Preparation and Properties of Zinc Diacrylate-Modified Montmorillonite/Rubber Nanocomposite

Polymers for Advanced Techs

Chodák

Mošková

et al. 2017

Rubber magnetic composites were prepared by incorporation of strontium ferrite into rubber compounds based on acrylonitrile butadiene rubber and ethylene propylene diene monomer rubber. The sulfur, peroxide, and mixed sulfur/peroxide curing systems were introduced as cross-linking agents for rubber matrices. The aim was to investigate the influence of curing system composition on curing process and cross-link density of composite materials. Then, static and dynamic mechanical properties and thermal and magnetic characteristics were investigated in relation to the cross-link density of rubber magnetic composites and structure of the formed cross-links. The changes of dynamical and physicomechanical properties were in close correlation with the change of cross-link density, whereas the tensile strength of magnetic composites showed increasing trend with increasing amount of peroxide in mixed curing systems. On the other hand, thermal conductivity and magnetic characteristics were found not to be dependent on the curing system composition. Incorporation of magnetic crystalline ferrites into various rubber matrices leads to the preparation of magnets, known as ferrite rubber magnets. [5][6][7][8] Rubber magnetic composites are materials that consisted of at least 2 phases, magnetic powder as filler and continuous rubbermatrix. An advantage of these materials is the fact that they are possible to be prepared and processed by the technologies typically used for polymer composites processing. Rubber magnetic composites show excellent flexibility and easy workability, and moreover, they are characterized by good magnetic characteristics. They can be bent, coiled, and shaped without the loss of their magnetic characteristics. Additionally, they are very resistant to corrosion; therefore, no surface treatment is necessary.A lot of vulcanization systems have already been investigated as cross-linking agents for rubber formulations, among which sulfur and peroxide curing systems are still the most frequently used.Sulfur vulcanization is the oldest method used for cross-linking of unsaturated elastomers. It is a complex process that leads to the forming of different types of sulfide cross-links between macromolecules of rubber, namely, monosulfide C-S-C, disulfide C-S 2 -C, and polysulfide cross-links C-S x -C (x = 3-6). In general, sulfur-cured vulcanizates exhibit good tensile properties, high tensile and tear strength, and good elastic behavior, but weak high-temperature stability and poor resistance to aging. 9-13The application of peroxide curing system in cross-linking of elastomers leads to the forming of covalent carbon-carbon crosslinks between elastomer chain segments. C-C bonds have higher dissociation energy in comparison with sulfidic cross-links; therefore, peroxide-vulcanized elastomers exhibit higher thermal stability and good resistance to thermo-oxidative aging. Good electrical properties, low compression set, and no discoloration of the final products are next cognitive features of peroxide cured vulcaniz...

Section: Resultsmentioning

confidence: 99%

Section: Influence Of Curing System Composition On Physicomechanicamentioning

confidence: 99%

Cross‐linking and properties of rubber magnetic composites cured with different curing systems

Polymers for Advanced Techs

Chodák

Mošková

et al. 2017

“…The study of reaction mechanisms of co‐agents during peroxide curing of rubber compounds has been the subject of ongoing study 35,37,38 . According to some scientific works, 39‐41 zinc based co‐agents can form various types of physical and chemical linkages within the rubber matrix. Moreover, formation of ionic cross‐links and clusters has been suggested, too 42 .…”

Section: Resultsmentioning

confidence: 99%

Low frequency electromagnetic shielding efficiency of composites based on ethylene propylene diene monomer and multi‐walled carbon nanotubes

Polymers for Advanced Techs

Kvasničáková

Plavec

et al. 2020

Ethylene propylene diene monomer rubber was filled with multi-walled carbon nanotubes to prepare composite materials with the effect of electromagnetic radiation (EMR) shielding. Sulfur-based curing system as well as peroxide curing system were used for vulcanization of rubber compounds. The main goal of the work was the investigation of curing system composition and filler content on curing process, physical-mechanical properties, cross-link density, and shielding efficiency of the prepared composites. The results showed that curing characteristics and cross-link density of composites were dependent on both, amount of carbon nanotubes and curing system composition. The incorporation of filler resulted in the enhancement of physical-mechanical properties of composites. Higher values of tensile strength were found to have composites cured with organic peroxide in combination with coagent. The achieved results also demonstrated that carbon nanotubes filled rubber composites are suitable candidates for applications, in which shielding of EMR at low frequencies is based on reflection.

“…26,35–37 It has also been demonstrated that zinc methacrylate exhibits a strong adhesion to polar materials. 38,39 Ferrites are complex compounds of metal oxides. Due to the presence of metal and oxygen ions they belong to the polar materials.…”

Section: Resultsmentioning

confidence: 99%

Combined sulfur and peroxide curing systems applied in cross-linking of rubber magnets

Polymers and Polymer Composites

Kvasničáková

Dosoudil

et al. 2020

In the present work, barium ferrite in constant loading was dosed to the rubber matrices based on NR, SBR and NBR. Sulfur, peroxide and mixed sulfur and peroxide curing systems were applied for cross-linking of rubber magnetic composites. The application of sulfur or peroxide curing system leads to the formation of different types of linkages between rubber chain segments. As the structure of the formed cross-links plays a significant role in determining the final properties of rubber articles, the main aim of the work was to use the combination of curing systems in order to suppress the disadvantages of both systems and possibly to highlight their benefits. The results showed that composition of curing system has considerable influence on cross-link density of composites, which was subsequently reflected in typical change of physical-mechanical properties and glass transition temperature. The tensile strength was improved with increasing amount of peroxide curing system. The reason can be attributed to the presence of co-agent zinc methacrylate, which exhibits strong adhesion to magnetic filler and thus it contributes to the improvement of compatibility and homogeneity on the interphase filler–rubber. On the hand, there was observed no influence of curing system composition or type of rubber matrix on magnetic characteristics of composites.