Chlorinated Rubber from Latex

1952 ◽  
Vol 25 (3) ◽  
pp. 609-620 ◽  
Author(s):  
G. J. van Amerongen
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Chemical Stability ◽  
Hypochlorous Acid ◽  
Mechanical Stability ◽  
Chlorine Content ◽  
Rubber Latex ◽  
Synthetic Rubber ◽  
Satisfactory Method ◽  
New Applications

Abstract This work was undertaken to find new ways for producing chlorinated rubber from rubber latex. Methods have been applied during which coagulation of the latex and hyprochlorination of the rubber are avoided. Passing gaseous chlorine through stabilized and strongly acidified Hevea latex proves to be a satisfactory method for the chlorination of rubber. To avoid coagulation of the latex, certain nonionogenic or cationogenic emulsifiers have to be added. A high acidity of latex prevents the formation of hypochlorous acid and improves the mechanical stability of the latex. A chlorinated rubber latex is produced, the chlorinated rubber of which contains virtually no oxygen and up to 61 per cent of chlorine. By subjecting this chlorinated rubber latex or the dry isolated chlorinated rubber to an aftertreatment, products of a satisfactory solubility and with a chlorine content up to 72 per cent have been obtained. Judging from the reactivity with aniline, maximum chemical stability is at 65 per cent chlorine content. As a similar chlorination technique is applicable to rubber hydrochloride and synthetic rubber latexes, it is seen that latexes in general are good starting materials for the production of chlorinated derivatives. Moreover, stable chlorinated rubber latexes are obtained which can be used as such, making new applications possible. Technical advantages of chlorinating rubber in latex above rubber in solution are the much higher rubber concentration which can be used, and the ease of cooling the less viscous latex during the reaction. For some applications it is advantageous that the original high molecular weight of the polymer can be conserved.

Determination of Peroxides in Synthetic Rubbers

1945 ◽  
Vol 18 (4) ◽  
pp. 874-876
Author(s):  
Richard F. Robey ◽  
Herbert K. Wiese
Keyword(s):  
Molecular Weight ◽  
Natural Rubber ◽  
Quantitative Determination ◽  
High Molecular Weight ◽  
Active Oxygen ◽  
Lower Molecular Weight ◽  
Synthetic Rubber ◽  
High Molecular Weight Polymers ◽  
Methanol Solutions

Abstract Peroxides are found in synthetic rubbers either as the result of attack by oxygen, usually from the air, or as a residue from polymerization operations employing peroxide catalysts. Because of possible detrimental effects of active oxygen on the properties of the rubber, a method of quantitative determination is needed. The concentration of peroxides in substances of lower molecular weight may be determined with ferrous thiocyanate reagent, either titrimetrically as recommended by Yule and Wilson or colorimetrically as by Young, Vogt, and Nieuwland. Unfortunately, many highly polymeric substances are not soluble in the acetone and methanol solutions employed in these procedures. This is also the case with hydrocarbon monomers, such as butadiene, containing appreciable concentrations of soluble high molecular weight polymers. Bolland, Sundralingam, Sutton and Tristram recommended benzene as a solvent for natural rubber samples and the reagent made up in methanol. However, most synthetic rubbers are not readily soluble even in this combination. The following procedure employs the ferrous thiocyanate reagent in combination with a solvent capable of maintaining considerable concentrations of synthetic rubber in solution. The solvent comprises essentially 20 per cent ethanol in chloroform.

Mechanical stability of high-molecular-weight polyacrylamides and an (acrylamidotert-butyl sulfonic acid)-acrylamide copolymer used in enhanced oil recovery

2014 ◽  
Vol 131 (20) ◽  
pp. n/a-n/a ◽  
Author(s):  
Abdul-Aziz Al-Hashmi ◽  
Rashid Al-Maamari ◽  
Ibtisam Al-Shabibi ◽  
Ahmed Mansoor ◽  
Hamed Al-Sharji ◽  
...  
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Enhanced Oil Recovery ◽  
Oil Recovery ◽  
Sulfonic Acid ◽  
Mechanical Stability

scholarly journals Inactivation of α2-Macroglobulin by Activated Human Polymorphonuclear Leukocytes

1994 ◽  
Vol 3 (2) ◽  
pp. 117-123 ◽  
Author(s):  
G. Deby-Dupont ◽  
J.-L. Croisier ◽  
G. Camus ◽  
D. Brumioul ◽  
M. Mathy-Hartert ◽  
...  
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Proteolytic Activity ◽  
Polymorphonuclear Leukocytes ◽  
Cytochalasin B ◽  
Hypochlorous Acid ◽  
Myeloperoxidase Activity ◽  
Trypsin Activity ◽  
Α2 Macroglobulin ◽  
Human Polymorphonuclear Leukocytes

The proteolytic activity of trypsin releases the dye Remazol Brilliant Blue from its high molecular weight substrate, the skin powder (Hide Powder Azure, Sigma), with an increase in absorbance at 595 nm. Active α2- macroglobulin (80 μg/ml) totally inhibits the proteolytic activity of trypsin (14 μg/ml) by trapping this protease. But after a 20 min incubation of α2-macroglobulin at 37°C with 2 × 106human polymorphonuclear leukocytes activated by N-formyl-L-methionyl-L-leucyl-L-phenylalanine (10−7M) and cytochalasin B (10−8M), 100% of trypsin activity was recovered, indicating a total inactivation of α2-macroglobuHn. Incubation with granulocyte myeloperoxidase also inactivates α2-macroglobulin. Hypochlorous acid, a by-product of myeloperoxidase activity, at a concentration of 10−7M also inactivates α2-macroglobulin, which indicates that an important cause of α2-macroglobulin inactivation by activated polymorphonuclear leukocytes could be the activity of myeloperoxidase.

scholarly journals Thioalkyl- and Sulfone-Substituted Poly(p-Phenylene Vinylene)s

2018 ◽  
Author(s):  
Martina Rimmele ◽  
Klaus Ableidinger ◽  
Adam V. Marsh ◽  
Nathan J. Cheetham ◽  
M. Josef Taublaender ◽  
...  
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Low Cost ◽  
Photophysical Properties ◽  
Quantum Yields ◽  
Phenylene Vinylene ◽  
Structural Variations ◽  
Interesting Class ◽  
New Applications ◽  
Exceptional Stability

Poly(p-phenylene vinylene)s (PPVs) have been studied for decades, but research on this interesting class of conjugated polymers is far from being completed. New applications like in bioimaging keep emerging and even simple structural variations are still waiting to be explored. Surprisingly, not even dithioalkyl-substituted PPVs (S-PPVs) have been reported in the peer-reviewed literature, although the corresponding dialkoxy-substituted PPVs (O-PPVs) like MEH-PPV or MDMO-PPV are most frequently used and although thioalkyl substituents can improve the material properties significantly. We herein report the development of a highly efficient, scalable two-step synthesis of Gilch monomers for S-PPVs starting from low-cost 1,4-diiodobenzene. A low-temperature polymerization protocol has been developed for these monomers, affording high-molecular weight S-PPVs in excellent yields. The thermal, electrochemical, and photophysical properties of S-PPVs are reported to highlight the potential of these polymers. Furthermore, treatment with dimethyldioxirane is demonstrated to result in rapid conversion into sulfone-substituted PPVs (SO<sub>2</sub>-PPVs), introducing a route to high-molecular weight SO<sub>2</sub>-PPVs with exceptional stability and solid-state photoluminescence quantum yields of up to 0.46.

Natural and Synthetic Rubber. II. Reduction of Isoprene by Na-Nh3

1929 ◽  
Vol 2 (3) ◽  
pp. 452-452
Author(s):  
Thomas Midgley ◽  
Albert L. Henne
Keyword(s):  
Molecular Weight ◽  
Double Bond ◽  
Low Temperature ◽  
High Molecular Weight ◽  
Liquid Ammonia ◽  
Volatile Hydrocarbon ◽  
Hydrogen Addition ◽  
Synthetic Rubber ◽  
Reaction Proceeds ◽  
Natural And Synthetic

Abstract The reduction of isoprene by sodium in liquid ammonia was attempted to determine: (1) whether reduction would take place in preference to polymerization and (2) the location of the added hydrogen. Isoprene was added to sodium dissolved in liquid ammonia and a 60% yield of 2-methyl-2-butene resulted. No other volatile hydrocarbon was found. High molecular weight hydrocarbons were formed but were not investigated. It is thus shown: (1) that the predominant reaction proceeds in accordance with the equation C5C8+2Na+2NH3=C5C10+2NaNH2 and (2) that hydrogen adds to isoprene in the 1,4-position, in agreement with Thiele's theory. The hydrogen addition is similar to the bromination of isoprene at low temperature. If properly conducted the latter reaction stops after 2 atoms of bromine have been added to 1 molecule of isoprene; the resulting compound, 1,4-dibromo-2-methyl-2-butene, is characterized b the inactivity of its double bond toward bromine. Similarly, 2-methyl-2-butene obtained by reduction of isoprene is not reduced to isopentane by an excess of Na—NH3 reagent.

scholarly journals Preparation and Characterization of Low-Molecular-Weight Natural Rubber Latex via Photodegradation Catalyzed by Nano TiO2

Polymers ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 1216 ◽  
Author(s):  
Suhawati Ibrahim ◽  
Nadras Othman ◽  
Srimala Sreekantan ◽  
Kim Tan ◽  
Zairossani Mohd Nor ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Titanium Dioxide ◽  
Natural Rubber ◽  
Chemical Structure ◽  
Sol Gel ◽  
Natural Rubber Latex ◽  
Low Molecular Weight ◽  
Rubber Latex ◽  
Liquid Natural Rubber ◽  
New Applications

Natural rubber is one of the most important renewable biopolymers used in many applications due to its special properties that cannot be easily mimicked by synthetic polymers. To sustain the existence of natural rubber in industries, modifications have been made to its chemical structure from time to time in order to obtain new properties and to enable it to be employed in new applications. The chemical structure of natural rubber can be modified by exposure to ultraviolet light to reduce its molecular weight. Under controlled conditions, the natural rubber chains will be broken by photodegradation to yield low-molecular-weight natural rubber. The aim of this work was to obtain what is known as liquid natural rubber via photodegradation, with titanium dioxide nanocrystals as the catalyst. Titanium dioxide, which was firstly synthesized using the sol–gel method, was confirmed to be in the form of an anatase, with a size of about 10 nm. In this work, the photodegradation was carried out in latex state and yielded low-molecular-weight natural rubber latex of less than 10,000 g/mol. The presence of hydroxyl and carbonyl groups on the liquid natural rubber (LNR) chains was observed, resulting from the breaking of the chains. Scanning electron microscopy of the NR latex particles showed that titanium dioxide nanocrystals were embedded on the latex surface, but then detached during the degradation reaction.

The Action of Hypochlorous Acid on Rubber

1934 ◽  
Vol 7 (2) ◽  
pp. 327-329
Author(s):  
G. F. Bloomfield ◽  
E. H. Farmer
Keyword(s):  
Hypochlorous Acid ◽  
Practical Importance ◽  
Chlorine Content ◽  
Acid Molecule ◽  
Reaction Products ◽  
Rubber Latex ◽  
Preceding Article ◽  
High Degree ◽  
Analogous Behavior ◽  
Molecular Proportion

Abstract It has been previously observed that when rubber latex is treated with cold aqueous hypochlorous acid, the simple additive attachment of the hypochlorous acid molecule at the ethylenic center of each C5H8 unit of the rubber molecule may be accompanied by a considerable amount of substitutional chlorination (cf. preceding article). An analogous behavior has now been found to characterize the interaction of dissolved rubber (rubber solutions) with hypochlorous acid, but in this case marked differences in the properties of the reaction products become manifest. In the treatment of dissolved rubber some evidence of substitutional chlorination is directly apparent, even where the amount of hypochlorous acid does not exceed one molecular proportion per C5H8 unit, and considerable replacement of hydrogen by chlorine occurs when the reagent is present in excess of this amount; indeed, by using a suitable excess of the latter, it is possible to obtain chlorinated materials with a maximum chlorine content of 66 per cent. Now it is of practical importance to note that, whereas the chlorinated materials obtained from latex are characterized by a high degree of insolubility, the analogous materials from dissolved rubber are relatively soluble, and in the case of some of the more highly chlorinated materials are readily soluble in the ordinary solvents for rubber.

scholarly journals Thioalkyl- and Sulfone-Substituted Poly(p-Phenylene Vinylene)s

2018 ◽  
Author(s):  
Martina Rimmele ◽  
Klaus Ableidinger ◽  
Adam V. Marsh ◽  
Nathan J. Cheetham ◽  
M. Josef Taublaender ◽  
...  
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Low Cost ◽  
Photophysical Properties ◽  
Quantum Yields ◽  
Phenylene Vinylene ◽  
Structural Variations ◽  
Interesting Class ◽  
New Applications ◽  
Exceptional Stability

Poly(p-phenylene vinylene)s (PPVs) have been studied for decades, but research on this interesting class of conjugated polymers is far from being completed. New applications like in bioimaging keep emerging and even simple structural variations are still waiting to be explored. Surprisingly, not even dithioalkyl-substituted PPVs (S-PPVs) have been reported in the peer-reviewed literature, although the corresponding dialkoxy-substituted PPVs (O-PPVs) like MEH-PPV or MDMO-PPV are most frequently used and although thioalkyl substituents can improve the material properties significantly. We herein report the development of a highly efficient, scalable two-step synthesis of Gilch monomers for S-PPVs starting from low-cost 1,4-diiodobenzene. A low-temperature polymerization protocol has been developed for these monomers, affording high-molecular weight S-PPVs in excellent yields. The thermal, electrochemical, and photophysical properties of S-PPVs are reported to highlight the potential of these polymers. Furthermore, treatment with dimethyldioxirane is demonstrated to result in rapid conversion into sulfone-substituted PPVs (SO<sub>2</sub>-PPVs), introducing a route to high-molecular weight SO<sub>2</sub>-PPVs with exceptional stability and solid-state photoluminescence quantum yields of up to 0.46.

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