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High internal phase emulsions (HIPEs) are commonly stabilized by a large amount of surfactants that should be removed after the polymerization of the continuous phase, and the resulting polyHIPEs from W/O HIPEs are usually brittle and chalky. Herein we report on an amphiphilic polymerizable polyurethane (PPU) macromolecular surfactant synthesized by polyaddition reaction of diisocyanates and polyols, which can well stabilize up to 88% internal phase volume of W/O HIPE with a content of only 5 wt% based the oil phase. Compared with the HIPEs stabilized by traditional surfactant Span 80, HIPEs stabilized by PPU at either room temperature or 70 °C are much more stable owing to the increased viscosity which can inhibit droplet coalescence. Moreover, the resulting polyHIPEs not only have several times higher mechanical properties than those stabilized by Span 80 but also have higher elasticity. The effects of concentration of PPU on the morphology and mechanical properties of the resulting polyHIPEs were investigated. It was found that with the increase of PPU content, the average void and window sizes decreased, while the compression strength increased. Cyclic compression tests were performed to examine reversible compressibility and durability of these polyHIPEs. The polymerizable polyurethane macromolecular surfactant (PPU) synthesized through the polyaddition reaction of diisocyanates and polyols can solely stabilize high internal phase emulsions (HIPEs), and highly interconnected macroporous polymer produced by the polymerization of HIPE stabilized with PPU, known as polyHIPE, can withstand large deformation compression with no visible cracks. [ABSTRACT FROM AUTHOR]

This work focused on the preparation and investigation of polyurethane (SO-PU)-containing sunflower oil glycerides. By transesterification of sunflower oil with glycerol, we synthesized a glyceride mixture with an equilibrium composition, which was used as a new diol component in polyurethanes in addition to poly(ε-caprolactone)diol (PCLD2000). The structure of the glyceride mixture was characterized by physicochemical methods, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), nuclear magnetic resonance spectroscopy (NMR), and size exclusion chromatography (SEC) measurements. The synthesis of polyurethanes was performed in two steps: first the prepolymer with the isocyanate end was synthesized, followed by crosslinking with an additional amount of diisocyanate. For the synthesis of the prepolymer, 4,4′-methylene diphenyl diisocyanate (MDI) or 1,6-hexamethylene diisocyanate (HDI) were used as isocyanate components, while the crosslinking was carried out using an additional amount of MDI or HDI. The obtained SO-PU flexible polymer films were characterized by attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). The so-obtained flexible SO-PU films were proved to be suitable for the preparation of potentially biocompatible and/or biodegradable scaffolds. In addition, the stress versus strain curves for the SO-PU polymers were interpreted in terms of a mechanical model, taking into account the yield and the strain hardening. [ABSTRACT FROM AUTHOR]

A thermal conductive structural adhesive (TCSA) plays a crucial role in battery performance and safety. TCSA made of polyurethane (PU) has not only a good thermal conductivity but also good mechanical strength and substrate bonding strength. However, it has to be cost‐effective and easy to be prepared. This work aims to synthesize a series of castor oil‐based PU TCSAs with different amounts of thermal conductive powder using commercially available castor oil polyols, isocyanates, Al2O3, and additives. The shear strength of the TCSA containing 88% thermally conductivity powder reached 5.6 MPa, which was similar to that without the thermal conductivity fillers, but its toughness significantly decreased. Its thermal conductivity was as high as 1.8 W/mK, and it was thermally stable below 270°C. [ABSTRACT FROM AUTHOR]

Polyurethanes (PUs) are versatile polymers used in industries at large scale. PUs are in used in the form of foam, elastomers, adhesives, fibers, thermosets, thermoplastics, etc. Polyols and isocyanates are the two compounds used to synthesize PU. Day by day increasing price of crude oil and its destructive impact on the environment motivate researchers to develop bio‐PU. Seed oils are attracting nowadays because of their renewability and low cost. They are the best substitutes for fossil fuel‐based polyol used in the preparation of PUs. However, these bio‐based PUs show lower thermal, mechanical properties, which needs improvement to further their utilization. The need to maintain a cleaner environment for the survival of both aquatic and terrestrial lives including human beings is very crucial and is a subject of increasing concern to the environmentalists. The removal of heavy metals, dyes, and organic pollutants from wastewater before their discharge in the environmental is very important due to its polluting effect on the underground water. This review article emphasizes on to provide insight on the developments in the field of chemistry, types, and synthesis of various PUs, as well as on the components used to synthesize bio‐based PUs and water treatment applications. Additionally, details on the PU's environmental friendliness are highlighted, with a focus on their potential to recycling and recovery. This review also highlights the details of the synthesis, uses, and potential futures of PU composites. [ABSTRACT FROM AUTHOR]

Purpose: This study aims to extend the pot life without altering the qualities and performance of the coating, which is important to increase when manufacturing polyurethane coatings. Design/methodology/approach: An acrylic polyol from a mixture of different monomers of hydroxypropyl methacrylate, methacrylic acid, 2-ethylhexyl acrylate, methyl methacrylate and n-butyl methacrylate was prepared with different ratios of 2,4-pentanedione as a pot life extender. The reaction takes place in presence of di-tert-butyl peroxide as initiator with samples (T1–T7). The physical properties of prepared acrylic polyol were characterized. Then, coating polyurethane varnish was prepared from the prepared acrylic polyol with an aliphatic polyisocyanate in a 1:1 equivalent ratio of OH:NCO at room temperature, in presence of paint thinner (diluents/solvent) and dibutyltin dilaurate as a catalyst to give samples (T1C–T7C). This coating was evaluated via Fourier-transform infrared spectroscopy, drying time, hardness and gloss, distinctness of image and reflected image quality. Findings: The coating has a prolonged pot life while still maintaining the other qualities, thanks to the greater 2,4-pentanedione content. Originality/value: It is desired to have a paint which has a satisfactory pot life, short curing time and reduces many drawbacks such as inefficient working and deterioration of the paint before application. [ABSTRACT FROM AUTHOR]

Using three phosphorus oxychloride as coupling agents and polyethylene glycol (PEG) as phase change materials, a novel polyol containing flame retardant element P is prepared by bonding the polyethylene glycol in polyether polyol skeleton. Furthermore, the polyols containing flame retardant element P are used to react foamy with polyisocyanate to prepare a novel flame retardant polyurethane phase change materials (RPUF-PEG/P). Influences of that flame retardant element P and PEG on the flame retardancy, thermal stability and smoke-suppression property of RPUF-PEG/P were investigated using Fourier-transform infrared spectroscopy, limiting oxygen index (LOI) measurement, UL-94 horizontal burning level test, thermogravimetric analysis, smoke density test and cone calorimeter test. Results showed that flame retardant element P and PEG can endow RPUF-PEG/P with a great fame retardancy and thermal stability. The LOI of RPUF-PEG10/P9 was increased from 25.2 to 39.6% as compared to pure RPUF, and the density, heating rate and residual carbon content were 480 kg/m3, 0.95 °C/min and 21.46%, respectively, meeting the highest grade in UL-94 horizontal burning level test. Besides, the total heat release of RPUF-PEG10/P3 was 271.34 kw/m2, while the time to Ignition of RPUF-PEG10/P3 was increased from 4 to 22 s. Moreover, it is observed that PEG has a minimal impact on the flame retardancy and smoke generation, but the maximum smoke density, smoke density rating and total smoke production of RPUF-PEG/P increased as the increase of the P contents. [ABSTRACT FROM AUTHOR]

In this study, a new epoxidized oil from Citrullus colocynthis seed oil (CCSO) was obtained for a potential application in the formulation of polyurethane coatings. Initially, the fatty acid composition of CCSO was determined by gas chromatography–mass spectrometry (GC–MS). Subsequently, the epoxidation of CCSO was performed with in situ generated peracetic acid, which was formed with hydrogen peroxide (30 wt.%) and glacial acetic acid and catalyzed with sulfuric acid. The reaction was continued at a molar ratio of 1.50:1.0 of hydrogen peroxide to double bond (H2O2:DB) for 6 h at a controlled temperature of 60 °C. The resulting epoxidized oil was then used to produce a bio-based polyol by hydroxylation. The molar ratio of epoxy groups to methanol and distilled water was maintained at 1:11:2, and the reaction was carried out for 2 h at a controlled temperature of 65 °C. The major functional groups of the epoxidized oil and its polyol were validated by Fourier-transform infrared (FT-IR) and proton nuclear magnetic resonance (1H NMR) spectroscopies. A polyurethane (PU) coating was produced from the synthesized polyol and 3HDI isocyanurate, keeping the molar ratio of NCO:OH at 1:1. The resulting PU coating was then applied to glass and aluminum panels (Al 1001). After the film was cured, the properties of the PU coating were evaluated using various techniques including pencil hardness, pendulum hardness, adhesion, gloss, chemical resistance, and EIS tests. The results show that the PU coating obtained from CCSO is a promising new raw material for coating applications. [ABSTRACT FROM AUTHOR]

The search for innovative and sustainable solutions to improve the energy efficiency of the construction industry has been a hot topic for researchers due to the tremendous impact of insulator materials in the thermal comfort of buildings. In the present work, an innovative lightweight composite material with thermal insulation properties was developed, for the first time, by using cardoon particles and polyurethane. The formulation of the composite material was optimized in terms of cardoon fraction and the polyol/isocyanate ratio, to achieve the best compromise between internal bond (IB) strength and thickness swelling (TS). The best performing composite was PU75-CP45, with 45 wt% of cardoon particles and 75% of isocyanate, achieving an IB of 0.41 MPa and a TS of 5.3%. Regarding insulation properties, the PU75-CP45 composite material exhibits a promising performance when compared to conventional construction industry materials by tuning its thickness. Additionally, the composite material presented very low emissions of volatile organic compounds and formaldehyde (bellow to legislation levels) and high resistance to biological degradation. [ABSTRACT FROM AUTHOR]

Polyurethanes (PUs) pose great potential in diverse applications, including the functionalization of fabrics, owing to their promising mechanical characteristics and biological compatibility. Here, a green synthesis of PUs has been carried out using the dispersion polymerization technique. The process includes the production of soybean oil-polyol through epoxidation, the preparation of PUs through the formation of polyurethane pre-polymer using an aromatic diisocyanate, i.e., toluene-2,4-diisocyanate, and different mole ratios of sodium alginate used as chain extender. Polyurethane dispersions were obtained by adding specific amount of distilled water. Further, structural attributes of soybean-sodium alginate-based waterborne polyurethanes (SO-SA-PUAro) were identified using an ATR-based Fourier Transform Infrared (FTIR) spectrophotometer, and physico-chemical properties like solid contents, physical appearance, and dispersion stability were observed and co-related with other outcomes. Moreover, synthesized polyurethane dispersions were applied to the plain weaved polyester-cotton blended textile substrate using pad-dry-cure methods. Significant gradual improvements in textile attributes like tensile strengths (from 873 N/m to 989 N/m on warp and 639 N/m to 729 N/m on warp and weft side of fabrics respectively), rubbing fastness (from 3 to 4/5 and 2 to 4 for dry and wet rubbing tests respectively), washing fastness (from 3–4 to 4–5), anti-pilling property (from 2–3 to 4–5), crease recovery angle (from 1.96 cm to 2.74 cm and 1.95 cm to 2.62 cm on warp and weft sides of the fabrics respectively), bending lengths (from 98° to 122° and 88° to 114° on warp and weft sides of the fabrics respectively), and anti-microbial tests (26 mm for E.coli and 27 mm for Cocci bacterial strains) were observed with increasing moles of sodium alginate as chain extender. However, a decreasing trend in tear strengths (from 12.89 lbf/in to 11.65 lbf/in and 10.12 lbf/in to 8.92 lbf/in on warp and weft sides of the fabrics) of the treated fabrics was noted. The outcomes of the study demonstrated that polyurethanes synthesized through bio-based polyol and chain extender have considerably enhanced the textile attributes of fabric and are good alternatives to replace petroleum-based raw materials. [ABSTRACT FROM AUTHOR]

In this work, ladder‐like polyphenylsiloxane containing silanol groups was used for modification of polyurethane (PU) based on MDI and polypropylene oxide polyol. The obtained coatings have excellent mechanical performance and adhesion to steel. This improvement was confirmed through a combination of characterization techniques. The tensile strength and strength adhesion to steel increase by more than one order of magnitude when polysiloxane fraction increased from 10 to 50 wt.%. With an increase loading level, the coating transforms from hydrophilic to hydrophobic. The reinforcement effect was motivated by restriction of molecular mobility in PU matrix as was shown by solid‐state 1H NMR spectroscopy and formation of chemical bonds between PU and polysiloxane units. [ABSTRACT FROM AUTHOR]

This study introduces fractionated lignin as an innovative component in the formulation of rigid polyurethane/polyisocyanurate (PUR/PIR) foams. Low‐density PUR/PIR rigid foams were prepared by replacing 80% of the petrochemical‐based polyol with a hybrid poplar (HP) lignin, recovered via alkaline pretreatment, and also with a fraction of this lignin, isolated via the Aqueous Lignin Purification with Hot Agents (ALPHA) process. The as‐recovered HP and ALPHA‐fractionated HP lignins were characterized to determine hydroxyl content, molecular weight (Mw) distribution, and pH. Both lignin‐based foams met minimum standard requirements in terms of closed cell content, compression strength, and thermal conductivity. Notably, the foams made with ALPHA‐based lignin outperformed the as‐recovered lignin‐based foams in all measured foam properties. Moreover, the ALPHA‐based foam had comparable performance to the control foam (without lignin) except for density and even surpassed the control foam in closed cell content and compressive strength. This investigation of the molecular properties of lignin suggests that significant reductions in lignin average molecular weight and polydispersity (PDI) can positively impact the properties of lignin‐based rigid foams. [ABSTRACT FROM AUTHOR]

Polyurethanes (PU) are unique heteropolymers with a wide range of physicomechanical properties, fields of use and high development potential. PU is obtained by condensation of diisocyanate and various polyol compounds. The peculiarities of the structure and synthesis of commercial polyols based on the products of secondary oil processing, namely oligomeric glycols, oxides and dicarboxylic acids are presented. [ABSTRACT FROM AUTHOR]

Sustainability and renewability are the terms that concern most researchers today. In the world of paints and adhesives, polyurethane (PU) is a popular material due to the enormous possibilities in the choice of raw materials. The scientific community today is more focused on adopting water-based and low-solvent or solvent-free technologies instead of traditional solvent-based routes in the synthesis of PUs. Adopting more ecological routes is a step towards achieving the goal of sustainable and renewable development. The use of bio-derived monomers not only contributes to the goal of sustainable development but also eliminates the uncertainty of price, availability and environmental hazards associated with traditional petroleum-derived monomers. Among the biologically derived resources, vegetable oils are the most promising and most studied raw materials in the PU industry due to their abundance, inherent biodegradability, non-toxicity and low price. Since primitive times they had traditionally been used for coatings and adhesive applications. Today, the full field use of vegetable oil-based monomers or polymers as raw material is an excellent effort for a sustainable future in the world of coatings and adhesives worldwide. The review highlights recent advances in vegetable oil-based polyols as an environmentally friendly material for PU coating and adhesive applications. [ABSTRACT FROM AUTHOR]

The aim of this review article is to show the most recent research on obtaining waterborne polyurethane (WPU) coatings and adhesives using polyester polyol from polyethylene terephthalate (PET) waste, and describing their properties, in the search for a more sustainable product. WPU is obtained in two stages: (1) PET-based polyester polyol synthesis and (2) WPU synthesis. In the first stage, glycolysis is the most widely used degradation method for PET and zinc acetate catalyst to obtain polyester polyol, resulting in oligoesters. Studies with different degradation agents (propylene glycol, triethylene glycol and polyethylene glycol) of PET were highlighted, resulting in different oligoesters. A trend was observed in polyester polyol from the reaction of the post-consumption PET oligoester of using vegetable oil, particularly castor oil. A promising process was also found to obtain PU from polyester polyol in a single stage with renewable oil, which traditionally involves two stages. In the second stage, the processes using acetone solvent and prepolymer mixture were the most commonly used to prepare WPUs. The different synthesis pathways result in different WPU properties, which consequently serve different markets. It was found that adding polyester polyol to the flexible segment of WPUs (synthesized with PET and vegetable oil) led to a more flexible product, an important quality for coatings and adhesives. The presence of cutting agents, chain extenders and nanoparticles had a positive influence on the thermal stability of WPUs. The thermal degradation temperature of WPUs increased by up to 19 °C when PET oligoesters were used for their synthesis, compared to those synthesized without PET oligoesters. Moreover, the initial WPU degradation temperature can increase by up to 60%, depending on the type of glycol (propylene glycol, triethylene glycol, polyethylene glycol) and the PET/glycol molar ratio used in oligoester synthesis (1:2 or 1:10). [ABSTRACT FROM AUTHOR]

Depletion of fossil fuels and climate issues are calling for renewable sources of chemicals such as modern biomass, yet converting biomass into chemicals is challenging due to the inherent molecular complexity of biomass composition. Here, we review recent methods for the production of polyols from vegetable oil, lignin, and carbohydrates. We also review the production of polyurethane from biomass polyols. Conversion of vegetable oil into polyols is done by epoxidation, hydroformylation, and transesterification. Conversion of lignin into polyols is done by solvothermal liquefaction, hydroxymethylation, oxypropylation, and phenolation. [ABSTRACT FROM AUTHOR]

A synthetic strategy for the preparation of novel and reprocessable biobased polyisobutylene (PIB) – polyurethane (PU) network with soybean oil (SBO) derivative was reported. For this purpose, SBO triglycerides were converted to a polyol with primary hydroxyl functionalities via UV activated thiol-ene chemistry. Optimization of grafting of hydroxyl groups was performed by varying the process parameters such as ratios of both initiator and thiol to double bond as well as the irradiation time. SBO/PIB based PU network (X-SBO/PIB-PU) was then prepared by successful integration of the SBO based polyol to PIB-PU formulation as a co-polyol. The resultant network formed a nearly optically clear film which can be swollen in good solvent. Selective cleavage of the ester bonds by acid catalyzed hydrolysis was found to be an efficient way to solubilize the network by enabling the recovery of polyurethane segments with carboxylic acid functionalities. Thermal, mechanical and microstructural characterization data confirmed that hydrolysis of the network can be conducted without disturbing the polyurethane structures with high mechanical and thermal stability. It has been suggested that hydrolyzed X-SBO/PIB-PU (H-SBO/PIB-PU) with polar functional groups can then be used as building block in the development of polymer conjugates formulated with rigid polymers and nanocomposites. [ABSTRACT FROM AUTHOR]

A novel castor oil‐based multifunctional polyol (CM) is fabricated through mild thiol‐ene photo induced reactions using castor oil (CO) and 1‐thioglycerol (MPD) as building blocks. The effect of the reaction time, molar ratio of thiol to carbon–carbon double bond, and the loadings of photo‐initiator are optimized. The resulting CM is combined with CO and employed as cross‐linkers to prepare castor oil‐based water‐borne polyurethane emulsion with desirable mechanical properties and water resistance. Owing to the incorporation of CM cross‐linker with high hydroxyl value of 371 mg KOH/g (which is 2.27 times higher than that of the CO), the prepared castor oil‐based waterborne polyurethane (CMWPU) possesses compacted 3D network structure with high cross‐linking degree, leading to improved glass transition temperature (45 °C), tensile strength (10.8 MPa), water contact angle (87.4°), and decreased water absorption rate (16.12%) with 20% CM additions. Overall, this work illustrates the feasibility of introducing bio renewable CM combined with CO to develop castor oil‐based WPU employing a sustainable development strategy. [ABSTRACT FROM AUTHOR]

To study the rheological and aging properties of vegetable oil–based polyurethane (V-PU) modified asphalt, V-PU terminated with an –NCO group was synthesized from renewable castor oil, and liquefied MDI-100LL and 10–40 wt% V-PU modified asphalts were prepared. Temperature classification, multiple stress creep recovery (MSCR), and linear amplitude scanning (LAS) tests were carried out. The results showed that the modulus, the creep recovery rate (R), and the yield stress and yield strain of the V-PU modified asphalts significantly increased in the order: 0 wt% < 10 wt% < 20 wt% < 40 wt% < 30 wt%, while the phase angle and the unrecoverable creep compliance (Jnr) changed in the opposite order, and the high temperature grade of 30 wt% V-PU modified asphalt was 4 grades higher than that of the base asphalt, which indicated that the addition of V-PU enhanced the fatigue, permanent deformation, and recovery deformation resistance. The 30 wt% sample exhibited phase inversion had the best performance. Comprehensive FTIR, GPC, and fluorescence microscopy analyses showed that the molecular weight significantly increased and the V-PU molecules agglomerated after aging. The excess –NCO groups of V-PU prepolymer react with water in the air and the active hydrogen in the asphalt system and finally form a cross-linked three-dimensional network structure with the asphalt to improve performance. The mechanism of intramolecular cementation reaction and the aging process of V-PU modified asphalt was creatively derived. [ABSTRACT FROM AUTHOR]

Flame retardant polyurethane was synthesized via introducing thermally reversible covalent Diels–Alder (DA) adducts into the polyurethane main chain. Firstly, furan-terminated polyurethane prepolymer(PU-Furan) was synthesized from the reaction between isocyanate-terminated prepolymer with or without DOPO-based polyester polyols and furfuryl amine. Secondly, polyurethane with DA adducts (PU-DA) was obtained via Diels–Alder reaction between PU-Furan and commercial 1,1′-(methylenedi-1,4-phenylene) bismaleimide. PU-Furan and PU-DA were characterized by DSC, TGA and 1H NMR, confirming the introduction of the DA adducts into the polyurethane chain. The results of the limiting oxygen index test, Underwriter Laboratory 94 vertical burning (UL-94) test and cone calorimeter test demonstrated that the introduction of the DA adducts improved the flame retardancy of the polyurethane significantly, especially when the polyurethane with flame-retardant element P, due to the synergism flame-resistant effect between flame-retardant element P and thermally reversible DA adducts. [ABSTRACT FROM AUTHOR]

The study focuses on the synthesis of polyurethane (PU)‐based coating from modified castor oil (CO) via an in situ polymerization process. CO was modified by employing multiple process steps, that included epoxidation, followed by transesterification and acrylation to get the required polyol for PU synthesis. The structural properties were studied using Fourier transform infrared and 1H NMR spectra. Thermogravimetric analysis (TGA) and differential scanning calorimetry revealed an increase in the final degradation temperature and glass transition temperature from 358 and −46.58 °C to 368 and −37.43 °C respectively after transesterification followed by acrylation of epoxidized CO. Hydroxyl value, acid value, amine value and viscosity were observed to change from 208 mg/KOH, 1.75, 13.09 and 428 mPa s to 233 mg/KOH, 1.16, 19.53 and 318 mPa s after transesterification and acrylation of epoxidized CO. Paint formulations at variable OH:NCO ratios like 1:0.9, 1:1 and 1:1.1 were optimized by following the cross‐cut tape test, lap‐shear test, abrasion resistance test and pencil hardness test. Crosslinking density of the paint samples was calculated and the morphological properties of the optimized coating sample were studied using a scanning electron microscope. TGA was carried out to study the thermal properties of the coating. © 2022 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Polyurethane (PU), currently replacing existing synthetic materials worldwide, is a synthetic polymer derived from polyols, isocyanates, and a chain extender added by condensation reactions. PU wastes which are difficult to recycle, are commonly discarded in landfills and flow into ecosystems, thereby causing serious environmental problems. In recent years, insect-associated microbes have become a promising, eco-friendly strategy as an alternative to plastic recycling. This study aimed to evaluate the potential of Serratia sp. HY-72 strain isolated from the intestine of the Asian mantis (Hierodula patellifera) for PU degradation. The 65 kDa family I.3 lipase which degrades PU was identified and characterized, with a specific activity of 2,883 U mg−1 . The bacterial filtrates and the recombinant lipase degraded Impranil (a colloidal polyester-PU dispersion, 100 g l−1 ) by 85.24 and 78.35% after 72 h incubation, respectively. Fourier transform infrared spectroscopy analysis revealed changes in Impr anil functional groups, with decreased C=O functional group and aliphatic chain signals, and increased N-H bending with C-N stretching and C-O stretching. The current study also revealed that the HY-72 strain biodegraded the commercial PU foams (polyester- and polyether- PU) with 23.95 and 10.95% weight loss after 2 weeks, respectively with changes in surface morphology and structure such as cracks, roughness, and surface roughening. Altogether, this is one of the few studies reporting biodegradation of PU by the insect associated microbe. These findings suggest that the insect-associated microbe could be a promising resource for biodegradation and recycling of plastic waste. [ABSTRACT FROM AUTHOR]

Biobased polyurethane nanocellulose nanocomposites were synthesized from cottonseed oil as the source for the biopolyol. The prepared composites were used to study the adsorption of Rhodamine B dye from water. Low functional polyol was derived from cottonseed oil using one-pot synthesis method. Nanocellulose was derived from pineapple leaves and then it was surface-functionalized via silylation. In-situ polymerization technique was used to incorporate the silylated nanocellulose into the polyurethane matrix. The prepared polyol from cottonseed oil was found to have an OH functionality of 2 which was confirmed by Fourier transform infrared spectroscopy (FT-IR) and Nuclear magnetic resonance (NMR) spectroscopy. Low functionality of polyol is the key factor in achieving flexible porous polyurethane. The silylated nanocellulose, polyurethane, and composites were characterized by FT-IR, X-ray diffraction analysis (XRD), and Scanning electron microscopy (SEM). The adsorption parameters were optimized using the Taguchi methodology and the adsorption efficiency was determined by carrying out adsorption at optimized parameters (5 wt% loading of silylated nanocellulose, pH 9, and temperature of 30 °C) for 8 h. Studies showed that the prepared composite has a high adsorption efficiency of 597 mg/g of silylated nanocellulose towards Rh-B. [ABSTRACT FROM AUTHOR]

In the transition to renewably sourced, biodegradable polymers, the preparation of low viscosity polyester‐polyols has posed a challenge for renewable polyurethane (PU) development. Low viscosity polyols not only reduce the requirement for high process temperatures but also decrease manufacturing time. In our efforts to incorporate increasing ratios of bio‐based monomers into renewable PUs, we mixed diacids such as even carbon sebacic acid and odd carbon azelaic acid along with a renewable diol. This provided library of 2000 g/mol molecular weight polyester‐polyols, and structures were established by 1H and 13C NMR analysis. The prepared polyester‐polyols offered lower viscosity and enable lower fabrication temperatures to make TPUs, and their structure and material metrics were evaluated. The formation of TPUs is ascertained from FTIR and NMR analysis. The final TPUs displayed good physical and mechanical properties. These TPUs exhibited Tg in the range of −56.5 to −39.7°C, corresponding to TPU soft block structure, and Tm between 98.3 and 105.1°C originating from the hard segment. Prepared TPUs exhibit excellent biodegradation under compost environmental conditions. These TPUs showed up to 57% decrease in molecular weight by GPC analysis after 9 weeks of biodegradation, and respirometer analysis displayed up to 97% biodegradation over 120 days. [ABSTRACT FROM AUTHOR]

A series of polyurethane (PU) copolymers was synthesized by 4,4‐Methylene diphenyl diisocyanate (MDI) with different polyols of polyether, polyether carbonate (PEC), and polycarbonate with the same molecular weight via a one‐step copolymerization process. The synthesized PU containing the ether carbonate groups exhibited a relatively higher glass transition temperature (Tg) above 45°C; in comparison, a value of 12.4°C for the polycarbonate sample and −22°C for the polyether sample was observed. The film made of PEC samples produced by solvent indicated an increment of Tg from 14.6 to 59.6°C after annealing for 6 h, which might be due to the rearrangement of chain structure, which led to an assembling of carbonate groups and resulted in a hindrance of chain mobility. For shape memory examination of the PU copolymers, all samples showed remarkable ability as recovery rate above 91% after 3 cycles test. PEC‐type PU polymers reveal potential high‐temperature micro shape memory material applications. [ABSTRACT FROM AUTHOR]

Polyurethanes are gaining increasing interest for their use as structural components subjected to cyclic loads, such as leaf springs. Thermoset polyurethane (PUR) based technology offers some advantages, such as fatigue resistance, low viscosity, and fast curing. However, current PUR formulations present two major drawbacks: their petrochemical origin and high reactivity. The aim of this work was to develop a novel biobased PUR (BIO-PUR) with the required mechanical properties and processability for manufacturing structural composites by resin transfer moulding (RTM). For this purpose, a high functionality and high hydroxyl index castor-oil-based polyol was used combined with a biobased glycerol (BIO-Gly) to increase the crosslinking density and improve the final properties of the BIO-PUR. The viscosity and reactivity of the different systems were studied by means of rheology tests and differential scanning calorimetry (DSC). Thermal and mechanical properties were studied by dynamic mechanical analysis (DMA) and flexural tests. Furthermore, the RTM process of a representative part was simulated and validated through the manufacturing and testing of plates. The properties of the BIO-PUR resin systems were strongly influenced by the addition of biobased glycerol and its effect on the crosslinking density. The combination of a high functionality and hydroxyl index biobased polyol with the biobased glycerol resulted in a high-performance BIO-PUR with the required reactivity and final properties for structural applications. [ABSTRACT FROM AUTHOR]

In this research paper, we investigated the impact of soft segment crystallization, the cross‐linking density (CLD) and elastic modulus of the synthesized thermoset polyurethanes on their shape memory performance (SMP). A group of tri‐block copolymers of poly(ϵ‐caprolactone) (PCL) and poly(tetramethylene glycol) (PTMG) with PCLx‐PTMG2000‐PCLx architecture were synthesized and used as polyols in a thermoset polyurethane (PU) structure. Crystallization of the soft segments was controlled through changing PCLx blocks' length. Graphene nanoplatelets, with a fixed content of 0.50 wt.%, was used as the cross‐linker and the nano‐filler to tune elasticity of the PUs. Analysis of crystallization showed that by increasing PCLx's length from 0 to 2000 D caused a drastic change in the crystallization behavior of the polyols. The polyols used in the thermoset PU nanocomposite led to a wide spectrum of elastic modulus at temperatures close to room temperature. The elastic modulus at room temperature ranged from 20 to 100 MPa. The changes in elastic modulus, CLD and soft segments' crystallization resulted in a complex SMP behavior, which was studied in‐detail. The shape recovery rate was also studied, which showed the impact of crystallites' melting, CLD and elastic modulus through a three‐stage shape recovery. [ABSTRACT FROM AUTHOR]

In the past decades, polyurethane has emerged as a new material that has been widely developed and applied in coated controlled release fertilizers (CRFs). Particularly in recent years, the excessive consumption of petroleum resources and increasing demand for sustainable development have resulted in considerable interest in bio-based polyurethane coated controlled-release fertilizers. This review article focuses on the application and progress of environmentally friendly bio-based materials in the polyurethane-coated CRF industry. We also explore prospects for the green and sustainable development of coated CRFs. Using animal and plant oils, starch, lignin, and cellulose as raw materials, polyols can be produced by physical, chemical, and biological means to replace petroleum-based materials and polyurethane film coating for CRFs can be prepared. Various modifications can also improve the hydrophobicity and degradability of polyurethane film. A growing body of research on bio-based polyurethane has revealed its great potential in the production and application of coated CRFs. The purpose of this review is to highlight the practicality of bio-based materials in the application of polyurethane-coated CRFs and to clarify their current limitations. [Display omitted] [ABSTRACT FROM AUTHOR]

The automobile paint industry normally consumes petro‐based feedstock as the raw material, which is non‐renewable and emits a higher amount of volatile organic compound, that pollutes the environment. This study focuses on the use of eco‐friendly castor oil (CO) as a substitute for petro‐based feedstocks; while synthesizing polyurethane (PU)‐based automobile clear coats. An acrylate‐PU/nano‐silica (NS) hybrid coating was developed, which was derived from CO‐based polyol. CO was modified by employing a process that includes epoxidation, followed by transesterification, and acrylation to synthesize the required polyols, which is used for acrylate‐PU paint synthesis via the in‐situ polymerization process. Triallyl isocyanurate (TI) modified NS particles were incorporated with the paint matrix by the ultrasonication method to enhance the paint properties. Experimental findings revealed that with the incorporation of NS particles, char residue, Young's modulus, abrasion resistance, and cross‐cut adhesion % increased by 71.31%, 42%, 0.28%, and 5% respectively. Also, glass transition temperature, pencil hardness, nanoindentation depth, water contact angle, and cross‐linking density were increased from −12.16°C, 2H, 3300 nm, 81.71°, and 0.90 mol/m3 to 1.65°C, 3H, 2000 nm, 92.26°, and 1.78 mol/m3 respectively. The UV‐visibility spectra, haze, transmittance, and gloss parameter showed the enhanced optical properties of the paint samples. PU/NS composite coating developed showed equivalent properties as that of the commercial clear coat. [ABSTRACT FROM AUTHOR]

Waste soybean oil resulting from repeated cooking and heating is a significant component of food industry waste. Transforming this waste soybean oil into eco-friendly and various products offers an efficient solution to enhance resource utilization. This study employed thermal cycling treatment to simulate the cooking process of soybean oil and analyzed its impact on synthesizing epoxidized soybean oil, soybean oil polyols, and soybean oil-based waterborne polyurethanes. Waste soybean oil was demonstrated to be a cost-effective feedstock for producing vegetable oil-based waterborne polyurethanes. For more diversified applications, the synthesized waterborne polyurethanes were utilized in the preparation of carbon quantum dots, resulting in a diverse range of colors through the incorporation of gardenia pigments. Moreover, through complexing with gelatin, robust composite films and multicolored fluorescent anti-counterfeiting inks were produced. The waterborne polyurethane is found to form a composite cross-linking network with gelatin, resulting in an increase in tensile strength of 130.72% and elongation at break of 258.98% for the composite film compared to the pure gelatin film. In comparison to physical blending, chemical grafting of gardenia pigment enhances the printability and firmness of the ink. The printed pattern produced by the ink emits a vivid blue fluorescence when excited at a wavelength of 365 nm, making it valuable for anti-counterfeiting ink applications. [Display omitted] • A waste soybean oil-based waterborne polyurethane was successfully prepared. • Adjustable CDs were synthesized with soybean oil-based waterborne polyurethane. • The polyurethane/gelatin composite film shows excellent mechanical property. • The composite ink has good printing suitability and anti-counterfeiting value. [ABSTRACT FROM AUTHOR]

Although current technology related to transformation of carbon‑carbon double bonds and ester groups of plant oils into hydroxyl groups have created variety of polyols for bio-based polyurethane, the resulting polyurethane always demonstrated poor mechanical properties and low glass transition temperature (T g) due to lack of rigid units of these plant oil-based polyols. In this study, a strategy was proposed to utilize sucrose stearates with rigid pyran-furan ring and flexible side chains as plant-derived polyols which long-flexible fatty acids extracted from vegetable oils were bound to sucrose through ester bonds. These sucrose stearates could be directly used as Plant-derived polyols without any modification step for introducing hydroxyl groups on fatty acid chains applied by traditional technology in which the residual hydroxyl groups in the sucrose unit acted as the reactive sites for the following polymerization. A series of sucrose stearate-based polyurethanes were synthesized by reacting sucrose stearates with 1,6-diisocyanatohexane in a stoichiometric ratio. The resulting polyurethane membranes showed high transparency (>90 %, colorless), high friction resistance (7H), high water resistance, high glass transition temperature (105 °C) and excellent mechanical performance due to synergistic effect of rigid main chains of sucrose and flexible side chains of stearates. This study reported a new strategy for bio-based polyols and high performance polyurethanes which could find potential applications as functional and renewable biomass-based coatings, membranes or plastics. • Sucrose stearates with rigid sucrose structure and flexible fatty acid chain as novel polyols • Sucrose stearate-based polyurethanes with high glass transition temperature • Sucrose stearate-based polyurethane membranes and coatings with superior stiffness and hydrophobicity [ABSTRACT FROM AUTHOR]

Polyesteramide polyol was synthesized by employing aminolysis with a base catalyst with custard apple seed oil as source material. It was afterward esterified with phthalic anhydride to form polyesteramide polyol. Polyurethane coatings are produced by combining polyesteramide polyols, which are synthesized, with hexamethylene diisocyanate trimer (HDI). The co-precipitation technique was used to synthesize a nickel-aluminum layered double hydroxide (Ni-Al LDH). Subsequently, the synthesized Ni-Al LDH was further modified by incorporating the corrosion inhibitor 2-mercaptobenzothiazole (MBT) into its interlayer space by the in-situ method. The synthesized Ni-Al LDH and Ni-Al-MBT LDH are then incorporated into the polyesteramide polyol to enhance the anti-corrosive properties of the polyurethane coatings. The synthesized diethanolamide, polyesteramide polyol, and LDH have been characterized using FTIR whereas SEM and XRD are specific to LDH analysis. EIS, DSC, TGA, salt spray, contact angle, and mechanical testing such as thickness, adhesion flexibility, scratch hardness, impact resistance, and pencil hardness are focused on coating evaluation. The incorporation of LDH led to a substantial enhancement in the coating's corrosion resistance, as evidenced by a decrease in corrosion. Incorporating LDH and MBT-LDH improved the scratch resistance of the coating by 1.5 kg compared to plain PU coating, whereas hardness properties also improved slightly. In anticorrosive analysis, it is observed that LDH and MBT-LDH show better anticorrosive performance as compared to plain PU coating. [Display omitted] • Utilization of waste seed-based oil for the development of coating and its performance improvement with layered materials. • Synthesis and characterization of polyesteramide polyol from custard apple seed oil. • Incorporation of nickel-aluminum layered double hydroxide (Ni-Al LDH) and LDH-MBT into the polyesteramide polyol. • Characterization- FTIR, SEM, XRD, EIS, DSC, TGA, salt spray, and mechanical testing to evaluate the LDH-modified coatings. • Significant improvement in corrosion resistance observed in the LDH-modified polyurethane coatings. [ABSTRACT FROM AUTHOR]

Amorphous structural CO2‐polyol was used to modify ester‐based water‐borne polyurethanes (WPUs), resulting in improved low temperature film forming and comprehensive hydrolysis/oxidation resistance properties. Excellent intact films can be easily formed even at 3°C by adding 5% CO2‐polyol into the ester‐based WPUs (namely PU5CO2). Moreover, WPUs modified by CO2‐polyol show superior hydrolysis/oxidation resistance properties than that of control samples based on castor oil or poly(propylene oxide) glycol. PU5CO2 showed significantly enhanced retention tensile strength from 40% to 68.2% than that of pure ester‐based WPU after 5 h immersion in 1.5% NaOH solution, indicating an improved hydrolysis resistance. In addition, the PU5CO2 displayed boosted oxidation resistance property with retention strength increased from 39% to 65%. Notably, the all‐around aging resistance of ester‐based WPUs intensified with an increase of CO2‐polyol content. This work indicates that the CO2‐polyol may be a promising modified material to improve comprehensive hydrolysis/oxidation resistance and low temperature film forming for ester‐based WPUs. [ABSTRACT FROM AUTHOR]

Carbon dioxide (CO2) capture from natural gas, and further utilization is an essential issue for greenhouse gas reduction. Poly(ionic liquid)s (PILs) assemble ILs unique properties, with those of polymers being versatile materials for CO2 capture from flue gas (CO2/N2) and natural gas (CO2/CH4). PILs based on polyurethanes obtained with different polyols and ILs cations were blended in different proportions aiming to improve PILs CO2 sorption capacity. Two different polyols structures (PC and PG) and ILs counter cations (imidazolium and phosphonium) were tested to evaluate how they influence PILs blends CO2 sorption performance. PILs and PILs blends were characterized by SEC, FTIR, DSC, TGA, DMTA, AFM, and CO2 sorption that were carried out using the pressure-decay technique. PILs blends presented good thermal stability and mechanical properties. PILs blend polyurethane backbones compositions can be tuned aiming to increase CO2 sorption capacity. As far as we know, all obtained PILs blends presented higher CO2 sorption capacity results compared with other Poly(ionic liquid)s reported in the literature. The best CO2 sorption result was obtained for PIL blend with imidazolium (PLIPC95-PG5-BMIM = 116.9 mgCO2/g at 303.15 K and 10 bar). [ABSTRACT FROM AUTHOR]

Polyurethane (PU) is one of the most versatile polymers available and can be found in an infinite number of formats ranging from rigid or flexible foams to elastomers. Currently, most Rigid PU Foam (RPUF) waste is landfilled, even though a small amount is mechanically recycled, in which the material is conditioned in size to a very fine powder, which is introduced as a filler. In this work, chemical recycling of two types of rigid PU foams is studied, the major difference being the aliphatic or aromatic nature of the isocyanate used in the synthesis. A solvolysis process is developed, a chemical depolymerization that breaks the chains by means of a chemical agent, a solvent, in the presence of a catalyst and under controlled process conditions. The glycolysis products are purified by vacuum distillation, centrifugation, and acid water treatment, depending on the most suitable process for each waste type. Optimal process conditions are established to obtain high-purity green polyols by performing a set of catalytic glycolysis reactions at laboratory scale with the previously conditioned RPUF waste samples. The physicochemical properties of the polyols, such as hydroxyl value, acid value, average molecular weight (Mn), and viscosity, are analyzed. The chemical structure and thermal stability of the polyols are studied by means of FTIR and TGA, respectively. Partial substitution of the commercial polyol (up to 15 wt.%) by the recycled polyols for RPUF synthesis is studied and characterized. [ABSTRACT FROM AUTHOR]

This study investigated the synthesis of bio-based polyurethane (PU) film from palm kernel oil-based polyols (PKO-p) at four different isocyanate-to-polyols (NCO/OH) ratios comprising 100/100, 100/150, 100/200, and 100/250. The PU film was prepared by mixing 2,4-methylene diphenyl diisocyanate (MDI) and PKO-p in acetone using the pre-polymerization technique under a nitrogen atmosphere at room temperature. The effect of the NCO/OH ratio on the properties of the PU films was analyzed through infra-red spectroscopy, molecular weight distribution, thermal behavior, and impedance spectroscopy. According to the infra-red spectroscopic analysis, the formation of urethane linkages (--NHCOO--) after the polymerization was indicated through the disappearance of isocyanate (N=C=O) peak and the appearances of secondary amine, carbonyl, carbamate, ether, and ester groups in the PU chain. In addition, the Gel Permeation Chromatography (GPC) showed that the weight of average molecular weight (MW) increased with increasing NCO/OH ratio up to 1.23 x 106 g mol-1. Nevertheless, higher content of PKO-p resulted in a low crosslink PU (4 % crosslink) and poor physical properties such as soft, sticky, and easy to tear due to the non-hydrogen bonded urethane. Moreover, the glass-transition temperature (Tg) reduced from 67 °C to 30 °C with the increase in PKO-p content. Despite all samples experienced the same thermal stability at 187 °C, a significant difference was observed in the mass loss of NCO/OH ratios. The highest thermal degradation was found at (100/200) NCO/OH ratio with Tmax = 444 °C. Furthermore, the piezoelectricity characteristic of pristine PU recorded the bulk resistant of up to ~107 -- 105 Ω which reduced further after the presence of lithium iodide (LiI) salts as the charge carrier with the calculated ionic conductivity around 10-5 S cm-1. Thus, this study demonstrated the promising physicochemical properties of PU film from PKO-p for polymer electrolyte application. [ABSTRACT FROM AUTHOR]

The operation of mechanical equipment inevitably generates vibrations and noise, which are harmful to not only the human body but also to the equipment in use. Damping materials, which can convert mechanical energy into thermal energy, possess excellent damping properties in the glass transition region and can alleviate the problems caused by vibration and noise. However, these materials mainly rely on petroleum-based resources, and their glass transition temperatures (Tg) are lower than room temperature. Therefore, bio-based materials with high damping properties at room temperature must be designed for sustainable development. Herein, we demonstrate the fabrication of bio-based millable polyurethane (BMPU)/hindered phenol composites that could overcome the challenges of sustainable development and exhibit high damping properties at room temperature. BMPUs with a high Tg were prepared from modified poly (lactic acid)-based polyols, the unsaturated chain extender trimethylolpropane diallylether, and 4,4′-diphenylmethane diisocyanate, and 3,9-Bis-{1,1-dimethyl-2[β-(3-tert-butyl-4-hydroxy-5-methylphenyl-)propionyloxy]ethyl}-2,4,8,10-tetraoxaspiro [5,5]-undecane (AO-80) was added to prepare BMPU/AO-80 composites. Finally, the properties of the BMPUs and BMPU/AO-80 composites were systematically evaluated. After adding 30 phr of AO-80, the Tg and maximum loss factor (tan δmax) of BMPU/AO-80 composites increased from 7.8 °C to 13.5 °C and from 1.4 to 2.0, respectively. The tan δmax showed an improvement of 43%. Compared with other polyurethanes, the prepared BMPU/AO-80 composites exhibited higher damping properties at room temperature. This study proposes a new strategy to reduce society's current dependence on fossil resources and design materials featuring high damping properties from sustainable raw materials. [ABSTRACT FROM AUTHOR]

A novel polymeric resin formulation is developed to mitigate sand production from subterranean formations composed of unconsolidated or weakly consolidated sands via a chemical sand consolidation approach. The developed formulation aims to minimize the formation permeability loss commonly observed in a chemical sand consolidation treatment. The new formulation is a water‐in‐oil high internal phase emulsion with poly(ε‐caprolactone) polyol and isophorone diisocyanate monomer incorporated in the external oil phase. Highly porous, emulsion templated polyurethane forms through the reaction between polyol and isocyanate under elevated temperature. Additionally, CO2 generated through the reaction between excess isocyanate monomer and water leads to the formation of more pores in the cross‐linked polymeric network. When the developed formulation is applied for sand consolidation treatment, the interconnected pores formed after resin curing act as "channels" in the consolidated products and allow the produced fluid such as oil, water, or gas to easily flow through, thereby limiting permeability reduction. The effectiveness of using porous polyurethane material for sand consolidation is evaluated through a compressive strength and permeability study of the consolidated sandpacks prepared with this chemistry. [ABSTRACT FROM AUTHOR]

The world production of polyurethanes (PU) currently exceeds 18 mln. tons. Moreover, it is expected that, by 2024, it will become greater than 24 mln. tons. We present a survey of works available from the literature and analyzing the methods of recycling of polyurethanes aimed at the reduction of the amount of PU wastes, environmental protection, and prevention of waste dumping in the landfills. Mechanical processing proves to be the oldest and simple method used for the processing of PU wastes. The process of chemical recycling of polyurethane by glycolysis is regarded as the most environmentally friendly and economically competitive method. Glycolysis of polyurethane is a process of chemical depolymerization based on the reaction of transesterification of polyols and glycols in a molecule of urethane. This process makes it possible to destroy the polyurethane matrix and either to release polyol or to generate new recycled polyol. The possibility of application of different glycols and catalysts in the reaction of catalytic transesterification is demonstrated. [ABSTRACT FROM AUTHOR]

In this study, nineteen unmodified lignins from various sources (hardwood, softwood, wheat straw, and corn stover) and isolation processes (kraft, soda, organosolv, sulfite, and enzymatic hydrolysis) were used to replace 30 wt.% of petroleum-based polyol in rigid polyurethane/polyisocyanurate (PUR/PIR) foam formulations. Lignin samples were characterized by measuring their ash content, hydroxyl content (Phosphorus Nuclear Magnetic Resonance Spectroscopy), impurities (Inductively Coupled Plasma), and pH. After foam formulation, properties of lignin-based foams were evaluated and compared with a control foam (with no lignin) via cell morphology, closed-cell content, compression strength, apparent density, thermal conductivity, and color analysis. Lignin-based foams passed all measured standard specifications required by ASTM International C1029-15 for type 1 rigid insulation foams, except for three foams. These three foams had poor compressive strengths, significantly larger cell sizes, darker color, lower closed-cell contents, and slower foaming times. The foam made with corn stover enzymatic hydrolysis lignin showed no significant difference from the control foam in terms of compressive strength and outperformed all other lignin-based foams due to its higher aliphatic and p-hydroxyphenyl hydroxyl contents. Lignin-based foams that passed all required performance testing were made with lignins having higher pH, potassium, sodium, calcium, magnesium, and aliphatic/p-hydroxyphenyl hydroxyl group contents than those that failed. [ABSTRACT FROM AUTHOR]

• Rebiopolyols – new components. • New products characterized by a lower carbon footprint. • Chemolysis of polyurethane biofoams. • Polyurethane systems in which 100 % of the petrochemical polyol was replaced with new repolyols. The primary goal of the research presented here was to evaluate the possibility of chemolysis of polyurethane biofoams synthesized from vegetable oil-based biopolyols with different chemical structures. As a reference material, a foam synthesized in 100 % from a petrochemical polyol was used. Chemolysis of polyurethane foams was conducted by using diethylene glycol as a solvent with a 1.5:1 wt ratio of biopolyurethane scraps to glycol. The reaction was carried out at 180 °C for 100 min in the presence of potassium hydroxide as a catalyst. The results of the chemolysis of different polyurethane foams were evaluated in terms of the hydroxyl number, amine value, viscosity, molecular weight and FTIR analysis of the new rebiopolyols. It can be concluded that the chemical structures of different biopolyols (obtained through the method of transesterification of vegetable oils with two different reagents and a two-step method of epoxidation and oxirane rings opening) that are used to make biopolyurethane foams have an impact on the course of the chemolysis process and the properties of resultant rebiopolyols. In order to verify the application possibilities of the new components obtained in accordance with the idea of circular economy, extreme conditions were applied in the form of complete replacement of the polyol in the reference foam with the rebiopolyols. It was found that replacing the petrochemical polyol with the repolyol results in partial cell opening, and replacing this component with the rebiopolyols results in open-cell foams. Only the rebiopolyol derived from the biofoam with the biopolyol obtained by transesterification of oil with triethanolamine was not suitable for use in a polyurethane system because its reactivity was too high. In conclusion, there is no need to use catalysts to obtain new biofoams from rebiopolyols given the catalytic nature of the new biocomponents. [ABSTRACT FROM AUTHOR]

In the present study, a range of sustainable, biocompatible and biodegradable polyurethanes (PU-1 to PU-4) were synthesized using different combinations of biobased polyol (obtained through the epoxidation of soybean oil, followed by ring opening with ethanol) and polyethylene glycol (PEG) and isophorone diisocyanate. The sustainable chain extender used in this study was synthesized by the esterification of lactic acid with ethylene glycol (EG). The synthesized PU samples were characterized through scanning electron microscopy (SEM), Fourier transformed infrared (FTIR) and nuclear magnetic resonance (1H NMR and 13C NMR) spectroscopy. Wetting ability and thermal degradation analysis (TGA) of the samples were also studied. Subsequently, these PUs were examined as potential drug delivery systems using Gabapentin as a model drug, which was loaded in the polymer matrix using the solvent evaporation method. The drug release studies were carried out in 0.06 N HCl as a release medium according to the method outlined in the United States Pharmacopeia. The maximum drug release was observed for sample PU-P1, which was found to be 53.0 % after 6 h. Moreover, a comparison of different PU samples revealed a trend wherein the values of drug release were decreased with an increase in the PEG content. [ABSTRACT FROM AUTHOR]

The incorporation of nanofillers and the use of biobased polyols might have a deleterious effect on the aging performance of rigid polyurethane foams (RPUFs) applied in the insulation and marine industries. To study this, RPUFs obtained from petroleum based (RPUF) and castor oil (RPUFRIC) polyols were nanostructured with bacterial nanocellulose (BNC) up to 0.3 wt%. Water immersion experiments revealed that the normalized water absorption (NWA) at the steady state was not affected by lower BNC contents (<0.2 wt%). Higher BNC contents caused a complex effect on post‐cure and foaming, generating cell size expansion as well as shrinkage. In‐situ DMA aging analysis revealed that the specific storage modulus (E'sp) under flexural conditions of the RPUFRIC and RPUF decreased by a maximum amount of 7.27% and 6.19%, respectively. The effect of BNC on the E'sp was negligible, expect for the case of the RPUF, where higher BNC concentrations (>0.2 wt%) caused a decrease of up to 13.69%. The previous results reinforce the hypothesis that the incorporation of BNC in both conventional and biobased polyurethane systems do not cause significant changes on the aging performance of the resulting foams, provided that low BNC concentrations are employed. [ABSTRACT FROM AUTHOR]

Chemical recycling, in particular hydrogenative depolymerization, offers a promising way to utilize plastic waste. This report covers the manganese‐catalyzed hydrogenation of polyurethane materials to the corresponding monomeric units. The key to success is a Mn pincer complex as a potent hydrogenation catalyst in combination with elevated temperatures (up to 200 °C) and appropriate solvents to ensure sufficient solubility of the polymers. A wide range of polyurethane samples of varying polyol and isocyanate compositions, some of which feature significant amounts of urea functionalities, are depolymerized, releasing polyetherols and diaminotoluene (TDA) in yields of up to 89 % and 76 %, respectively. [ABSTRACT FROM AUTHOR]

Methyl oleate, a kind of vegetable oil derivatives, was used as the raw material to synthesize novel polyols containing nitrogen and phosphorus (PNP) by three steps: amidaion, epoxidation, and ring‐opening reaction. The structure of the ensuing PNP was characterized by gel permeation chromatography, Fourier transform infrared spectroscopy, and nuclear magnetic resonance spectroscopy. Then, polyurethane films were prepared by mixing the resulting polyols (PNP) and poly‐(tetra methylene glycol) with isophorone diisocyanate in different proportions. After that, the thermostability of polyurethane films was investigated by limiting oxygen index (LOI), thermogravimetry, and cone calorimeter test. Similarly, mechanical property of polyurethane films was studied by tensile test. The results showed that as the amount of PNP increased, the tensile strength of polyurethane films increased from 2.0 to 13.5 MPa, the LOI values of polyurethane films went up from 20.1% to 25.5%. Moreover, the initial decomposition temperature of polyurethane films improved from 280 to 312°C and the total heat release drooped from 32.2 to 21.7 kW/m2 without adding any other flame retardant. Therefore, it was observed that the polyurethane films have superior thermal stability and mechanical property and appear suitable for a wide range of applications. [ABSTRACT FROM AUTHOR]

The upcycling of waste biomass into valuable materials by resource‐efficient chemical transformations is a prime objective for sustainable chemistry. This approach is demonstrated in a straightforward light‐driven synthesis of polyols and polyurethane foams from the multi‐ton waste products of cashew nut processing. The photo‐oxygenation of cardanol from nutshell oil results in the formation of synthetically versatile hydroperoxides. The choice of the workup method (i. e. reduction, hydrogenation, epoxidation) enables access to a diverse range of alcohols with tunable alkene and OH functions. Condensation with isocyanates to give rigid polyurethane foams provides a resource‐efficient waste‐to‐value chain that benefits from the availability of cardanol and installation of OH groups from aerial O2. [ABSTRACT FROM AUTHOR]

In the current study, a combination of acrylic polyol (AP) and ester polyol (EP) were synthesized and reacted at variable ratios with hexamethylene diisocyanates and isophorone diisocyanates to prepare a transparent two‐component polyurethane (PU) coating formulation. The formations of the polyol system, isocyanate system, and the PU systems were confirmed by 1H nuclear magnetic resonance and Fourier‐transform infrared spectroscopy. Transparency of the coatings was examined using haze, and gloss measurement, which showed acrylic‐ester‐polyurethane (aePU‐5 and aePU‐6) have 91.5% and 91.8% transparency and gloss of 90.3 and 90.7 GU respectively. The thermal properties like Tg and the thermal stability of the coatings were verified using differential scanning calorimetry, and thermogravimetric analysis respectively which was found to increase with increasing EP content and decreasing AP content which may be ascribed to improved compatibility of copolymers, and homogeneity in PU along with enhanced crosslinking density. The degree of adhesion of coating with the substrate was validated from lap‐shear, and cross‐cut tape test which showed improved performance at AP:EP ratio of 60:40. The coatings were found to exhibit resistance toward pencil hardness with aePU‐5 and aePU‐6 having the optimum resistance of 9H. The surface morphology and topography were observed under scanning electron microscopy, and atomic force microscopy, respectively. The outcome confirms the higher smoothness of the surfaces subjected to the increase in EP content. The PU system with 40 wt% AP content and 60 wt% EP designated as aePU‐5 was found to exhibit optimum performance. [ABSTRACT FROM AUTHOR]

The current study presents an attempt to develop two molecules, namely sulfonated aromatic diol (SAD) and sulfonated aromatic diamine (SADAM), to induce flame retardancy, thermal stability, and dispersion ability for water-based polyurethane dispersions (WPUDs). The previously reported itaconic acid-based polyester polyol was used for prepolymer synthesis as well as for chain extension. Pre- and post-sulfonated compounds were subjected to characterization tests such as FTIR, 13C-NMR, 1H-NMR, and CHNS for confirmation of their structures. The standard dispersant used for the basis of comparison was commercially available dimethyl propionic acid (DMPA). WPUDs were synthesized in different molar concentrations of DMPA, SAD, and SADAM, and the covalent incorporation of all three molecules in the polymer backbone was confirmed by FTIR. The WPUD films were subjected to various thermal tests like TGA and DSC as well as mechanical tests like flexibility and pencil hardness. WPUD films obtained from SADAM showed a remarkable increase in Tg as well as char content. The THRI values for SAD- and SADAM-based films were better than DMPA-based films. SAD- and SADAM-based WPUD films also showed an increase in LOI value and UL-94 ratings with the maximum LOI value of 26. Dispersions based on DMPA showed better stability as compared to dispersions based on SAD and SADAM. [ABSTRACT FROM AUTHOR]

Hexamethylene diisocyanate (HMDI) reacts with 4-bromo-1H-pyrazole as a blocking agent to form blocked adducts of isocyanates. The adducts were characterized by FTIR, NMR, thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). In the FTIR spectra, disappearance of a peak at 2250–2270 cm−1 is the indication of blocking of diisocyanate molecule with 4-bromo-1H-pyrazole blocking agent. The DSC thermogram shows that at 185 °C, the blocked adduct de-blocks and HMDI and blocking agent 4-bromo-1H-pyrazole has been regenerated. At 185 °C, regenerated HMDI reacts with polyols of different molecular weights to form polyurethane. The polyurethanes were characterized by FTIR, NMR, DSC, TGA and contact angle measurements. These are useful for hydrophilic coating. [ABSTRACT FROM AUTHOR]