Search

Renewable resource based polyol derived from undecylenic acid, a by-product of castor oil, was successfully synthesized by three consecutive reactions: methylation, thiol-ene addition, and amidation. The biobased polyol is a sulfur- and nitrogen-containing polyol. The structure was confirmed by FTIR, NMR, and mass spectroscopic techniques. The undecylenic acid based polyol was used as a polyol along with phosphated cardanol-based polyol in the preparation of polyurethane coatings. The obtained polyurethanes were assessed for their properties by various techniques such as thermogravimetric analysis (TGA), dynamic mechanical and thermal analysis (DMTA), Universal testing machine (UTM) and electrochemical study. Interestingly, the biobased polyol improved mechanical property such as toughness of the material when it was incorporated in different weight percentages to the phosphated cardanol-based polyol. Moreover, the synergistic effect of the phosphorous and biobased polyol with the elements - sulfur and nitrogen, enhanced the anti-corrosion and antimicrobial natures of the polyurethane coating. The corrosion rate was drastically decreased from 3.0 × 10–4 to 1.8 × 10–7 mm per year for the prepared polyurethane coatings.

Water-based polyurethane coatings give a soft feeling for surface engineering for advanced wear- and friction-resisted purposes. In this work, we synthesized three types of polyols from castor oil applying short- and high-efficiency method for potential soft coating uses, as an appropriate alternative for methods that use a rotary evaporation and a vacuum oven in polyol synthesis. Castor oil was epoxidized in the presence of two types of catalysts, i.e. γ-alumina (ECOAl) and formic acid (ECOF). Although we could not detect unwelcome reactions taking place in the reaction chamber that should reduce the content of oxirane oxygen, the relative percentages of double bond conversion to oxiran for ECOAl and ECOF were theoretically 96% and 74%, respectively. Ring opening reaction of ECOAl was performed by two types of saponified castor oil utilizing Dean–Stark trap, an appropriate alternative for methods that use a rotary evaporation and a vacuum oven in polyol synthesis. The synthesized polyols were characterized by FTIR (ATR), gel permeation chromatography (GPC), differential scanning calorimetry (DSC), viscometer and OH number evaluation. Different weight percentages of the polyol samples having Tg values of ca. -6.5 °C and OH number of 6.2 were applied in synthesis of water-based polyurethane (WPU). It was found that WPU with 40 wt.% polyol has a minimum particle size and minimum poly dispersity index. WPU with 60 wt.% polyol exhibited the highest molecular weight, while it had the lowest viscosity, water absorption, glossiness, hardness, adhesion and Tg. By such structural manipulations we provided a basis for enhancement of properties of coatings for future works.

A series of novel industrially relevant halogen-free flame retardant self-curable silanized waterborne polyurethane (WPU) coatings were successfully synthesized. The effect of reactive-type phosphorus flame retardant diol (Exolit® OP560) incorporation into PU structure was investigated. High limit oxygen index (LOI) value of 30.4% accompanied by V0 classification of UL-94 vertical burning test confirmed promising flame retardancy of the WPU film containing 8.7 wt% OP560. Furthermore, microscale combustion calorimeter (MCC) indicated the obvious decrease in the heat release rate (HRR), the temperature of maximum HRR, total HR, and HR capacity (HRC) of WPUs by adding phosphorus diol. TGA, SEM, MCC, and TG-IR studies revealed that great improvement in flame retardancy was due to not only integral char formation through the synergistic effect of phosphorus and silicon but also gas dilution effect. Moreover, bio-based polyol (castor oil) was added to the formulation to increase water contact angle and water resistance. High flame retardancy and enhanced mechanical properties make this formulation highly relevant for industrial applications.

A series of novel polyurethane polyols was successfully synthesized using cyclic carbonate/polyamine chemistry. By harnessing the potential of this environmentally friendly synthetic route, non-isocyanate polyurethane polyols with varying hydroxyl content and molecular weights were prepared for thermosetting coating applications. Fourier Transform Infrared (FTIR) and Proton Nuclear Magnetic Resonance (H NMR) spectroscopy confirmed the formation of expected functional groups. By curing with an amino resin crosslinker in varying amounts, coatings with significantly different mechanical properties -from highly flexible to very hard- were obtained. The study showed that coatings designed with higher urethane content in the backbone show improved adhesion to the substrate. Results also revealed that the flexibility of the backbone structure of the polyol and the amount of crosslinker used have a significant influence on the flexibility, impact resistance, and chemical resistance of cured thermoset coatings.

Flame retardant waterborne polyurethanes (WBPU) were synthesized by reacting a phosphorous based polyester polyol with isophorone diisocyanate (IPDI) in different mole ratios of NCO:OH in three steps. In first step, the polyester polyol was synthesized by reacting tris(bisphenol-A)mono phosphate (TBAMP), sebacic acid, polyethylene glycol which was characterised by measuring acid value and hydroxyl value. Fourier transform infrared spectroscopy, nuclear magnetic resonance spectroscopy and gel-permeation chromatographic techniques were used for the characterization of polyester polyol. In second step, the polyurethanes were synthesized by reacting polyester polyol with diisocyanate in different proportions. In third step, the polyurethane was neutralised using tertiaryamine. A calculated amount of water was then added at this stage followed by addition of a chain extender at controlled pH. This resulted into waterborne polyurethanes. By varying the proportion of NCO/OH, four WBPUs have been prepared. These WBPUs were subjected for coating and casting purposes. Physico-chemical properties such as particle size, dispersion stability, viscosity were measured. The flame retardency of casted films were studied by LOI (limiting oxygen index) and UL-94 test methods. Thermal properties were determined using thermogravimatric analysis (TGA) technique of casted film. Chemical resistance and Mechanical properties of the coated samples have been found out.

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-in-water (O/W) emulsion system, whereas eugenol was utilized for the synthesis of polyester polyol by solvent-less 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 °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 the present study, preparation, characterization and coating properties of plant oils based organic-inorganic hybrid materials [OIHM] are described. Polyols from Castor oil [CO], Linseed oil [LO] and tetraethoxyorthosilane [TEOS] serve as organic and inorganic constituents, respectively. OIHM are prepared by “hydrolysis-condensation” reactions. The hydroxyl groups of polyols condensed with TEOS, forming silica anchored polyol based OIHM which on addition reaction with isocyanate formed polyurethane hybrids [COHM-PU and LPOHM-PU]. In FTIR spectra of OIHM, absorption bands at 800 cm −1 (Si O Si sym str) and 1090.0 cm −1 (Si-O-Si assym str) confirmed the formation of nano silica, that occurred as unagglomerated and spherical particles as observed in TEM micrographs of OIHM. Thermogravimetric analysis showed the onset of degradation at 220 °C–225 °C. OIHM showed moderate to good antibacterial behavior against E.coli and S.aureus . OIHM coatings showed good corrosion rate and inhibition efficiency in 3.5 wt% NaOH, 3.5 wt% HCl and performed well in salt fog environment. The corrosion rate and IE% values for COHM-PU were found to be 1.534 × 10 −2 mm/yr and 94.208%, and 9.923 × 10 −3 mm/yr and 95.062% for LPOHM-PU, in 3.5 wt% NaOH for 0.5 mol loading of TEOS. In 3.5 wt% HCl, corrosion rate was 9.78 × 10 −3 mm/year for COHM-PU with IE% value as 91.90% and 7.98 × 10 −3 mm/year for LPOHM-PU with IE% value as 93.44%. OIHM were developed via a synergistic approach wherein plant polyols provide matrix for the production of SiO 2 ; the latter act as reinforcements improving the performance properties in hybrid polyurethane. OIHM may serve as platform chemicals for numerous industrial products such as paints and coatings.

Poly (ethylene terephthalate) (PET) products consumption has been increased dramatically over the past few decades which have resulted in generation of large quantity of PET waste. Disposal of this waste is a global concern due to its nonbiodegradability. In the present study, we report the effect of electron beam (EB) radiations on degradation of PET and its subsequent effect on glycolysis by using excess ethylene glycol (EG). The results as analyzed by molecular weight determination showed an increase in the extent of depolymerization of PET proportional to the dose of EB irradiation. The irradiated PET samples were further subjected to chemical recycling by glycolysis using conventional and microwave method in presence of excess EG and zinc acetate (0.5%) as a catalyst. Depolymerization of PET by EB irradiation resulted in increased yield of BHET after variable time intervals. The recycled material BHET was subjected to esterification using linseed oil fatty acid, further epoxidation using formic acid and hydrogen peroxide and subsequent hydrolysis to prepare ecofriendly polyol. The individual step product was analyzed for its physical and chemical parameters like% NVM, hydroxyl value, acid value, iodine value, oxirane oxygen content etc. and also characterized by spectroscopic analysis like FTIR, 1H NMR, 13C NMR and GPC technique for molecular weight determination. Polyurethane coatings based on this polyol were prepared using various commercial polyisocyanate curing agents. The coated films were evaluated for their optical, mechanical and chemical properties. Thermal properties of coatings were investigated by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA).

Nano-sized CuO particles were prepared insitu via “one-pot, solvent-less” microwave-induced synthesis, by environmentally benign polyol process using polyol obtained from Linseed oil by (non-aqueous) condensation reaction, for the first time. Linseed polyol acts as solvent, base matrix providing functional groups, and stabilizer; the reaction is devoid of any additive, catalyst or solvent. In the prepared nanocomposites [LPE-CuO], CuO nanoparticles shaped somewhat like rods, assembled themselves in a “T-fashion”. The antifungal effects of synthesized particles were investigated against four clinical isolates of different Candida species. Results showed that the synthesized compound LPE-0.06 was found to be most effective, followed by LPE-0.05 and LPE-0.04. The rapid actions of the synthesized compounds on fungal cells suggested membrane-located targets. We investigated the effect of MIC90 values of these compounds on H+-ATPase mediated proton pumping by different Candida species. In the absence of glucose, the mean inhibition rate of H+ extrusion caused by MIC of LP was 28.09%, LPE: 33.04%, CuAc: 36.86%, LPE-0.04: 58.54%, LPE-0.05: 69.82% and LPE-0.06: 78.07%, respectively. Antifungal mechanism of action suggested that the synthesized compounds exert their antifungal activity by targeting H+-ATPase mediated proton pumping. Inhibition of H+-ATPase activity leads to intracellular acidification and consequently cell death. Results obtained in this study indicated strong antifungal activity of synthesized compounds against all the Candida species and suggest that the inhibition of fungal H+ ATPase is responsible for the antifungal activity of the test compounds. LPE-CuO can be employed as antifungal polyester and polyurethane coatings. The present work is consistent with the Principles (Principle 1,2,3,4,5,6,7,8, 12) of Green Chemistry.

Novel biobased poly(ester-urethane)s (PUDs) were synthesized by solvent free homogeneous solution polymerization of poly(caprolactone) diol (PCL), castor oil-based polyols (COLs), dimethylolpropionic acid (DMPA), isophorone diisocyanate (IPDI) and 1,4-butane diol (BD) as the chain extender. The polyurethane dispersions were prepared by adding required amount of triethylamine (TEA) and water. In this Work, castor oil-based polyols have been synthesized using the depolymerized oligoester obtained from glycolysis of PET waste with poly(ethylene glycol) (PEG 400) and castor oil. The effects of the soft segments content on the thermal and coatings properties of resulting polyurethane films have been examined by Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and measurement of the coatings properties. Phase separation of polyurethane shows a strong correlation with crystallization behaviour of the polyurethane prepared. It is established that all PUD samples containing PCL as a part soft segment with different molar ratio of castor-oil polyol are crystallisable polymers. The results from XRD analysis have showed that highest degree of crystallinity (23 and 22%) is reached in polyurethanes based on the largest content PCL diol (CPU77 and CPU73). The thermal stability of samples based on (COL/PCL molar ratio 0.25:0.75) possesses the best thermal properties but less values hardness coatings which can be ascribed to a decrease of the hard segment i.e. DMPA content in polyurethane dispersions. The long-term stability of polyurethane dispersions has been investigated using UV vis spectroscopy. The physico-mechanical properties such as hardness adhesion test and gloss of the dried films have also been determined considering the effect of soft segment content on coating properties. (C) 2016 Elsevier B.V. All rights reserved.

Medium oil alkyd resins based on the glycolyzed PET waste and different generations of aliphatic hyperbranched polyesters with linseed and sunflower oil fatty acids, which are of interest to the coating industry, were investigated. Different resin compositions were synthesized and characterized by IR and 1H NMR spectroscopy. The effect of oil fatty acid type, glycolyzed products, functionality of the polyols on thermal and film performance properties was studied. The onset of decomposition of all samples displayed at values above 200 °C which render them suitable for the processing requirements of most conventional coating applications. All films had good adhesion, bending, impact and ductility. The gloss and hardness increased with increasing the degree of branching and consequently, the molecular weight in the resin backbone. The presence of G3 as polyol enhanced the thermal stability and film properties of coatings.

Novel alkyd resins based on the Camelina sativa oil as a new renewable raw material and glycerol as a polyol component were synthesized. Selected epoxidized vegetable oils (linseed oil and camelina oil) as new functional modifiers were used in the alcoholysis reaction with purified camelina oil. The influence of the added epoxidized linseed oil and epoxidized camelina oil on the course of alkyd resin synthesis and the properties of the final products were investigated. The glycerol-based alkyd resins with improved properties were produced.

With increasing desires to protect the environment, volatile organic solvent emissions have been restricted, and there is a trend in developing waterborne polyurethanes. However, poor water resistance and low mechanical strength of waterborne polyurethane are major obstacles. Herein, we propose a terpene-modified polysiloxane-based polyurethane that solves the above-stated problems. In the presence of the Karstedt catalyst, isobornyl acrylate (IBOA) was introduced into the branch of hydrogen-containing silicone oil (HSO) through the hydrosilylation reaction. Then, it was mixed with an alkaline aqueous solution to convert the remaining Si H bonds to Si−OH bonds, which can be used as a polyol component (IBOA-Si-OH). Then, the mixtures of IBOA-Si-OH and polypropylene glycol-400 (PPG-400) were used as polyol components to react with polyisocyanate-3100 (PI-3100) in preparing a two-component waterborne polyurethane. Compared with the unmodified polyurethane film, the contact angle of the polyurethane film modified with IBOA-Si-OH was greater than 102°, which increased by 28°. The water absorption test showed that the modified polyurethane membrane nearly doubled its ability to prevent water penetration (from 18.11 % to 9.38 %). Although the introduction of silicone improved the water resistance of waterborne polyurethane, the mechanical properties were reduced. The introduction of IBOA into the silicone side chain improved the mechanical properties of polyurethane. Comparing WPU-Si with WPU-2, the tensile strength improved by 85.56 % (from 3.47 MPa to 6.44 MPa). Thermogravimetric analysis and dynamic thermomechanical analysis indicated that silicone reduced Tg and thermal stability, but participation of IBOA made up for this deficiency. Terpene biobased compounds have great potential and application prospects in the modification of polymer materials.

Conventional thermoset polyurethane polymers are crosslinked by reaction of a polyisocyanate compound with a polyol. Herein are described alternative crosslinking polyurethanes (ACPUs) for coatings and related applications that cure by azide-alkyne cycloaddition. Commercial polyisocyanate resins including allophanate, isocyanurate, and biuret types were reacted with propargyl alcohol or 2-hydroxyethyl propiolate to yield polyurethane resins with terminal alkyne functionality. Various polyols, including polyether, polyester, and polyacrylic types were modified to convert their hydroxyl functionality to azide functionality. The best performance was obtained with an alkyne component based on Desmodur XP 2580 and an azidated polyol based on Setalux D A 870 BA. Clear, high-solids, two-component coatings were prepared with and without Cu(I) catalyst. The coating performance properties including pencil hardness, MEK double rubs, and glass transition temperature (Tg) were comparable to a conventional polyurethane control coating made from the precursor resins. Azide-alkyne formulations in the presence of copper catalyst exhibited faster curing kinetics than the polyurethane control. Propiolate-based systems showed significantly faster curing kinetics compared to the propargylated systems with or without Cu(I) catalyst. A study of azide:alkyne stoichiometry surprisingly showed that higher crosslink density of ACPUs may be obtained by formulating with 35–50 mol% excess azide component.

Alternative crosslinking polyurethanes (ACPUs) were created by reacting a commercial allophanate-modified polyisocyanate with propargyl alcohol to yield a poly(alkynyl carbamate); a polyazide co-reactant was created from an acrylic polyol. Conversion of the polyisocyanate into the corresponding poly(propargyl carbamate) resulted in a dramatic viscosity increase. Poly(alkynyl carbamate) prepolymers with lower viscosities were designed by replacing various fractions of the propargyl alcohol with commercial glycol ether plasticizers, ethylene glycol monoethyl ether (EGMEE), diethylene glycol monomethyl ether (DEGMEE), and diethyleneglycol monobutyl ether (DEGBE). Triethylene glycol monopropargyl ether was also studied to provide plasticization with no sacrifice of alkyne functionality. For each commercial glycol ether plasticizer, viscosity was unaffected or increased at a loading level of 10 mol%. At 25 mol%, average viscosity reduction was 36 %, with DEGBE yielding the greatest reduction at 55 %. At 33 mol%, no further decreases were observed. Triethylene glycol monopropargyl ether yielded a 76 % reduction in viscosity at 33 mol%; 100 mol% substitution yielded no further reduction. Coatings produced from the modified poly(alkynyl carbamate)s were softer and displayed lower glass transition temperatures compared to a polyisocyanate/polyol control and a 100 % propargylated poly(alkynyl carbamate)/polyazide control. Solvent resistance of the modified coatings was the same as the controls except for those created from DEGBE and from DEGMEE at 33 mol%.

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.

New advanced and high-performance particleboard was made from bamboo waste combined with bio-polyurethane adhesive based on recycled palm oil. The bio-polyol modified recycled palm oil (MRPO) was synthesized in a single step, by epoxidation and ring-opening reactions. The physical properties and chemical structure of MRPO polyol were studied and confirmed by FT-IR, respectively. The bio-polyurethane adhesive was then synthesized using MRPO polyol and polymeric diphenyl-methane diisocyanate (p-MDI). The gel time kinetics of the MRPO polyurethane adhesive was investigated. For the particleboard preparation, the bamboo surface fiber was treated with 5% KOH for producing particleboard. The morphology of the bamboo surface fiber after surface treatment was characterized by SEM and elemental chemistry of surface was analyzed by EDX. Increasing the adhesive content (15 to 60 %wt) and NCO index (100 to 180) increased the flexural strength, elastic modulus and water absorption resistance of the particleboard. In addition, the effect of coating on the surface of particleboard with MRPO polyurethane adhesive on mechanical properties and ultraviolet (UV) weathering resistance were studied. The coated particleboard showed higher surface gloss, less color changes, and delayed degradation from UV sunlight aging. Also, the mechanical properties and water absorption resistance of the particleboard were improved by MRPO polyurethane adhesive coating on the particleboard. The results demonstrated the benefits of using MRPO polyol in the form of a new polyurethane adhesive to produce particleboard from bamboo waste, supporting the concept of eco-friendly materials.

UV curable acrylic end capped polyurethane dispersions were obtained by the acetone process, using different molecular weight polyols. Photo Differential Scanning Calorimetry (Photo-DSC) was employed to study the effect of the photoinitiator concentration as well as the curing temperature in the curing reaction rate. The penetration capacity of UV radiation was determined by “in situ” Attenuated Total Reflectance Infrared Spectroscopy (ATR-FTIR). In addition, Temperature Modulated Differential Scanning Calorimetry (TM-DSC) was used to calculate the crosslinking degree through the measurement of the Heat Capacity (Cp). According to Photo-DSC data, the conversion of the curing reaction increased with temperature and no dependence with the photoinitiator concentration was found. Cp values of the cured samples enabled us to compare the crosslinking degree as a function of photoinitiator concentration, polyol molecular weight and curing temperature.

In this paper, the effects of structural and process variables on wear resistance of polyurethane/carbon black coatings on the 6061 aluminum substrate are studied. These coatings are widely used in different industries because of their outstanding thermal, chemical stabilities and excellent mechanical properties. The parameters were polyol type (ester or ether), NCO/OH ratio and pigment concentration. The experiments were carried out based on the design of experiments using Taguchi method. Abrasion resistance tests were performed with a Taber Abrasion test device, and its morphology was examined by scanning electron microscopy (SEM). Fourier-transform infrared (FTIR) spectroscopy was used to characterize the synthesized polymer. The analysis of variance showed that among the studied parameters, polyol type and pigment concentration have the most significant effects on wear resistance. Coating with polyester polyol increases the wear resistance due to possible hydrogen bonding between hard and soft segments. Furthermore, the pigment particles provide equivalent physical crosslinks, so it increases the wear resistance. Finally, the coated sample including polyester polyol, 12phr carbon black and NCO/OH ratio equal to 1.4, provide the best wear resistance i.e. 0.2 mg. Also, the results showed that abrasion and cohesive wear are the dominant mechanisms for describing the wear behavior of studied coatings.

In this paper, a low temperature liquefiable dimethylol propionic acid (LDMPA) was designed by the condensation of e-caprolactone(CL) with dimethylol propionic acid (DMPA). A series of waterborne polyurethanes were successfully synthesized by using LDMPA. The structure and properties of the waterborne polyurethanes were characterized by IR, particle size analysis and tensile tests. It was found that with increasing LDMPA content, the particle size of the waterborne polyurethane emulsion decreased. The results of tensile tests showed that with increasing LDMPA content, the tensile strength and elongation at break of the samples increased at first and then deceased. DMA results showed that compared with samples using dimethylol propionic acid (DMPA), the introduction of LDMPA into WPU chain could reduce waterborne polyurethane’s micro-phase separation degree.

Spray applied, two component, 100% volatile organic compounds-free polyurethane coatings were prepared from bio-based rapeseed oil polyols. Six polyol systems were developed using rapeseed oil polyols and different chain extenders (diethylene glycol, triethylene glycol, dipropylene glycol, N-methyl diethanolamine), defoamers, molecular sieves. Systems were formulated with and without dibuthyltin dilaurate catalyst. Then polyurethane coatings were developed by reacting polyol systems with isocyanate components with different functionalities (a polymeric methylene diphenyldiisocyanate (MDI) Voratec SD 100, MDI prepolymer Suprasec 2416, a polymeric MDI Suprasec 2651). The impact of polyol and chain extender structure and parameters on development of polyol systems was discussed. Technological parameters (gel time, tack-free time) were studied and results showed that formulations have short gel time and thus can be applied on surfaces in up-right position. Coatings showed good physical and mechanical properties that meet the requirements that are defined for V type two component polyurethane coatings in the ASTM D16 standard. Using The Fourier transform infra-red spectral analysis and Shore D hardness measurement the post-curing of polyurethane coatings was studied. Hydrolytic stability tests showed that developed coatings are suitable for application with water involved since they display water absorption

In this paper, UV-curable castor oil-based polyfunctional polyurethane acrylate (COME-PUA) was synthesized via photo-click chemistry and isocyanate polyurethane reaction. Facile and highly efficient side-chain functionalization of castor oil (CO) was first achieved via thiol-ene photo-click chemistry with β-mercaptoethanol (ME). 1 H NMR result indicated that almost 100% conversion of double-bond in CO was observed within 10 min, and the average hydroxyl functionality of the obtained polyol COME was about 6. Next, COME was modified by isocyanate polyurethane reaction with hydroxypropyl acrylate (HPA), isophorone diisocyanate (IPDI) and PEG-200 as the chain extender in order to prepare the resin COME-PUA. Results of both 1 H NMR and FTIR revealed that the targeted COME and COME-PUA were successfully synthesized. Furthermore, UV-curing kinetic of COME-PUA was revealed by real-time FTIR, showing a higher UV-curing rate than the common CO-PUA. Finally, some physical properties of curing films were studied.

An anionic polyol (MPP) dispersion was prepared by introducing maleopimaric acid (MPA) into polyester polyol chain through esterification reaction. The influences of catalyst content, molar ratio of alcohol to acid, 5-sulfoisophtalic acid sodium salt (5-SSIPA) content and MPA content on particle size, stability and rheological property of MPP dispersion were investigated. The optimized conditions for the synthesis of stable MPP dispersion were identified as 1 wt% catalyst content, 1.4:1 molar ratio of alcohol to acid, 2.86 wt% 5-SSIPA content, and 15 wt% MPA content. The MPP dispersion was then applied to the preparation of a novel maleopimaric acid-based two-component waterborne polyurethane (2K-WPU) coating. Incorporating MPA into MPP dispersion leaded to the maleopimaric acid-based 2K-WPU coating with improved tensile strength, gloss, pencil hardness, water resistance and ethanol resistance. The results suggested that MPP dispersion provided a potential application in the field of 2K-WPU coating.

Microcapsules containing isophorone diisocyanate (IPDI) as healing agents for using in self-healing polymers have been successfully prepared via interfacial polymerization of polyurethane (PU). Microcapsules were manufactured using different polyols including 1,4-butandiol, 1,6-hexanediol and glycerol. The fabrication of PU prepolymer and microencapsulation of IPDI were proved by Fourier transform infrared (FTIR) and thermo-gravimetric analysis (TGA). High yields of IPDI/PU microcapsules were obtained using 1,4-butandiol and 1,6-hexanediol as polyol monomers as determined by TGA. Scanning electron microscopy (SEM) showed synthesis of smooth spherical microcapsules of 1.7 and 3 μm in diameter using 1,4-butandiol and 1,6-hexanediol as polyol, respectively.

Herein, a novel omniphobic polyurethane (PU) coating has been prepared from bio-based acetylated starch (ac-Starch) as the polyol and hexamethylene diisocyanate trimer (HDIT) as the cross-linking agent. A small amount of monocarbinol terminated polydimethylsiloxane (PDMS−OH), as a lubricating ingredient, is introduced into the coating through covalent attachment with excess HDIT to prevent large scale phase separation with other coating components. By adjusting PDMS content (0.5–3.0 wt.%), ac-Starch based PU coatings with high transparency (>97 %) and excellent anti-smudge properties are obtained. Specifically, various liquid contaminants such as inks, water- and oil-based substances are easily removed from the coating surface, either through “sliding-off” or “beading” and “wiping-off” without any traces left behind. In addition, these coatings could provide anti-corrosion properties for metal surfaces. Thus, such bio-based “green” coatings with omniphobic properties are promising for protecting surfaces from contamination and corrosion, which is critical for the sustainable development of functional coating materials.

Solvents play a huge role in the manufacturing of various acrylic resins due to their ability to control the molecular weight, reduce the viscosity and enhance the flow and levelling of the coatings. However, they contribute significantly to volatile organic content (VOC) which is a key parameter in the field of coatings industry. In view to minimise VOC, various polyols have been studied as reactive diluents/solvents to replace conventional solvents in acrylic polyol synthesis. In this manuscript, 1,3-propanediol oligomer, a 100 % bio-based oligomer has been used to completely replace the conventional solvent in the acrylic polyol synthesis. 1,3-propanediol not only acts as a solvent but also takes part in the curing process by reacting with polyurethane (PU) cross-linkers. To achieve the same properties as solvent based acrylic polyol resins, suitable monomers, initiators and reaction conditions were explored. Most of our designs exhibited viscosity in the range of Z6 to Z8 on Gardener scale at 25 °C. A solitary design resulted in a viscosity of Z4-Z5, which was well within our required parameters. This acrylic polyol resin based on 1,3-propanediol was cross-linked with PU cross-linkers in clear coat. The obtained film was then studied using various analytical techniques such as dynamic mechanical analyser (DMA), thermogravimetric analysis (TGA), gel permeation chromatography (GPC) and fourier transform infrared (FTIR) spectroscopy. The advantage with 1,3-propanediol based solvent free acrylic polyol resin is the reduction of VOC from 400 g/L to ∼ 160 g/L. It is observed that the coatings obtained from this acrylic polyol resin exhibited comparable performance in two component (2 K) PU coatings to that of in-house solvent borne acrylic systems having high VOCs.

Flame retardant polyether ester urethanes have been synthesized by reacting di phosphorous based polyether ester polyol with IPDI and HDI. Four sets of polyurethanes were prepared using two different NCO molar ratios. Physico-chemical properties of polyols and polyurethanes were measured. Instrumental techniques like FTIR, GPC, and NMR were used for the characterization of the polymers. LOI and UL-94 were used to determine the flame retardant properties of polyurethane films. The morphological study was done using SEM which reveals that an increase in NCO ratio increases microphase separation in polyurethanes. The thermal and mechanical properties of polyurethanes were determined using instrumental analysis. Chemical resistance properties of coated films were studied using acid and alkali and ionized water.

In order to obtain waterborne two-component polyurethane (WB 2K-PUR) with good mechanical properties as well as excellent corrosion resistance, a series of hydroxyl-based polyurethane (HO-WPU) were synthesized using isophorone diisocyanate (IPDI), dimethylolpropionic acid (DMPA), and different proportions of polyether polyol (PTMEG) and polyester polyol (P1012) in this paper. Then WB 2K-PUR coatings were prepared with water-dispersible isocyanates (WDPI) as curing agent. The influence of the proportion of polyester polyols and polyether polyols in soft segments on coatings properties was studied. The characteristics of the coatings were analyzed by Fourier transform infrared spectroscopy (ATR-IR), contact angle, differential scanning calorimetry (DSC), dynamic mechanical thermal analysis (DMTA) and atomic force microscopy (AFM). The results showed that the mechanical properties and corrosion resistance of polyester and polyether polyols with appropriate proportion are improved significantly. The mechanism tended to be that with the addition of polyester, more hydrogen bonds were formed between the molecules, which increased the compactness of the coating as a physical crosslinking point. However, the ester groups have a strong affinity to water molecules, so the hydrophilicity of the coating was increased by excessive polyester polyols, and the shielding effect on the corrosion medium was reduced. With the inclusion of 40 % (g/g) P1012 in polyols, the coating has satisfied comprehensive properties.

Flame retardant branched polyether ester urethanes were prepared by reacting phosphorous based polyether ester polyol with three different types of diisocyanates like IPDI, HMDI, and TDI. Branched polyether ester polyol has been synthesized through ring-opening of pyromellitic dianhydride followed by esterification. This prepared branched polyol was used for the preparation of branched polyurethanes through condensation polymerization. Modification of Na-MMT clay is done to improve the interlayer distance between two silicates sheets for the preparation of BPEEU nanocomposite through the intercalation method. The interlayer distance of clay after modification was increased by 3.78 Ao, which was measured using XRD. Morphological study shows an addition of 3% O-MMT clay gives excellent properties whereas the addition of 5% clay in polymer matrix increases aggregation and brittleness of branched polyurethanes which results in failure of coating and casting. The addition of clay increases thermal stability by 30–4p0%. The hardness and tensile strength of neat BPEEUs increased with the addition of 3% O-MMT clay in BPEEUs. Flame retardant property of branched polyurethanes nanocomposites shows that clay particle does not have any impact on the flammability of polymer. Branched polyurethanes show excellent chemical and solvent resistance properties due to the presence of the high number of polypropylene in the molecular structure.

Coatings made of waterborne polyurethane dispersions are a promising alternative to solvent-borne ones but their mechanical and thermal properties under harsh outdoor conditions such as high temperature and humidity are somewhat limited. In this work saturated polyesters (PBA) with different molecular weights (800–2600 g/mol) were synthesized by reacting adipic acid with 1,4 butanediol. These polyols, an internal emulsifier, and an aliphatic diisocyanate were used as raw materials to synthesize polyurethane (PU) aqueous dispersions with solids contents of 29–38 wt%. The increase of the molecular weight of the polyol decreased the mean particle size of the PU dispersions from 308 to 78 nm. Polyurethane (PU) films were obtained by water evaporation of the PU dispersions and they were annealed at 80 °C for 2 h. Accelerated aging studies were performed by submerging the PU films in the water at 80 °C for 2 h. The PU films synthesized with the polyols with lower molecular weight exhibited enhanced phase miscibility, giving place to storage and loss moduli of similar magnitudes in a wide temperature range and they were less susceptible to hydrolytic degradation. Microphase miscibility was favored when shorter polyols are used. Contact angle measurement and cross-hatch adhesion test on PU coatings placed on stainless steel plate, before and after annealing and water aging were carried out. All PU coatings retained the adhesion to the substrate after aging, the PU coatings synthesized with shorter polyols exhibited enhanced adhesion. The authors thank the University of Antioquia for the “Estudiante Instructor” grant and to CODI for the economic and time support on the project 785 registered in the act 2018-19331.

Different aliphatic waterborne polyurethane dispersions (PUDs) were synthesized by using different polyols (Mw: 1000 Da) of randomly copolymerized polycarbonate diols with hexamethylene and pentamethylene (C6–C5), tetramethylene (C6–C4) and trimethylene (C6–C3); these copolymers differed in the length of the methylene groups and the structural regularity due to the combination of even and odd units. Brookfield viscosity, extent of particle crowding and broadening of the particle size distribution of the PUD synthesized with C6–C4 polyol followed a different trend than for the other because of the even number of methylene units in the polyol. The PUDs showed monomodal particle size distribution which was narrower in C6–C4 (i.e. the dispersion with higher structural regularity) and the mean particle size decreased by decreasing the length of the methylene unit of the copolymer. The properties of the polyurethanes were affected by the phase separation between the hard and soft segments, the more regular packing of even methylene units in the copolymer and the crystallized polar segments due to carbonate groups. Thus, the glass transition values of the soft segments in the polyurethanes were similar because of the more regular packing of even methylene units in C6–C4 polyol and the crystallized segments produced by interactions of carbonate groups. PU(C6–C5) and PU(C6–C4) showed similar degree of phase separation, the higher degree of phase separation corresponded to PU(C6–C3). Furthermore, the crystallinity of the polyurethanes increased with decreasing the number of methylene units in the polyol, but PU(C6–C4) was the most crystalline because of the more regularly packed even methylene groups in the polyol chain. The thermal stability of the polyurethanes increased from PU(C6–C5) to PU(C6–C3) because the more net interactions between the carbonate groups in the soft segments. The lower was the number of methylene groups between carbonate units in the copolymer, the higher was the elastic modulus of the polyurethanes. The tensile strength and elongation-at-break values of the polyurethanes increased by increasing the number of methylene groups between carbonate units in the copolymer. Finally, the peel strength was maximal in the joint made with PU(C6–C5) and the shear strength was the highest in the joint made with PU(C6–C3), in agreement with the variation of the viscoelastic and mechanical properties of the polyurethanes. Financial support by UBE CHEMICAL EUROPE Corporation is acknowledged.

Industrial-grade cardanol and 2-mercaptoethanol were reacted to generate hydroxyl-functionalized cardanol by UV, free-radical-initiated thiol-ene coupling between the double bond moieties of the cardanol long carbon side chain and thiol functional groups. The average hydroxyl number of the hydroxyl-functionalized cardanol was controlled by reaction time, with the hydroxyl values of this ranging within 168–201 mg KOH g −1 . This cardanol was then used as a polyol to prepare cardanol-based polyurethane with hexamethylene diisocyanate and a NCO/OH ratio of 1. To compare the effect of cardanol-based polyols with the properties of cardanol-based polyurethane, cardanol modified with 10-undecylenate was used as a raw material to prepare cardanol-based polyols, including the long carbon chain of 10-undecylenate. All properties were examined, and data revealed that cardanol-based polyols including this long carbon chain can improve the hydrophobic and mechanic properties of the cardanol-based polyurethane.

A series of novel carbamate group-containing quaternary ammonium salts (QASs) have been synthesized, which were subsequently used as antimicrobial agent and incorporated into polyurethane coatings through crosslinking with terpene-based polyol and polyisocyanate. The chemical structures of QASs were characterized by FT-IR, 1H NMR, and 13C NMR. The effects of QASs on the properties of coatings were investigated. The results showed that the resulting coatings exhibited significant antimicrobial activity against both Staphylococcus aureus and Escherichia coli by introducing QASs into the polyurethane networks. Furthermore, with the increasing of QAS content, the antimicrobial activity and adhesion of the coatings were enhanced, while the pencil hardness, water resistance and thermal stability of the coatings were decreased.

Glycolysis of poly(ethylene terephthalate) (PET) waste using different molar ratio of poly(ethylene glycol) (PEG400), was used to produce saturated hydroxyl-functional polyester polyols with castor oil (CO) by transesterification process. The waterborne polyurethane (WBPU) adhesives were synthesized from these saturated polyester polyols, isophorone diisocyanate (IPDI), dimethylolpropionic acid (DMPA), and hexamethoxymethyl melamine (HMMM) as cross-linking agent by a conventional prepolymer process. The glycolyzed polyols and polyester polyos formations were characterized using Fourier transform infrared spectroscopy (FTIR) and the molecular weights were determined using gel permeation chromatography (GPC). The cross-linking reaction between WBPU and HMMM was verified using FfIR and H-1 NMR analysis. Thermal properties were investigated by thermogravimetric analysis (TG). Thermal stability of cross-linked WBPU significantly increased with decreasing castor oil content in the process of transesterification to obtain polyester polyol as a soft segment. The T-15% and T-50% (the temperature where 15 and 50% weight loss occurred) of WBPU increased with the decreasing of castor oil content in the obtained polyester polyols, caused by the steric hindrance of polyester polyol with higher castor oil content, in the process of cross-linking reactions with HMMM. The physico-mechanical properties of WBPU, such as hardness, adhesion test, and gloss of the dried films were also determined considering the effect of participation of HMMM in cross-linking reactions with polyurethane, on coating properties. (C) 2014 Elsevier B.V. All rights reserved.

Renewable resources used in the preparation of polymers are falling in the class of biomaterials which are rich in hydrocarbons and most of the times obtained from parts of profusely available agriculture feedstock. Use of non-edible vegetable oils and their fatty acids are currently the raw materials focused in synthesizing polymeric materials as renewable sources due to increasing economic and environmental concerns of petroleums. The current oil based polymers are prepared by consuming petroleum based anhydrides and dicarboxylic acids. With this investigation, we tried to substitute almost all components of petroleum feed stock by renewable sources in preparation of polyol. Initially palmitic acid was used as a renewable source to prepare palmitamide by amidation reaction. Further amide was converted into the polyesteramide resin (PEPAD) by reacting it with another renewable resource, i.e. dimer fatty acid which is the dimerized product of unsaturated fatty acids of vegetable oils. Structure of the prepared resin was confirmed by spectroscopic techniques and resin was also characterized by end group analysis like hydroxyl and acid values. The molecular weight of PEPAD was ranged between 2590 and 2760 g mol−1. Palmitic acid based polyesteramide was used to prepare polyurethanes by varying amount of diisocyanate. The transparent polyurethane films and coatings were obtained and examined for water absorption, contact angle, hardness, coating properties, solvent, acid and alkali resistances. The thermal properties of the polyurethane films were estimated by TGA and discussed. It was found that change in NCO content affected on transparency as well flexibility of the prepared films. It also noticed that thermal stability was shifted toward higher range by increasing mole (NCO/OH) ratios due to formation of urea linkages.

An anionic polyol (T-PABA) dispersion was prepared by modifying terpene-based epoxy resin with para-aminobenzoic acid. Then T-PABA dispersion was crosslinked with a hexamethylene diisocyanate (HDI) tripolymer to prepare waterborne polyurethane/epoxy resin composite coating. The rheological properties and particle size distribution of the composite system were characterized by rotary rheometer and laser particle size analyzer. The crosslinked composite product has good thermal resistant properties, with glass-transition temperatures ( T g ) about 40% and 50% weight loss temperatures ( T d ) in the range of 400–420. The smooth and transparent film obtained from the composite product has good flexibility, adhesion, impact strength, antifouling and blocking resistance properties. The impact strength, pencil hardness, water-resistant and thermal-resistant properties of the composite products increased with the molar ratio of isocyanate group to active hydrogen of T-PABA.

In the present work, hyperbranched urethane alkyd high solid coatings were formulated by mixing hyperbranched alkyd and isocyanate trimer. Initially, a second generation hyperbranched polyol (HBP) was synthesized using dipentaerythritol (DPE) as a core material and 2,2-bis(methylol)propionic acid (BMPA) as a chain extender. This was reacted with varying concentrations of linseed oil fatty acid (LOFA) to make a series of hyperbranched alkyd (HBA) resins. Viscosity and volume solid of the HBA resins were measured. The resins were characterized by Fourier transform infrared (FTIR), and 13C Nuclear magnetic resonance (13C NMR) spectroscopic techniques. The hyperbranched alkyd resins containing varying amount unreacted hydroxyl groups were cured with hexamethylene diisocyanate (HDI) trimer (Desmodur N 3390) depending on their NCO: OH ratio to make hyperbranched urethane alkyd coatings. A series of such coatings were made by mixing HBA/isocyanate trimer (Desmodur N 3390) ratio with respect to the hydroxyl group present on the HBA. The performance of the coated specimens was evaluated by various techniques such as pull-off adhesion strength, tensile strength, abrasion resistance, scratch resistance, flexibility, and impact resistance tests. The weathering properties of the coated specimens were evaluated by UV-Weatherometer. Corrosion resistance of the coated specimens was evaluated by electrochemical impedance spectroscopy (EIS), salt spray, seawater immersion and humidity tests. It was observed that, there exists an optimum coating composition in terms of NCO: OH (HBA: Desmodur N 3390) ratio which showed excellent enhancement in terms of the mechanical, weathering and corrosion resistance properties than remaining coating compositions.

Epoxidized soy bean oil (ESBO) polyether polyols have been prepared and evaluated as potential bio-renewable replacements for bisphenol A based epoxy coatings. Zinc triflate was found to be more efficient in catalyzing the ESBO hydroxyl reaction than methanesulfonic acid or boron trifluoride etherate. With an excess of n-butanol, ESBO epoxide groups ring open to give the expected polyether polyol, but as the n-butanol concentration is reduced, dimers, trimers, and higher molecular weight analogs of the triglycerides appear. Weight average molecular weight can be increased in a controlled fashion to over 10,000 Da by using trimethylolpropane (TMP) in place of n-butanol. The addition of solvent reduces molecular weight of the polyether polyol, at an equivalent TMP level while still allowing good reaction control. These polyether polyols can be cured with phenolic resins, but solvent and blush resistance, adhesion, and wedge bend flexibility are inferior to a commercial bisphenol A epoxy control. ESBO polyether polyols were then grafted with an acrylic monomer mix that included methacrylic acid using initiators with high grafting efficiencies. Neutralization with a base allowed the formation of stable aqueous dispersions. However, use of an initiator with a low grafting efficiency under the same conditions did not produce a stable aqueous dispersion. A simple blend of a pre-formed acrylic with the ESBO polyether polyol likewise did not form a stable dispersion. Solvent borne and water borne ESBO polyether polyol acrylic grafted co-polymers were cured with phenolic, benzoguanamine and melamine crosslinkers. Films were comparable to a commercial BPA epoxy control having excellent solvent and blush resistance, good adhesion, and good flexibility.

Three waterborne polyurethane dispersions derived from polyester, polyether and polycarbonate diols with molecular weight of 1000 Da were synthesized by the acetone method and used as coatings on stainless steel 304 plates. The properties of the dispersions and the polyurethane films were influenced by the polyol nature. The polyurethanes obtained with polyether or polyester showed higher degree of phase separation between the soft and the hard segment. The higher adhesive strength under shear stresses was obtained in the joints produced with the waterborne dispersion obtained with polycarbonate diol. The properties of the polyurethane coating obtained with polycarbonate diol on stainless steel 304 were significantly higher as compared with the others. Improved performance of coatings obtained with polycarbonate diol was ascribed to the higher polarity of the carbonate groups that contributed to additional hydrogen bond formation between soft segments with respect to those obtained with polyether or polyester. Financial support by UBE Chemical Europe.

A series of hyperbranched waterborne polyurethanes (HWPU-4, HWPU-6 and HWPU-12) containing hydrophobic end groups were prepared by the hyperbranched core and the polyurethane prepolymer. The core was polyol including pentaerythritol (PE-4), hyperbranched polyester with six hydroxyl end groups (HPE-6) and hyperbranched polyester with 12 hydroxyl end groups (HPE-12). The polyurethane prepolymer was synthesized by hexamethylene diisocyanate (HDI), polyethylene glycol (PEG) and hexadecanol. The structures of the hyperbranched cores and HWPUs were characterized by Fourier transform infrared spectra (FTIR), nuclear magnetic resonance spectra (1H NMR and 13C NMR) and gel permeation chromatography (GPC). The influences of HWPU content and structure on its thickening property were studied by the measurement of rotary viscosity. The results showed that the thickening effect of HWPU enhanced with the increase of HWPU content in the aqueous polyurethane emulsion. The thickening effect of HWPU-6 was superior to that of HWPU-4 and HWPU-12 with the same length of hydrophilic chain. In addition, the thickening effect of HWPU with the same core was related to the length of hydrophilic chain and the relative content of hydrophobic end groups.

Some preliminary investigations on “green” preparation, morphology and antibacterial behavior of Linseed polyol nanocomposite [LMPOL] for antibacterial polyurethane coatings are summarised. Nanocomposite is prepared in situ with Linseed polyol [LP] matrix as organic and Copper acetate as inorganic constituent by “solventless one-pot” chemical reaction. The presence of characteristic absorption bands in FTIR spectra confirmed the formation of LMPOL. TEM analysis showed the presence of nano-sized metal oxide in LMPOL. LMPOL showed good antibacterial behavior against E. coli and S. aureus . The interactions between LMPOL and bacterial surfaces lead to good antibacterial efficacy, suggesting membrane disruption based cell death. LMPOL may serve as an excellent starting material for antibacterial polyurethane coating. The approach is an excellent example for the preparation of “green” polyol from “green” resource en route Green Chemistry for protective polyurethane coatings.