Modeling the optimal rubber composition using industrial waste

Due to the complex composition of the rubber compound, the optimization of the formulation for its preparation is a complex process. The experiments required to determine the optimal composition are a multi-step process that requires time and money. The purpose of this article is to use the method of mathematical modeling to determine the optimal composition of a rubber compound with the addition of industrial waste. Sulfur of the Tengiz deposit and metallurgical production slags were used as industrial waste. The Protodyakonov equation was used to derive the generalized equation and check its adequacy. The escaped equations were used to prepare the rubber compound. The process of vulcanization of the mixture with and without the addition of waste was carried out. The kinetics of vulcanization of the optimized mixture has been studied. The optimized composite provides higher minimum and maximum torque levels, shorter initiation times and optimal cure times compared to a blend without additive. Tensile tests have shown that the composition of the rubber compound, selected by the method of mathematical modeling, is not inferior to the standard formulation. The computational model for determining the optimal composition of the rubber compound can be used for research and applied purposes in various industries related to rubber.

The use of terephthalic acid diamide in rubbers based on NBR-40

In the present work, the kinetics of aminolytic degradation of polyethylene terephthalate with a mixture of amino alcohols (monoethanolamine and triethanolamine) was studied to obtain terephthalic acid diamide (N, N'-bis (2-hydroxyethyl) terephthalamide).The degradation reaction was carried out at atmospheric pressure and periodically stirring the reaction mass, followed by purification of the product by recrystallization.The dependence of the yield of the target product (N, N'-bis (2-hydroxyethyl) terephthalamide) on the reaction time and temperature, as well as on the ratio of the components, was revealed. The possibility of using diamide as one of the components of rubbers to expand the ingredient base in the rubber industry is considered. The effect of the obtained diamide on the kinetics of vulcanization of rubbers based on nitrile butadiene rubber (NBR-40) was studied, and the physicochemical and physicomechanical properties of the obtained vulcanizates were examined. In a similar way, the effect of an oligomer obtained by polycondensation of this terephthalic acid diamide was studied. The choice of SKN-40 rubber as the basis is due to the high polarity of the rubber and its good compatibility with the obtained terephthalic acid diamide and its oligomer.The accelerating effect of terephthalic acid diamide in combination with 2-mercaptobenzothiazole (MBT) on sulfur vulcanization of rubbers based on NBR-40 was revealed. The time to reach the optimum vulcanization is reduced by 4 min. In the case of using only terephthalic acid diamide, without the use of common accelerators, the optimum point of vulcanization shifts toward a longer time.In the case of using only terephthalic acid diamide, without the use of common accelerators, the optimum point of vulcanization shifts toward a longer time. Introduction diamide of terephthalic acid or its oligomer results in a change of physical and mechanical properties of the rubber - strength at break and elongation at break. The kinetics of the swelling of the resulting rubbers in toluene and gasoline was studied for four hundred hours. A decrease in the degree of swelling of vulcanizates in gasoline was observed with the introduction of terephthalic acid diamide instead of the zinc oxide vulcanization activator. Possible options for further application and use of the obtained terephthalic acid amide and its oligomer are considered.

SERINOL DERIVATIVES FOR THE SUSTAINABLE VULCANIZATION OF DIENE ELASTOMERS

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.

INFLUENCE OF DIANILINE CROSS-LINKING SYSTEMS ON THE STRUCTURE, CURING MECHANISM, AND PROPERTIES OF POLYACRYLICESTER ELASTOMER

ABSTRACT To develop high-performance polyacrylicester (ACM) elastomeric components with higher scorch safety and superior thermal and mechanical properties, we replaced aliphatic diamine curatives with aromatic dianiline curatives. The influence of dianiline curatives 4,4′-(4,4′-isopropylidenediphenyl-1,1′-diyldioxy)dianiline, 4,4′-(hexafluoroisopropylidene)bis(p-phenyleneoxy)dianiline, and 4,4′-(1,1′-biphenyl-4,4′-diyldioxy)dianiline on the network structures and thermal, dynamic mechanical, and mechanical properties of ACM vulcanizates was investigated. The kinetics of vulcanization was analyzed for different dianiline curatives, with the use of rheometer curves. To understand the electronic properties and study the relation between chemical structure and reactivity, density functional theory was used. The time–temperature superposition principal was used to evaluate the activation energy for degradation of cross-linked samples. Finally, the curing mechanism of ACM in the presence of dianiline curative was studied with X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy. These spectroscopic analyses suggested that the reaction mechanism took place via two steps: the first step was formation of the amide linkage and the second step was formation of imide linkages.

Processing and Properties of Fire Resistant EPDM Rubber-Based Ceramifiable Composites

Low softening point temperature glassy frit, reinforcing silica, wollastonite and dicumyl peroxide were incorporated into ethylene-propylene-diene (EPDM) rubber matrix in different amounts in order to obtain ceramifiable composites. Kinetics of vulcanization of the mixes was measured. Mechanical properties, micromorphology, thermal properties and combustibility of the vulcanizates were studied as well as compression strength of the ceramic residue obtained after heat treatment. Studies show that optimal amount of glassy frit from the point of view of ceramification effectiveness in dispersed mineral phase is 40 % wt.

THE INFLUENCE OF THE METHOD OF RUBBER ISOLATION FROM LATEX ON THE PROPERTIES OF ELASTOMERIC MATERIALS BASED ON BUTADIENE-NITRILE RUBBERS

The properties of butadiene-nitrile rubbers obtained by various methods of synthesis and isolation from latex and rubbers based on them were studied in the article. The surface free energy of samples was determined using the Owens, Wendt, Rabel and Kaelble method. It was shown that the surface energy of elastomeric materials is affected 1) by non-rubber components, the content and nature of which are determined by the method of obtaining and isolating rubber from latex and 2) by the number of nitrile groups in the rubber macromolecule. The kinetics of vulcanization of rubber compounds based on the investigated rubbers has been studied. It was shown that rubber compounds based on rubbers containing a residual emulsifier are vulcanized longer. Elastic-strength properties were studied, and it was concluded that rubbers based on butadienenitrile rubbers synthesized by various methods with the same content of bound nitrilacrylic acid have different physico-mechanical properties and cannot be used interchangeably without changing the formulation and technological parameters of their processing.

Vulcanization behavior of NBR with organically modified clay

The rheometric measurements were used to study the kinetics of vulcanization of the nanocomposites nitrile butadiene rubber (NBR)/organically modified montmorillonite in different concentrations. The presence of clay has modified the rheometric properties of rubber. However the Ea values were not significantly modified with the presence of nanofiller.

Copolymerization of Isobutene and Isoprene at “High” Temperature with Syncatalyst Systems Based on Aluminum Organic Compounds

New catalyst systems based on alkylaluminum derivatives and halogen or interhalogen compounds were found highly efficient in the synthesis of high-molecular-weight IIR at temperatures above − 50°C. The reaction mechanism was studied in detail for the system Et2AlCl + Cl2. The reactions occurring between chlorine, isobutene, Et2AlCl, and the solvent (CH3Cl) were elucidated and studied under various experimental conditions (e.g. presence or absence of light, simultaneous presence of the copolymerization system components, temperature, type of halogen, use of model compound of isobutene). It was concluded that halogenium ions, i.e. Cl+, Br+, or I+, are the initiating species. Kinetic and conductometric investigations showed that scarcely dissociated ion pairs, e.g. Cl+[Et2AlCl2]−, were formed in the absence of monomer; but in the presence of isobutene, a noticeable increase of the electrical conductivity and rapid polymerization occurred. The maximum polymerization rate was first order with respect to the concentrations of monomer, Cl2, and Et2AlCl. In the homopolymerization of isobutene, transfer to monomer and termination reactions were negligible. The MW of IIR was found to be mainly dependent on the concentrations of the catalyst components, on isoprene concentration, and on temperature. The reactivity ratio of isobutene with isoprene was found to be r1=2.5±0.5 at −35°C, while the activation energies relative to MW were −5.8 ± 0.4, kcal/mol for polyisobutene, and −5.7 ± 0.7 and − 4.3 ± 0.5 kcal/mol for IIR containing, respectively, 1.3 and 1.9 mol% of isoprene. The evaluation of some physicochemical and technological properties of typical IIR produced with the system Et2AlCl + Cl2, indicated that isoprene is randomly distributed along the chains and that the MWD is monomodal, while the glass transition temperature, tensile properties, mechanical-dynamic spectra, and kinetics of vulcanization are very similar to those of commercial IIR. Very preliminary data, referring to several classes of new catalyst systems yielding IIR having good properties, were also obtained. The syncatalyst systems here described can work in a homogeneous phase consisting of an aliphatic hydrocarbon besides methyl chloride, still giving IIR with high MW. Therefore, a completely homogeneous process can be envisioned for the synthesis of IIR at −50°C thus avoiding a great part of the fouling problems of the slurry process. The economic advantage of using “high” temperatures of polymerization is briefly discussed in terms of energy savings.