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Article
Publication date: 2 May 2017

Salwa H. El-Sabbagh, Doaa Samir Mahmoud, Nivin M. Ahmed, A.A. Ward and Magdy Wadid Sabaa

This paper aims to study the role of organobentonite (OB) as a filler to improve the mechanical strength of styrene butadiene rubber (SBR). Organoclay was first prepared…

Abstract

Purpose

This paper aims to study the role of organobentonite (OB) as a filler to improve the mechanical strength of styrene butadiene rubber (SBR). Organoclay was first prepared by modifying bentonite with different concentrations of N-cetyl-N, N, N-triethyl ammonium bromide. A series of SBR composites reinforced with OB were prepared using master-batch method.

Design/methodology/approach

The curing characteristics, mechanical properties, thermal behavior, dielectric properties and morphology of SBR/OB composites were investigated.

Findings

The elastic modulus and tensile strength of composites were increased by inclusion of OB, while the elongation at break was decreased, due to the increase in the degree of cross-linking density. Thermal gravimetric analysis revealed an improvement in the thermal stability of the composite containing 0.5 cation exchange capacity (CEC) OB, while the scanning electron micrographs confirmed more homogenous distribution of 0.5CEC OB in the rubber matrix. Also, SBR/0.5CEC OB showed low relative permittivity and electrical insulating properties.

Research limitations/implications

Bentonite has been recognized as a potentially useful filler in polymer matrix composites because of their high swelling capacity and plate morphology.

Practical implications

OB improves the cured rubber by increasing the tensile strength and the stiffness of the vulcanizate.

Social implications

Using cheap clay in rubber industry lead to production of low cost products with high efficiency.

Originality/value

The clay represents a convenient source because of their environmental compatibility. The low cost and easy availability make the modified clay used as fillers in rubber matrices, and the resultant composites can be applied in variety industrial of applications such as automobile industries, shoe outsoles, packaging materials and construction engineering.

Details

Pigment & Resin Technology, vol. 46 no. 3
Type: Research Article
ISSN: 0369-9420

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Article
Publication date: 3 August 2020

Salwa H. El-Sabbagh, Nivin M. Ahmed, Doaa Samir Mahmoud and Wael S. Mohamed

The purpose of this paper is to evaluate the efficiency of commercial silica, silica fume-waste (SF) and modified silica fume-waste (mSF) as reinforcing filler in…

Abstract

Purpose

The purpose of this paper is to evaluate the efficiency of commercial silica, silica fume-waste (SF) and modified silica fume-waste (mSF) as reinforcing filler in acrylonitrile-butadiene rubber (NBR) and ethylene propylene diene monomer (EPDM) through the mixing process of rubber. The composites were prepared using different loadings of silica fume and commercial silica in EPDM and NBR composites. Structural characterization of silica and SF was done using X-ray fluorescence and scanning electron microscopy (SEM). The surface of silica fume waste was modified using poly methyl methacrylate/butyl acrylate through emulsion polymerization to increase the interaction between silica and rubber, then consequently better dispersion in rubber matrix was obtained. The mSF waste was characterized using FT-IR spectra and transmission electron microscopy.

Design/methodology/approach

The investigated rubber mixes and vulcanizates were evaluated by measuring the curing characteristics, mechanical testing, thermogravimetric analysis and morphological studies (SEM). The mechanical properties of composites including tensile strength, elongation at break and modulus were estimated and analyzed.

Findings

The results revealed that the composites (NBR and EPDM) containing mSF as filler exhibited better rheological and mechanical properties compared to unmodified silica waste and commercial silica. The SEM analysis indicated that the mSF was homogeneously dispersed through the surface of NBR and EPDM composites. Also, results showed that (NBR and EPDM) composites exhibited remarkable improvements in tensile strength, elongation at break and hardness in the presence of mSF; they also showed an increase in the thermal stability. This means that the treatment of surface SF can improve its dispersion in rubber.

Research limitations/implications

Silica cannot be applied in rubber matrix without surface modification because of their incompatibility; their dispersion is not good without surface modification.

Practical implications

The modified silica surface is considered as effective reinforcing filler which can replace other fillers because of its lower surface energy and enhanced intercalating behavior in rubber.

Social implications

This study is just a start in establishing rubber projects with wide applications in the industry and providing a cheap local product while preserving the quality and that is the use of factory waste, which helps in protecting the environment from pollution.

Originality/value

mSF is cheap with relatively high purity, which make rubber/mSF composites appear as new grade of material that can be used in different media rather than rubber.

Details

Pigment & Resin Technology, vol. 50 no. 1
Type: Research Article
ISSN: 0369-9420

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Article
Publication date: 5 October 2020

Doaa Samir Mahmoud, Medhat Lotfy Tawfic, Abdel Gawad Rabie and Salwa H. El-Sabbagh

The purpose of this paper is to prepare superabsorbent polymers (SAPs) based on acrylic acid, which is considered hygroscopic material to incorporate in rubber…

Abstract

Purpose

The purpose of this paper is to prepare superabsorbent polymers (SAPs) based on acrylic acid, which is considered hygroscopic material to incorporate in rubber formulation, which results in producing moisten rubber that is used as roofing sheets.

Design/methodology/approach

SAPs were synthesized via free radical bulk polymerization technique using different content of cross-linker N, N'-methylenebisacrylamide and potassium persulfate. Differential scanning calorimeter, thermal gravimetric analysis, Fourier transform infrared spectroscopy and transmission electron microscopy were used to characterize SAPs and confirmed the formation of cross-linked hydrogel structure. The water absorbency and the gel fraction for sodium polyacrylate (NaPA) were investigated. Then, the influence of obtained NaPA on the swelling behavior of the prepared natural rubber (NR) compound has been discussed.

Findings

Absorption characteristics and gel fraction of NaPA were found to depend on the content of the cross-linker in the system. SAPs are used to improve the absorbance behavior and performance of the NR to produce, roofing sheets using in hot weather. The morphology of the obtained rubber compound was well-explained by using a scanning electron microscope.

Research limitations/implications

The research provides a simple way to produce moisten rubber that can be used as a roofing sheet to overcome warm weather.

Originality/value

Moisten rubber roofing sheets provide a low-cost option in many developing countries with hot climates, and thus, help save the environment from global warming.

Details

Pigment & Resin Technology, vol. 50 no. 3
Type: Research Article
ISSN: 0369-9420

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Article
Publication date: 5 May 2015

Salwa H El-Sabbagh, Doaa S. Mahmoud, M. F. Zawrah, Nivin M. Ahmed and Magdy W. Sabaa

The purpose of this paper is to evaluate the efficiency of organobentonite (OB) as reinforcing filler in acrylonitrile-butadiene rubber (NBR). The composites were prepared…

Abstract

Purpose

The purpose of this paper is to evaluate the efficiency of organobentonite (OB) as reinforcing filler in acrylonitrile-butadiene rubber (NBR). The composites were prepared using different loadings of OB and studying in details their properties. A series of OB was modified using surfactant N-cetyl-N, N, N-trimethyl ammonium bromide (CTAB) with concentrations 0.5, 1 and 2 cation exchange capacity (CEC) of bentonite.

Design/methodology/approach

The different bentonites were characterized using different analytical and spectro-photometric techniques, such as infra red, X-ray diffraction, thermogravimetric analysis and scanning electron microscopy, while rubber vulcanizate rheological, morphological, swelling and thermal properties were examined using different standard instrumental testing and methods.

Findings

The study revealed that the modification of bentonite using CTAB showed significant enhancement on NBR properties, and the optimum filler loading was 12 phr for both 0.5CEC OB and 2CEC OB. These modified bentonites improved reinforcing properties to NBR vulcanizates. Also, results showed that composites exhibited remarkable improvements in tensile strength, elongation at break and hardness in the presence of modified bentonite and also an increase in thermal stability.

Research limitations/implications

Na-B cannot be applied in rubber matrix without modification because it is incompatible with it.

Practical implications

The modified bentonite is considered as efficient reinforcing filler which can replace other fillers because it has lower surface energy and improved intercalating behaviour in rubber matrix.

Originality/value

These papered bentonites are cheap with relatively high purity, which make rubber/clay composites emerge as new class of material and can be used in different fields other than rubber.

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Article
Publication date: 5 April 2021

Hoda Sabry Othman, Maher A. El-Hashash, S. H. El-Sabbagh, A. A. Ward and Galal A.M. Nawwar

Calcium and Zinc lignates were proven to be good antioxidants for rubber composites. The purpose of this paper is to evaluate the copper lignate antioxidant activity along…

Abstract

Purpose

Calcium and Zinc lignates were proven to be good antioxidants for rubber composites. The purpose of this paper is to evaluate the copper lignate antioxidant activity along with evaluating its electrical conductivity in rubber composites.

Design/methodology/approach

The antioxidant activity of the Cu-LSF complex was compared with that of standard commercial antioxidant additives as a green alternative. The rheological characteristics, thermal aging and mechanical and electrical properties were evaluated for the NBR vulcanizates containing the different antioxidants in the presence or absence of coupling agents.

Findings

Results revealed that the Cu-LSF complex (5 phr) can function as a compatibilizing, antioxidant and electrical conductivity agent.

Originality/value

The new copper complex prepared from paper-pulping black liquor of wastes could be used as a green antioxidant and electrical conductivity agent in rubber composites.

Details

Pigment & Resin Technology, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 0369-9420

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Article
Publication date: 2 March 2015

Salwa H El-Sabbagh and Nivin M. Ahmed

This paper aims to express in detail the rheological, morphological and thermal properties of unpigmented and pigmented styrene-butadiene rubber composites with new…

Abstract

Purpose

This paper aims to express in detail the rheological, morphological and thermal properties of unpigmented and pigmented styrene-butadiene rubber composites with new prepared inorganic pigment based on kaolin covered with a thin layer of calcium and magnesium oxides or mixed oxide of both together. These new pigments combine the properties of both their constituents (kaolin and metal oxides), which are a new trend in inorganic pigments called core-shell pigments. The pigments used for comparison are kaolin (K), CaO/kaolin (CaO/K), MgO/kaolin (MgO/K) and CaO.MgO/kaolin (CaO.MgO/K).

Design/methodology/approach

The different pigments were characterized using different analytical and spectrophotometric techniques, such as X-ray diffraction, scanning electron microscopy/energy dispersive X-ray and transmission electron microscopy, while rubber vulcanizates' rheological, morphological, swelling and thermal properties were examined using different standard and instrumental testing and methods.

Findings

The study revealed that there is a significant effect of the new prepared pigments on SBR properties, where the optimum pigment loading was 40 phr for CaO/kaolin, while it was 2.5 phr for MgO/kaolin. Studying the effect of different ratios of oxides on kaolin (5, 10 and 20 per cent), different loadings of these pigments ranging between 2.5 and 40 phr were done for each pigment. These modified kaolin or core-shell metal oxide/kaolin pigments imparted new and improved reinforcing properties to SBR vulcanizates.

Research limitations/implications

No research limitations were found.

Practical implications

Core-shell MgO/kaolin pigments are eco-friendly and can replace other expensive pigments that are usually used as fillers in the rubber industry with less expenses and comparable efficiency.

Originality/value

These new pigments are cheap and efficient and can be used in different fields other than rubber.

Details

Pigment & Resin Technology, vol. 44 no. 2
Type: Research Article
ISSN: 0369-9420

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Article
Publication date: 29 April 2014

Khlood S. Abdel Zaher, R.H. Swellem, Galal A.M. Nawwar, Fathy M. Abdelrazek and Salwa H. El-Sabbagh

The purpose of this paper is to study the efficiency of lignin/silica and calcium lignate/calcium silicate as natural antioxidants in styrene-butadiene rubber (SBR…

Abstract

Purpose

The purpose of this paper is to study the efficiency of lignin/silica and calcium lignate/calcium silicate as natural antioxidants in styrene-butadiene rubber (SBR) vulcanizates.

Design/methodology/approach

It has been found that thermal aging data of the aged sample revealed that SBR vulcanizate undergoes crosslink reactions that lead to embrittlement and ultimately failure. Incorporation of lignin/silica or calcium lignate/calcium silicate, however, resulted in significant improvement of the degradation profile of the vulcanizates at 90±1°C. Loss of tensile strength and flexibility during aging of the SBR compounds with 8 phr lignin/silica or calcium lignate/calcium silicate was mild relative to unfilled polymer, indicating a restricted degradation due to the presence of the investigated compounds. The results obtained revealed that the investigated compounds are good antioxidant, and the evaluation was confirmed by physico-mechanical properties of the vulcanizates, FT-IR spectroscopy, transmission (TEM) and scanning (SEM) electron microscope.

Findings

It was noticed that SBR vulcanizates having 8 phr of lignin/silica or calcium lignate/calcium silicate exhibited the best mechanical properties in comparison with other concentrations (1, 2, 4, 6 and 10 phr). Also, results revealed that the lignin/silica derivatives are efficient antioxidants in SBR vulcanizates compared to vulcanizates containing conventional antioxidants used in rubber industry, namely polymerized 2,2,4-trimethyl-1, 2-dihydroquinoline (TMQ), and N-isopropyl-N'-phenyl-P-phenylenediamine (IPPD).

Research limitations/implications

All these results indicated that lignin/silica and calcium lignate/calcium silicate in SBR had good heat resistance and aging resistance, calcium lignate/calcium silicate has an application limitation as not all vulcanizates need to use CaCO3/calcium salts.

Practical implications

Lignin is usually seen as a waste product of pulp and paper industry and is often used as fuel for the energy balance of the pulping process. It is simple isolation along with silica from rice straw and using it as an antioxidant added further practical utility for this waste.

Originality/value

The importance of lignin/silica derivatives is arisen from their biodegradability and their ease availability from rice straw black liquor.

Details

Pigment & Resin Technology, vol. 43 no. 3
Type: Research Article
ISSN: 0369-9420

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Article
Publication date: 1 May 2006

Salwa H. El‐Sabbagh, Nivin M. Ahmed and Mohamed M. Selim

A new method for modifying the properties of aluminium oxide had been developed which allowed alumina to be used as a white, reinforcing filler in various rubber…

Abstract

Purpose

A new method for modifying the properties of aluminium oxide had been developed which allowed alumina to be used as a white, reinforcing filler in various rubber composites to replace carbon black, producing high performance white rubber vulcanizates comparable to those loaded with carbon black that could be coloured if needed.

Design/methodology/approach

Alumina was treated with small amounts of ammonium molybdate. Characterisation of modified aluminium oxide was carried out using transmission electron microscopy (TEM) and scanning electron microscopy (SEM). Also, evaluation of the pigments prepared, in terms of oil absorption, specific gravity, and bulking value using international standard testing methods was performed. The morphology of the natural rubber composites loaded with the new modified alumina were studied using SEM. Kraus equation was used to analyse the extent of polymer‐pigment interaction, while Mooney‐Rivlin relation was employed to study the near equilibrium stress‐strain behaviour.

Findings

The results showed that, the pigment had a significant effect on the rheological characteristics (scorch, cure time, etc.), mechanical properties, stress and strain at yield and at rupture of white rubber vulcanizates prepared resulting in high performance.

Research limitations/implications

As concentration of molybdenum oxide increased in the alumina crystals, the reinforcing effect in rubber composites also increased till an optimum concentration where such a reinforcing effect reversed. However, investigation of the application of these pigments in other systems such as an anticorrosive pigment in paint formulations and reinforcing filler in polyester composites could also be interesting.

Practical implications

The pigments prepared could be used as reinforcing filler in plastic composites and also as anticorrosive pigment in paint formulations.

Originality/value

Aluminium oxide is a cheap compound. The originality of the work lay in the finding that by adding trace amounts of molybdenym to it, aluminium oxide's properties changed dramatically resulting in more effective action in reinforcing rubber composites filled with such modified alumina, producing white rubber composites with comparable properties to those loaded with carbon black, and may exceed them in some cases. This allowed the preparation of coloured rubber with good rheological and physical properties.

Details

Pigment & Resin Technology, vol. 35 no. 3
Type: Research Article
ISSN: 0369-9420

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Article
Publication date: 8 November 2011

Galal Nawwar, Sayed Yakout, M.S.A El‐Sadiek and Salwa El‐Sabbagh

The purpose of this paper is to study the effect of new heterocyclic compounds on styrene butadiene rubber (SBR) mixes.

Abstract

Purpose

The purpose of this paper is to study the effect of new heterocyclic compounds on styrene butadiene rubber (SBR) mixes.

Design/methodology/approach

It has been found that the starting material 1 could react with cyromazine (2) and/or 4‐aminoantipyriene (4) as amino compounds in the presence of triethylorthoformate and in the boiling dioxane to yield triazine‐3 and/or pyrazolo 5 derivatives, respectively. The chemical structures of the new products 3 and 5 have been established by their elemental analyses spectroscopic data IR, Ms and 1H, 13C NMR. These two compounds were evaluated as antioxidants in SBR, and this evaluation was confirmed by physico‐mechanical properties of vulcanizates, IR spectra and scanning electron microscope.

Findings

The difference between maximum torque MH and minimum torque ML (ΔM), tensile strength, modulus and elongation at break increases in the presence of prepared antioxidants while the equilibrium swelling decreased. The rubber vulcanizates were subjected to thermal oxidative aging at 90°C for up to seven days. It has been found that new compounds 3 and 5 can protect SBR vulcanizates against oxidative deterioration.

Research limitations/implications

The solubility of the prepared compounds 3 and 5 is very poor and they are only soluble in dimethyl formamide (DMF) or dimethyl sulphoxide (DMSO) which have high boiling points. Also, new compounds 3 and 5 have melting points (above 300°C).

Practical implications

Triazine and antipyrine derivatives have many medical and industrial applications.

Originality/value

The new synthesized compounds revealed excellent antioxidant behaviour in comparison with the commercial antioxidant phenyl‐β‐naphthyl amine (PβN) which is used in industry.

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Article
Publication date: 10 July 2007

E.M.A. Yakout and S.H. El‐Sabbagh

Evaluation of uracil and/or benzothiazol derivatives as antioxidants in natural rubber mixes.

Abstract

Purpose

Evaluation of uracil and/or benzothiazol derivatives as antioxidants in natural rubber mixes.

Design/methodology/approach

Cyanoacetylurea 1, as a precursor, was prepared at a good yield from widely available, low‐cost chemicals. Compound 1 was treated with triethylorthoformate and amine derivatives in one pot reaction affording the target uracil derivative 3. Replacement of the cyano group in 1 by benzothiazol led to obtaining the interesting N‐hydroxy uracils containing benzothiazole moiety 5 at a good yield. Some of the compounds prepared was selected and were evaluated as antioxidants in natural rubber mixes. The rheometric characteristic of the compounded rubber and the physico‐mechanical properties of the vulcanizates were determined.

Findings

The cure rate index, tensile strength and modulus increased while the equilibrium swelling decreased, i.e. compound 5 behaved as a secondary accelerator. The rubber vulcanizates were subjected to thermal oxidative ageing at 90°C for up to seven days. It has been found that uracil and/or benzothiazol derivatives can protect natural rubber vulcanizates against oxidative deterioration.

Research limitations/implications

The compounds prepareds were difficult to dissolve, they needed solvents with high boiling points, e.g. DMF, DMSO to be dissolved and even then they are not completely dissolved.

Practical implications

Uracil and or benzothiazol derivatives have many industrial applications.

Originality/value

The new compounds were prepared from very cheap and widely available chemicals. The compounds synthesised showed good antioxidant behaviour in comparison with the commercial antioxidant (phenyl‐β‐naphthyl amine) industrially used.

Details

Pigment & Resin Technology, vol. 36 no. 4
Type: Research Article
ISSN: 0369-9420

Keywords

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