Price variations, limited availability, non-biodegradability and environmental importance have led to an increased demand for renewable alternatives to petroleum-based counterparts. In line with the requirements, the present study focused on the preparation of mahua-oil-derived polyols for the formulation of nanocomposite polyurethane (PU) coatings. The polyol was characterized using H-1 NMR and FTIR spectroscopy, gel permeation chromatography and end group analysis. Silver-doped hydroxyapatite nanoparticles (Ag-HAPs) were also synthesized from waste chicken eggshell as another renewable alternative. These nanoparticles were incorporated into the PU matrix in varying amounts (0.4-3.2 wt%) to improve the performance of the PU coatings. The surface morphology of Ag-HAPs and their PU composites was studied by optical microscopy and SEM. The resulting nanocomposite PU coatings showed enhanced mechanical and protective properties such as pencil hardness, flexibility, adhesion, chemical resistance and corrosion protection compared with pristine PU coatings. In addition, the incorporation of Ag-HAPs increased the hydrophobicity of the composite film evidenced by higher contact angles. X-ray Diffraction (XRD) and TGA confirmed the amorphous nature of the PU matrix and that it exhibited better thermal stability with increasing nanoparticle content. Overall, the developed nanocomposite coatings offer a promising sustainable substitute to petroleum origin materials and demonstrate excellent thermal stability and anticorrosion performance.

ABSTRACT The present study demonstrated the development of polyurethane (PU) nanocomposite coatings incorporating biobased cardanol‐modified alkyd polyol and MoS 2 nanoparticles. Initially, biobased cardanol diol was synthesized by ring‐opening of cardanol monoglycidyl ether. Thereafter, alkyd resin was produced from prepared cardanol diol by solution condensation polymerization. ATR‐FTIR and 1 H NMR spectroscopies were used for the polyol structure confirmation. Then, the polyol was converted to PU coatings by reacting it with isophorone diisocyanate (IPDI) and modified using a loading of changing percentages (0.5%, 1%, 2%, and 4%) of MoS 2 nanoparticles. The corrosion performance of the resulting coatings was studied using immersion and electrochemical methods. The results showed that increasing the concentration of MoS 2 nanoparticles enhanced the corrosion resistance of PU nanocomposite coatings. The uniform distribution of MoS 2 nanoparticles was observed in the coatings, as evidenced by optical microscopy and scanning electron microscopy (SEM). Thermal stability was investigated by thermogravimetric analyzer (TGA), which showed increased stability with increasing nanoparticle loading percentage. The nanocomposite coatings exhibited better adhesion, flexibility, hydrophobicity, and chemical resistance than the PU coating in the absence of nanoparticles and the uncoated sample (mild steel panel). The amorphous and hydrophobic natures of coatings were observed by X‐ray diffraction (XRD) and contact angle estimation, respectively.

Bio-based materials have emerged as an environment friendly alternative to petrochemical based materials due to their sustainability, lower carbon footprint, and cost effectiveness. In UV-curable coatings, reactive diluents are used as a substitute for conventional organic solvents, which are otherwise contributing to volatile organic contents (VOCs) in controlling viscosity suitable for application of UV cured coatings. In this study, bio-based polyester-based polyurethane acrylate (PUA) was synthesized from castor oil glycidyl ether (COGE) via threestep process. First, acrylate polyester polyol (APEP) was synthesized by ring opening reaction of COGE with acrylic acid. Second, NCO-terminated polyurethane prepolymer was prepared by reacting 2-hydroxyethyl methacrylate (HEMA) with isophorone diisocyanate (IPDI). Finally, the prepolymer was reacted with APEP to form the final PUA oligomer. The structural features of synthesized intermediate and products were confirmed by 1H NMR spectroscopy, ATR-FTIR, and end group analysis. A series of solventless UV-cured coatings was prepared by incorporating different percentages (10-20 %) of reactive diluents-trimethylolpropane triacrylate (TMPTA) and 1, 4-butanediol diacrylate (BDDA) into the PUA oligomer under UV light. The resulting cured coatings were evaluated for their physicochemical properties. The decrease in viscosity of coating has been observed after addition of reactive diluent. The anticorrosion properties of coatings were assessed by immersion and electrochemical methods in a 3.5 % NaCl solution. Coatings were also characterized by differential scanning calorimeter and thermogravimetric analysis to evaluate the glass transition temperature (Tg) and thermal stability. Contact angle measurements and X-ray diffraction were used to explore the hydrophobicity and crystallinity of cured films. The cured PUA coatings with reactive diluents demonstrated excellent physicochemical properties, thermal stability, swelling resistance, and anticorrosion performance. This work highlights the potential of bio-based UVcurable, solvent-free PUA system as sustainable alternatives for the development of bio-based coating using reactive diluent.

PurposeEffects of corrosion are very dire and mitigation of corrosion holds prime importance. Protective coatings play major role in preventing corrosion of metals and coating application is the most convenient, economical and quick solution. The purpose of the study is development of protective coatings to effectively mitigate corrosion of metal components.Design/methodology/approachA high-performance anticorrosion coating was prepared using multiple monomers and paste of functional and reinforcing fillers with extenders to protect metal components from corrosion in aggressive environmental conditions. The structures of copolymers synthesized with multiple monomers were studied by the NMR and FT-IR spectroscopic techniques. The percentage conversion of different proportions of various monomers was estimated using gas chromatography technique. The functional paste to impart superior anticorrosion properties was prepared using various functional and reinforcing fillers. The final coatings were prepared by mixing these resins with functional paste in various proportions.FindingsThe prepared anticorrosion coating was tested for high-performance mechanical and chemical properties and it was witnessed that the said coating offered desired performance properties needed for protecting metal components from corrosion.Research limitations/implicationsAs such it is overcoming drawbacks of two pack systems and thus has almost no limitations or implications for application on metal substrate.Practical implicationsBeing formulated as a single pack, it is free from drawbacks otherwise involved in two pack system of conventional paints. The coating system developed is very easy to apply using conventional tools, namely, brush, spray and roller techniques. The formulation is made in such a way that it has fast-drying properties. Makes painting or coating operations cost effective and confirm the performance.Social implicationsThe findings of the research have anticorrosion nature that can enhance the life span of the substrates. It is specially designed for metal substrate and can protect metal substrate from corrosion in most aggressive conditions. Thus, it helps to reduce losses due corrosion and increase safety of metal structures and human being as well. As it is based on conventional material but with new formulation and technology, it has commercial possibilities to explore.Originality/valueUnlike conventional protective coating systems, the said coating offered disruptive features like single pack systems and fast drying at ambient temperature along with high-performance properties. The coating formulation was observed to have a great importance in industry for effective corrosion mitigation and to reduce losses due to corrosion.

A series of biobased alkyd resins having hydroxyl functionalities was synthesized using Madhuca indica (mahua) seed oil as a renewable source on reaction with various diacids and anhydrides. Functional group transformation and alkyd formation were confirmed by ATR-FT-IR and proton NMR spectroscopies as well as by end group analysis. Polyols containing hydroxyl functionalities were utilized in combination with polymeric methylene diphenyl diisocyanate (PMDI) to produce polyurethane (PU) in the form of coatings, which were examined for their gloss, impact, flexibility, cross-cut adhesion, etc. Anticorrosion property of coatings was investigated by immersion method and by electrochemical method in an aqueous salt solution. Additionally, coatings were subjected to their thermal behavior study using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). While crystalline and amorphous behaviors of PUs were studied by X-ray diffraction (XRD). The mahua oil-based PUs revealed excellent coating properties, thermal stability, and anticorrosion performance. Thus, untapped mahua oil can act as a good source of replacement for petroleum in the preparation PU coatings.

The present investigation demonstrates renewable cardanol-based polyol for the formulation of nanocomposite polyurethane (PU) coatings. The functional and structural features of cardanol polyol and nanoparticles were studied using FT-IR and 1H NMR spectroscopic techniques. The magnetic hydroxyapatite nanoparticles (MHAPs) were dispersed 1–5% in PU formulations to develop nanocomposite anticorrosive coatings. An increase in the strength of MHAP increased the anticorrosive performance as examined by immersion and electrochemical methods. The nanocomposite PU coatings showed good coating properties, viz., gloss, pencil hardness, flexibility, cross-cut adhesion, and chemical resistance. Additionally, the coatings were also studied for surface morphology, wetting, and thermal properties by scanning electron microscope (SEM), contact angle, and thermogravimetric analysis (TGA), respectively. The hydrophobic nature of PU coatings increased by the addition of MHAP, and an optimum result (105°) was observed in 3% loading. The developed coatings revealed its hydrophobic nature with excellent anticorrosive performance.

The development of eco-friendly materials is a major challenge tackled by preparing polymers of renewable origin as an alternative to the petroleum sources and by reducing repairing cost via formulating self-healing materials. In this study, cardanol and eugenol are used as renewable-phenols for the formulation of microcapsule based self-healing anticorrosive coatings. Cardanol was used to prepare microcapsules through an oil-inwater (O/W) emulsion system, whereas eugenol was utilized for the synthesis of polyester polyol by solventless melt condensation polymerization. The structure of polyol was confirmed by FTIR and NMR spectroscopies, while formation and surface morphology of microcapsules was confirmed by the FE-SEM. The thermal stability of microcapsules stood up to 232 degrees C as tested by TGA. The prepared microcapsules were dispersed in polyol formulations and crosslinked with methylene diphenyl diisocyanate to obtain self-healing smart PU coatings. The self-healing property of the prepared coatings was observed under FE-SEM. The developed coatings showed good physico-chemical properties such as gloss, crosscut adhesion, flexibility, pencil hardness, and MEK rub test. The corrosion resistance of the formulated self-healing coatings was found to be increased with increase in the quantity of microcapsules as studied by immersion and electrochemical methods.

In this study, a new strategy for novel chitosan-based ion-imprinted polymer (IIP) preparation was adopted for selective separation and recovery of Zn(II) ions from aqueous environmental samples using batch extraction experiments. The Zn(II) ion-imprinted polymer was prepared by precipitation copolymerisation of methacrylamide and 2,2- azobisisobutyronitrile along with Zn(II) ions and toluene as a functional complexing monomer, initiator, template ion, and porogenic solvent, respectively, in the presence of chitosan. The ethylene glycol dimethacrylate and tetraethyl orthosilicate were used as cross-linking agents. The prepared Zn(II) ion-imprinted polymer was characterised by Fourier transform infrared spectroscopy, field emission scanning electron microscopy equipped with energy-dispersive X-ray spectroscopy, X-ray diffraction, thermogravimetric analysis, and inductively coupled plasma-optical emission spectroscopy to determine the structural and functional IIP variations before and after Zn(II) adsorption. Characterisation results suggested the formation of Zn(II) ion-imprinted polymer with excellent thermal stability and also have the potential for selective Zn(II) extraction. Further, the Zn(II) sorption using IIP sorbent was also evaluated as a function of pH, IIP sorbent dosages, Zn(II) ion concentration, sorption time, and IIP sorbent reusability. The Zn(II) sorption equilibrium was studied using various isotherm and kinetic models, and the result suggested that the Langmuir and pseudo-second-order model as the best to explain the sorption process. Sorption capacity was calculated using Langmuir isotherm linear equation and its value was found to be 3.06 mg/g. The method detection limit (MDL) and limit of quantification (LOQ) of sorbent were calculated as 0.1 and 0.3 mg/L, respectively. Finally, the developed sorbent Zn(II) IIP was found to be effective in the selective extraction of Zn(II) from the tap and river water samples.

Background Standardization of topical therapy dosage is important to ensure optimum use and dosage of topical medications. One of the concepts frequently used in the standardization of topical treatment is the Finger-tip unit (FTU). While practitioners, both dermatologists and pharmacists, are generally aware of FTU, practical use is less. Objectives We aimed to evaluate views and practices related to FTU among both dermatology and pharmacy faculty and to elicit and validate suggestions for improving standardization. Methods We surveyed a group of Dermatologists and Pharmacists-in two phases-in phase 1 (n = 44), an electronic survey was used as a tool to understand their practices regarding FTU, and to obtain suggestions regarding standardization of topical medication delivery. In phase 2 (n = 40), the main suggestions for improvement were resent to the group to rate and validate the same. Results The awareness of FTU was high among the experts, but practical use of the FTU for patient counselling was less frequent. The group gave suggestions to standardize applications. All these suggestions got high ratings on both feasibility and possible effectiveness in the second phase, with the highest rating being for the suggestion of "Placing QR codes on ointment/cream tubes which link to websites with educational materials/ videos on FTU/topical drug dosing." Conclusion Awareness regarding FTU is high among both dermatologists and pharmacists, however practical use is less. Strategies to improve standardization of topical drug dosing can be formulated through collaboration involving both dermatologists and pharmacists.

The manuscript represents epoxidation of linseed oil to be coated on urea granules for their control release. Linseed oil was epoxidized in the presence of acetic acid and hydrogen peroxide. Structural transformation of unsaturated oil to epoxy group was confirmed by FTIR and end group analysis. Thereafter, the epoxidized linseed oil (ELO) was coated on the surface of urea granules and crosslinked subsequently using triethylenetetramine (TETA) a renewable substrate. Coated urea as an essential release component was first characterized for coating using optical microscope and SEM images. The control release behaviour of the prepared coated urea fertilizer was studied using dissolution and release urea from the crosslinked structure. The results demonstrated fast dissolution of pristine urea that is responsible for unwanted losses, toxicity, and harmfulness to environment, while coated with ELO and crosslinked with TETA required more time as necessary for slow and control release. The results demonstrated epoxidized oil as a green solution to coat urea granules for its control release.

Two types of crosslinked hydrogels viz. first based on copolymer of acrylic acid and acrylamide and grafting of both monomers on guar gum were prepared and characterized using FTIR, SEM, and TGA for their structural, morphological, and thermal behaviors. Release mechanism of ZnSO4.H2O from both hydrogels was studied using ICP-OES in aqueous solutions of different pH and 0.9% NaCl salt solutions, which fit with Korsmeyer-Peppas and Peppas-Sahlin kinetic models. Swelling, release, and degradations were found to be improved for guar gum based hydrogels over hydrogels obtained from monomers of petroleum origin and demonstrated possible applications in slow release of a micronutrient for agriculture sectors.

The manuscript represents synthesis of pH and salt responsive hydrogel based on guar gum as a renewable substrate for drug delivery of natural anticancer drug i.e. curcumin. Initially acrylic acid grafted guar gum (GG-g-PAA) hydrogel was obtained in the presence of ammonium persulphate as a redox initiator. Structural stability of grafted copolymer was improved using N, N-methylenebisacrylamide as a crosslinker with simultaneous loading of curcumin as a natural anticancer drug. Delivery rate of curcumin from GG-g-PAA was studied by UV spectrophotometer. The neat and drug loaded hydrogels were characterized using FTIR, NMR, TGA, and SEM techniques for their structural, morphological, and thermal behaviours. Swelling of the hydrogels and water diffusion properties were studied in salt and aqueous solutions of different pH. Finally, the fabricated hydrogel matrices were tested for curcumin release studies to understand the release kinetic. The results indicated that the prepared renewable source based hydrogel can be used in drug delivery of curcumin as a natural medicine. As curcumin and guar gum are products of agricultural food crops viz. turmeric and guar, the current research can be a good contribution towards preparation of an eco-friendly drug delivery system based on agriculture products.

This review describes the preparation of nonedible vegetable oil (NEVO)-based polyols and their application in anticorrosive and antimicrobial polyurethane (PU) coatings. PUs are a class of versatile polymers made up of polyols and isocyanates. Renewable vegetable oils are promising resources for the development of ecofriendly polyols and the corresponding PUs. Researchers are interested in NEVOs because they provide an alternative to critical global food issues. The cultivation of plant resources for NEVOs can also be popularized globally by utilizing marginal land or wastelands. Polyols can be prepared from NEVOs following different conversion routes, including esterification, etherification, amidation, ozonolysis, hydrogenation, hydroformylation, thio-ene, acrylation, and epoxidation. These polyols can be incorporated into the PU network for coating applications. Metal surface corrosion and microbial growth are severe problems that cause enormous economic losses annually. These problems can be overcome by NEVO-based PU coatings, incorporating functional ingredients such as corrosion inhibitors and antimicrobial agents. The preferred coatings have great potential in high performance, smart, and functional applications, including in biomedical fields, to cope with emerging threats such as COVID-19.

Nowadays self-healing coating technologies has reported rapid growth and provides stability to increase lifetime, reduce replacement cost, advance safety, and improves aesthetic value of products. The speedy growing research on self-healing of polymer products can be realized by enormous publications appeared in recent days in terms of patents, research papers, reviews, and books or book chapters. Most of the publications dealing with self-healing technologies are specialized and focused on specific topics such as capsule-based, stimuli–responsive polymeric materials, and supramolecular forces, while minimum attention has been pair on explaining A–Z of self-healing for organic coatings especially for newcomers, industry persons or manufacturers who wish to design or use self-healing coatings. Except intellectual documents, rests of others are having academic interest in designing and development of self-healing systems. Considering the need, this chapter has written for getting introduction, importance, and ways of self-healing to the interested one.

A series of bio-based polyester polyols with hydroxyl chain end was prepared using eugenol as a renewable source and various renewable diacids such as dimer, sebacic, succinic, and maleic acids. The functional group transformations and structure of monomer and polyols were analysed by the spectroscopic techniques. The hydroxyl functional polyester polyols were reacted with methylene diphenyl diisocyanate (MDI) to obtain polyurethane (PU) coatings. The prepared PUs were used as anticorrosive coatings and their performance was checked by dipping and electrochemical methods against 3.5 % sodium chloride (NaCl) solution. The developed coatings revealed excellent physico-mechanical properties such as transparency, gloss, flexibility, and cross-cut adhesion. Surface morphology and thermal stability of PU coatings were examined under scanning electron microscopy (SEM), atomic force microscopy (AFM), and thermogravimetric analysis, respectively.

Algae are a group of photosynthetic marine or freshwater plants that exhibit high CO2 capturing capacity. Algae have been among the most promising renewable resources for overcoming climate change issues. In this study, algae oil (AO) was chemically transformed to polyols through two-step reactions and incorporated into value-added and industrially important polyurethane (PU) coatings. First, AO was reacted with diethanolamine to afford fatty amide. Then, polyetheramide polyols (AEAs) were prepared by reacting the fatty amide with bisphenol-A, 1,4-butanediol, or isosorbide. PU coatings were prepared by reaction between the AEAs and diphenylmethane diisocyanate. The PUs exhibited typical semicrystalline and three-step degradation behaviors with enhanced gel content values, supporting the high reactivity of the AEAs as polyols. The hydrophobic characteristics of the fatty acid chains of the AEAs resulted in decreased water absorption of the PUs, which improved the antimicrobial characteristics of the PUs. In particular, the PU coatings exhibited excellent resistance against alkaline aqueous media and organic solvent (xylene) along with reasonable gloss, hardness, flexibility. In saline aqueous media, the PU coatings exhibited anticorrosion performance superior to that of typical poly(tetramethylene ether) glycol-based PU coating. This study demonstrates the high potential of the PUs as anticorrosion and antimicrobial materials from the environmentally friendly renewable resource.

Generally, the coating properties of polymeric compounds are enhanced by using nanomaterials as fillers which are non-biobased. In this project, the hydroxyapatite (HAP) was obtained from waste fish scales and the biobased hyperbranched polyol (HyBP) was synthesized from castor oil. The series of nanocomposites were prepared by adding various amounts of HAP (0.5% wt, 1% wt, and 2% wt) in HyBP along with isophorone diisocyanate (IPDI) (maintaining the NCO:OH, ratio at 1.2:1). These mixtures were coated on mild steel panels and glass plates. The synthesized HyBP was characterized by FTIR, 1HNMR, and 13CNMR techniques. The HAP was characterized by FTIR, FESEM, and XRD techniques. The surface morphology of prepared nanocomposites was studied by FESEM, XRD, and AFM techniques. The nanoparticle size was determined by TEM technique. The thermal behavior of nanocomposites was studied by TGA technique. The coating properties were determined by impact strength, crosscut adhesion, and flexibility test. The corrosion properties of the coatings were determined by the immersion test as well as electrochemical test.

In the present work, the bio-based hyperbranched polyol (COHBP) was prepared by using castor oil and dimethylol propionic acid (DMPA). The molecular structure of COHBP was determined by FTIR and NMR. Polyurethanes of castor oil (PU - COs) and castor oil based hyperbranched polyol (PU - COHBPs) were prepared by using various diisocyanate as cross-linking agent at NCO: OH, ratio of 1.2:1, in presence of dibutyltin dilaurate (DBTDL) as catalyst. Finally, these polyurethanes were coated on glass plate and mild steel panels. Thermal behavior of PU-COs and PU - COHBPs were studied by thermo-gravimetric analyzer (TGA). The mechanical properties of the coated panels were estimated by performing various tests such as cross-cut adhesion, scratch resistance, impact resistance, mar resistance, flexibility, and pencil hardness. Chemical resistance property of coating was evaluated by immersion method. The polyurethanes films were characterized by gel content. The corrosion rate of each coating plate was determined by electrochemical method. The surface morphology of coating films was studied by AFM and SEM, while their crystallinity was estimated by XRD analysis. The properties of PU - COHBPs were compared with PU - COs. It was found that PU - COHBPs showed excellent coating performance as compared to PU - COs.