S-N Compounds as Delayed Action Chemicals in Vulcanization

1980 ◽  
Vol 53 (3) ◽  
pp. 393-436 ◽  
Author(s):  
E. Morita
Keyword(s):  
Physical Properties ◽  
Crosslinking Agent ◽  
Crosslinking Reaction ◽  
Chemical Bonds ◽  
Curing Time ◽  
Structural Types ◽  
Curing Agents ◽  
Delayed Action ◽  
N Compounds ◽  
Crosslinking Agents

Abstract Since the discovery by Goodyear in 1839 that the physical properties of rubber may be improved with sulfur, it has been the most commonly used crosslinking agent. The rubber industry is concerned with the production of homogeneous products with appropriate physical properties, by compounding rubber with ingredients, including crosslinking agents, followed by processing, molding, and introduction of chemical bonds. Economically, it is advantageous to apply high temperature which reduces processing and curing time. However, application of high temperatures frequently causes premature cure. Compounding adjustments are often required in the plants to prevent scorch, especially by the use of compounds with S—N bonds as accelerators, vulcanizing agents, and also as prevulcanization inhibitors or retarders which delay the crosslinking reaction of sulfur and rubber. There are several reviews relating to accelerators, retarders, and vulcanization, which discuss S—N compounds as delayed action curing agents. This review covers the development of S—N compounds as delayed action chemicals for vulcanizing rubber, the various structural types, properties, applications, and the mechanism of their function during vulcanization.

scholarly journals Investigation on the Physical Properties of 100% Cotton Knit Fabric by Treating with Crossslinking Agents

2018 ◽  
Vol 8 (02) ◽  
Author(s):  
Imana Shahrin Tania ◽  
Md. Zulhash Uddin ◽  
Kawser Parveen Chowdhury
Keyword(s):  
Physical Properties ◽  
Textile Industry ◽  
Crosslinking Agent ◽  
Areal Density ◽  
Cotton Fabrics ◽  
Formaldehyde Content ◽  
Different Types ◽  
Chemical Companies ◽  
Finishing Agent ◽  
Crosslinking Agents

TApplication of crosslinking agent to impart wrinkle recovery property on cotton fabrics is very popular for textile industry. This paper represents the effect of different crosslinking agent on the physical properties and the wrinkle recovery of cotton knit fabric. Here five different types of crosslinking agent from three different chemical companies were used. The work was divided into two parts .At first; crosslinking agents were applied on cotton fabric than various related tests were done on the treated and untreated fabric. Better crease resistancy was found on the finishing agent having high formaldehyde content .The other important properties like tensile strength, dimensional stability, stiffness, abrasion resistance pilling resistance and areal density was studied here. Among them some properties were improved and some were fall down.

scholarly journals ВПЛИВ ХІМІЧНОЇ БУДОВИ ЗШИВАЮЧИХ АГЕНТІВ НА ФІЗИЧНІ ВЛАСТИВОСТІ ПОЛІМЕРНИХ ПЛІВОК НА ОСНОВІ КРОХМАЛЮ

2018 ◽  
Vol 122 (3) ◽  
pp. 19-24
Author(s):  
Т. С. Асаулюк ◽  
О. Я. Семешко ◽  
Ю. Г. Сарібєкова
Keyword(s):  
Physical Properties ◽  
Tartaric Acid ◽  
Polymer Films ◽  
Chemical Structure ◽  
Practical Importance ◽  
Crosslinking Agent ◽  
Physicomechanical Properties ◽  
Polymer Materials ◽  
Atmospheric Moisture ◽  
Crosslinking Agents

To study the effect of active functional groups of cross-linking agents on the physical properties of starch polymer films. Standardized methods for studying the indicators of physical properties of polymer films have been applied. The paper presents the results of the study of the effect of crosslinking agents of different chemical structure on the physicomechanical properties, the influence of atmospheric moisture and the resistance to wet treatments of starch polymer films. An improvement in studied parameters of the films with the use of L-tartaric acid was established. It has been proved that the use of L-tartaric acid as a crosslinking agent makes it possible to improve the physical properties of polymer films based on starch. The obtained experimental results are of practical importance for the development of new environmentally friendly polymer materials.

Chemical and physical properties of self-crosslinked poly(vinyl chloride)/nitrile rubber nanocomposites prepared by melt-mixing process

2011 ◽  
Vol 31 (2-3) ◽  
Author(s):  
Elnaz Esmizadeh ◽  
Ghasem Naderi ◽  
Mir Hamid Reza Ghoreishy ◽  
Gholam Reza Bakhshandeh
Keyword(s):  
Physical Properties ◽  
Vinyl Chloride ◽  
Crosslinking Agent ◽  
Processing Temperature ◽  
Crosslinking Reaction ◽  
Butadiene Rubber ◽  
X Ray Diffraction ◽  
Melt Mixing ◽  
Poly Vinyl Chloride ◽  
The Fourier Transform

Abstract In this article, poly(vinyl chloride) (PVC)/acrylonitrile butadiene rubber (NBR)/clay nanocomposites were melt-mixed using the computerized Brabender plasticorder. During preparation of the nanocomposites self-crosslinking (crosslinking without aid of any crosslinking agent) occurs and affects all properties of a sample. The extent of crosslinking reaction depends on the processing temperature, rotor speed and mixing temperature and it increased with increasing each of mixing parameters. The mechanism of the self-crosslinking reaction was examined by the Fourier transform infrared spectroscopy test. The morphology of the materials was characterized using X-ray diffraction and scanning electron microscope. The swelling test and tensile test were applied to distinguish the effects of self-crosslinking phenomena on physical properties of NBR/PVC nanocomposites. Dynamic mechanical thermal analysis tests of nanocomposites were also performed to study the physical properties, such as glass transition temperature (T g). The results showed that the crosslinking reaction made a material more strong with high modulus and tensile strength. Thus, it can be deduced that crosslinks convert the NBR/PVC nanocomposites to stiffer materials that are less penetrable by the solvent. The results drawn from the loss tangent (tan δ) curves of nanocomposite samples can be used as further evidence for the above conclusions.

scholarly journals Effect of Curing Agents on Electrical Properties of Low-Temperature Curing Conductive Coatings and Thermodynamic Analysis

Coatings ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 656
Author(s):  
Junjie Shu ◽  
Yang Wang ◽  
Bei Guo ◽  
Weihua Qin ◽  
Lanxuan Liu ◽  
...  
Keyword(s):  
Electrical Properties ◽  
Low Temperature ◽  
Surface Resistance ◽  
Advanced Manufacturing ◽  
Curing Time ◽  
Conductive Coatings ◽  
Exponential Factor ◽  
Design Expert ◽  
Surface Method ◽  
Curing Agents

Silver-based high-conductivity coatings are used in many advanced manufacturing equipment and components, and existing coatings require high-temperature curing. This paper studies the effects of different curing agents on the electrical properties of low-temperature curing (<100 °C) conductive coatings, and analyzes the effects of different curing temperatures and curing time on the surface resistance, square resistance and resistivity of conductive coatings. The response surface method in Design Expert was used to construct the model, and the curing thermodynamics of different curing agents were analyzed by DSC. It was found that curing agents with lower Tm and activation energy, higher pre-exponential factor and more flexible segments are beneficial to the preparation of highly conductive coatings.

Terephthalaldehyde as better crosslinking agent in crosslinked chitosan hydrogel for selective removal of anionic dyes

2021 ◽  
Author(s):  
Madhvi Garg ◽  
Navneet Bhullar ◽  
Bharat Bajaj ◽  
Dhiraj Sud
Keyword(s):  
Crosslinking Agent ◽  
Selective Removal ◽  
Synthetic Dyes ◽  
Anionic Dyes ◽  
Chitosan Hydrogel ◽  
Ultrasound Radiation ◽  
Radiation Induced ◽  
Crosslinked Chitosan ◽  
Chitosan Hydrogels ◽  
Crosslinking Agents

The present manuscript reports the ultrasound radiation induced synthesis of grafted chitosan hydrogels (CAAT and CAAG) using terephthalaldehyde/glutaraldehyde as crosslinking agents and its application for removal of synthetic dyes from...

scholarly journals Design and Gas Separation Performance of Imidazolium Poly(ILs) Containing Multivalent Imidazolium Fillers and Crosslinking Agents

Polymers ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1388
Author(s):  
Kathryn E. O’Harra ◽  
Emily M. DeVriese ◽  
Erika M. Turflinger ◽  
Danielle M. Noll ◽  
Jason E. Bara
Keyword(s):  
Small Molecules ◽  
Crosslinking Agent ◽  
Gas Permeation ◽  
Polymeric Matrix ◽  
Separation Performance ◽  
Ionic Polymers ◽  
Co2 Solubility ◽  
Imidazolium Cations ◽  
Crosslinking Agents ◽  
Gas Separation Performance

This work introduces a series of vinyl-imidazolium-based polyelectrolyte composites, which were structurally modified via impregnation with multivalent imidazolium-benzene ionic liquids (ILs) or crosslinked with novel cationic crosslinkers which possess internal imidazolium cations and vinylimidazolium cations at the periphery. A set of eight [C4vim][Tf2N]-based membranes were prepared via UV-initiated free radical polymerization, including four composites containing di-, tri-, tetra-, and hexa-imidazolium benzene ILs and four crosslinked derivatives which utilized tri- and tetra- vinylimidazolium benzene crosslinking agents. Structural and functional characterizations were performed, and pure gas permeation data were collected to better understand the effects of “free” ILs dispersed in the polymeric matrix versus integrated ionic crosslinks on the transport behaviors of these thin films. These imidazolium PIL:IL composites exhibited moderately high CO2 permeabilities (~20–40 Barrer), a 4–7× increase relative to corresponding neat PIL, with excellent selectivities against N2 or CH4. The addition of imidazolium-benzene fillers with increased imidazolium content were shown to correspondingly enhance CO2 solubility (di- < tri- < tetra- < hexa-), with the [C4vim][Tf2N]: [Hexa(Im+)Benz ][Tf2N] composite showing the highest CO2 permeability (PCO2 = 38.4 Barrer), while maintaining modest selectivities (αCO2/CH4 = 20.2, αCO2/N2 = 23.6). Additionally, these metrics were similarly improved with the integration of more ionic content bonded to the polymeric matrix; increased PCO2 with increased wt% of the tri- and tetra-vinylimidazolium benzene crosslinking agent was observed. This study demonstrates the intriguing interactions and effects of ionic additives or crosslinkers within a PIL matrix, revealing the potential for the tuning of the properties and transport behaviors of ionic polymers using ionic liquid-inspired small molecules.

scholarly journals Novel composite Zr/PBI-O-PhT membranes for HT-PEFC applications

2013 ◽  
Vol 4 ◽  
pp. 481-492 ◽  
Author(s):  
Mikhail S Kondratenko ◽  
Igor I Ponomarev ◽  
Marat O Gallyamov ◽  
Dmitry Yu Razorenov ◽  
Yulia A Volkova ◽  
...  
Keyword(s):  
Fuel Cells ◽  
Crosslinking Agent ◽  
Composite Membranes ◽  
Thermomechanical Analysis ◽  
Polymer Electrolyte Fuel Cells ◽  
Model Reaction ◽  
Chemical Bonds ◽  
Durability Test ◽  
High Degree ◽  
Excellent Stability

Novel composite membranes for high temperature polymer-electrolyte fuel cells (HT-PEFC) based on a poly[oxy-3,3-bis(4′-benzimidazol-2″-ylphenyl)phtalide-5″(6″)-diyl] (PBI-O-PhT) polymer with small amounts of added Zr were prepared. It was shown in a model reaction between zirconium acetylacetonate (Zr(acac)4) and benzimidazole (BI) that Zr-atoms are capable to form chemical bonds with BI. Thus, Zr may be used as a crosslinking agent for PBI membranes. The obtained Zr/PBI-O-PhT composite membranes were examined by means of SAXS, thermomechanical analysis (TMA), and were tested in operating fuel cells by means of stationary voltammetry and impedance spectroscopy. The new membranes showed excellent stability in a 2000-hour fuel cell (FC) durability test. The modification of the PBI-O-PhT films with Zr facilitated an increase of the phosphoric acid (PA) uptake by the membranes, which resulted in an up to 2.5 times increased proton conductivity. The existence of an optimal amount of Zr content in the modified PBI-O-PhT film was shown. Larger amounts of Zr lead to a lower PA doping level and a reduced conductivity due to an excessively high degree of crosslinking.

Structure-Property Relationships of N,N′-Dinitroso-P-Phenylene-Bis (Hydroxylamine) Salts. Vulcanization of Nonhalogenated Elastomers

1962 ◽  
Vol 35 (1) ◽  
pp. 141-146 ◽  
Author(s):  
Rock F. Martel ◽  
David E. Smith
Keyword(s):  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Silver Salt ◽  
Crosslinking Agent ◽  
Authentic Sample ◽  
Zinc Powder ◽  
Metallic Silver ◽  
Crosslinking Reaction ◽  
Oxides Of Nitrogen ◽  
Structure Property

Abstract In a previous report the vulcanization activity of N,N′-dinitroso-p-phenylene-bis(hydroxylamine) salts in Neoprene WRT was discussed. The vulcanization was catalyzed by addition of stoichiometric amounts of aluminum or zinc powder (based upon percentage of allylic chloride), very possibly via the metal halide formed in situ. Natural rubber could not be vulcanized with these materials, however, differential thermal analysis indicated that amine-treated neoprene undergoes a crosslinking reaction at above normal curing temperatures. This evidence led us to propose that bisalkylation (α and/or β) at the allylic position is responsible for the formation of crosslinks. The mechanistic path is shown in Equations 1 and 2, and the analogy with the SN2′ activity of diamines in neoprene is quite apparent. The crosslinks III and/or IV are shown as the β form and one of the possible a structures. A number of structures for the α form have been proposed. The β structure has been known for some time. Our primary interest at this point was to extend the activity of N,N′-dinitroso-p-phenylene-bis(hydroxylamine) salts to elastomers which do not contain halogen. Any hope of achieving this goal depended, for the most part, upon whether or not certain of these materials would produce p-dinitrosobenzene, a known crosslinking agent, during the vulcanization cycle. The silver salt of phenylnitrosohydroxylamine, the monosubstituted counterpart of the bis(hydroxylamine) structure, decomposes readily to nitrosobenzene, nitric oxide and metallic silver. Accordingly, we prepared the di-silver salt of N,N′-dinitroso-p-phenylene-bis(hydroxylamine). The maximum rate of decomposition of this material was determined by differential thermal analysis, and occurred at 295° F. When 1.0 g of the di-silver salt was heated [see Reaction (3)] at 200° F for 2 hours, 0.3 g of a yellow solid sublimate was collected on a cold finger. The infrared spectrum of the yellow solid was identical with that of an authentic sample of p-dinitrosobenzene. Oxides of nitrogen were also visible in the reaction vapors (brown coloration).

Crosslinking Reaction of Rubber with Aldehydes

1970 ◽  
Vol 43 (2) ◽  
pp. 188-209
Author(s):  
Y. Minoura ◽  
M. Tsukasa
Keyword(s):  
Solid State ◽  
Organic Acids ◽  
Physical Properties ◽  
Lewis Acids ◽  
Solid State Reactions ◽  
Crosslinking Reaction ◽  
Reaction Products ◽  
Toluenesulfonic Acid ◽  
Ionic Reaction ◽  
Acidic Catalysts

Abstract The reactions of rubber with aldehydes have previously been studied in latex or in solutions and the reaction products formed by cyclization, condensation, or addition, have been reported. In the present study, solid-state reactions of rubber with aldehydes were carried out. It was found that crosslinked rubbers may be obtained by press curing in the presence of aldehydes with acidic catalysts. Poly-chloroprene and Hypalon especially undergo these reactions without a catalyst or with a small amount of catalyst. In the experiments using various aldehydes, some improvements in the properties of the crosslinked rubber were observed when aldehydes such as paraformaldehyde or α-polyoxymethylene were used. Some Lewis acids such as SnCl2·2H2O were found to be more effective catalysts than the above, and it was found that organic acids such as p-toluenesulfonic acid could also be used. The curing seemed to be an ionic reaction. The physical properties of the crosslinked rubber are similar to those of sulfur-cured rubbers.

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