Fahmina Zafar

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.

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.

Alumina‐Incorporated Polyesteramide from Non‐Edible Seed Oils

To improve the physico‐mechanical and chemical resistance properties, lower the curing temperature of annona squamosa and pongamia glabra seeds oils based polyesteramides [ASPEA, PGPEA], as well as to convert the non‐edible seed oils into value added products, their respective alumina‐incorporated polyesteramides resins [Al‐ASPEA, Al‐PGPEA] have been synthesized. The resins and their coatings have been tested for their chemical, physico mechanical and chemical/corrosion resistance properties. These properties were compared among the prepared resins and with that of previously reported alumina filled linseed polyesteramide [Al‐LPEA]. It was observed that Al‐PGPEA‐71, which has the highest amount of oleic acid chains, shows the best physico‐mechanical and chemical resistance properties.

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.

Catalytic degradation of methylene blue by biosynthesised copper nanoflowers using F. benghalensis leaf extract

This study reports the unprecedented, novel and eco-friendly method for the synthesis of three-dimensional (3D) copper nanostructure having flower like morphology using leaf extract of Ficus benghalensis. The catalytic activity of copper nanoflowers (CuNFs) was investigated against methylene blue (MB) used as a modal dye pollutant. Scanning electron micrograph evidently designated 3D appearance of nanoflowers within a size range from 250 nm to 2.5 μm. Energy-dispersive X-ray spectra showed the presence of copper elements in the nanoflowers. Fourier-transform infrared spectra clearly demonstrated the presence of biomolecules which is responsible for the synthesis of CuNFs. The catalytic activity of the synthesised CuNFs was monitored by ultraviolet-visible spectroscopy. The MB was degraded by 72% in 85 min on addition of CuNFs and the rate constant (k) was found to be 0.77 × 10-3 s-1. This method adapted for synthesis of CuNFs offers a valuable contribution in the area of nanomaterial synthesis and in water research by suggesting a sustainable and an alternative route for removal of toxic solvents and waste materials.

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.

Development of bio-derived nanostructured coordination polymers based on cardanol–formaldehyde polyurethanes with ‘d5’ Mn(II) and ‘d10’ Zn(II) metal nodes: synthesis, characterization and adsorption behavior

The synthesis of bio-based coordination polyurethanes (PUs) is an alternative route to conventional petro-based PUs for the green and sustainable development of coordination PUs. In the present study, we report the development of bio-based nanostructured coordination PUs with the aid of using cost effective, non-toxic, biodegradable and abundantly available renewable resource such as cardanol (Col) as a starting precursor and divalent transition metal ions Mn(II), ‘d5’ and Zn(II), ‘d10’ as metal centres for their potential use in the adsorption/removal of environmental pollutants, such as Congo red (CR) dye, in industrial waste water treatment. The composition and geometry of coordination PUs were confirmed by spectral techniques (FTIR and UV-visible), elemental analysis and magnetic moment. The curing behavior was investigated using ATR-FTIR technique. Thermal techniques (TGA/DTG/DTA and DSC) indicated their good thermal stability. Morphology (XRD, SEM-EDX, and HR-TEM) techniques indicated their amorphous/semi-crystalline and layered nanostructured and nanoporous patterns. The preliminary adsorption properties towards CR dye of the synthesized coordinated PUs was also investigated by a batch adsorption technique and it was found that the synthesized nanostructured and nanoporous coordination PU could be used as an effective dye adsorbent.

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.