Mechanically Strong, Hydrophobic, Antimicrobial, and Corrosion Protective Polyesteramide Nanocomposite Coatings from Leucaena leucocephala Oil: A Sustainable Resource.

The aim of this research work is to develop polyesteramide [LMPEA] nanocomposite coating material [LMPEA/Ag] using N,N-bis(2-hydroxyethyl) fatty amide obtained from non-edible Leucaena leucocephala [LL] seed oil [LLO], and maleic anhydride, reinforced with silver nanoparticles [SNPs], biosynthesized in Leucaena leucocephala leaf extract. UV, XRD, TEM, and particle size analyses confirmed the biosynthesis of NP (37.55 nm). FTIR and NMR established the structure of LMPEA formed by esterification reaction, without any solvent/diluent. Coatings were mechanically strong, well adherent to substrate, flexibility retentive, hydrophobic, and antimicrobial as evident from good scratch hardness (2-3 kg), impact resistance (150 lb per inch), bend test (1/8 inch), high water contact angle measurement value (109°) relative to pristine LMPEA coating (89°), and broad-spectrum antimicrobial behavior against MRSA, P. aeruginosa, E. coli, A. baumannii, and C. albicans. LMPEA and LMPEA/Ag exhibited high corrosion protection efficiencies, 99.81% and 99.94%, respectively, in (3.5% w/v) NaCl solution for 20 days and safe usage up to 200 °C. The synthesized nanocomposite coatings provide an alternate pathway for utilization of non-edible Leucaena leucocephala seed oil through a safer chemical synthesis route, without the use/generation of any harmful solvent/toxic products, adopting "Green Chemistry" principles.

Synthesis and characterization of polyvinyl alcohol/corn starch/linseed polyol-based hydrogel loaded with biosynthesized silver nanoparticles.

Nanocomposite hydrogel film was prepared from Polyvinyl alcohol [PVA], Corn Starch [CS], Linseed oil polyol [LP], and silver nanoparticles [NP]. LP was prepared by epoxidation and hydration of Linseed oil [LO]. IR and NMR supported the insertion of hydroxyl groups in LP by epoxide ring opening reaction at epoxidized LO. Silver NP were biosynthesized using aqueous leaves' extract from locally grown Ocimum forsskaolii Benth [LEO] plant. FTIR, XRD, UV and TEM confirmed the synthesis of NP (size 30 to 39 nm). Transparent and foldable hydrogel film resulted by blending the constituents (PVA, CS, LP and NP), crosslinking by glutaraldehyde, at room temperature, and showed expansion in water, different pH solutions, biodegradation and good antibacterial and antifungal activity against tested microbes. Linseed polyol influenced the structure, morphology, hydrophilicity, improved swelling ability and thermal stability and accelerated biodegradation of hydrogel films. NP were well adhered to LP globules that were embedded in PVA/CS matrix as strung set of beads (LP globules) decorated with black pearls (spherical NP). Silver NP conferred antimicrobial behavior to hydrogel film as observed by antimicrobial screening on different microbes. The results were encouraging and showed that such hydrogel films may find prospective applications in antimicrobial packaging.

Application of FTIR-ATR spectroscopy to confirm the microwave assisted synthesis and curing of Cashew nut shell liquid derived nanostructured materials.

The present work reports the development of nanostructured material from Cashew nut shell liquid (CNSL, an agro byproduct of cashew industry, 87% cardanol) to evaluate their potential in antibacterial applications as a substitute of petroleum feedstock via an energy-efficient method. The nanostructured material was synthesized by coordination polymerization reaction of cardanol and divalent Mn(II) salt with the aid of microwave irradiations. FTIR spectroscopy was used to confirm the proposed structure of the synthesized materials. FTIR-ATR spectroscopy was employed to verify the curing of material by comparing the spectra of the cured samples with the frequencies of uncured samples. Magnetic moment and UV-visible spectroscopy were used to confirm the proposed structure of the material further. Morphology of the synthesized material was investigated by XRD, optical microscopy, SEM and TEM and thermal behaviour by TGA/DTG/DSC technique. Agar diffusion method was utilized to investigate the antibacterial activity of the synthesized material against bacterial strains E. coli, K. pneumoniae, B. subtilis and S. aureus. N2 adsorption-desorption was investigated to check BET specific surface area and BJH pore size distribution of the same. The results revealed that the synthesized materials were obtained as semicrystalline, porous, thermally stable and nanostructured film forming materials with moderate to good antibacterial activity against different nosocomial bacteria. They can be used as thermally stable antibacterial agents in the field of films/coatings for health care applications.

Synthesis, characterization, antibacterial and corrosion protective properties of epoxies, epoxy-polyols and epoxy-polyurethane coatings from linseed and Pongamia glabra seed oils.

The aim of this paper is to investigate the structures and properties of epoxidized linseed and Pongamia glabra oils (LOE/POE), their derived products-epoxy-polyols (HLOE/HPOE), epoxy-polyurethanes (EU=LOPU/POPU) and EU coatings. Changes in epoxy equivalent, iodine value, hydroxyl value and percent saturation of oil backbone in due course of epoxidation and hydroxylation reactions, were plotted as a function of time. Spectral (IR, (1)H NMR and (13)C NMR), physico-chemical and thermal (TGA and DSC) analyses of aforementioned resins were performed by standard methods. Physico-mechanical and chemical resistance tests reveal that coatings of LOPUs perform better than those of POPUs. It was found that properties of oil epoxy-polyurethane coatings are mainly governed by: (i) fatty acid composition and nature of starting oils, (ii) extent of epoxidation, (iii) number and location of hydroxyls and residual double bonds in the final product and (iv) the presence of long dangling chains. PO, HLOE and LOPUs exhibit good antibacterial activity against Escherichia coli at very small MIC. These EU systems can be safely employed unto 220 degrees C.