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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]

Continuous development in the formulation and processing techniques of polyurethane (PU) coatings improves an aesthetic appearance as well as protection against environmental factors. In this study, the formulation of PU coating with polyethylene glycol 600 (PEG600), isophorone diisocyanate (IPDI), and trimethoxysilylpropylcarbamoyloxyhexane (TMSCH) silane‐based additive is optimized to obtain high scratch‐resistant coating. An addition of 43.1 wt.% TMSCH in PU formulation resulted in a significant improvement in the scratch resistance and wettability properties compared with pure PU film. The homogenously prepared micron‐thick coatings are characterized using scanning electron microscopy analysis and Fourier transform infrared spectroscopy. The results confirm the presence of silane additives in the PU coating matrix. The mechanical properties improved due to the increased crosslinking networks via the formation of urethane bonds by increasing the TMSCH in PU formulation. Prepared PU coating showed combined features of transparency, hydrophobicity, scratch resistance, and mechanical strength that make it a promising candidate for household appliances. [ABSTRACT FROM AUTHOR]

Catalysts are often employed to enable nonisothermal reaction kinetic studies when tracking cure progression of polyurethane reactions. However, when quickly reacting, catalyzed materials are prepared through mixing followed by the addition of fillers or additives, subsequent processing of the partially reacted material becomes difficult. Here, chemorheology is used to track changes in viscoelastic properties of uncatalyzed polybutadiene‐diisocyanate reactions for multiple days, which quantifies the degree of cure during polymerization. Viscosity profiles are accurately captured by the two‐stage Arrhenius model (r2>0.95), and conversion progress is adequately represented by the Kamal–Sourour model (r2>0.76). Transition state analysis via Wynne–Jones–Eyring–Evans theory (WJEE) reveals the presence of an associative mechanism according to entropic and enthalpic activation energies ΔS# = −96.9 J K−1 and ΔH# = 36.4 kJ, respectively. These rheokinetic modeling results align with Fourier transform infrared spectroscopy findings. To the knowledge, no rheokinetic studies have tracked cure progress of this uncatalyzed system for the extended timeframe presented here. The cure profile also presents unique viscosity growth, representative of molecular weight buildup, compared to catalyzed systems. This finding emphasizes the novelty of applying previously developed chemorheological models to multiday thermosetting reactions within a flow field in a manner that is generalizable to many long‐term curing systems. [ABSTRACT FROM AUTHOR]

This work presents the synthesis and characterization of new TPUs obtained by melt polyaddition using 1,1′-methanediylbis(4-isocyanatocyclohexane) (HMDI, Desmodur W®), a new unconventional chain extender, i.e., (methanediyldibenze-ne-4,1-diyl)dimethanediol, and five types of soft segments differing in structure and molar masses. The structure of the obtained polymers was determined (by using the Fourier transform infrared spectroscopy and X-ray diffraction methods), and the physicochemical (reduced viscosity, density), optical (UV-VIS), processing (MFR) and thermal (DSC and TGA-FTIR) as well as surface, antibacterial and cytotoxic properties were determined. Based on the results obtained, it can be stated that the type of soft segment used significantly affects the properties of the obtained polymers. The most favorable properties for use in medicine were demonstrated by materials based on a polycarbonate soft segment. [ABSTRACT FROM AUTHOR]

Organic rectorite (OREC) can significantly improve the resistance of asphalt to deformation and aging, but it tends to cause low-temperature cracking. To solve this defect, a novel idea that develops an OREC and polyurethane (PU) composite-modified asphalt binder has been put forward in this work. Various modified asphalt binder systems containing different combinations of OREC and PU contents were prepared by the melt blending method. The storage stability of the OREC/PU-modified asphalt binders was studied. The high- and low-temperature properties of binders were investigated by dynamic shear rheometer and bending beam rheometer tests. The microstructure and modification mechanism of the binders were characterized by gel permeation chromatography, differential scanning calorimetry, and Fourier transforms infrared spectroscopy. The results showed that the OREC/PU-modified asphalt binder displayed good high-temperature storage stability. However, excessively high content of OREC will adversely affect the storage stability of asphalt. In the 2% by weight OREC/9% by weight PU modified asphalt system, OREC and PU exhibited excellent synergistic effects. And the high- and low-temperature properties of the asphalt were significantly improved. The introduction of OREC/PU reduces the Tg of the asphalt binder and the enthalpy during temperature change. The modified asphalt has good low-temperature flexibility through the physical and chemical interaction between polyurethane and asphalt during the modification process. PU can intercalate OREC and react with active hydrogens in asphalt to generate cross-linked structures to enhance the high- and low-temperature properties of the asphalt binder. [ABSTRACT FROM AUTHOR]

The high-quality reutilization of waste styrene–butadiene–styrene copolymer (SBS) modified asphalt mixtures is a difficult issue in the field of highways today, and the main reason is that conventional rejuvenation technology fails to achieve the effective rejuvenation of aged SBS in binder, causing significant deterioration in the high-temperature performance of the rejuvenated mixture. In view of this, this study proposed a physicochemical rejuvenation process using a reactive single-component polyurethane (PU) prepolymer as the repairing substance for structural reconstruction and aromatic oil (AO) as a common rejuvenator used to supplement the lost light fractions of asphalt molecules in aged SBSmB, according to the characteristics of oxidative degradation products of SBS. The joint rejuvenation of aged SBS modified bitumen (aSBSmB) by PU and AO was investigated based on Fourier transform infrared Spectroscopy, Brookfield rotational viscosity, linear amplitude sweep, and dynamic shear rheometer tests. The results show that 3 wt% PU can completely react with the oxidation degradation products of SBS and rebuild its structure, while AO mainly acted as an inert component to increase the content of aromatic components, thereby reasonably adjusting the compatibility of chemical components of aSBSmB. Compared with the PU reaction-rejuvenated binder, the 3 wt% PU/10 wt% AO rejuvenated binder had a lower high-temperature viscosity for better workability. The chemical reaction between PU and SBS degradation products dominated in the high-temperature stability of rejuvenated SBSmB and had a negative impact on its fatigue resistance, while the joint rejuvenation of 3 wt% PU and 10 wt% AO not only gave a better high-temperature property to aged SBSmB but could also have the capacity to improve its fatigue resistance. Compared to virgin SBSmB, PU/AO rejuvenated SBSmB has comparative low-temperature viscoelastic behavior characteristics and a much better resistance to medium-high-temperature elastic deformation. [ABSTRACT FROM AUTHOR]

Vibration and noise-reduction materials are indispensable in various fields. Polyurethane (PU)-based damping materials can dissipate the external mechanical and acoustic energy through molecular chain movements to mitigate the adverse effects of vibrations and noise. In this study, PU-based damping composites were obtained by compositing PU rubber prepared using 3-methyltetrahydrofuran/tetrahydrofuran copolyether glycol, 4,4′-diphenylmethane diisocyanate, and trimethylolpropane monoallyl ether as raw materials with hindered phenol, viz., and 3,9-bis{2-[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)proponyloxy]-1,1-dimethylethyl}-2,4,8,10-tetraoxaspiro[5.5]undecane (AO-80). Fourier transform infrared spectroscopy, thermogravimetric analysis, differential scanning calorimetry, dynamic mechanical analysis, and tensile tests were conducted to evaluate the properties of the resulting composites. The glass transition temperature of the composite increased from −40 to −23 °C, and the tan δMax of the PU rubber increased by 81%, from 0.86 to 1.56 when 30 phr of AO-80 was added. This study provides a new platform for the design and preparation of damping materials for industrial applications and daily life. [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]

Lignin-based polyol was obtained via oxyalkylation reaction with propylene carbonate using eucalyptus kraft lignin isolated from the industrial cooking liquor by the Lignoboost® procedure. This lignin-based polyol (LBP) was used without purification in the preparation of polyurethane (PU) adhesives combined with polymeric 4,4′-methylenediphenyl diisocyanate (pMDI). A series of adhesives were obtained by varying the NCO/OH ratio of PU counterparts (pMDI and LBPs) and their performance was evaluated by gluing wood pieces under predefined conditions. The adhesion properties of the novel PU adhesive were compared with those of a commercial PU adhesive (CPA). The occurrence and extent of curing reactions and changes in the polymeric network of PA were monitored by Fourier transform infrared spectroscopy (FTIR) and dynamic mechanical analysis. Although the lap shear strength and glass transition temperature of the lignin-based PU adhesives have increased steadily with the NCO/OH ratio ranging from 1.1–2.2, chemical aging resistance can be compromised when the NCO/OH is very low. It was found that the lignin-based PU adhesive with an NCO/OH ratio of 1.3 showed better chemical resistance and adhesion efficiency than CPA possibly because the NCO/OH in the latter is too high as revealed by FTIR spectroscopy. Despite some lower thermal stability and shorter gelation time of lignin-based PU than CPA, the former revealed great potential to reduce the use of petroleum-derived polyols and isocyanates with potential application in the furniture industry as wood bonding adhesive. [ABSTRACT FROM AUTHOR]

There is an urgent need for developing degradable polymeric systems based on bio-derived and sustainable materials. In recent years, polyurethanes derived from castor oil have emerged due to the large availability and sustainable characteristics of castor oil. However, these polymers are normally prepared through tedious and/or energy-intensive procedures or using high volatile and/or toxic reagents such as volatile isocyanates or epoxides. Furthermore, poor investigation has been carried out to design castor oil derived polyurethanes with degradable characteristics or thorough specifically sustainable synthetic procedures. Herein, castor oil-derived polyurethane with more than 90% biomass-derived carbon content and enhanced degradable features was prepared through a simple, eco-friendly (E-factor: 0.2), and scalable procedure, employing a recently developed commercially available biomass-derived (61% bio-based carbon content) low-volatile polymeric isocyanate. The novel material was compared with a castor oil derived-polyurethane prepared with a commercially available fossil-based isocyanate counterpart. The different castor oil-derived polyurethanes were investigated by means of water uptake, soil burial degradation, and disintegration tests in compost. Characterization analyses, including thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) and scanning electron microscopy (SEM), were carried out both prior to and after degradation tests. The results suggest potential applications of the degradable castor oil-derived polyurethane in different fields, such as mulch films for agricultural purposes. [ABSTRACT FROM AUTHOR]

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A novel gel polymer electrolyte (GPE) with polydopamine (PDA) modified thermoplastic polyurethane (TPU) porous membranes as the matrix skeleton and N-methyl-N-methoxyethyl pyrrolidine bis (fluorosulfonyl) imine (Pyr 12O1 FSI) ionic liquid (IL) as the plasticizer is successfully demonstrated to be suitable for sodium ion batteries (SIBs). The GPE exhibits excellent heat resistance due to the non-flammability of Pyr 12O1 FSI. Moreover, Density Functional Theory (DFT) and Fourier transform infrared spectroscopy (FTIR) results indicate that there is a strong intermolecular interaction between PDA, TPU and IL, thus greatly improving the structural stability and mechanical properties of this GPE. In addition, the functional groups (-OH and –NH–) in PDA have strong hydrogen bonds with TFSI− in sodium bis (trifluoromethanesulfonyl) imide (NaTFSI), which can immobilize TFSI− anions and promote Na+ selective transport. Therefore, the ionic conductivity and Na+ transference number of the GPE-based SIBs are significantly increased to 3.57 × 10−4 S cm−1 and 0.34 at 30 °C. As a consequence, Na|TPU@PDA-IL GPE|Na symmetric cells exhibit an ultra-long cycle life for 1200 h at 0.1 mA cm−2. This work provides an approach to develop GPE for high safety and excellent electrochemical performance SIBs. • A polyurethane-pyr 12O1 FSI gel polymer electrolyte is modified by polydopamine. • Polydopamine facilitates to fix TFSI-of sodium salt, thereby promoting t Na+. • Pyr 12O1 FSI improves the security and reliability of the gel polymer electrolyte. [ABSTRACT FROM AUTHOR]

Chlorobenzenes (CBs) are persistent and potentially have a carcinogenic effect on mammals. Thus, the determination of CBs is essential for human health. Hence, in this study, novel polyurethane–polysulfone/calix[4]arene (PU-PSU/calix[4]arene) nanofibers were synthesized using an electrospinning approach over in-situ coating on a stainless-steel wire. The nanosorbent was comprehensively characterized using scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT-IR) techniques. The SEM analysis depicted the nanofiber's unique morphology and size distribution in the range of 50–200 nm. To determine the levels of 1,2,4-trichlorobenzene, 1,2,3-trichlorobenzene, and 1,2,3,4-tetrachlorobenzene in water samples, freshly prepared nanosorbent was employed using headspace-solid phase microextraction (HS-SPME) in combination with gas chromatography micro electron capture detector (GC-µECD). Other calixarenes, such as sulfonated calix[4]arene, p-tert-calixarene, and calix[6]arene were also examined, and among the fabricated sorbents, the PU–PSU/calix[4]arene showed the highest efficiency. The key variables of the procedure, including ionic strength, extraction temperature, extraction duration, and desorption conditions were examined. Under optimal conditions, the LOD (0.1–1.0 pg mL−1), the LDR (0.4–1000 pg mL−1), and the R2 > 0.990 were determined. Additionally, the repeatability from fiber to fiber and the intra-day and inter-day reproducibility were determined to be 1.4–6.0, 4.7–10.1, and 0.9–9.7%, respectively. The nanofiber adsorption capacity was found to be 670–720 pg/g for CBs at an initial concentration of 400 pg mL−1. A satisfactory recovery of 80–106% was attained when the suggested method's application for detecting chlorobenzenes (CBs) in tap water, river water, sewage water, and industrial water was assessed. [ABSTRACT FROM AUTHOR]

The main aim of the study was to synthesize and analyze spectral data to determine the structure and stereometry of the carbon-based porous material internal structure. Samples of a porous biomaterial were synthesized through anionic polymerization following our own patent and then carbonized. The samples were investigated using MALDI ToF MS, FTIR ATR spectroscopy, optic microscopy, SEM, confocal laser scanning microscopy and CMT imaging. The analysis revealed the chemical and stereological structure of the obtained porous biomaterial. Then, the parameters characterizing the pore geometry and the porosity of the samples were calculated. The developed material can be used to collect adsorption of breathing phase samples to determine the parity composition of exhaled air. [ABSTRACT FROM AUTHOR]

Polyaniline has been extensively used for the corrosion protection of polymeric materials. However, there have been few studies on its combined antimicrobial activity when used in combination with silver molybdate. In this study, we synthesized silver molybdate (Ag 2 MoO 4) crystals using a homogeneous precipitation method. Polyaniline-dodecylbenzenesulfonic acid/castor oil(PANI-DBSA/CO) mixtures were prepared in an encapsulated state by in situ polymerisation. Subsequently, PANI/Ag 2 MoO 4 -PU interpenetrating polymer network(IPN) composite coatings(P/A-PU) were produced by dispersing Ag 2 MoO 4 and PANI-DBSA/CO in polyurethane using ultrasonic dispersion. The composite coatings were characterized using Fourier transform infrared spectroscopy(FTIR), X-ray diffraction analysis(XRD), and transmission electron microscopy(TEM). The study confirmed that composite coatings with uniformly dispersed nanoparticles of PANI and Ag 2 MoO 4 encapsulated by CO and epoxy resin E-44 grease exhibit improved physico-mechanical characteristics. The research also evaluated the effect of nanoparticles on the corrosion behaviour of the coatings using electrochemical impedance spectroscopy and kinetic potential polarisation experiments. The study investigated the antimicrobial properties of P/A-PU composite coatings on Escherichia coli(E.coli) and Staphylococcus aureus(S.aureus) by conducting bacterial growth curves, protein leakage, and fluorescence staining experiments. The aim was to establish a causal connection between the coated surfaces and the observed antimicrobial properties. The study demonstrated that incorporating IPN of polyaniline polyurethane into the coating composites improved their anticorrosive properties. Furthermore, the addition of silver molybdate at a mass ratio of 0.3 % resulted in a remarkable 99 % antimicrobial activity against E.coli and S.aureus. [Display omitted] [ABSTRACT FROM AUTHOR]

In this study, a novel boric acid-incorporated polyurethane (BPU) foam was synthesized and its several physical and biological properties were investigated. In order to determine the effect of the incorporated boric acid (BA) particles into the foam, mechanical and physical properties (apparent density, contact angle), analytical (Fourier transform infrared spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, inductively coupled plasma optical emission spectrometry), morphological (scanning electron microscopy (SEM), micro-computed tomography), thermal characteristics (thermogravimetric analysis, differential scanning calorimetry) and antibacterial activity were examined. The addition of BA particles to the PU foam improved the thermal and mechanical properties, as BA strengthened the polymeric structure through hydrogen bonds with PU. Mechanical analyses and contact angle measurements revealed that the BPU foam demonstrated better mechanical properties (94.0 kPa) and higher hydrophobicity values (108.52°) with respect to PU foam (52.9 kPa and 37.35°, respectively). According to microscopy analyses, micro-CT images confirmed SEM images in which PU foam has an open cell structure, whereas BPU foam has a closed cell structure. The antibacterial activity test results demonstrate that incorporation of BA to the PU structure significantly improved the antibacterial properties of the PU foam against both of Gram-positive and Gram-negative bacteria. This study suggests that the addition of BA into PU structure enhanced the antibacterial activities of PU foam while improving its physical, mechanical and thermal properties. As a result, BA incorporation should be classified as a promising alternative to improve the properties of PU foams. [ABSTRACT FROM AUTHOR]

Newly synthesized polyurethane (PU)–polydopamine (Pda)/CeO2 (cerium oxide) nanocomposite-coated mild steel was investigated for its corrosion protection performance and mechanical properties in 3.5% NaCl by electrochemical techniques. The functionalization of CeO2 nanoparticles by Pda was confirmed by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction analysis (XRD), scanning electron microscopy/energy dispersive X-ray analysis (SEM/EDX), transmission electron microscopy (TEM), and thermogravimetric analysis (TGA). The results derived from the electrochemical impedance spectroscopy (EIS) and polarization studies indicated the superior anticorrosive activity of PU–Pda/CeO2 nanocomposite coatings compared to those of plain PU coatings due to the synergetic effect of Pda/CeO2 and polyurethane. Decreased corrosion current was detected at the scratch of the PU–Pda/CeO2 nanocomposite-coated mild steel surface by scanning electrochemical microscopy (SECM) compared to other studied coatings. Addition of Pda-wrapped CeO2 nanoparticles into the PU coating resulted in the blockage of charge transfer at metal/electrolyte interface which reduced the dissolution of mild steel. It is due to the synergistic effect of Pda and CeO2 which strengthens the anticorrosive property. It was revealed from the SEM/EDX analysis that the formation of the corrosion products at the metal/electrolyte interface behaved as the passive layer which reduced the dissolution of steel. The incorporation of Pda-functionalized CeO2 nanoparticles to PU enhanced the mechanical properties of the coated surface which complimented the electrochemical studies. The superior anticorrosive property of the proposed nanocomposite coatings provides a new horizon in the development of high-performance anticorrosive coatings for various industries. [ABSTRACT FROM AUTHOR]

This research presents tensile modulus and strength of flax-glass hybrid FRP (HFRP) flat coupons with different fibre volume fractions and fabric stacking sequences under constant hygrothermal (50 °C and 95% RH) and cyclic weathering (water spray-ultraviolet radiation) environments for six months. Two types of polymer (i.e., epoxy (EP) and polyurethane (PUR)) were employed in HFRP. Fourier transformed infrared spectroscopy (FTIR) was performed to identify the changes in functional groups of flax fibres and polymer matrix after exposures. The glass transition temperature (T g) of polymer matrix was measured by differential scanning calorimetry (DSC), which was used to study the influence of environmental exposure on T g. The 3D diffusion coefficients of EP-based flax FRP and glass FRP laminates were determined based on experimental moisture uptake and Fick's law. A coupled mass diffusion-stress analysis based on finite element (FE) model was conducted to simulate the moisture diffusion and swelling behaviour of HFRP. The results showed that hygrothermal and weathering exposures hardly affected tensile modulus of HFRP regardless of the matrix type. After the environmental exposure, EP-based HFRP experienced lower retention ratio of tensile strength (65.4–88.0%) compared to PUR-based HFRP (80.7–94.1%) because of higher moisture absorption in the EP-based HFRP. The influence of fabric stacking sequence on tensile strength reduction varied with different fibre volume fractions in EP-based HFRP, which was explained by the combined effects of the internal stress and damage propagation at flax-glass interface. [ABSTRACT FROM AUTHOR]

Silylation of epoxidized soybean oil (ESBO) was carried out by epoxy ring opening reaction of methoxy and ethoxy silane compounds.¹ H NMR and FTIR spectra confirmed that two novel bio-based polyols, PSiTh and PSiAm, were obtained through the ring opening of epoxy by the mercapto and amino moieties of MPTMS and APTES, respectively. Polyurethanes of these polyols were prepared using 4,4´ - methylene-bis(phenyl isocyanate) (MDI) to incorporate silanol groups into polymer network and were labeled as PUSiTh and PUSiAm, respectively. To see the impact of silanol and phosphorous groups on flame retardant properties, the chain extended polyurethanes, PUSiThCE and PUSiAmCE were also prepared with bisphenol-A bis (hydroxy phenyl phosphonate) (BABHPP). Polyurethanes bearing thio-ether bonds besides alkoxy silane groups were characterized using FTIR spectroscopy. Prepared foams exhibited significant thermal stability and flame retardant properties with a limiting oxygen index (LOI) of 22-24%. Chain extended polyurethanes had 11-13 % higher LOI value than the corresponding non-chain extended polyurethanes. [ABSTRACT FROM AUTHOR]

This paper shows two ways of efficiency improvement of bio-polyol synthesis to generate more environmental and economic benefits. The application of waste oil in the synthesis of plastic components allows recycling of such municipal waste and is consistent with the principles of Green and Sustainable Chemistry. The economic aspects are associated with analyzing the influence of different catalysts on the time and temperature of ring opening reactions as well as the costs of the catalysts used in this process. This work presents the impact of three types of catalysts, (sulfuric acid, acid diethyl ether complex and tetrafluoroboric acid solution in water) on the ring opening reactions of epoxidized cooking oils and the properties of the final bio-polyols. The application of sulfuric acid in this experiment required a much higher temperature than in the case of the catalysts based on tetrafluoroboric acid and a longer reaction time. The shortest reaction time was achieved using tetrafluoroboric acid diethyl ether complex but the costs of this catalyst limit its possible application. However, similar products were obtained when using a tetrafluoroboric acid solution in water and the costs of this catalyst are acceptable for industrial applications. The properties of the bio-polyols and the tendency for the occurrence of the oligomerization reaction depended on the type of the catalysts used and were confirmed by the means of Fourier transform infrared spectroscopy, gel permeation chromatography, MALDI-TOF as well as by viscosity changes. It was concluded that the type of the catalyst and its concentration have a major impact on the physical and chemical properties of the resultant bio-polyols. [ABSTRACT FROM AUTHOR]

The purpose of this study is to fabricate porous polyurethane membranes that maintain oil absorption performance even when the surface is contaminated. The segmented polyurethane (SPU) films were prepared by the solvent casting method and the porous SPU membranes were prepared by electrospinning. A superhydrophobic methylsilicone network was formed both on the hydroxylated SPU (SPU−OH) film and membrane surfaces by condensation with methyltrichlorosilane. The morphological changes to the methylsilicone-network-coated SPU (SPU−OH−Si) were observed by field emission scanning electron microscopy. The changes in the chemical components on the surface by the introduction of the methylsilicone network were confirmed by attenuated total reflection Fourier transform infrared spectroscopy, and the type of wettability of the surface was confirmed to be superhydrophobicity and superoleophilicity on the SPU−OH−Si film or membrane by contact angle measurements. The self-cleaning performances of the prepared surfaces were confirmed using methylene blue, Oil Red O, and SiC adsorption tests. As a result, the SPU−OH−Si surface displayed excellent self-cleaning properties, as well as oil removal performance, in contaminated water. Furthermore, the oil absorption property was preserved even when the membrane was pre-contaminated with SiC particles. [ABSTRACT FROM AUTHOR]

Self-healing polymeric materials have attracted considerable interests due to the capability of healing the cracks generated in functional materials autonomously, resulting in improved reliability and life cycle. This paper is intended to develop a self-healing polymeric binder for energetic composites by incorporation of reversible covalent bonds into polyurethane. A novel polyurethane was synthesized from NCO-terminated prepolymer with furfuryl amine, and cross-linked with bismaleimide via Diels-Alder (DA) reaction. The chemical structures of the intermediates and products of Diels-Alder polyurethane (DAPU) were firstly confirmed by nuclear magnetic resonance (1H NMR), Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC). Then, the thermal reversibility and the self-healing performances of DAPU based energetic composites were systematically studied by DSC, polarizing optical microscopy (POM) and tensile testing. All the results showed that the as-prepared DAPU had high self-healing efficiency and remarkable mechanical performance, providing potential applications as a promising self-healing material in repairing the cracks generated in energetic composites. • Self-healing polymeric binder with Diels-Alder bonds can be easily synthesized. • The as-prepared Diels-Alder polyurethane has perfect self-healing properties. • The self-healing polyurethane has stronger mechanical properties than commercial polyurethane. • Energetic composites contained self-healing polyurethane exhibit evidently high self-healing capability. • The self-healing energetic composites present remarkable mechanical performance. [ABSTRACT FROM AUTHOR]

• Porous polyurethane foam was prepared by solvent casting/salt leaching technique. • The PU foam was coated with the water extract of propolis (PU/WEP). • PU/WEP exhibited good antibacterial activity against E. coli and S. aureus. • PU/WEP showed appropriate cellular biocompatibility. • PU/WEP could significantly accelerate the wound healing process in vivo. Wound dressings with antimicrobial and wound healing accelerating properties are emerging as valuable options to prevent wound infection and improve the wound healing process. In this study, high porous polyurethane (PU) foams were successfully prepared using salt leaching/solvent casting method and were coated with propolis as a well-known anti-bacterial agent. The wound dressings were subjected to detail analyzes using electron microscopy, reflectance Fourier transform infrared spectroscopy, mechanical properties, contact angle measurement, ratio swelling, porosity measurement, and in vitro and in vivo evaluations. The prepared wound dressings had high porosity (more than 80%) with homogeneous pore structure and sufficient interconnectivity. The increase of propolis concentration (10%–30%) caused tensile strength decrease (5.26 ± 0.40–2.99 ± 0.11 MPa), elongation at break increase (372 ± 12–434 ± 22%), contact angle decrease (114.52 ± 2.31° to 35.53 ± 1.65°), water absorption decreased (243 ± 15–207 ± 14%) and enhancement of the antibacterial activity against Escherichia coli and Staphylococcus aureus. The propolis coated wound dressing exhibited significant enhancement of in vitro cellular compatibility and in vivo wound healing which had direct relative with coated propolis concentration. Therefore, propolis-coated polyurethane wound dressing can be an appropriate candidate for more pre-clinical investigations. [ABSTRACT FROM AUTHOR]

Bio‐based new polyurethanes (PU) were synthesized from microbially converted castor oil. Castor oil was used as a raw material to synthesize 7,10,12‐trihydroxy‐8(E)‐octadecenoic acid (TOD) by the strain Pseudomonas aeruginosa PR3. Subsequently, hexamethylene diisocyanate (HMDI) was used in different ratios and reacted with TOD to produce new PU. Fourier transform‐infrared spectroscopy, nuclear magnetic resonance spectroscopy, and gas chromatography/mass spectrometry were used to confirm the identity of TOD. Differential scanning calorimetry, thermogravimetric analysis, and tensile property testing were used to investigate the thermal and mechanical properties of PU. PU synthesized based on TOD had a tensile strength of 45.4 MPa with low elongation at break of 8.16% at an isocyanate/hydroxyl ratio of 2.0. To modify the properties of PU, TOD was blended separately with polyethylene glycol or polycaprolactone diol at different weight ratios before reacting with HMDI. The modified polymer showed improved thermal stability and comparatively higher elongation at break. This is the first study demonstrating the conversion of castor oil into TOD that can be used stand alone or as a blend for PU synthesis. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • New mixed matrix membranes (MMMs) were fabricated. • Dispersion of nanoparticles was controlled by adjusting nanoparticles chemistry. • The gas-separation performance of the MMMs is higher than that of the pristine membrane. Abstract This paper presents a study on control of nanoparticles dispersion in the hard and soft segments of a polyurethane (PU) membrane, via adjusting surface groups of the nanoparticles. The dispersion control allows for tailoring physical and transport properties of the membrane. PU-based mixed-matrix membranes (MMMs) embedded with cyanuric chloride and its derivatives, melamine, and 2,4,6-trihydazino-1,3,5-triazine (THDT) nanoparticles, are prepared. The MMMs are characterized using FTIR, XRD, TGA, DSC, and SEM analyses, and tensile strength tests. Peak assignment of the bonded carbonyl, crystallinity change, mechanical properties of the membranes, possible hydrogen-bonding of the PU backbone and the nanoparticles, and permeation tests indicate that cyanuric chloride nanoparticles are dispersed in the hard segments, whereas melamine and the THDT nanoparticles are distributed in the soft domains. As the cyanuric chloride nanoparticle concentration of the MMMs increases, the gas permeabilities and O 2 /N 2 , CO 2 /CH 4 and CO 2 /N 2 selectivities of the membranes increase. In the case of THDT and melamine, as the filler loading increases, the permeabilities of the gases decrease, whereas O 2 /N 2 , CO 2 /CH 4 and CO 2 /N 2 selectivities increase. A 10 wt% incorporation of THDT into the PU increases CO 2 /N 2 and CO 2 /CH 4 selectivities by 92% and 75%, respectively. These results point to the potential of cyanuric chloride nanoparticles for simultaneous improvement of gas permeability and selectivity, and the potential of melamine and THDT nanoparticles for preparation of highly selective nanocomposite membranes for CO 2 removal. [ABSTRACT FROM AUTHOR]

In this paper, the effect of chemical treatments on date palm fibers (DPFs) properties was studied; DPFs were first treated with a 5 wt% NaOH aqueous solution for 1 h and then modified using two types of silane coupling agents (3-Mercaptopropyltrimethoxysilane and 3-Aminopropyltrimethoxysilane) with various concentrations (0.1, 0.5, 1 and 2 wt%) to improve the interfacial properties of DPFs with polymeric matrices. SEM observations showed the formation of silane layers on the alkalized surface of DPFs. The Fourier-transform infrared (FTIR) results showed that the salinization was successfully performed by forming covalent Si-O-C bonds between DPF and silane coupling agent. The pull-out behavior of treated fibers was also investigated using two matrices; polyurethane (PU) and epoxy. The obtained results showed that the treatments have successfully improved the interfacial bond characteristics of DPF-PU and DPF-Epoxy systems. [ABSTRACT FROM AUTHOR]

Abstract: Three polyurethane formulations were prepared on the basis of siloxane; two formulations contained 1% and 3% of a hydroxyl functionalized polyhedral oligomeric silsesquioxane [POSS (ROH)2] nano-particles (as a co-chain extender) and one was without nano-particle. Structures of the polyurethanes were characterized by FTIR and SEM. The effect of POSS nano-particles on properties of the synthesized PUs was examined for vascular applications by tensile test, contact angle, SEM, AFM and endothelial cells viability evaluation. Properties of the polyurethane with 1% POSS were compared with those of PU without POSS and the results showed 66% increase in the elongation-at-break, 53% increase in tensile strength and 33% increase in modulus, 9.45% increase in contact angle, 76.7% reduction in surface roughness and 9.46% increase in cell viability. It was also shown that a polyurethane containing 1% of POSS nano-particles in its structure developed the highest hydrophobicity, which resulted in its lowest potential for thrombosis.Graphical Abstract: [ABSTRACT FROM AUTHOR]

Abstract The cooperative improvement of strength and toughness of rigid polyurethane (RPU) is a vital requirement as a structural material. In this work, 0.2 wt% short carbon fibers (CFs) reinforced RPU composites with high strength and toughness were prepared. The effects of fiber surface treatment and the mechanical properties of RPU composites were studied. Scanning electron microscopy (SEM) was performed to observe the surface morphology of the CFs as well as the fracture surfaces of the composites. Fourier-transform infrared spectroscopy (FT-IR) and contact angle instrument were used to analyze the surface functional groups and the surface energy of CFs, respectively. The results indicated that the surface roughness, the content of OH groups and the surface energy of carbon fibers increased after oxidation modification. Compared with pure RPU, the tensile, bending and impact strength of modified CFs/RPU composites were increased by 38.8%, 22.4% and 71.4%, respectively. Dynamic thermomechanical analysis (DMA) and SEM indicated the positive effects of oxidation modification on the interfacial bonding between modified CFs and RPU matrix. Highlights • The surface roughness, active groups and surface energy of carbon fibers were all increased by oxidation treatment. • A large amount of hydroxyl groups were introduced on the carbon fiber surface by air oxidation modification. • Hydroxyl groups could react with the isocyanate groups to improve the interfacial adhesion of composites. • The strength and toughness of the modified carbon fibers/RPU composites were greatly increased. • Compared with pure RPU matrix, impact strength of modified carbon fibers/RPU composites were increased by 71.4%. [ABSTRACT FROM AUTHOR]

Potato protein (PP), the main product of thermal and acidic coagulation of potato juice obtained from potatoes during starch production, was selected as a reinforcement filler in polyurethane (PU) foams. Rigid polyurethane foams (RPUFs) were successfully obtained from a two-component system and modified with PP, in the range of 0.1–5 wt% of total polymer mass content. The influence of PP on the RPUFs morphology and on physical and mechanical properties of the obtained porous materials were studied. PU foams were characterized using morphological, mechanical and thermal analysis. The results show that an addition of 0.1 wt% PP improves compressive strength (the final strength up to 230 kPa) due to the strengthening effect of the filler, low thermal conductivity (0.029 W/m·K) and low water absorption (14.3%). The results obtained in this study confirm that the addition of PP over a certain optimal level has a negative effect on the cell morphology, leading to a deterioration of the physico-mechanical properties of the modified foams. [ABSTRACT FROM AUTHOR]

Carbon black (CB) is a preferred nano-reinforcer for conventional polymers, but it exhibit poor dispersibility, which makes it difficult for further application in the coating industry. Here we prepared hydroxylated carbon black (OCB) by a mild oxidation process and then covalently encapsulated with a urethane chains shell via in situ polymerization, and thus encapsulated carbon black (EOCB) particles were achieved. Surface chemical composition of the EOCB particles was thoroughly characterized by FT-IR, TGA, XPS, and EA techniques, and its dispersion properties in aqueous medium were studied by DLS, natural sedimentation, and TEM analyses. It was found that EOCB possessed a high encapsulation percentage, and showed excellent self-dispersibility and prominent stability in aqueous medium. Furthermore, intensive investigation demonstrated that PUB/EOCB composite, that prepared by blending EOCB particles with a polyurethane binder (PUB), exhibited improved mechanical property, water resistance and matting appearance, which probably due to the strong hydrogen bonds between the EOCB particles and the PUB matrix. This work provides a potential avenue for designing CB-based microcapsules and makes it promising application in waterborne coatings. [ABSTRACT FROM AUTHOR]

Abstract: Two series of polyurethane (PU), based on polycaprolactone (PCL) as soft segments with two different molecular weights (2000 and 530 Da), and hexamethylene diisocyanate (HDI) and 1,4-butandiol (BDO) as hard segments were synthesized to fabricate curcumin-loaded electrospun nanofibrous PCL-based PU substrate. Chemical structures of the synthesized PUs were characterized by FTIR and NMR spectroscopy techniques. The thermal properties were analyzed by differential scanning calorimetry (DSC) and surface hydrophilicity was studied by static contact angle and bulk hydrophilicity was evaluated by water uptake test. Thereafter, bead-free PU nanofiberous substrate containing curcumin was fabricated by electrospinning and morphology of the mats was observed by scanning electron microscopy (SEM). Mechanical properties of the electrospun mats in comparison with polymeric films were assessed by a universal test machine. The in vitro release of curcumin was studied by UV–Vis spectroscopy. The optical density of the bacterial solutions was used to evaluate the antibacterial activity of the curcumin-loaded nanofibrous mats against Escherichia coli (E-coli ATCC: 25922). The results showed that curcumin-loaded PU synthesized by PCL with molecular weight of 2000 Da displayed better mechanical properties as well as better antibacterial properties in wound dressing application.Graphical abstract: [ABSTRACT FROM AUTHOR]

Bio-based polyurethane (PU) composites with superior thermal and mechanical properties have received wide attention. This is due to the recent rapid developments in the PU industry. In the work reported here, novel nano-composites with graphene oxide (GO)-modified Sapium sebiferum oil (SSO)-based PU has been synthesized via in situ polymerization. GO, prepared using the improved Hummers method from natural graphene (NG), and SSO-based polyol with a hydroxyl value of 211 mg KOH/g, prepared by lipase hydrolysis, were used as raw materials. The microstructures and properties of GO and the nano-composites were both characterized using Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and tensile tests. The results showed that GO with its nano-sheet structure possessed a significant number of oxygen-containing functional groups at the surface. The nano-composites containing 1 wt % GO in the PU matrix (PU1) exhibited excellent comprehensive properties. Compared with those for pure PU, the glass transition temperature (Tg) and initial decomposition temperature (IDT) of the PU1 were enhanced by 14.1 and 31.8 °C, respectively. In addition, the tensile strength and Young's modulus of the PU1 were also improved by 126% and 102%, respectively, compared to the pure PU. The significant improvement in both the thermal stability and mechanical properties for PU/GO composites was attributed to the homogeneous dispersion and good compatibility of GO with the PU matrix. The improvement in the properties upon the addition of GO may be attributable to the strong interfacial interaction between the reinforcing agent and the PU matrix. [ABSTRACT FROM AUTHOR]

In this study, preparation and characterization of isophorone diisocyanate (IPDI) filled polyurethane (PU) microcapsules were studied. At first, a pre-polymer was synthesized through reaction of toluene 2, 4- diisocyanate (TDI) with 1, 4-butanediol using either cyclohexanone or n -butyl acetate solvent. The synthesized pre-polymer was characterized using Fourier transform infrared spectroscopy, gel permeation chromatography, and free isocyanate content. Polyurethane-based microcapsules containing reactive isocyanates were synthesized using TDI-based pre-polymer and IPDI as the shell and core materials, respectively. Shape and morphology of prepared microcapsules were studied using optical microscopy and scanning electron microscopy (SEM). The spherical microcapsules prepared in this study had a diameter of 50–200 μm and shell thickness of 2–20 μm. The synthesis procedure developed in this work, replaces toxic solvents commonly used in the preparation of PU microcapsules, namely cyclohexanone and chlorobenzene, with a more benign solvent, namely n -butyl acetate. SEM microscopy of the scratched epoxy specimens showed appropriate healing performance using both type of microcapsules. [ABSTRACT FROM AUTHOR]