final linear region of a low rate, characterizing the reaction of the double bonds in the vinyl side chains of 1,2-structure. By extrapolation of the linear region to the ordinate axis it is possible to determine the relative contents of the 1,4- (and hence of the 1,2-) structure in the polymer. 3. The kinetic curves for the interaction of the polymer solutions with iodine chloride are of analogous form. The initial region of the kinetic curve represents addition at the double bonds, while the linear region corresponds to the substitution reaction. By extrapolation of the linear region to the ordinate axis it is possible to determine the actual double bond content of the polymer. 4. The kinetic curves for iodine liberation are also of similar form ; here the linear region corresponds to the substitution reaction, and the initial region corresponds to the cyclization reaction. The amount of iodine liberated in this reaction is a linear function of the content of the 1,2-structure in the polymer. 5. Mainly the double bonds of the 1,4-structure react when sulfur interacts with the polymer solutions. The total rate of sulfur addition is a linear function of the content of the 1,4-structure. 6. The activation energy for sulfur addition increases with increasing relative content of the 1,2-structure in the polymer. 7. Formation of sulfur crosslinks in vulcanizates occurs mainly as the result of reactions in the 1,4 polymer structure. In consequence, the degree of crosslinking ΔE/ΔS is a linear function of the relative content of 1,4-structure in the polymer.

scholarly journals Construction of Biological Flame Retardant Layer on Cotton Fabric via Photografting of Nucleotide/Amino Acid Monomers

2021 ◽  
Author(s):  
yutong liu ◽  
Xiao Wang ◽  
Zhenbao Li ◽  
Ju Wei ◽  
Bing Du
Keyword(s):  
Flame Retardant ◽  
Cotton Fabric ◽  
Chemical Structure ◽  
Pyrolysis Temperature ◽  
Cotton Fabrics ◽  
Scanning Electron Micrographs ◽  
Double Bonds ◽  
H Nmr ◽  
Ft Ir ◽  
Synergistic Flame Retardant

Abstract The 5’-adenylicacid (AMP-Na2) is modified to introduce unsaturated double bonds for photografting onto cotton fabrics together with L-cysteine (L-Cys) monomer to prepare synergistic flame-retardant cotton fabrics. The chemical structure of AMP-Na2/L-Cys monomers, the surface morphology, residual carbon morphology, thermal property and flame retardant property of photografted flame retardant cotton fabrics are analyzed. FT-IR and 1H NMR spectra verified the AMP-Na2 and L-Cys monomers with unsaturated double bonds. Scanning electron micrographs revealed the carbon residue of photografted fiber maintains a natural curled and fibers shape. TGA showed the major pyrolysis temperature of photografted cotton fabric declined by 42℃, with the weight loss reduced by 21.6%, proving that good charring effect. The continuous burning and smoldering time of photografted cotton fabric are decreased to 0s. The experimental results indicate that AMP-Na2/L-Cys monomers can reveal good durability and remarkable flame retardancy property to cotton fabrics via facile treatment of photografting.

scholarly journals Reactivity of Polymers on Exposure to Nitrogen Dioxide

2010 ◽  
Vol 4 (4) ◽  
pp. 281-290
Author(s):  
Evgeny Davydov ◽  
◽  
Irina Gaponova ◽  
Georgy Pariiskii ◽  
Tatyana Pokholok ◽  
...  
Keyword(s):  
Free Radical ◽  
Nitrogen Dioxide ◽  
Chemical Structure ◽  
Elevated Temperatures ◽  
Carbon Chain ◽  
Hydroxyl Groups ◽  
Double Bonds ◽  
Simple Method ◽  
Alkyl Radicals

The mechanism of reactions of nitrogen dioxide with polymers of different classes is considered. In reactions with carbon-chain polymers at 298 K, nitrogen dioxide can only add to extrinsic double bonds that are formed in the synthesis of the polymers. The mechanism of reactions of nitrogen dioxide with polymers of different classes is considered. In reactions with carbon-chain polymers at 298 K, nitrogen dioxide can only add to extrinsic double bonds that are formed in the synthesis of the polymers. These reactions resulted in dinitro compounds and nitro nitrites. At elevated temperatures, carbonyl and hydroxyl groups are formed in these polymers along with nitration products. Active participants of NO2 reactions with rubbers are double bonds converting into nitroalkyl and alkyl radicals initiating then free radical conversions of these polymers. Polymers containing amide, urethane and imide groups are rather sensitive to NO2. These materials undergo essential changes in the chemical structure with formation of stable nitrogen-containing radicals. The reactions of nitrogen dioxide provide a simple method of the spin-labeled polymer preparation.

scholarly journals Polyunsaturated-fatty-acid oxidation in Hydra: regioselectivity, substrate-dependent enantioselectivity and possible biological role

1994 ◽  
Vol 300 (2) ◽  
pp. 501-507 ◽  
Author(s):  
V Di Marzo ◽  
C Gianfrani ◽  
L De Petrocellis ◽  
A Milone ◽  
G Cimino
Keyword(s):  
Fatty Acids ◽  
Arachidonic Acid ◽  
Acid Oxidation ◽  
Reaction Products ◽  
Double Bonds ◽  
Regenerative Processes ◽  
Hydra Vulgaris ◽  
Degree Of Unsaturation ◽  
Keto Acids ◽  
Linoelaidic Acid

A novel and abundant lipoxygenase-like activity converting cis-eicosa-5,8,11,14-tetraenoic acid (arachidonic acid) into (11R)-hydroxyeicosatetraenoic acid has been recently described in homogenates of the freshwater hydrozoan Hydra vulgaris. In this study, other substrates for this enzyme were selected from the polyunsaturated fatty acids (PUFAs) present in H. vulgaris, and the chemical natures of the hydroperoxy and hydroxy derivatives produced, as well as the activity of some of the latter on hydroid tentacle regeneration, were investigated. The highest conversion among C20 fatty acids was observed for arachidonic acid, and among C18 fatty acids for cis-octadeca-9,12,15- and cis-octadeca-6,9,12-trienoic (alpha- and gamma-linolenic) acids. Cis double bonds on the 10th carbon atom from the aliphatic end of the substrate (e.g. C-9, C-11 and C-13 respectively in C18, C20 and C22 PUFAs) were regiospecifically peroxidized. Conversely, trans-octadeca-9,12-dienoic (linoelaidic) acid was not a substrate for lipoxygenase activity. Enantioselectivity of lipoxygenation depended on the degree of unsaturation of the substrate, with the amount of the R enantiomer increasing when passing, for example, from cis-eicosa-11,14-dienoic to cis-eicosa-5,8,11,14,17-pentaenoic acid. Regiospecific formation of keto acids was observed only when incubating C18 PUFAs. Commercially available hydroxyacids corresponding to the reaction products of some of the most abundant H. vulgaris PUFAs were tested for effects on Hydra tentacle regeneration. An enhancement of average tentacle number, in a fashion depending on the stereochemistry and on the number of double bonds, was found for two compounds, thus suggesting for the 11-lipoxygenase-like enzyme a role in the production of metabolites potentially active in the control of hydroid regenerative processes.

Radical polimerization of methyl α-crotonyloxymethyl) acrylate to soluble polymer bearing pendant double bonds

2000 ◽  
Vol 43 (6) ◽  
pp. 457-464 ◽  
Author(s):  
Bunichiro Yamada ◽  
Makoto Azukizawa ◽  
Tomoaki Hirayama
Keyword(s):  
Double Bonds ◽  
Soluble Polymer ◽  
Polymer Bearing

Kinetic of Oxidative Polymerization of Benzylidene-Phenylenediamines and Investigation of their Thermal Properties

2019 ◽  
Vol 816 ◽  
pp. 124-128
Author(s):  
Timur A. Borukaev ◽  
A.Kh. Shaov ◽  
R.M. Otarova ◽  
L.R. Pashtova ◽  
A.Kh. Salamov
Keyword(s):  
Thermal Properties ◽  
Heat Resistance ◽  
Chemical Structure ◽  
Oxidative Polymerization ◽  
Cation Radical ◽  
Kinetic Studies ◽  
Chain Growth ◽  
Double Bonds

Oxidative polymerization of benzylidenephenylenediamines produced polymers containing conjugated double bonds. Kinetic studies of the processes of oxidative polymerization of benzylidenephenylene diamines were carried out. The obtained kinetic dependencies allowed us to suggest the mechanism of oxidative polymerization of benzylidenephenylenediamines, which flows through the stage of formation of the cation radical, dimmer, tetramer, leading eventually to the formation of the polymer. In this case the limiting stadia is the formation of cation-radical, and chain growth occurs by N-C. A study of the thermal properties of the polymers showed that polybenzylidenephenylenediamines is characterized by rather high values of heat resistance. It was found that the process of destruction of most of the synthesized polymers occurs in several stages and depends on the chemical structure of the macromolecule.

Sign in / Sign up

Export Citation Format

Share Document