A.M.A. Nada, M.A. Yousef, K.A. Shaffei and A. Salah
Bagasse and rice straw lignins undergo different treatments, e.g. acid hydrolysis, oxidation with hydrogen peroxide and thermal treatment, before being used as a partial…
Abstract
Bagasse and rice straw lignins undergo different treatments, e.g. acid hydrolysis, oxidation with hydrogen peroxide and thermal treatment, before being used as a partial replacement for phenol in phenol formaldehyde resin. These treatments improved the resin formation properties of the lignin. The effect of these treatments on the improvement of the properties of the resin produced has the following sequence: lignin treated with HCl (1‐3N) > lignin treated with H2O2 (1‐3 per cent) > thermally treated lignin (120‐140°C). The improvement of the properties of the resin produced from bagasse lignin is greater than that produced from rice straw lignin. The treatment of rice straw lignin with acid increases its ability to form a resin. Treatment of rice straw lignin with acid leads to its increased concentration in the phenol lignin formaldehyde resin with good properties. In general, the resin produced from treated lignin has better properties than resin produced from untreated lignin.
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R.M. Mohsen, A.M. Ramadan, K.A. Shaffei and A.S. Badran
A newly developed polyvinyl acetate (PVA) emulsion latex for adhesive has been prepared by the semicontinuous process using a newly developed octyl aldehyde sodium…
Abstract
A newly developed polyvinyl acetate (PVA) emulsion latex for adhesive has been prepared by the semicontinuous process using a newly developed octyl aldehyde sodium bisulphite‐potassium persulphate redox pair initiation system. In this work the amount of polyvinyl alcohol (PVA) as a protective colloid has been changed and it was found that only a little amount of (PVA) together with the newly developed adduct could cause a stable latex with excellent mechanical properties for bonding wood which favours this redox system in large industrial applictions. Also monodisperse latex particles with low polydispersity index can be prepared by using 1% PVA coupled with the newly developed redox system. Finally the developed latex has been incorporated and the corresponding shear strength were measured.
A.M.A. Nada, M.A. Yousef, K.A. Shaffei and A.M. Salah
Lignin precipitated from different black liquors wasted from the cooking of rice straw, bagasse and cotton stalks, to produce pulp and paper, can replace phenol by up to 40 per…
Abstract
Lignin precipitated from different black liquors wasted from the cooking of rice straw, bagasse and cotton stalks, to produce pulp and paper, can replace phenol by up to 40 per cent in phenol formaldehyde resin. The properties of the resin produced from bagasse lignin formaldehyde are nearly the same as when the resin IS produced from phenol formaldehyde. Replacement of phenol by lignin in phenol formaldehyde resin has an economical effect and reduces the pollution caused by draining black liquor into rivers and streams. The properties of the resin produced from rice straw lignin are lower than resin from bagasse and cotton stalk lignin. The effect of increasing the content of lignin in the resin on the resin properties was studied. The effect of polymerization time and temperature on the resin properties is also clarified. The molecular structure of the lignins used plays an important role on the properties of the phenol lignin formaldehyde produced.
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Gomaa Abdel-Maksoud, Aya Abdallah, Rana Youssef, Doha Elsayed, Nesreen Labib, Wael S. Mohamed and Medhat Ibrahim
This study aims to evaluate the efficiency of using some polymers at different concentrations in the consolidation of vegetable-tanned leather artifacts.
Abstract
Purpose
This study aims to evaluate the efficiency of using some polymers at different concentrations in the consolidation of vegetable-tanned leather artifacts.
Design/methodology/approach
New vegetable-tanned leather samples were prepared. The consolidants used were polyacrylamide (PAM) and polymethyl methacrylate/hydroxyethyl methacrylate (MMA-HEMA). Accelerated heat aging was applied to the untreated and treated samples. Analytical techniques used were Fourier transform infrared spectroscopy (FTIR), digital microscope, scanning electron microscope (SEM), change of color and mechanical properties.
Findings
The characteristic FTIR bands showed the effect of accelerated heat aging on the molecular structure of the studied samples, but treated and aged treated samples used were better than aged untreated samples. Microscopic investigations (digital and SEM), and mechanical properties proved that 2% was the best concentration for polymers used. The change in the total color difference of the treated and aged treated samples was limited.
Originality/value
This study presents the important results obtained from PAM and poly(MMA-HEMA) used for the consolidation of vegetable-tanned leather artifacts. The best results of the studied polymers can be applied directly to protect historical vegetable-tanned leathers.
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The purpose of this paper is to describe how lignosulphonate modified ketone formaldehyde resins containing functional groups such as hydroxyl, carbonyl, phenol, were produced via…
Abstract
Purpose
The purpose of this paper is to describe how lignosulphonate modified ketone formaldehyde resins containing functional groups such as hydroxyl, carbonyl, phenol, were produced via in situ modification of ketone/formaldehyde resins. Cyclohexanone‐formaldehyde (CF‐R), acetophenone‐formaldehyde (AF‐R) and methyl ethyl ketone‐formaldehyde (MEKFR) resins were in situ modified with lignosulphonate in the presence of sodium hydroxide. The paper reports the synthesis of lignosulphonate‐modified resins with a one step method of in situ modification of ketonic resin. The roles of the types of the ketone, lignosulphonate concentration, the solubility, molecular weight and thermal properties of the product were investigated.
Design/methodology/approach
Ketone, formalin (37 per cent aqueous solution), lignosulphonate were mixed and 20 per cent aqueous NaOH solution was added to produce the resin.
Findings
There was improvement of the properties of the lignosulphonate modified ketonic resins produced from waste black liquor. The lignosulphonate modified ketone‐formaldehyde resins were soluble in common organic solvents.
Research limitations/implications
The reaction mixture must be stirred continuously. Subsequently, 37 per cent formalin was added dropwise in total while refluxing. The amount of aqueous NaOH solution is limited since the formed resin may become insoluble in common organic solvents. The water was removed from MEKFR, successively by evaporating with rotary evaporator.
Practical implications
This study provides the application of ketonic resins. The modified ketonic resins containing lignosulphonate groups may also promote the adhesive strength of a coating. The cell walls of various cell types of plants, for example, wood fibres, vessels, and tracheid, have lignin as an important constituent. It constitutes 20‐30 per cent of the weight of wood.
Originality/value
Lignosulphonate modified ketonic resins have been synthesized in the presence of a base catalyst. These resins have higher Tg or Tm values and molecular weight than CFR and AFR alone and also have thermoset property. Environmental and ecological concerns have increased the attention paid by the chemical industry to renewable raw materials.
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M.A. Abd El‐Ghaffar, N.A. Abdelwahab and E.A.M. Youssef
The purpose of the paper is to examine the synthesis of polyaniline (PAn) and poly(m‐toluidine) (PmT) via an inverse emulsion polymerisation pathway and evaluate of the…
Abstract
Purpose
The purpose of the paper is to examine the synthesis of polyaniline (PAn) and poly(m‐toluidine) (PmT) via an inverse emulsion polymerisation pathway and evaluate of the synthesised polymers as corrosion inhibitors for steel protection in surface coatings.
Design/methodology/approach
PAn and PmT were prepared by inverse emulsion polymerisation using ammonium persulphate as an initiator and sodium dodecylbenzene sulphonate (SDBS) as an emulsifier. Spectrophotometric measurements were conducted to characterise the prepared polymers. Latex paint formulations were prepared and dry paint films were evaluated for their physical, mechanical and corrosion protection performance.
Findings
The prepared conducting polymers of PAn and PmT are good candidates for enhancing the corrosion protection of steel. They showed good performance as corrosion inhibitors in latex paints without bad side effects on the physico‐mechanical properties of paint films.
Practical implications
Recent advances in corrosion protection of steel by coatings via inverse emulsion polymerisation of aniline and m‐toluidine have improved performance of anti‐corrosive water‐borne paints. Using formulations based on this new technology, offer uncompromised high performance eco‐friendly anti‐corrosive water‐borne systems that answer the future industrial demands from the economical and environmental points of view.
Originality/value
PAn and PmT prepared by inverse emulsion polymerisation showed promising results as corrosion inhibitors for steel protection. The polymerisation process was conducted in water (emulsion polymerisation) and the polymer lattices were incorporated in water borne paints from ecological and economical points of view.
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E.A.M. Youssef, D.E. El‐Nashaar and M.A. Abd El‐Ghaffar
Itaconic acid was reacted with phenylene diamine (ortho, meta and para) and o‐tolidine in boiling dekalin, using Dean and Stark apparatus. The polymers prepared were evaluated for…
Abstract
Itaconic acid was reacted with phenylene diamine (ortho, meta and para) and o‐tolidine in boiling dekalin, using Dean and Stark apparatus. The polymers prepared were evaluated for their suitability as antioxidants for natural rubber vulcanizates. The amide polymers prepared showed high efficiency as antioxidants for rubber vulcanizates, exceeding the performance of commercial antioxidants. In addition, the results obtained are encouraging and support the use of these polymers from both the environmental and economical points of view.