Polyurethane Nanocomposite Coatings Research Articles

Polyurethane Nanocomposite Coatings Coupled with Titanium-Based Conversion Layers for Enhanced Anticorrosion, Icephobic Properties, and Surface Protection.

This study examines the efficacy of icephobic polyurethane nanocomposite coatings in mitigating corrosion on an aluminum substrate. A titanium-based conversion coating is applied to modify the substrate, and the research focuses on optimizing the dual functionalities of icephobicity and anticorrosion within the polyurethane coatings while ensuring strong substrate adhesion. The coatings are formulated using fluoropolyol, isocyanate, and silica nanoparticles treated with polydimethylsiloxane. Surface properties are analyzed using contact angles, contact angle hysteresis measurements, and atomic force microscopy, and the coatings' icephobicity is evaluated through differential scanning calorimetry, freezing time delay, ice adhesion under impact and non-impact conditions, and ice accretion tests. The corrosion resistance and adhesive strength of the coatings are assessed using electrochemical impedance spectroscopy and cross-cut tests, respectively. Increasing the concentration of silica nanoparticles to 10 wt.% increases contact angles to 167°, although the 4 wt.% coating produces the lowest contact angle hysteresis (3° ± 0.5°) and ice nucleation temperature (-23 °C). The latter coating is then applied to a substrate pretreated with a titanium/cerium-based conversion coating. This prepared surface maintains an ice adhesion of about 15 kPa after 15 icing/de-icing cycles and provides approximately 90 days of surface protection (|Z|lf = 1.6 × 109 Ω·cm2). Notably, the impedance value exceeds that of untreated substrates, underscoring the effectiveness of the titanium/cerium-based conversion coating in enhancing both corrosion resistance and coating adhesion to the substrate.

Reliability modeling to predict in‐service weatherability of polyurethane nanocomposite coatings: Approach, comparison and validation

AbstractThis article addresses the challenge of comparing in‐service weatherability among newly developed coatings. The study aims to compare the durability of three thermoplastic polyurethane‐based coatings specifically formulated for defense inflatables. It introduces a reliability model that incorporates two weathering stresses, namely, ultra‐violet radiation and temperature, to predict the service life of the coatings. A life–stress relationship has been established from the accelerated aging tests, which facilitates the determination of material service life at use level conditions. Notably, the analysis underscores the significant improvement in service lifetime achieved with nanocomposite‐based coatings. The validity of the proposed model is established through comparison with real‐world field test data, emphasizing the effectiveness of the approach in assessing and comparing the performance of the three coated samples. The insights gained from this research will surely contribute to enhancing the durability assessment of coated systems in real‐world conditions for various fields of applications.Highlights Introduces a unique method to compare weatherability of three polyurethane coatings. Reliability model predicts service life under UV and temperature stresses. Life–stress relationship via accelerated aging for accurate service life. Nanocomposite coatings show longer service life than conventional ones. Model validated with field data, confirming practical applicability.

Outstanding performance of flower-like NiO nanostructures in epoxied soybean oil-based polyurethane nanocomposite coatings: Investigation of anticorrosion and antibacterial properties

Nowadays, nanocomposite coatings have gained much attention from both academic and industrial aspects mainly because of the outstanding properties which they can offer simultaneously. Specifically, anti-corrosion properties can make them one of the best choices to solve destructive corrosion problems. Nickel oxide (NiO) nanoparticles have been synthesized to create these outstanding properties in vegetable oil-based polyurethane coatings. To this end, epoxidized soyabean oil was utilized to synthesize polyol and produce polyurethane coatings, and NiO nanoparticles were incorporated into the obtained coatings. The obtained coatings were evaluated through the FTIR, H NMR, and FESEM techniques and their performance in terms of water uptake, anticorrosion and antibacterial properties were investigated. The obtained results clearly showed that the presence of NiO nanoparticles has had an undeniable effect on the performance of the coating in protecting mild steel substrate against corrosion. Moreover, using these nanoparticles has created remarkable antibacterial properties in the coating besides improved mechanical performance compared to pure polyurethane coating.

High performance polyurethane nanocomposite coatings based on 2D materials for improved anticorrosion and flame-retardant applications

Cobalt disulphide (CoS2), 3-amino-5-ethoxy-1,2,4-triazole (AET), and graphene oxide, also known as GO, were added to polyurethane (PU) coatings to improve their anticorrosion and fire-retardant properties. To analyze the structural and morphological behaviours of the films of pure CoS2, AET/CoS2, GO/CoS2, and GO/AET-CoS2, SEM/EDX, TEM, TGA, XPS, and XRD techniques were used. The peak heat release rate (PHRR) and total heat release (THR) of polyurethane-graphene oxide/AET-CoS2 were significantly lower than those of polyurethane, with differences of 64.7% and 52.8%, respectively, demonstrating better flame retardancy. The anticorrosive, hydrophobic, and flame-retardant characteristics of the PU-GO/AET-CoS2 nanocomposite were confirmed using mechanical testing and electrochemical methods. Impedance studies confirmed that the corrosion protection performance of PU-GO/AET-CoS2 in seawater was much greater (22,481 kΩ cm2) than that of the plain polymer (157 kΩ cm2). The PU-GO/AET-CoS2 nanocomposite coated AA7039 aluminium alloy had the lowest aluminium ion dissipation as evidenced by SECM investigations. The PU-GO/AET-CoS2 coating had superior hydrophobic properties (WCA: 164°). Therefore, PU-GO/AET-CoS2 could be exploited as a potential material for coatings in industrial processes.

Advanced Anticorrosive Graphene Oxide-Doped Organic-Inorganic Hybrid Nanocomposite Coating Derived from Leucaena leucocephala Oil.

Metal corrosion poses a substantial economic challenge in a technologically advanced world. In this study, novel environmentally friendly anticorrosive graphene oxide (GO)-doped organic-inorganic hybrid polyurethane (LFAOIH@GO-PU) nanocomposite coatings were developed from Leucaena leucocephala oil (LLO). The formulation was produced by the amidation reaction of LLO to form diol fatty amide followed by the reaction of tetraethoxysilane (TEOS) and a dispersion of GOx (X = 0.25, 0.50, and 0.75 wt%) along with the reaction of isophorane diisocyanate (IPDI) (25-40 wt%) to form LFAOIH@GOx-PU35 nanocomposites. The synthesized materials were characterized by Fourier transform infrared spectroscopy (FTIR); 1H, 13C, and 29Si nuclear magnetic resonance; and X-ray photoelectron spectroscopy. A detailed examination of LFAOIH@GO0.5-PU35 morphology was conducted using X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and transmission electron microscopy. These studies revealed distinctive surface roughness features along with a contact angle of around 88 G.U preserving their structural integrity at temperatures of up to 235 °C with minimal loading of GO. Additionally, improved mechanical properties, including scratch hardness (3 kg), pencil hardness (5H), impact resistance, bending, gloss value (79), crosshatch adhesion, and thickness were evaluated with the dispersion of GO. Electrochemical corrosion studies, involving Nyquist, Bode, and Tafel plots, provided clear evidence of the outstanding anticorrosion performance of the coatings.

Improved Anticorrosion Properties of Polyurethane Nanocomposites by Ti3C2Tx MXene/Functionalized Carbon Nanotubes for Corrosion Protection Coatings

The corrosion protection of MXene-based composite coatings is challenging due to the relatively low dispersion of MXene in organic coatings. In this work, waterborne polyurethane (WPU) composites containing hybrid nanoadditives of Ti3C2Tx MXene and functionalized carbon nanotubes (CNTs) were fabricated. The thermal stability, surface hydrophobicity, surface roughness, and mechanical properties of the nanocomposites containing MXene or MXene/CNT hybrid additives were studied. Electrochemical methods, including electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization scans, were utilized to evaluate the anticorrosion properties of the nanocomposite coatings when applied to copper substrates. The polyurethane sample with 0.95 wt % Ti3C2Tx MXene and 0.05 wt % CNTs showed the lowest corrosion rate of 2.1 × 10–3 μm year–1. Additionally, the EIS results revealed that the corrosion resistance of WPU/MXene coatings significantly increased by adding 0.05 wt % CNTs. The mechanism of the improved anticorrosion performance of the WPU/MXene/CNT composite coating is illustrated. Moreover, the importance of optimizing the concentration of the CNTs is discussed to obtain better corrosion protection. The polyurethane nanocomposite coatings reported in this work present great potential as corrosion protection coatings for metals and other surfaces.

Improved anticorrosion, flame retardant and mechanical behaviors of multifunctional polyurethane nanocomposite coatings for industrial applications

The anticorrosion, flame retardant, and mechanical properties of polyurethane (PU) coatings have been enhanced by the inclusion of zirconium disulphide (ZrS2), 2-mercapto-5-(methoxy)-1,3,4-thiadiazole (MMTD), and graphene oxide (GO). The structural and morphological behaviours of the films for the different coating formulations were investigated using SEM/EDX (Scanning Electron Microscopy with Energy Dispersive X-Ray Spectroscopy), TEM (Transmission Electron Microscopy), TGA (Thermogravimetric Analysis), XPS (X-ray Photoelectron Spectroscopy), and XRD (X-ray Diffraction) analysis. With the inclusion of just 0.3% GO/MMTD-ZrS2, the dielectric constant of PU at 1 Hz was increased by 85 times. Additionally, when compared to plain PU, the PU-GO/MMTD-ZrS2 demonstrated increased flame retardancy with significant decreases in the peak heat release rate (pHRR) and total heat released (THR), or reductions of 65% and 52%, respectively. The addition of GO/MMTD-ZrS2 compound to the PU matrix improves the PU coating's anticorrosive, hydrophobic, flame retardancy, and mechanical performance. The hyper hydrophobic behavior is verified by its water contact angle (WCA), which is 168˚. Additionally, it was discovered that PU-GO/MMTD-ZrS2 had considerably higher coating resistance (20,997.1 kΩ.cm2) compared to the other coatings under investigation. PU-GO/MMTD-ZrS2 was found to have a microhardness of 1355 MPa and a binding strength of 17.9 MPa, respectively. This means that the PU-GO/MMTD-ZrS2 nanocomposite could be applied in industrial settings as a coating substance.

A Wind Tunnel Experimental Study of Icing on NACA0012 Aircraft Airfoil with Silicon Compounds Modified Polyurethane Coatings.

Ice formation on the aerodynamic surfaces of an aircraft is regarded as a major problem in the aerospace industry. Ice accumulation may damage parts, sensors and controllers and alter the aerodynamics of the airplane, leading to a range of undesired consequences, including flight delays, emergency landings, damaged parts and increased energy consumption. There are various approaches to reducing ice accretion, one of them being the application of icephobic coatings. In this work, commercially available polyurethane-based coatings were modified and deposited on NACA 0012 aircraft airfoils. A hybrid modification of polyurethane (PUR) topcoats was adopted by the addition of nanosilica and three-functional spherosilicates (a variety of silsesqioxane compound), which owe their unique properties to the presence of three different groups. The ice accretion on the manufactured nanocomposites was determined in an icing wind tunnel. The tests were performed under three different icing conditions: glaze ice, rime ice and mixed ice. Furthermore, the surface topography and wetting behavior (static contact angle and contact angle hysteresis) were investigated. It was found that the anti-icing properties of polyurethane nanocomposite coatings strongly depend on the icing conditions under which they are tested. Moreover, the addition of nanosilica and spherosilicates enabled the reduction of accreted ice by 65% in comparison to the neat topcoat.

Synergistic effect of polybenzoxazine/ZrO2 encapsulated polyurethane nanocomposite coatings for enhanced barrier properties of steel in seawater

PurposeThe purpose of this study is to use polybenzoxazine (Pbz) functionalized ZrO2 nanoparticles to synthesize polyurethane (PU)-PbZ/ZrO2 nanocomposite. The results derived from the electrochemical impedance spectroscopy (EIS) and polarization studies indicated the superior anticorrosive activity of PU-Pbz/ZrO2 nanocomposite coatings compared to those of plain PU coatings. The decreased corrosion current was detected on the scratch of the PU-Pbz/ZrO2 nanocomposite-coated mild steel surface by scanning electrochemical microscopy (SECM) compared to other studied coatings. The superior anticorrosive and mechanical properties of the proposed nanocomposite coatings provide a new horizon in the development of high-performance anticorrosive coatings for various industries.Design/methodology/approachThe Pbz functionalized ZrO2 nanoparticles were characterized by Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM) with energy dispersive X-ray analysis (EDX) and thermogravimetric analysis (TGA) in terms of the structural, morphological and thermal properties of these coatings. A different formulation of coatings such as PU, PU-Pbz, PU-ZrO2 and PU-Pbz/ZrO2 were prepared and investigated for their corrosion protection performance on mild steel in natural seawater by electrochemical techniques. The surface morphological studies were done by SEM/EDX and XRD analysis.FindingsThe superior anticorrosive property of the proposed nanocomposite coatings provides a new horizon in the development of high-performance anticorrosive coatings for various industries. Addition of Pbz wrapped ZrO2 nanoparticles into the PU coating resulted in the blockage of charge transfer at the metal/electrolyte interface, which reduced the dissolution of mild steel. It was revealed from the SEM/EDX analysis that the formation of the corrosion products at the metal/electrolyte interface behaved as the passive layer which reduced the dissolution of steel.Originality/valueThe inclusion of polybenzoxazine functionalized ZrO2 nanoparticles to the polyurethane coating reinforces the barrier and mechanical properties of PU-Pbz/ZrO2 nanocomposite, which is due to the synergistic effect of ZrO2 and Pbz.

Bio-based polyurethane nanocomposite thin coatings from two comparable POSS with eight same vertex groups for controlled release urea

Nanocomposite modification has attracted much attention in improving properties of bio-based polymer coating material for coated fertilizer. Herein two comparable polyhedral oligomeric silsesquioxanes (POSS), with eight poly(ethylene glycol) (PEG) and octaphenyl groups attached to the cage, respectively, were successfully incorporated into thin castor oil-based polyurethane coatings via in-situ polymerization on the urea surface. The nanostructure coatings are environmentally friendly, easy to prepare, and property-tunable. The results show that the vertex group of POSS had a pronounced influence on dispersion level and interaction between polyurethane and POSS that well-tuned the release pattern and period of coated urea, even at the coating rate as low as of 2 wt%. The liquid POSS with long and flexible PEG groups had better compatibility and dispersibility in polyurethane matrix than the solid POSS with rigid octaphenyl groups, as evidenced by SEM/EDS. The unique properties were resulted from the different extents of physical crosslinkings. This modification of bio-based polyurethane coating with POSS provided an alternative method of regulating and controlling the properties of coated fertilizer.

Enhanced outdoor durability of polyurethane nanocomposite coatings with green reduced graphene oxide nanoplatelets

Obtaining the highest possible level of weathering resistance to protect the polymeric composites against sunlight and free radicals is the primary function of every exterior composite, such as polyurethane (PU). In this paper, a typical PU matrix was modified by two differently reduced graphene oxide nanosheets to enhance long-term weathering stability. The synthesized graphene oxide nanosheets were reduced by Nettle leaves extract as a green reductant and hydrazine as a typical reducing agent. The graphene oxide and two reduced species were embedded in PU to investigate their impact on weathering stability. Several techniques were employed to assess the weathering performance during 1400 h exposure to artificially accelerated conditions. Achieving superior weathering performance approved the effective role of reduced graphene oxide (especially green reduced) in elevating weathering stability of PU nanocomposites. The active mechanisms involved in such improvement were extensively discussed.

Hydrophobic functionalization of cellulose nanocrystals for enhanced corrosion resistance of polyurethane nanocomposite coatings

A stiff, hydrophobic, and corrosion protective polyurethane (PU) nanocomposite coatings have been fabricated via the incorporation of surface modified cellulose nanocrystals (CNC). The modification of CNC involves surface grafting of varying levels of epoxy functionalized silane (ES). The effect of reaction time and concentration of ES on the level of grafting were evaluated using Fourier Transform Infrared Spectroscopy (FTIR), Elemental analysis (EA), X-ray photoelectron spectroscopy (XPS), water contact angle measurement (WCA) and dispersibility test. It was found that prolonged reaction time and the high mole ratio of ES to CNC improve thermal properties and material wettability of the modified CNC. The incorporation of modified CNC in PU not only improved thermomechanical properties but also reduced the water absorption properties of the PU composites, which could be attributed to the improvement in the dispersion and enhanced interfacial adhesion between the nanoparticle and the PU matrix. Salt spray and electrochemical impendence spectroscopy (EIS) studies, which were carried out on mild steel coated with the fabricated nanocomposite (PU/ES-CNC), exhibited better anticorrosion behaviors as compared to PU. Overall, the CNC modification through silanization is a robust, eco-friendly, and scalable process, making it an appealing material for a range of polymer composite applications.

Nano-cerium dioxide synergistic potential on abrasion resistance and surface properties of polyurethane-nanocomposite coatings for esthetic and decorative applications on wood

Development of an antiabrasion and optical shield clearcoat for wooden art and decorative works improves its esthetic durability and lifetime. In this study, the synergistic potentials of cerium dioxide nanoparticles (NPs) were exploited to improve the abrasive, structural, and surface properties of polyurethane (PU)/silica nanocomposite coatings applied on the thermally modified spruce wood. Microhardness, adhesion strength, contact angle, and UV–Vis spectroscopy were used to evaluate the nanocomposite coatings’ surface properties. FE-SEM and EDS techniques were also employed to scrutinize distribution of NPs in the structure of nanocomposite coatings. The results showed that the abrasion resistance significantly improves by increasing the content of silica NPs. However, microhardness and performance of nanocomposite coatings containing a high percentage of silica diminished due to the aggregation of NPs and poor crosslinking of the polymer matrix. The presence of cerium dioxide NPs as a synergistic function in the PU coatings containing nano-silica enhanced the abrasion resistance as well as the glass transition temperature and caused enhanced hardness. Incorporation of cerium dioxide NPs exhibited an incremental effect on the adhesion strength of nanocomposite coatings. However, its presence in high concentration caused an adverse impact on the transparency of the nanocomposite films. In addition, wettability of PU/silica composites remained constant after incorporating high levels of cerium oxide NPs. These findings suggest that use of Ce–Si NPs hybrid/blend in the structure of PU coatings can assure the durability of wood coatings for esthetic applications and interior decoration by strengthening the surface, mechanical, and optical properties.

Enhancing the adhesion strength of polyurethane coatings by dispersing layered silicates via sonication and high-shear mixing method

Low adhesion strength of polyurethane coating to a steel substrate is often attributed to poor steel preparation. However, the ratio of diisocyanate/polyol and dispersion of fillers within a polyurethane coating matrix influence the adhesion strength, optical and corrosion resistance properties. Poor dispersion of nano-fillers in a polymer coating matrix can lead to low adhesion strength, because close packing of nanoparticles often hides the hydroxyl groups required to form polar–polar bonds with the steel surface. This study combines sonication and high-shear mixing methods with shorter mixing times to prepare polyurethane nanocomposite coatings with various clay concentrations while keeping the ratio of diisocyanate/polyol constant. Fourier-transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM) and X-ray diffraction, thermogravimetric analysis and pull-off are used to characterize polyurethane nanocomposite coatings. FTIR results confirm that sonication and high-shear mixing successfully prepare polyurethane-based coatings. TEM shows uniformly dispersed clay particles in polyurethane matrices. The adhesion strength improved on addition of 1–5 wt% C30B organoclay, with the highest improvement (34.4%) at 3 wt% loading. The corrosion resistance of polyurethane coatings was improved by the incorporation of organoclays into their matrices. Onset degradation temperature is also delayed by 4.1–8.5% as the clay concentration increased from 1 to 5 wt%.

Low gloss waterborne polyurethane coatings with anti-dripping and flame retardancy via montmorillonite nanosheets

A series of low gloss organic montmorillonite/waterborne polyurethane nanocomposite (OWPU) coatings with polycaprolactone (PCL) and hydroxyl terminated polybutadiene (HTPB) were prepared, characterized and then applied to polyvinyl chloride leather. Small-angle XRD and TEM examinations indicated that montmorillonite was exfoliated into individual single-layer nanosheets in HTPB, and retained separate shapes in subsequent synthesis and preparation. The OWPU dispersions with higher nanosheets contents exhibited a larger average particle size and a less negative zeta potential obtained through DLS. A rougher coating surface topography of OWPU compared with pristine WPU was observed by SEM, which reduced the 60° gloss to 4.6 GU within the matt range. Moreover, TGA results indicated that the nanosheets effectively increased thermal stability of hard segments and soft segments derived from PCL, but had little effect on that of soft segments derived from HTPB. Furthermore, rheological analysis confirmed the nanosheets promoted cross-linking and cyclization of HTPB at high temperature, thereby imparting anti-dripping properties to OWPU coatings. Cone calorimeter test and SEM results showed that flame retardancy of OWPU was improved by forming a charred layer with sheet-cluster structure. In addition, incorporation of the nanosheets was also capable of changing the surface touch feeling of OWPU coatings from sticky to some dry alike.

Weathering, salt spray corrosion and mar resistance mechanism of clay (nano-platelet) reinforced polyurethane nanocomposite coatings

Weathering, salt spray corrosion and mar resistance mechanism of clay (nano-platelet) reinforced polyurethane nanocomposite coatings

Fluorophore-Decorated Carbon Nanotubes with Enhanced Photothermal Activity as Antimicrobial Nanomaterials

Alternative approaches to inactivate bacteria through physical damage provide an important solution to problems associated with colonization of material surfaces by antibiotic-resistant bacteria. Here, we present the utilization of carbon nanotubes functionalized with near-infrared (NIR)-absorbing fluorophores as effective photothermal agents that can kill bacteria through laser-activated heat generation. The array of 3,3′-diethylthiatricarbocyanine (DTTC) fluorophores self-assembled on the surface of multiwalled carbon nanotubes (MWNTs) acted as a light-harvesting antenna that increased the NIR light absorption and heat generation capacity of the MWNTs. The MWNT/DTTC nanohybrids generated elevated temperatures reaching 92 °C upon 15 min NIR laser irradiation, resulting in a 77% killing efficiency on Pseudomonas aeruginosa cells in dispersion. When the MWNT/DTTC nanohybrids were embedded into a waterborne polyurethane matrix, the resulting surface coatings presented temperatures reaching 120 °C in only 2 min of laser irradiation, where multiple laser irradiation cycles did not affect the generated temperature elevations. MWNT/DTTC–polyurethane nanocomposite coatings were also demonstrated to kill all P. aeruginosa cells attached to the surface, indicating their strong potential as light-activated antimicrobial and antibiofilm coatings.

Weathering, salt spray corrosion and mar resistance mechanism of clay (nano-platelet) reinforced polyurethane nanocomposite coatings

Performance properties like weathering and corrosion resistance are critical for automotive top coats. Using two types of clays Cloisite 30B(C30B) and Cloisite 20 A(C20 A), a 2 K polyurethane (PU) pack coating formulation was modified at nanoscale. These coatings show better resistance to salt spray (500 h) and accelerated weathering conditions (1000 h). When observed under atomic force microscopy (AFM) nanoscale morphology of these nanocomposite coatings show globular (C30B) and rod-like (C20 A) hard segment formation of size˜200 nm, which compared to pristine PU coatings are more uniformly formed and evenly distributed across the microscale surface (surface texturing). Visual, spectroscopic & chemical analysis confirmed better performance of nanocomposite coatings under ultraviolet/humidity and salt cycles. Dry film thickness & gloss; dft1000 (G[1000]) was reduced by 25% (32%) for pure PU, 14.03% (16.7%) for PU-3C30B and 20% (22.7%) for PU-3C20 A respectively. The overall colour difference in CIELab values ΔE* was 9.794, 7.623 and 8.450 for PU, PU-3C30B and PU-3C20 A. Salt spray (500 h) rusted about 35% area of mild steel (ms panels) for PU, while for PU-3C30B and PU-3C20 A it was only 5% and 10% respectively. Fourier transform infrared (FTIR) shows better retention of functional groups in aged and corroded nanocomposite coatings versus pristine coatings. This proves that two dimensional clay particles when duly exfoliated interact with hard segments and play a significant role in resisting weathering forces, salt spray corrosion and even mar.

Influence of carbon nanodots encapsulated polycarbazole hybrid on the corrosion inhibition performance of polyurethane nanocomposite coatings

Carbon nanodots encapsulated in a polycarbazole hybrid-dispersed polyurethane nanocomposite coating with new exciting perspectives for high-performance anticorrosive coatings are shown.

Functional antimicrobial and anticorrosive polyurethane composite coatings from algae oil and silver doped egg shell hydroxyapatite for sustainable development

Petroleum products need to be replaced by renewable materials because of their ecological impact due to their non-degradable nature and tendency to shortages and price fluctuation. The present investigation reports the preparation of polyesteramide polyol (PEA-RIC) from renewable sources like algae oil and ricinoleic acid from castor oil. It was characterized by 1H NMR and FT-IR spectroscopic techniques, while molecular weight was determined by size exclusion chromatography. Silver doped hydroxyapatite nanoparticles (Ag-HAP NPs) prepared using waste chicken egg-shells were incorporated uniformly in PEA-RIC and their morphology was studied by scanning electron microscopy. Polyol containing Ag-HAP NPs was cross linked using diisocyanate to obtain polyurethane (PU) nanocomposite coatings. Their anticorrosion performance was studied by potentiodynamic polarization (PDP) method while antibacterial activity was measured against Gram-negative (E. coli) and positive (S. aureus) bacteria. These nanocomposite coatings on metallic substrate inhibited both bacteria when checked by turbidimetric method and interestingly exhibited good resistance to bacterial adhesion and bio-film formation as evidenced by SEM analysis. These coatings showed improved hydrophobicity, adhesion, anticorrosive properties and chemical resistance as compared to PU without nanoparticles.. Thermal stability and Tg were found to improve with increasing concentration of Ag-HAP NPs when checked by TGA and DSC. Such coating originating from renewable materials exhibits high applicability in curbing the losses due to corrosion and assists sustainable development.