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11 – 20 of over 26000The Chemical Information System (CIS) is a system of approximately 30 databanks available as a dial‐up online source of interactively available information for chemical compounds…
Abstract
The Chemical Information System (CIS) is a system of approximately 30 databanks available as a dial‐up online source of interactively available information for chemical compounds and their properties. The system was formerly known as the NIH/EPA Chemical Information System on account of its inception and development by two US Government agencies — The National Institutes of Health and Environmental Protection Agency. It is in particular the involvement by the EPA that explains the emphasis of the system on environmental information and the importance of the CIS as a source of data in this area. The databanks are by and large numeric and text databanks containing actual values and observations (quantitative and qualitative results), in contrast to bibliographic databases which, in general, contain only references to the sources of information. The data is compiled by many different producers and ranges widely in terms of applications. The information available can be broadly categorised as:
H. Abd El‐Wahab, F. Abd El‐Hai, M. Abd El‐Fattah and L. Lin
Demands for coatings with superior technical characteristics have induced the use of composite coatings, which usually represent an extremely strong product. The resin blend…
Abstract
Purpose
Demands for coatings with superior technical characteristics have induced the use of composite coatings, which usually represent an extremely strong product. The resin blend technique is a simple and useful method for improving paint properties. Coal tar resins are the most economical coating extensively used in the industry; short oil‐length alkyd resins are usually used for air and force‐dry industrial coatings for metal surfaces. The purpose of this paper is to evaluate coating blends composed of these resins, in particular, the effects of short oil‐length alkyd additive on the properties of coal tar binder.
Design/methodology/approach
One way to achieve new types of binders is to make combinations of the existing ones, in an ideal case retaining the desirable properties of both. The alkyd has important properties over the original drying oil. To achieve the goal of improving coal tar resin properties, short oil‐length alkyd was blended with it. The prepared short oil‐length alkyd was characterised using IR and 1HNMR spectroscopy. The mixing ratio of short oil‐length alkyd with coal tar was up to 25 per cent. The compatibility of coating blend was characterised by scanning electron microscope. The physical, mechanical and chemical properties of the coating blend in addition to the corrosion resistance were determined according to ASTM methods.
Findings
In spite of a large number of synthetic resins being available for use in paint formulations, the alkyd resins surpassed all of them in versatility and low cost. The blend of short oil‐length alkyd resin with coal tar has yielded better coating blend properties. The coating blend showed significant enhancement of physical, mechanical and chemical properties such as gloss, drying time, adhesion, scratch hardness, acid and solvent resistance because the coating blend combines the properties of thermosetting and thermoplastic resins.
Research limitations/implications
Alkyd resins are the most extensively used synthetic polymers in the coating industry. Modification of coal tar blend based on other type of polyester resins could also be studied in order to assess the applicability of the coal tar blend system found for other applications.
Practical implications
These types of alkyd resins can be applied in other bitumen composites as additives and reinforce agent.
Originality/value
The paper shows how the low‐cost modified coal tar binder can be used for air and force‐dry industrial coatings for metal surfaces.
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The purpose of this paper is to synthesize MeO‐type pigments, focusing on the oxides containing zinc and magnesium.
Abstract
Purpose
The purpose of this paper is to synthesize MeO‐type pigments, focusing on the oxides containing zinc and magnesium.
Design/methodology/approach
Oxides ZnO and MgO were synthesized, their morphology was evaluated, and their impact on the physical properties of the paint film were assessed. A pigment of ZnO/core‐shell type also was synthesized. The physical‐chemical property of the synthesized pigments and the anticorrosion efficiencies of the paint films pigmented by them were determined. The binder used in the researched coatings was epoxy‐ester resin.
Findings
The shape of the particles was identified in the synthesized pigments. X‐ray diffraction analysis revealed the degree of precipitation and lattice parameters. All of the synthesized pigments had good anticorrosion efficiency in an epoxyester coating.
Practical implications
The synthesized pigments can be used conveniently in coatings protecting metal substrates against corrosion.
Originality/value
Of benefit is the fact that the synthesized pigments do not contain any environmentally harmful substances.
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The present study focused on examining the effect of treated wastewater (TWW) on soil chemical properties. Also, efforts were made to compare the soil chemical properties under…
Abstract
Purpose
The present study focused on examining the effect of treated wastewater (TWW) on soil chemical properties. Also, efforts were made to compare the soil chemical properties under TWW irrigation with that under groundwater (GW).
Design/methodology/approach
During the years 2021 and 2022, surface and subsurface soil samples were randomly collected in triplicate by using an auger fortnightly at two depths (20 and 40 cm) from the selected spot areas to represent the different types of irrigation water sources: TWW and GW. Samples of the GW and the TWW were collected for analysis.
Findings
This study examines the impact of TWW on soil characteristics and the surrounding environment. TWW use enhances soil organic matter, nutrient availability and salt redistribution, while reducing calcium carbonate accumulation in the topsoil. However, it negatively affects soil pH, electrical conductivity and sodium adsorption ratio, although remaining within acceptable limits. Generally, irrigating with TWW improves most soil chemical properties compared to GW.
Originality/value
In general, almost all of the soil’s chemical properties were improved by irrigating with TWW rather than GW. Following that, wastewater is used to irrigate the soil. Additionally, the application of gypsum to control the K/Na and Ca/Na ratios should be considered under long-term TWW and GW usage in this study area in order to control the salt accumulation as well as prevent soil conversion to saline-sodic soil in the future. However, more research is needed to thoroughly investigate the long-term effects of using TWW on soil properties as well as heavy metal accumulation in soil.
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Prakash Mahanwar, Abhijit Sathyanarayana, Vaishali Bambole and Sunil Sabharwal
– The paper aims to discuss the evaluation of anti-corrosive efficiency of conducting polymer, polypyrrole in water borne epoxy-polyamine coatings.
Abstract
Purpose
The paper aims to discuss the evaluation of anti-corrosive efficiency of conducting polymer, polypyrrole in water borne epoxy-polyamine coatings.
Design/methodology/approach
Polypyrrole (PPy) is synthesised by chemical oxidative polymerisation. The synthesised PPy is characterised by employing FT-IR, XRD, SEM and EDX analysis. The coatings are formulated using water borne epoxy cross-linked with aliphatic polyamine adduct and the effect of PPy on corrosion prevention is studied. PPy was used as anti-corrosive pigment in concentration varying from 1 to 5 wt.%. In addition to anti-corrosive property; mechanical properties, chemical resistance and weathering properties of the coatings containing PPy are studied, thereby obtaining a wholesome data about the quality and performance of these coatings.
Findings
The result obtained through various tests showed that the coating with 1 and 2% PPy exhibited excellent weathering resistance, mechanical properties and improved chemical resistance. Higher percentage loading of PPy (beyond 3 per cent) proves to be disastrous, as extended percolation networks are formed which results in rapid intense corrosion leading to fast coating breakdown.
Research limitations/implications
The anti-corrosion property of the coating can be tested by means of atmospheric exposure such as Florida test which produces a real time evaluation of the anti-corrosive nature of the coating at natural condition rather than accelerated weathering, thereby providing more reliable performance data for intended application purpose.
Practical implications
The results find application in anti-corrosive/performance paints for industrial application.
Originality/value
This research paper presents the results of anti-corrosion behaviour of PPy in water borne epoxy-polyamide coating. Based on this result, a highly effective anti-corrosive coating can be formulated by the addition of small percentage of PPy in combination with other conventional pigments, thereby enhancing corrosion protection. But care must be taken so as to avoid formation of extended percolation network of PPy which leads to rapid coating breakdown.
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S. Awasthi and D. Agarwal
The purpose of this paper is to describe how to synthesise polyurethane resins by using different polyester polyols and HDI isocyanurate. The polyester polyols were prepared by…
Abstract
Purpose
The purpose of this paper is to describe how to synthesise polyurethane resins by using different polyester polyols and HDI isocyanurate. The polyester polyols were prepared by reacting single diol with different diacids. The effects of these polyester polyols on the performance properties of the coating films are studied.
Design/methodology/approach
A series of hydroxyl‐terminated polyester polyols were synthesised by using 1,4‐cyclohexanedimethanol (1,4‐CHDM) with different diacids such as 1,3‐cyclohexanedicarboxylic acid (1,3‐CHDA), 1,4‐CHDA, adipic acid (AA), azelaic acid (AZA), and isophthalic acid (IPA). The general properties including acid number, hydroxyl number average molecular weight, polydispersity index, and viscosity of these polyester polyols were evaluated. Different coating formulations were developed by using polyester polyols and HDI isocyanurate. These coatings were applied on sand blasted mild steel panels and glass panels and were cured in hot air oven. Various mechanical, thermal and chemical resistance properties of the coating films were evaluated.
Findings
The paper shows that, the polyurethane coatings have good resistance to water and other chemicals and can be used safely in exterior applications. In polyester polyols for polyurethane coating, CHDA showed a good balance in mechanical properties, which may be attributed to its unique cycloaliphatic structure and 1,4‐substitution. The polyester polyol based on aromatic diacids provided polyurethane coatings with maximum hardness and high Tg.
Research limitations/implications
The polyurethane resins were prepared from polyester polyol (made up of cyclohexanedimethanol (CHDM) and CHDA, IPA, AA, and AZA). Besides, this, it can be synthesised from some other polyester polyols (having different acids and alcohols) or polyether polyols. In addition to this, some other isocyanates such as TDI, MDI, HMDI, etc. can also be used.
Practical implications
The paper has provided a better solution for developing high solid polyurethane coatings for exterior applications due to presence of cycloaliphatic compounds.
Originality/value
In this paper, cyclohexyl dibasic acids have been used as the replacement for the aromatic dibasic acids. In aromatic dibasic acids, the phenyl ring readily absorbs UV‐light limiting the photo‐oxidative stability of the polyesters. So, these studies will help to develop high‐solid polyurethane coatings which could find numerous industrial applications in surface coatings.
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The purpose of this paper is to develop eco‐friendly coatings based on low‐cost epoxide resins prepared by using a natural phenolic material such as cardanol (non‐toxic), in place…
Abstract
Purpose
The purpose of this paper is to develop eco‐friendly coatings based on low‐cost epoxide resins prepared by using a natural phenolic material such as cardanol (non‐toxic), in place of ordinary phenol (toxic), which can be self‐curable at an optimum temperature.
Design/methodology/approach
Cardanol‐formaldehyde novolac resins (CNs) were prepared by reacting cardanol with formaldehyde in different molar ratios varying from 1:0.6 to 1:0.9. Prepared CNs were epoxidised by reacting with epichlorohydrin to produce epoxide resins, which would be called as epoxidised CNs (ECNs). Further, ECNs were modified by reacting with diethanolamine (DEtOA), a secondary amine to introduce tertiary amino group(s) into the molecules, required for self‐curability of ECNs. These modified ECNs are referred to as MECNs. The molar ratio of ECNs to DEtOA was taken in accordance with epoxy functionality of epoxide resins (ECNs) which ranged from 0.5 to 2.9. Nine numbers of MECNs (MECN1 to MECN9) were prepared by using four epoxide resins. These resins viz. CNs, ECNs and MECNs were characterized by 1H NMR and FTIR spectroscopic methods for their structure elucidatation, and by gel permeation chromatography for determining their molecular weights.
Findings
The most suitable molar ratio of ECN:DEtOA for the preparation of MECNs was found to be 1:1. The CN prepared by using cardanol and formaldehyde in the molar ratio of 1:0.7 was used for the preparation of ECN2 and MECN2. Applied films of epoxide resins, designated as MECN2, had reasonably good physical and chemical resistance properties. With a wide cure window, the films of MECN2 were found to be self‐curable at an optimum cure schedule of 160°C/30 min. Owing to self‐curability of the developed epoxide resins, the coatings based on them did not require any additional/external crosslinker to be incorporated in the coating composition.
Research limitations/implications
The prepared epoxide resins (MECNs) had good physical and chemical resistance properties, but demonstrated low stability and low resistance to xylene, in particular.
Originality/value
The paper shows how the epoxide resins were prepared by using a low‐cost phenolic material (cardanol) which is obtained from natural renewable resources, instead of petroleum, and is non‐toxic. These developed coatings can be applied as primer coat and top coat on metallic substrates. True self‐curability of the coating films has been achieved via anionic polymerization.
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Kristina Voigt and Gerhard Welzl
Scientific information is more and more buried in the proliferation of commercial sites on the Internet. This means that valuable chemistry sites and chemical databases are…
Abstract
Scientific information is more and more buried in the proliferation of commercial sites on the Internet. This means that valuable chemistry sites and chemical databases are difficult to find. In this paper some databases selected by the authors are introduced. These sites can be divided into three groups: databases which used to be only available through commercial hosts; databases which are available commercially but parts of them on the free Internet; and databases of topical concern, e.g. chemical weapons. All the mentioned databases can be found in a structured format in the DAIN Metadatabase of Internet Resources for Environmental Chemicals, which is explained in this paper. An important further step to get out of the information labyrinth is the evaluation of the content of data‐sources for chemicals. Approaches have been made to analyze chemical databases applying discrete mathematical methods and multivariate statistics.
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Aarti P. More and Shashank T. Mhaske
The study aims to synthesise polyurethane dispersion from polyesteramide polyol. The polyesteramide polyol is a novel polyol for the synthesis of polyurethane dispersion.
Abstract
Purpose
The study aims to synthesise polyurethane dispersion from polyesteramide polyol. The polyesteramide polyol is a novel polyol for the synthesis of polyurethane dispersion.
Design/methodology/approach
Polyesteramide polyol has been synthesised from phthalic anhydride and fatty amide of mustard oil. Aminolysis of mustard oil had been carried out with diethanolamine. The novel polyurethane dispersion had been synthesised using a polyesteramide polyol as a precursor. Isophorone diisocyanate was used as an isocyanate component and polyurethane dispersion (PUDs) had been synthesised by an anionic method where DMPA was introduced to introduce –COOH groups as via grafting to the resin backbone. Triethylamine was used for neutralisation and, hence, for further dispersion in water. Hydroxyl ethyl methacrylate was used for the synthesis to introduce unsaturation in the backbone of PUDs. The coating was made by an UV curing process. The coating was characterised for mechanical properties, chemical properties, thermal properties as well as stain resistance.
Findings
The polyurethane dispersion formed through it has ester and amide linkage present in it. The acetone process is used for its synthesis. The nuclear magnetic resonance spectroscopy confirms the successful formation of polyesteramide polyol and PUDs. Even though long aliphatic chains present in polyol which may impart hydrophobicity the synthesis PUDs well dispersed in water. It is observed as the coating made from it have hardness and scratch resistance properties. The coating also exhibits good stain resistance properties.
Practical implications
The method is an easy one to synthesise polyurethane dispersion from polyesteramide polyol, which is based on ester and amide linkage.
Originality/value
To the best of the authors’ knowledge, this is the first report on synthesised polyurethane dispersion from polyesteramide polyol. The polyesteramide resin already proves its excellence and upcoming technology in the coating industry. Here, they are incorporated into the synthesis of polyurethane dispersion.
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Chemical databases have had a significant impact on the way scientists search for and use information. The purpose of this paper is to spark informed discussion and fuel debate on…
Abstract
Purpose
Chemical databases have had a significant impact on the way scientists search for and use information. The purpose of this paper is to spark informed discussion and fuel debate on the issue of citations to chemical databases.
Design/methodology/approach
A citation analysis to four major chemical databases was undertaken to examine resource coverage and impact in the scientific literature. Two commercial databases (SciFinder and Reaxys) and two public databases (PubChem and ChemSpider) were analyzed using the “Cited Reference Search” in the Science Citation Index Expanded from the Web of Science (WoS) database. Citations to these databases between 2000 and 2016 (inclusive) were evaluated by document types and publication growth curves. A review of the distribution trends of chemical databases in peer-reviewed articles was conducted through a citation count analysis by country, organization, journal and WoS category.
Findings
In total, 862 scholarly articles containing a citation to one or more of the four databases were identified as only steadily increasing since 2000. The study determined that authors at academic institutions worldwide reference chemical databases in high-impact journals from notable publishers and mainly in the field of chemistry.
Originality/value
The research is a first attempt to evaluate the practice of citation to major chemical databases in the scientific literature. This paper proposes that citing chemical databases gives merit and recognition to the resources as well as credibility and validity to the scholarly communication process and also further discusses recommendations for citing and referencing databases.
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