Eram Sharmin

Studies on ambient cured polyurethane modified epoxy coatings synthesized from a sustainable resource

Abstract Polyurethane resins are a class of thermosetting polymers largely used in high performance surface coatings and paints. Fast depletion of petroleum stock and increase in their cost puts limit to their use in future for production of petroleum-based resins. Consequently the need for utilization of renewable resources as substitute to petrochemical is pressing. We have attempted to synthesize polyurethane (PU) from linseed oil epoxy and have developed from it an anticorrosive coating. Trans hydroxylation of linseed oil epoxy was carried out in situ after a reported method. It was further reacted with toluylene diisocyanate to synthesize polyurethane. Physico-chemical characterization of the synthesized resin was carried out as per standard methods. Structural elucidation was carried out using IR, NMR spectral data. Physico-mechanical and weather resistance performance of the coated samples were also studied. It was found that the synthesized resin showed good performance in various corrosion tests. These studies show that the material holds promise for use as an effective anticorrosive coating compound.

Ambient Cured Tartaric Acid Modified Oil Fatty Amide Anticorrosive Coatings

A novel tartaric acid modified fatty amide diol (TAFA) was synthesized through the condensation polymerization of N,N‐bis(2‐hydroxy ethyl) linseed oil fatty amide and tartaric acid (TA).The structural elucidation of the TAFA resin was carried out by FT‐IR,1H‐NMR, and 13C‐NMR spectroscopic techniques. The physico‐mechanical and physico‐chemical characterization of the resin were done by standard methods. TAFA, when further reacted with butylated melamine formaldehyde (BMF) in different phr (part per hundred part of resin) (TAFA‐BMF) was found to cure at room temperature. The TAFA‐BMF cured system was subjected to spectroscopic analysis to ascertain the structure and curing scheme of the same. The thermal studies of these resins were carried out by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The physico‐mechanical properties and anticorrosive performance of TAFA‐BMF coatings were evaluated by standard methods. The effect of TA and BMF on thermal stability, physico‐mechanical and anticorrosive properties of resins was also investigated.

Polyurethane: An Introduction

The discovery of polyurethane [PU] dates back to the year 1937 by Otto Bayer and his coworkers at the laboratories of I.G. Farben in Leverkusen, Germany. The initial works focussed on PU products obtained from aliphatic diisocyanate and diamine forming polyurea, till the interesting properties of PU obtained from an aliphatic diisocyanate and glycol, were realized. Polyisocyanates became commercially available in the year 1952, soon after the commercial scale production of PU was witnessed (after World War II) from toluene diisocyanate (TDI) and polyester polyols. In the years that followed (1952-1954), different polyester-polyisocyanate systems were developed by Bayer.

Linseed oil polyol/ZnO bionanocomposite towards mechanically robust, thermally stable, hydrophobic coatings: a novel synergistic approach utilising a sustainable resource

Linseed oil polyol/ZnO bionanocomposite was prepared to obtain mechanically robust, thermally stable, hydrophobic coatings via a novel synergistic approach utilising a vegetable oil polyol for the first time. The synthesis process obviates the use of reducing agents, surfactants, reaction media, stabilizing agents, solvents, and other chemicals. Linseed polyol serves the purpose of obtaining ZnO nanoparticles. The linseed polyol backbone hosts hydroxyl and carboxylic groups that participate in the generation of ZnO nanoparticles in the polyol matrix (ester elimination, addition–elimination reaction). The progress of the reaction was monitored by recording FTIR spectra at regular intervals of time. The coatings obtained were scratch-resistant, impact-resistant, well-adherent, flexibility-retentive and hydrophobic, showing good chemical resistance under acidic, alkaline, and salt environments. Thermogravimetric analysis revealed that these coatings could be safely used up to 250 °C. The work described is consistent with the principles of “Green Chemistry” (Principles 1, 2, 3, 4, 5, 6, 7, 8, and 12), such as utilising a renewable feedstock, resorting to a solventless approach, and employing safer chemistry. The results showed that these coatings may be well employed as promising candidates towards environmentally friendly corrosion protective coatings.

Nanostructured coordination complexes/polymers derived from cardanol: “one-pot, two-step” solventless synthesis and characterization

Growing interests in the development of advanced functional materials from renewable resources due to the depleting petroleum resources, increasing costs, and associated hazards reflect global requirement for increased sustainability. Cardanol [Col] is an agro by-product of the cashew nut industry. It is cost effective, nontoxic, biodegradable and an abundantly available renewable resource. In the present study, we report the development of nanostructured coordination polymer [CP] self-standing transparent films from Col (as an organic linker or bridging-ligand) and Mn(II) ‘d5’ and Co(II) ‘d7’ divalent metal ions (as metal nodes) by a solid-state in situ method. The resulting CP films showed nanoporous morphology, amorphous behaviour, good thermal stability up to 260–300 °C, moderate antibacterial activity against Staphylococcus aureus (MTCC 902), Escherichia coli (ATCC 25922) and Pseudomonas aeruginosa (MTCC 2453) and also good anti-biofilm activity.

One Pot Preparation of Greener Nanohybrid from Plant Oil

Plants have been the prime resource of food, clothing, medicine and other basic needs of humans since primeval times. Today, much beyond this, the advancements in the knowledge of chemistry, development of sophisticated analytical instruments and techniques as well as the advent of nanotechnology have augmented their use manifolds as biofactories of nature. Plant oils serve as raw materials for polymers, nanohybrids and composites therefrom, for versatile advanced applications. On similar lines, the study presents preliminary account of “one-pot-preparation”, characterization and antibacterial behavior of microwave processed plant oil based nanohybrid.

Vegetable Seed Oil Based Waterborne Polyesteramide: A “Green” Material

In present work we have taken an attempt to develop vegetable seed oil [VSO] based microwave assisted (green route) waterborne polyesteramide (zero toxicity), a green material. VSO based waterborne polyesteramide [WBPEA] was synthesized by simple route through microwave irradiation within 4–5 min by amidation and condensation of oil. The structure of the material was confirmed with the spectral techniques. The thermal degradation analysis of WBPEA by TGA showed that the polymer was stable up to 220°C, suitable for use as degradable “green polymeric material” for a variety of applications.

Seed Oil Based Polyurethanes: An Insight

Seed oils [SO] are cost‐effective, eco‐friendly and biodegradable in nature. They bear functional groups such as carboxyls, esters, double bonds, active methylenes, hydroxyls, oxirane rings and others, amenable to several derivatization reactions. Their abundant availability, non‐toxicity and rich chemistry has established SO as focal point of polymer production, e.g., production of polyesters, alkyds, epoxies, polyols, polyethers, polyesteramides, polyurethanes and others. The escalating prices of petro‐based chemicals, environmental and health concerns have further beckoned the enhanced utilization of SO as polymer precursors. SO have attracted enormous attention as potential source of platform chemicals, at both laboratory and industrial scale. Today, oil-seed bearing crop plants are being raised and modified for uses in areas covering biodiesel, lubricants, folk medicines, cosmetics, plastics, coatings and paints.

Renewable Resources in Corrosion Resistance

Corrosion of metals or alloys occurs due to chemical or electrochemical reactions with their environment, which often results in drastic deterioration in the properties of metals or materials comprising thereof. Corrosion takes place on a steel surface, due to the development of anodic and cathodic areas, through oxidation and reduction reactions, forming of oxides of metals alloys. There are several corrosion causing agents or “corrodents” such as soot, sulphate salts, chloride ions, temperature, salinity, pH, dissolved gases, humidity, bacteria, sand, gravels, stones, mechanical stresses and also several protection methods employed for corrosion resistance such as the application of alloys, composites, inhibitors, cathodic and anodic protection, protective linings and coatings (Bierwagen, 1996; Ghali et al., 2007; Raja& Sethuraman, 2008; Sorensen et al.,2009). Notwithstanding, corrosion has become a gigantic problem today for every nation. The colossal detrimental impact of corrosion on the economy of a country can be manifested in billions of dollars spent annually to combat or control it.

Recent Advances in Environment-Friendly Alkyd Nanocomposites Towards “Greener” Coatings

Alkyd nanocomposites have attracted great attention in the field of heavy duty coating materials. This is due to the synergistic action of both alkyds (flexibility, biodegradabili‐ ty, compatibility, good gloss retention, durability, weathering resistance) and nanofil‐ lers (large surface area to volume ratio). Alkyd nanocomposites show good physicomechanical, physico-chemical, anticorrosive, and antimicrobial performances and thermal stability, with application as anticorrosive, anti-fog, self-cleaning, self-healing, and antimicrobial coatings. In view of present drives and legislations towards environ‐ ment-friendly coatings, alkyds have undergone modifications as waterborne, high solids, hyperbranched “greener” nanocomposites. The present chapter deals with a brief overview of alkyds, recent advances in environment-friendly alkyd nanocomposite coatings, and the effects of nanofillers on the performance (physico-mechanical, chemical/ corrosion resistance, thermal stability, and others) of “greener” alkyd nanocomposite coatings.