RECLAIMING OF GROUND RUBBER TIRE BY SAFE MULTIFUNCTIONAL RUBBER ADDITIVES: I. TETRA BENZYL THIURAM DISULFIDE

ABSTRACT The present paper describes the mechanical reclaiming of ground rubber tire (GRT) by safe tetra benzyl thiuram disulfide (TBzTD), a multifunctional rubber additive. The versatility of the proposed agent is that it acts as a reclaiming agent during reclaiming and as a curing agent during revulcanization of the reclaimed materials. In this regard, we want to introduce a safe reclaiming agent in reclamation of GRT for improving its physical and mechanical performance. Reclaiming GRT has been carried out in an open roll mixing mill at various time intervals and different concentrations of the reclaiming agent (TBzTD) in the presence of spindle oil. The degree of reclaiming has been evaluated by the measurement of sol content, gel content, Mooney viscosity, inherent viscosity of sol rubber, and degree of cross-link of the reclaimed materials as a function of milling time. Also, the influence of gel content on cross-link density at various time intervals on the open two roll mixing mill has been determined. A unique correlation between gel fraction and cross-link density obtained at various time intervals and concentrations of reclaiming agent indicate that an optimization of the concentration of safe TBzTD and milling time has a positive influence on improving the efficiency of reclamation. The reclaiming conditions have been optimized in view of the mechanical properties of the revulcanized GRT and the aging resistance properties of the revulcanized reclaim. The influences of the concentration on the mechanical properties in the revulcanized reclaim have also been studied. Scanning electron microscopy (SEM) studies further indicate the coherency and homogeneity in the revulcanized reclaimed rubber when reclamation is carried out by optimum concentration of safe TBzTD after maximum time of reclaiming.

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Boron nitride for modification of rubber based on isoprene elastomer

Voprosy Materialovedeniya ◽

10.22349/1994-6716-2019-100-4-105-112 ◽

2020 ◽

pp. 105-112

Author(s):

K. S. Zhansakova ◽

E. N. Eremin ◽

G. S. Russkikh ◽

O. V. Kropotin

Keyword(s):

Mechanical Properties ◽

Boron Nitride ◽

Gradual Increase ◽

Physical And Mechanical Properties ◽

Curing Time ◽

Cross Link ◽

Start Time ◽

Link Density ◽

Cross Link Density ◽

Isoprene Rubber

The work studies vulcanization characteristics of elastomers based on isoprene rubber filled with carbon black N330 and boron nitride (BN). The influence of the boron nitride (BN) concentration on technological, dynamic, physical and mechanical properties of elastomers has been researched. The application of boron nitride for producing rubber with good properties has been considered. With a gradual increase of the inert filler BN concentration up to 35%, a decrease in the curing rate by 33% and polymer cross-link density by 26% is observed. Moreover, the start time of vulcanization increases by almost 300%, the optimal curing time by 200%.

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PEG Cross-Linked Alginate Hydrogels with Controlled Mechanical Properties

MRS Proceedings ◽

10.1557/proc-530-37 ◽

1998 ◽

Vol 530 ◽

Cited By ~ 2

Author(s):

Petra Eiselt ◽

Jon A. Rowley ◽

David J. Mooney

Keyword(s):

Mechanical Properties ◽

Tissue Engineering ◽

Molecular Weight ◽

Elastic Modulus ◽

Cell Transplantation ◽

Cross Linking ◽

Cross Link ◽

Link Density ◽

A Cell ◽

Cross Link Density

AbstractReconstruction of tissues and organs utilizing cell transplantation offers an attractive approach for the treatment of patients suffering from organ failure or loss. Highly porous synthetic materials are often used to mimic the function of the extracellular matrix (ECM) in tissue engineering, and serve as a cell delivery vehicle for the formation of tissues in vivo. Alginate, a linear copolysaccharide composed of D-mannuronic acid (M) and L-guluronic acid (G) units is widely used as a cell transplantation matrix. Alginate is considered to be biocompatible, and hydrogels are formed in the presence of divalent cations such as Ca2+, Ba2+ and Sr2+. However, ionically cross-linked alginate gels continuously lose their mechanical properties over time with uncontrollable degradation behavior. We have modified alginate via covalent coupling of cross-linking molecules to expand and stabilize the mechanical property ranges of these gels. Several diamino PEG molecules of varying molecular weight (200, 400, 1000, 3400) were synthesized utilizing carbodiimide chemistry. Sodium alginate was covalently cross-linked with these cross-linking molecules, and mechanical properties of the resulting hydrogels were determined. The elastic modulus of the cross-linked alginates depended on the molecular weight of the cross-linking molecules, and ranged from 10-110 kPa. The theoretical cross-link density in the hydrogels was also varied from 3 to 47% (relative to the carboxylic groups in the alginate) and the mechanical properties were measured. The elastic modulus increased gradually and reached a maximum at a cross-link density of 15%. In summary, covalently coupled hydrogels can be synthesized which exhibit a wide range of mechanical properties, and these materials may be useful in a number of tissue engineering applications.

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Application of Peroxide Curing Systems in Cross-Linking of Rubber Magnets Based on NBR and Barium Ferrite

Advances in Materials Science and Engineering ◽

10.1155/2019/1640548 ◽

2019 ◽

Vol 2019 ◽

pp. 1-10

Author(s):

Ján Kruželák ◽

Andrea Kvasničáková ◽

Elena Medlenová ◽

Rastislav Dosoudil ◽

Ivan Hudec

Keyword(s):

Mechanical Properties ◽

Barium Ferrite ◽

Cross Linking ◽

Butadiene Rubber ◽

Cross Link ◽

System Composition ◽

Peroxide Curing ◽

Link Density ◽

Cross Link Density ◽

Curing Systems

Rubber magnetic composites were prepared by incorporation of barium ferrite in constant amount—50 phr into acrylonitrile-butadiene rubber. Dicumyl peroxide as the curing agent was used for cross-linking of rubber magnets alone, or in combination with four different types of co-agents. The main aim was to examine the influence of curing system composition on magnetic and physical-mechanical properties of composites. The cross-link density and the structure of the formed cross-links were investigated too. The results demonstrated that the type and amount of the co-agent had significant influence on cross-link density, which was reflected in typical change of physical-mechanical properties. The tensile strength increased with increasing amount of co-agents, which can be attributed to the improvement of adhesion and compatibility on the interphase filler-rubber due to the presence of co-agents. Magnetic characteristics were found not to be influenced by the curing system composition. The application of peroxide curing systems consisting of organic peroxide and co-agents leads to the preparation of rubber magnets with not only good magnetic properties but also with improved physical-mechanical properties, which could broaden the sphere of their application uses.

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