Modification of Rubber by Reaction with Maleic Anhydride

1958 ◽  
Vol 31 (3) ◽  
pp. 664-666
Author(s):  
Jean LeBras ◽  
Christian Pinazzi ◽  
Gérard Milbert
Keyword(s):  
Maleic Anhydride ◽  
Natural Rubber ◽  
Solid Phase ◽  
Operating Conditions ◽  
Chemical Derivatives ◽  
High Elasticity ◽  
Secondary Reactions ◽  
Derivatives Of ◽  
Reaction In Solution ◽  
Injurious Effects

Abstract The reaction between maleic anhydride and rubber has been studied in solution, by milling and by heating in the solid phase. However, as is most often the case with chemical derivatives of the rubber hydrocarbon, the operating conditions that were employed only yielded products exhibiting considerable impairment to the physical properties characteristic of rubber (especially its high elasticity) as a result of secondary reactions of scission, cyclization and crosslinking. It has subsequently been shown that it is possible, under certain conditions, to minimize these injurious effects, both in the case of the reaction in solution between natural rubber and maleic N-methylimide and in that of the reaction by milling between synthetic olefinic elastomers and maleic anhydride. Inspired by these studies, we have undertaken to re-examine, on more precise chemical bases, the reaction between the rubber hydrocarbon and maleic anhydride.

Chemical Derivatives of Synthetic Isoprene Rubbers

1947 ◽  
Vol 20 (3) ◽  
pp. 664-688
Author(s):  
I. D. D'Ianni ◽  
F. J. Naples ◽  
J. W. Marsh ◽  
J. L. Zarney
Keyword(s):  
World War Ii ◽  
Natural Rubber ◽  
Reaction Products ◽  
World War ◽  
The Past ◽  
Chemical Derivatives ◽  
The Subject ◽  
Intensive Investigation ◽  
Derivatives Of ◽  
Rubber Product

Abstract Natural rubber was the subject of intensive investigation with respect to its chemical reactions and the preparation of commercially useful derivatives. General reviews in this field have been written by Fisher, Schidrowitz, Jones, Sibley, Memmler, Dawson and Schidrowitz, and Farmer. Before World War II several of these reaction products, such as rubber hydrochloride (Pliofilm), isomerized rubber (Pliolite), and chlorinated rubber (Parlon), had been marketed successfully. During the past five years drastic restriction of the commercial use of natural rubber for chemical derivatives prompted the study of synthetic rubbers for this purpose. Endres recently reported on chlorinated and cyclized synthetic lubbers, with special emphasis on GR-S as the starting material. This paper deals particularly with derivatives of polyisoprene and other isoprene-containing synthetic rubbers which behave chemically very much like natural rubber because of the similarity in structure. It is shown that GR-S and other butadiene-containing synthetic rubbers, under the same conditions, are either nonreactive or behave differently. Because of its similarity to the natural rubber product, isomerized synthetic polyisoprene has been designated Pliolite S-1. Chlorinated synthetic polyisoprene is referred to as Pliochlor.

scholarly journals Chemical Derivatives of α-Chymotrypsinogen

1960 ◽  
Vol 235 (2) ◽  
pp. 396-404
Author(s):  
Djahanguir M. Abadi ◽  
Philip E. Wilcox
Keyword(s):  
Chemical Derivatives ◽  
Derivatives Of

scholarly journals Chemical Derivatives of α-Chymotrypsinogen

1961 ◽  
Vol 236 (5) ◽  
pp. 1328-1337
Author(s):  
Marilynn S. Doscher ◽  
Philip E. Wilcox
Keyword(s):  
Chemical Derivatives ◽  
Derivatives Of

scholarly journals Biocomposites of Epoxidized Natural Rubber/Poly(lactic acid) Modified with Natural Fillers (Part I)

2021 ◽  
Vol 22 (6) ◽  
pp. 3150
Author(s):  
Anna Masek ◽  
Stefan Cichosz ◽  
Małgorzata Piotrowska
Keyword(s):  
Tensile Strength ◽  
Lactic Acid ◽  
Natural Rubber ◽  
Epoxidized Natural Rubber ◽  
Poly Lactic Acid ◽  
Uv Aging ◽  
High Elasticity ◽  
Natural Fillers ◽  
Natural Additives

The study aimed to prepare sustainable and degradable elastic blends of epoxidized natural rubber (ENR) with poly(lactic acid) (PLA) that were reinforced with flax fiber (FF) and montmorillonite (MMT), simultaneously filling the gap in the literature regarding the PLA-containing polymer blends filled with natural additives. The performed study reveals that FF incorporation into ENR/PLA blend may cause a significant improvement in tensile strength from (10 ± 1) MPa for the reference material to (19 ± 2) MPa for the fibers-filled blend. Additionally, it was found that MMT employment in the role of the filler might contribute to ENR/PLA plasticization and considerably promote the blend elongation up to 600%. This proves the successful creation of the unique and eco-friendly PLA-containing polymer blend exhibiting high elasticity. Moreover, thanks to the performed accelerated thermo-oxidative and ultraviolet (UV) aging, it was established that MMT incorporation may delay the degradation of ENR/PLA blends under the abovementioned conditions. Additionally, mold tests revealed that plant-derived fiber addition might highly enhance the ENR/PLA blend’s biodeterioration potential enabling faster and more efficient growth of microorganisms. Therefore, materials presented in this research may become competitive and eco-friendly alternatives to commonly utilized petro-based polymeric products.

scholarly journals The Fluoride Anion-Catalyzed Sulfurization of Thioketones with Elemental Sulfur Leading to Sulfur-Rich Heterocycles: First Sulfurization of Thiochalcones

Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 822
Author(s):  
Grzegorz Mlostoń ◽  
Jakub Wręczycki ◽  
Katarzyna Urbaniak ◽  
Dariusz M. Bieliński ◽  
Heinz Heimgartner
Keyword(s):  
Elemental Sulfur ◽  
Fluoride Anion ◽  
Ring Size ◽  
Mild Conditions ◽  
Tetrabutylammonium Fluoride ◽  
Cesium Fluoride ◽  
Secondary Reactions ◽  
Derivatives Of

Fluoride anion was demonstrated as a superior activator of elemental sulfur (S8) to perform sulfurization of thioketones leading to diverse sulfur-rich heterocycles. Due to solubility problems, reactions must be carried out either in THF using tetrabutylammonium fluoride (TBAF) or in DMF using cesium fluoride (CsF), respectively. The reactive sulfurizing reagents are in situ generated, nucleophilic fluoropolysulfide anions FS(8−x)−, which react with the C=S bond according to the carbophilic addition mode. Dithiiranes formed thereby, existing in an equilibrium with the ring-opened form (diradicals/zwitterions) are key-intermediates, which undergo either a step-wise dimerization to afford 1,2,4,5-tetrathianes or an intramolecular insertion, leading in the case of thioxo derivatives of 2,2,4,4-tetramethylcyclobutane-1,3-dione to ring enlarged products. In reactions catalyzed by TBAF, water bounded to fluoride anion via H-bridges and forming thereby its stable hydrates is involved in secondary reactions leading, e.g., in the case of 2,2,4,4-tetramethyl-3-thioxocyclobutanone to the formation of some unexpected products such as the ring enlarged dithiolactone and ring-opened dithiocarboxylate. In contrast to thioketones, the fluoride anion catalyzed sulfurization of their α,β-unsaturated analogues, i.e., thiochalcones is slow and inefficient. However, an alternative protocol with triphenylphosphine (PPh3) applied as a catalyst, offers an attractive approach to the synthesis of 3H-1,2-dithioles via 1,5-dipolar electrocyclization of the in situ-generated α,β-unsaturated thiocabonyl S-sulfides. All reactions occur under mild conditions and can be considered as attractive methods for the preparation of sulfur rich heterocycles with diverse ring-size.

Relation between Molecular Weights and Physical Properties of Rubber Fractions

1941 ◽  
Vol 14 (3) ◽  
pp. 580-589 ◽  
Author(s):  
G. Gee ◽  
L. R. G. Treloar
Keyword(s):  
Molecular Weight ◽  
Natural Rubber ◽  
Physical Properties ◽  
High Molecular Weight ◽  
Elastic Properties ◽  
Elastic Material ◽  
Experimental Results ◽  
Molecular Weights ◽  
High Elasticity ◽  
Latex Rubber

Abstract As high elasticity is a property possessed only by substances of high molecular weight, it is of interest to enquire into the relation between the elastic properties of a highly elastic material such as rubber and its molecular weight. An investigation on these lines has been made possible through the work of Bloomfield and Farmer, who have succeeded in separating natural rubber into fractions having different average molecular weights. The more important physical properties of these fractions have been examined with the object of determining which of the properties are dependent on molecular weight and which are not. Fairly extensive observations were made on the fractions from latex rubber referred to as Nos. 2, 3 and 4 by Bloomfield and Farmer, and some less extensive observations were carried out on the less oxygenated portion of fraction No. 1 obtained from crepe rubber (called hereafter 1b) . Before considering these experimental results, and their relation to the molecular weights of the fractions, it will be necessary to refer briefly to the methods used for the molecular-weight determinations, and to discuss the significance of the figures obtained.

Moving Brick Receiver–Reactor: A Solar Thermochemical Reactor and Process Design With a Solid–Solid Heat Exchanger and On-Demand Production of Hydrogen and/or Carbon Monoxide

2019 ◽  
Vol 141 (2) ◽  
Author(s):  
Silvan Siegrist ◽  
Henrik von Storch ◽  
Martin Roeb ◽  
Christian Sattler
Keyword(s):  
Carbon Monoxide ◽  
Heat Exchanger ◽  
Solid Phase ◽  
Chemical Conversion ◽  
Operating Conditions ◽  
On Demand ◽  
Commercial Plant ◽  
Production Of Hydrogen ◽  
Solar Thermochemical ◽  
Oxidation Reactor

Three crucial aspects still to be overcome to achieve commercial competitiveness of the solar thermochemical production of hydrogen and carbon monoxide are recuperating the heat from the solid phase, achieving continuous or on-demand production beyond the hours of sunshine, and scaling to commercial plant sizes. To tackle all three aspects, we propose a moving brick receiver–reactor (MBR2) design with a solid–solid heat exchanger. The MBR2 consists of porous bricks that are reversibly mounted on a high temperature transport mechanism, a receiver–reactor where the bricks are reduced by passing through the concentrated solar radiation, a solid–solid heat exchanger under partial vacuum in which the reduced bricks transfer heat to the oxidized bricks, a first storage for the reduced bricks, an oxidation reactor, and a second storage for the oxidized bricks. The bricks may be made of any nonvolatile redox material suitable for a thermochemical two-step (TS) water splitting (WS) or carbon dioxide splitting (CDS) cycle. A first thermodynamic analysis shows that the MBR2 may be able to achieve solar-to-chemical conversion efficiencies of approximately 0.25. Additionally, we identify the desired operating conditions and show that the heat exchanger efficiency has to be higher than the fraction of recombination in order to increase the conversion efficiency.

scholarly journals A Characteristic of Selected Properties of Vulcanised Rubber Elements Used on the “Izabel” Inland Vessel

2018 ◽  
Vol 1 (1) ◽  
pp. 675-679
Author(s):  
Patrycja Pawłowska ◽  
Zbigniew Matuszak ◽  
Katarzyna Sosik ◽  
Mária Chovancová
Keyword(s):  
Hardness Test ◽  
Weather Conditions ◽  
General Concept ◽  
Operating Conditions ◽  
Shore Hardness ◽  
Final Phase ◽  
High Elasticity ◽  
Static And Dynamic Loads ◽  
Main Components ◽  
Elastic Deformability

Abstract Vulcanised rubber as a complex system is made from the basic component being virgin rubber and various components amounting to 10-15 per cent or even more. The material gains its most valuable properties in the final phase of processing i.e. vulcanisation. In mechanical as well as automotive engineering it is important for vulcanised rubber to be resistant to grease, oil and fuel in high operating temperatures. Being one of the very valuable isolation materials, vulcanised rubber is also characterised by dielectric and elastic properties as well as distinguished resistance to operating conditions (high/low temperature, weather conditions). All the above mentioned applications of vulcanised rubbers are also found in the shipyard industry. Their use is also very much predicated on the properties such as: ability to attenuate mechanical vibrations, high elasticity, considerable elastic deformability under static and dynamic loads, low permeability of water and gas, resistance to various chemicals, and other. The purpose of this article was to determine the hardness of vulcanised rubber samples obtained from various places on the “Izabel” inland barge. The scope of the study covered sampling and preparing the samples for testing (i.e. cleaning and degreasing the samples). Then, the hardness of the samples was measured using the Shore hardness test. The first part of the article presents the general concept of vulcanised rubber, its main components, properties, applications, and ageing. The second part focuses on the research scope and measuring the hardness of vulcanised rubber samples obtained from the “Izabel” inland barge.

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