Halogenation of Ethylene Propylene Diene Rubbers

1971 ◽  
Vol 44 (4) ◽  
pp. 1025-1042 ◽  
Author(s):  
R. T. Morrissey
Keyword(s):  
Natural Rubber ◽  
Double Bonds ◽  
Optimum Amount ◽  
Ethylene Propylene ◽  
Rubber Compounds ◽  
Rubber Part ◽  
Curing Agents ◽  
Diene Rubbers ◽  
Curing Systems

Abstract The ethylene propylene diene rubbers (EPDM) have been modified by halogenation. The reaction has been considered as one mainly of addition to the double bonds of the diene portion of the rubber. Dehydrohalogenation may occur to varying degrees, depending on the conditions of the reaction and the diene present in the rubber. Part of the halogen is believed to be in the allylic position. The halogenated EPDM may be vulcanized by sulfur as well as many of the curing agents used for other halogen-containing polymers. Both types of curing systems can function in the same compound. Therefore, the halogenated EPDM rubbers can be covulcanized with the highly unsaturated elastomers such as natural rubber, cis polybutadiene, and the SBR rubbers. The excellent properties, resistance to ozone, and flexing, of the halogenated EPDM can be imparted to these elastomers using standard curing systems. Also, the uncured tack of halogenated EPDM can be improved by increasing amounts of natural rubber. In addition, other advantages are adhesion of these blends to other rubber compounds and metal. It has been shown that the cure compatibility properties of the halogenated EPDM can be varied as the halogen is increased in the rubber. Evidence has been presented which shows there is an optimum amount of halogen necessary for the best properties in mixtures with other elastomers.

SERINOL DERIVATIVES FOR THE SUSTAINABLE VULCANIZATION OF DIENE ELASTOMERS

2018 ◽  
Vol 91 (4) ◽  
pp. 701-718 ◽  
Author(s):  
Vincenzina Barbera ◽  
Sara Musto ◽  
Giuseppe Infortuna ◽  
Valeria Cipolletti ◽  
Attilio Citterio ◽  
...  
Keyword(s):  
Natural Rubber ◽  
Building Block ◽  
Induction Time ◽  
High Selectivity ◽  
Rubber Compounds ◽  
Aldehydes And Ketones ◽  
Diene Rubbers ◽  
Kinetics Of ◽  
Derivatives Of ◽  
Kinetics Of Vulcanization

ABSTRACT 2-amino-1,3-propandiol (serinol) was used as the starting building block of synthetic pathways that led to the preparation of innovative chemicals suitable as ingredients for rubber compounds. Serinol based reactions were performed in the frame of a sustainable process, in the absence of any solvent and catalyst, with aldehydes and ketones, such as acetone, cinnamaldehyde and camphor. The synthesis of either imines or oxazolidines was obtained with high selectivity. Serinol, imine and oxazolidine derivatives of serinol were used as accelerator for the vulcanization of diene rubbers. They were proved to be efficient secondary accelerators in silica based compounds based on poly(styrene-co-butadiene) in place of diphenyl guanidine. The kinetics of vulcanization was investigated for natural rubber based compounds in the absence of any filler. With respect to serinol, the imine derivatives were able to enhance the induction time of vulcanization and to afford a similar vulcanization rate.

Peroxide vulcanization of natural rubber. Part I: effect of temperature and peroxide concentration

2014 ◽  
Vol 34 (7) ◽  
pp. 617-624 ◽  
Author(s):  
Ján Kruželák ◽  
Richard Sýkora ◽  
Ivan Hudec
Keyword(s):  
Natural Rubber ◽  
Effect Of Temperature ◽  
Side Reactions ◽  
Decomposition Products ◽  
Rubber Compounds ◽  
Peroxide Decomposition ◽  
Link Density ◽  
Rubber Part ◽  
Cross Link Density ◽  
Proper Balance

Abstract Four different peroxides as curing agents were used to prepare vulcanizates based on natural rubber (NR). The effects of temperature and peroxide concentration on the vulcanization characteristics of rubber compounds, cross-link density (ν) and physical-mechanical properties of equivalent vulcanizates were investigated. The results revealed that the vulcanization temperature and also the relative amount of peroxide decomposition products are of significant importance in the properties of vulcanizates. Lower vulcanization temperature and lower concentration of peroxides were found to be better factors, showing a proper balance between the degree of cross-linking of the rubber and degradation of the macromolecular chains by side reactions in relation to the crystallization of NR, which imparts vulcanizates based on NR outstanding properties.

VULCANIZATION OF RUBBER COMPOUNDS WITH PEROXIDE CURING SYSTEMS

2017 ◽  
Vol 90 (1) ◽  
pp. 60-88 ◽  
Author(s):  
Ján Kruželák ◽  
Richard Sýkora ◽  
Ivan Hudec
Keyword(s):  
Three Dimensional ◽  
Rubber Matrix ◽  
Cross Linking ◽  
Rubber Compounds ◽  
Dimensional Network ◽  
Fundamental Goal ◽  
Cross Links ◽  
Curing Agents ◽  
Curing Systems

ABSTRACT Vulcanization or curing is one of the most important processes in rubber technologies. During this process, plastic rubber compounds by parallel and subsequent physical and mainly chemical reactions change into highly elastic products—vulcanizates. The fundamental goal of curing is forming chemical cross-links between rubber macromolecules, which leads to the formation of a three-dimensional network or rubber matrix. A number of curing systems have been introduced in cross-linking of elastomers; each system has its own characteristics and composition; therefore, vulcanizates with different properties also can be prepared. We characterize organic peroxides as curing agents and their decomposition mechanisms and characteristics and bring a detailed view to understanding mechanisms between peroxides and different types of rubber matrices. Then, we focus on the classification and characterization of co-agents used in peroxide cross-linking and explain the mutual interactions and reaction mechanisms between peroxide, co-agents, and rubber matrices in relation to the properties of prepared materials. Finally, the drawbacks and the main features of final cross-linked materials are outlined.

Peroxide vulcanization of natural rubber. Part II: effect of peroxides and co-agents

2015 ◽  
Vol 35 (1) ◽  
pp. 21-29 ◽  
Author(s):  
Ján Kruželák ◽  
Richard Sýkora ◽  
Ivan Hudec
Keyword(s):  
Mechanical Properties ◽  
Natural Rubber ◽  
The State ◽  
Rubber Matrix ◽  
Cross Linking ◽  
Type I ◽  
Type Ii ◽  
Rubber Compounds ◽  
Rubber Part

Abstract Four types of peroxides in combination with two types of co-agents were used as cross-linking agents for the preparation of rubber compounds based on natural rubber. The effects of Type I and Type II co-agents on cross-linking and physical-mechanical properties of vulcanizates were investigated. The correlation between mechanisms of the interaction of co-agents with the rubber matrix in relation to the characteristics of tested systems was discussed. The results showed that the Type I co-agent influenced the rate and the state of cure. Physical-mechanical properties were improved by addition of the Type I co-agent. By contrast, the Type II co-agent had no contribution to the rate and state of cure. Moreover, physical-mechanical properties of vulcanizates deteriorated in the presence of this type of co-agent.

Sulfur-Cure-Compatible Blends of Halogenated Ethylene-Propylene Copolymers and Diene Rubbers

1976 ◽  
Vol 49 (2) ◽  
pp. 353-366 ◽  
Author(s):  
R. T. Morrissey
Keyword(s):  
Natural Rubber ◽  
Uv Light ◽  
Metal Halide ◽  
High State ◽  
Adhesive Properties ◽  
Economical Method ◽  
Ethylene Propylene ◽  
Good Adhesive ◽  
Diene Rubbers

Abstract The chlorination of ethylene-propylene copolymers represents a possible economical method of producing a sulfur-curable EPM polymer. There are many feasible uses for these polymers. However, their incompatibility of cure with the more generally used polymers such as SBR, cis-polybutadiene, and natural rubber has limited their use, particularly in blends. It has been found that this can be overcome by halogenation of the EPM in the presence of certain catalysts. Earlier studies of Crespi and Bruzzone have shown that dehydrochlorina tion must follow chlorination for the polymer to show a high state of cure and good rebound characteristics. It has been discovered that the presence of certain metal halide catalysts and uv light tend to promote not only the halogenation of the EPM but also the dehydrohalogenation process. Further modification of the chlorinated and brominated EPM can be produced by halogenating in two steps. The resulting halogenated EPM shows good cure compatibility with highly unsaturated polymers, such as natural rubber. The halogenated copolymers show good adhesive properties to blends of diene polymers and have been used as adhesives between EPDM and fabric.

Extraction and identification of fillers and pigments from pyrolyzed rubber and tire samples

1996 ◽  
Vol 54 ◽  
pp. 174-175
Author(s):  
P. Sadhukhan ◽  
J. B. Zimmerman
Keyword(s):  
Zinc Oxide ◽  
Electron Microscope ◽  
Carbon Black ◽  
Natural Rubber ◽  
Transmission Electron Microscope ◽  
Rolling Resistance ◽  
Synthetic Polymers ◽  
Nitrogen Atmosphere ◽  
Transmission Electron ◽  
Curing Agents

Rubber stocks, specially tires, are composed of natural rubber and synthetic polymers and also of several compounding ingredients, such as carbon black, silica, zinc oxide etc. These are generally mixed and vulcanized with additional curing agents, mainly organic in nature, to achieve certain “designing properties” including wear, traction, rolling resistance and handling of tires. Considerable importance is, therefore, attached both by the manufacturers and their competitors to be able to extract, identify and characterize various types of fillers and pigments. Several analytical procedures have been in use to extract, preferentially, these fillers and pigments and subsequently identify and characterize them under a transmission electron microscope.Rubber stocks and tire sections are subjected to heat under nitrogen atmosphere to 550°C for one hour and then cooled under nitrogen to remove polymers, leaving behind carbon black, silica and zinc oxide and 650°C to eliminate carbon blacks, leaving only silica and zinc oxide.

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