Bio-based Polyurethane Research Articles

Introducing a Sustainable Bio-Based Polyurethane to Enhance the Healing Capacity of Bitumen

This paper introduces the in-situ formation of biomodified polyurethane in bitumen as a novel strategy to enhance the healing capacity and aging resistance of bitumen. Bitumen is a substance that is known to have the capacity for healing. Self-healing bituminous composites can recover their properties. An increase in bitumen’s healing capacity can be facilitated using various modifiers. This study examined the merits of using a biobased polyurethane to both improve the healing capacity of bitumen and to enhance its resistance to aging through in-situ polymerization of polyurethane. The effect of aging on healing capacity was examined by studying specimens before and after aging in the laboratory. To do so, thermomechanical analysis and spectroscopy were used to characterize bitumen containing a biobased polyurethane from castor oil. It was found that the biobased polyurethane was quite compatible with bitumen, and the presence of polyurethane improved the overall thermomechanical properties of the bitumen. To evaluate the extent of healing, a time-sweep rheometry test was used to create samples with specific initial damage degrees. The degree of damage was selected to be a 30%, 45%, or 60% reduction in complex modulus. A healing index was calculated for each of the three damage levels after a 60-min rest period. The study results showed that the introduction of biobased polyurethane not only improved the healing index, it also mitigated the negative effects of aging on bitumen’s healing capacity. Compared to samples of unmodified bitumen, the average healing index of samples containing biomodified polyurethane was 1.3 times higher at 16% in the unaged state and 3.5 times higher at 7% in the aged state. In addition, the samples containing biomodified polyurethane showed better resistance to aging as evidenced by average 72% and 50% lower increases, respectively, in carbonyl and sulfoxide (known products of aging in bitumen) when exposed to the same aging protocol.

Preparation and Properties of Bio-Based Polyurethane Controlled Release Urea Coating with Photosensitivity.

In order to improve the photodegradation ability of fertilizer coating material and realize the sustainability of fertilizers, in this study, the commercially available photosensitive iron stearate (FeSt3) was wet-ground into submicrometer FeSt3 (SFeSt3) particles and used in preparation of a SFeSt3-modified bio-based polyurethane (PU)-coated controlled release urea (PU-SFe-CRU). The results showed that after 1 month photodegradation, the coating material had significant yellowing, the oxygen content of SFeSt3-modified PU (PU-SFe) increased by 56.89%, and its structure became more porous and looser than PU. The thermal stability of PU-SFe decreased, and more intermediate products were produced after exposure to UV light. The germination experiment showed that PU-SFe before and after photodegradation (up to 60 mg/L) had no adverse effect on the seed germination and bud growth of rice. Additionally, PU-SFe had a significantly higher Cr adsorption capacity after photodegradation due to the increase of the oxygen-containing group and specific surface. This study provides a theoretical basis for the research and development of photodegradable environment-friendly controlled release urea.

Colour of polyurethane foams filled with wood and wood derivatives exposed to two xylophagous fungi

This study addresses changes in aesthetical features of bio-based polyurethane (PU) foams filled with four forest-based particles (namely wood flour, wood bark, kraft lignin, and paper sludge), which were decayed by two wood-rot fungi. White-rot and brown-rot fungi were inoculated on these foams and further characterization results were obtained using colourimetric parameters measured according to the CIELab method. The fungi penetrated into both intra and intercellular spaces into the PU foams, although it neither changed the foam weight nor chemically interacted with the polymer cell wall. These fungi changed overall the appearance of the foams, which indicates that a protective strategy against these microorganisms may be of interest, especially for foam parts used in contact with wood products. The neat PU presented smaller colour stability if compared to the filled foams. Among the fillers, powdered kraft lignin stood out and can be indicated to produce valuable darkened PU parts with stable colour patterns.

Development and Characterizations of Engineered Electrospun Bio-Based Polyurethane Containing Essential Oils.

We report the fabrication of bio-based thermoplastic polyurethane (TPU) fibrous scaffolds containing essential oils (EO). The main goal of this study was to investigate the effects of essential oil type (St. John’s Wort oil (SJWO), lavender oil (LO), and virgin olive oil (OO))/concentration on the electrospinnability of TPU. The effects of applied voltage, flow rate, and end-tip distance on the diameter, morphology, and wettability of the TPU/EO electrospun fibers were investigated. The electrospun TPU/EO scaffolds were characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), contact angle (CA), and Fourier transform infrared spectroscopy (FTIR). The addition of oil resulted in an increase in the fiber diameter, reduction in the surface roughness, and, accordingly, a reduction in the contact angle of the composite fibers. TPU fibers containing SJWO and LO have a more flexible structure compared to the fibers containing OO. This comparative study fills the existing information gap and shows the benefits of the fabrication of essential-oil-incorporated electrospun fiber with morphology and size range with respect to the desired applications, which are mostly wound dressing and food packaging.

Huntsman develops partly bio-based PU for KEEN's plant-based soles

Footwear experts at Huntsman have helped KEEN Inc. develop a range of sneakers with plant-based soles. The Field to Foot (F2F) sneakers were created by KEEN's Advanced Concepts Team, utilizing a specially developed bio-based polyurethane system from Huntsman that contains a by-product from agricultural processing.

Bio-Based 2K PU Coating for Durable Textile Applications

Polyurethane (PU) coatings are often applied on high added value technical textiles. To date, most PU textile coatings are solvent based or water based. Recent advances are made in applying high solid and two-component (2K) PU on textiles. Currently, polymers made from renewable raw materials are experiencing a renaissance, owing to the trend to reduce CO2 emissions and switch to CO2-neutral renewable products. There is also the tendency towards the “bio, eco, natural” consciousness-awakening of the end consumer and the market-driven question to implement renewable materials. However, the application of bio-based coatings on textiles is limited. In this regard, the present study is conducted to develop bio-based 2K PU coating specifically designed for waterproof textiles. A 2K PU coating formulation, composed of bio-based polyol and bio-based isocyanate Desmodur Eco N7300, was made and directly applied on a polyester fabric prior to thermal curing in an oven. The coating was characterized via Fourier-transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The coatings were not thermoplastic and had a glass transition temperature of approximately 50 °C. Since a bio-based pentamethylene diisocyanate trimer (PDI-trimer), Desmodur Eco N7300 was used as an isocyanate source and not a diisocyanate derivative, and the resulting bio-based 2K coating was a thermoset instead of a thermoplastic. The effect of the additives and content of isocyanate on the elongation and stress at break was studied by performing tensile tests (ISO 13934-1) on 50 µm 2K PU films and comparing the obtained values. The performance of the coating was studied by evaluating the resistance to hydrostatic pressure initially and after washing, the Q-panel Laboratory UltraViolet (QUV) aging and the hydrolysis test. The developed bio-based 2K PU coating had excellent hydrostatic pressure, QUV aging resistance, hydrolysis resistance and wash fastness at 60 °C.

Bio-based polyurethane coating synthesized from modified castor oil - applicable in base coat of automobile paint

The current study reports the epoxidation of castor oil (CO) by using hydrogen peroxide as catalyst and formic acid as oxidizing agent. Subsequently bio based polyurethane based base coat was synthesized by using epoxidised castor oil (ECO) as polyol, Isophorone diisocyanate (IPDI) as curing agent and dibutylin dilaurate (DBTDL) as catalyst. The paint formulation with OH:NCO ratio 1:1.2 was optimized. An independent study was carried out employing the mechanical test like cross-cut tape test was carried out to evaluate th paint properties. Morphological and structural studies like FTIR, SEM, HNMR were carried out with the paint formulation. Thermal property studies like TGA, DSC were carried out with the paint. Gloss, weather resistance of the paint was evaluated.

Synthesis and Characterizations of Eco-Friendly Organosolv Lignin-Based Polyurethane Coating Films for the Coating Industry.

Three different formulations of bio-based polyurethane (PU), varying the weight ratio between Organosolv lignin and a commercial isocyanate, were synthesized. The coating formulations were characterized by SEM, pyrolysis-GC/MS, FTIR spectroscopy and FTIR mapping, which confirmed the successful formation of urethane bonds between commercial isocyanate and hydroxyl groups deriving from lignin. The coatings were applied on beech wood samples to measure color and contact angles, and eventually FTIR mapping of the coated wood samples was performed. FTIR mapping is an interesting tool to monitor the distribution of PU chemical bonds on the coating surface and to evaluate the homogeneity of the applied coating films. Increasing the lignin content of the PU coatings results in more red-yellow and darker tones, while the commercial PU coating is transparent. For a higher lignin concentration, the solid content as well as the weight gain of the applied coatings increase. A higher percentage of lignin in the prepared PU formulations leads to superficial cracks and therefore higher coating permeability compared to the commercial PU, but the prepared lignin-based PU coating still makes a raw wood surface significantly more hydrophobic. Apparently, additives such as film-formers with low surface tension to counteract cracks’ formation are necessary to improve the performance of lignin-based PU coatings.

Compression and morphological properties of a bio-based polyurethane foam with aluminum hydroxide

Compression and morphological evaluation of a new bio-based polyurethane foam (PUF) with aluminum hydroxide (ATH) added as flame retardant were carried out. The PUF was obtained from a blend of vegetable oils. Compression behavior of the polyurethane with different mass fractions of flame retardant (ATH) was investigated according to ASTM D1621–16. The ATH addition highly increased the compression yield strength of the specimens, going from 0.85 MPa (no ATH) to 2.34 MPa ( + 50%wt ATH). The compression yield strain did not show a noteworthy difference up to 40% ATH, presenting a significant decrement in the PUF + 50%ATH. The compression elasticity modulus increased from 15.40 MPa (no ATH) up to 139.77 MPa ( + 50%wt ATH). SEM images were used in order to evaluate the morphological structure of the foam. Regarding the cell sizes, there was no pattern observed, therefore, the cell sizes were adopted as random. The shapes of the cells were detected as elliptical in two different directions in the same cross-sectional area. The digital image correlation (DIC) technique showed higher strain values where the transverse ellipsoid-shaped cells were located, therefore, the load-oriented ellipsoids presented higher stiffness. Thus, the results for PUF with addition of ATH show that the bio-based material presented an important improvement in the compression properties, which allows this material to become more useful for different applications, such as furniture, building and automobile industries, as well as sandwich structures.

Dielectric and ionic transport properties of bio-based polyurethane acrylate solid polymer electrolyte for application in electrochemical devices

Solid polymer electrolyte has been extensively studied as an alternative to liquid electrolyte that is often affected by the leakage, deformation and limited range of operating temperature issues. The present study was conducted in an attempt to synthesize polyurethane acrylate (PUA) as a host polymer to evaluate polymer performance supplemented with Li salt as polymer electrolytes. PUA was prepared by the reaction of jatropha oil polyol with toluene 2,4-diisocyanate and hydroxylethylmethylacrylate. Lithium perchlorate (LiClO4) salt with different percentage of weight in the range of 5 wt. % to 25 wt. % was added to PUA to produce the PUA electrolyte. The mixtures were cured under UV radiation to obtain thin polymeric films with good thermal stability and ionic conductivity. PUA with 25 wt. % lithium salt has the highest conductivity of 6.40 × 10−5 S cm−1 at room temperature. The finding was supported by Fourier transform infrared (FTIR). Electrode polarization occurrence was interpreted by the complex dielectric constant (Ɛr), dielectric loss (Ɛi), real electrical modulus (Mr), imaginary electrical modulus (Mi) and tan σ. The effect of lithium salt addition was investigated by differential scanning calorimeter (DSC), thermogravimetric analysis (TGA), X-ray diffraction (XRD) and scanning electron microscopy (SEM) analyses. Additionally, the ionic transport properties, transference number measurement and electrochemical stability were presented.

Aliphatic Polyurethane Matrix for more sustainable UV-Resistant Composites

During the last years, composites based on renewable sources gained significant interest due to a globally increased awareness on sustainability. In order to address these challenges and to achieve ambitious sustainability targets, such as the reduction of greenhouse gas emissions, Covestro recently introduced composites from a new aliphatic and bio-based polyurethane, which bears a bio-content of ca. 70%. A combination of such bio-based polyurethanes with bio-based reinforcing fibers can lead for the first time to a composite with a bio-content of appr. 90%. Due to the aliphatic nature of the bio-based isocyanates, the resulting composites are characterized by an inherent UV- and weathering resistance, which makes them primarily suitable for outdoor applications and allows to omit additional protective coatings steps. A corresponding matrix material for pultruded composites, which is based on conventional raw materials, was launched under the brand name Desmocomp®.     

Dynamic Mechanical and Chemorheology Analysis for the Blended Epoxy System with Polyurethane Modified Resin

As the important matrix material, epoxy resin has been widely used in the composites for various fields. On account of the poor toughness of epoxy resin limiting their suitability for advanced applications, considerable interests have been conducted to modify the epoxy resin to meet the engineering requirements. In this study, the bio-based polyurethane (PU) modified resin was adopted to modify the pure bisphenol-A epoxy by blending method with various proportions. Aiming to illuminate the curing behavior, mechanical and thermal properties, the blended epoxy systems were characterized by viscosity-time analysis, dynamic mechanical analysis (DMA) at different frequencies and temperatures, mechanical tensile test, thermogravimetric analysis (TGA) and Fourier transform infrared (FT-IR) spectroscopy. The results indicated that the introduction of PU modified epoxy was found to significantly inhibit the viscosity growth rates especially when the content of PU modified epoxy resin is higher than 60%. Notwithstanding the dynamic modulus and Tg reduced with the increment of PU modified epoxy, remarkable increment on the elongation at break was found and the flexibility was greatly promoted with the introduction of PU modified epoxy. The proportion of PU modified epoxy in the blends should be put balance considerations to obtain optimal mechanical properties. TGA results and FTIR spectrum demonstrated that the addition of PU modified epoxy did not change the thermal decomposition mechanism and chemical reaction mechanism, but the addition of PU modified epoxy inhibits the curing reaction of epoxy resin by measured and calculated the damping temperature domain ΔT from 35.7°C to 48.9°C.

Synthesis of diols from jojoba oil via rhodium-catalyzed reductive hydroformylation: a smart way to access biobased polyurethanes

Diol was synthesised from Jojoba oil ester by a recyclable catalytic system and was used for biobased polyurethane synthesis.

Highly efficient synthesis of novel bio-based pentamethylene dicarbamate via carbonylation of pentanediamine with ethyl carbamate over well-defined titanium oxide catalysts

Highly efficient synthesis of bio-based pentamethylene dicarbamate from pentanediamine and ethyl carbamate was successfully achieved over the well-defined TiO2 catalysts, which provides a green and sustainable way for the production of bio-based isocyanates or polyurethane.

Polyurethane and its composites derived from bio-sources: Synthesis, characterization and adsorption studies

Polyols from chaulmoogra seed oil and grape seed oil were prepared by epoxidation and ring opening of oxirane ring using lactic acid in nitrogen atmosphere with a control over their functionality. Nanocellulose was derived from Desmostachya Bipinnata grass leaves and further surface functionalized. Modified nanocellulose was used as filler to prepare porous flexible bio-based polyurethane nanocomposites via in-situ polymerization. Adsorption of malachite green (MG) dye from wastewater using the prepared polyurethane composites was carried out. The effect of varying factors such as weight percentage of filers (modified nanocellulose), dosage of the adsorbent, pH, temperature and time on the MG adsorption have been studied experimentally. Material characterization for prepared materials was carried out using FTIR, NMR, TGA, DSC, and SEM along with other physical and chemical methods. FTIR results indicated the presence of peaks at 1704 cm−1 for –C=O stretching vibrations from urethane groups, 1531 cm−1 for –NH bending, 1232 cm−1 for –C–N stretching and 1105 cm−1 for –C–O stretching in the urethane group (–NHCOO–) thus, indicating the formation of urethane linkage in the polyurethane. Polyols with functionality around 2.8 were obtained from the oils, which has contributed to forming flexible polyurethanes. Morphological studies indicate the nano fibrillation of cellulose and closed-cell porosity in polyurethane and its composites. The flexible porous PU and its nanocellulose composites displayed improved thermal stability from 256.3°C to 270.5°C. Taguchi’s L27 orthogonal array have been applied for experimental design and optimization and the results were analyzed using ANOVA for raw and S/N ratio. It was found that pH is the most influential factor for adsorption lead by quantity of nanocellulose, time, dosage of the adsorbent and temperature.

A study on coconut fatty acid diethanolamide-based polyurethane foams.

The possibility of using coconut fatty acid diethanolamide, a derivate from coconut oil as a bio-based polyol for the synthesis of polyurethane foam was explored. The intrinsic tertiary amine moiety in this polyol (p-CFAD) endowed an auto-catalytic effect in the synthesis process of polyurethane foams, combined with a shorter cream and gelation time compared to the fossil-based polyol 3152. H-nuclear magnetic resonance (1H-NMR) and Fourier transform infrared spectrometry (FTIR) were conducted to characterize the chemical structural features of the p-CFAD, and rheology measurement showed the shear-thinning behavior due to the branched structure. A thermal conductivity comparable to the commercial rigid polyurethane foam was achieved when 40wt% fossil-based polyol 3152 was substituted with the bio-based p-CFAD. With the increased content of the p-CFAD, a transition of the physical properties from rigid PU foam to soft PU foam was observed. Scanning electron microscopy (SEM) revealed the occurrence of the interconnected pores on the cell walls with the increase of the added p-CFAD, implying the possibility of regulating the cellular structure and foam properties via the incorporation of the p-CFAD. Results showed the feasibility of using p-CFAD as a potential polyol in the development of bio-based polyurethane foams with high performance.

Bio-based polyurethane resin: An ecological binder for a novel class of building materials-composites

A novel application for mineral-filled composites with a bio-based polyurethane resin (BPR) binder was previously proposed to reduce the construction industry's carbon footprint. However, more details over the binder degradation conditions are necessary to clarify the composite usage in new sustainable building materials. Therefore, this work analyzed a castor oil-based polyurethane binder by its physical indexes (NBR 15845), mechanical properties (ASTM D 695), alterability by chemical reagents (ASTM D 543), humid atmosphere attack (NBR 8095), UV-rays exposure (ASTM G 53), thermogravimetry (TG/DTG), and differential scanning calorimetry (DSC). Besides, specimens of vermiculite/BPR composite were produced to evaluate the binder performance. BPR proved to be lightweight (1.19 g.cm−3) with a near-zero apparent porosity and water absorption. BPR was resistant to weathering action, while a slight variation in elastic modulus was detected during chemical attack. A thermal-stable filler is recommended for the building material application.

Influence of the Macromolecular architecture on the properties of biobased polyurethane tissue adhesives

Polyurethanes (PU) have recently emerged as promising biomaterials for tissue adhesive applications. Compared to other tissue adhesives, they offer substantial advantages such as the possibility to tailor adhesive strengths and curing times, for instance. All these properties are directly affected by the composition and final architecture. In this work, biobased two-components PU sealants were prepared, based on (i) an isocyanate-terminated prepolymer and (ii) a chain extender. Here, an exhaustive evaluation of the oligoester-diols and chain extenders influence on the sealants properties has been performed. In order to bring controlled variations on the final macromolecular architectures, three different prepolymers were prepared: two are based on poly(3-hydroxybutyrate) diol oligomers and another one on poly(lactic acid) diol oligomers, with a 50/50 isocyanate molar ratio of hexamethylene diisocyanate and biobased dimeryl diisocyanate. To study the chain extenders influence, five different aliphatic and linear bifunctional molecules were assessed, with varying length and functional groups reactivity. Ultimately, PUs obtained after the two-component systems curing were also fully characterized. They exhibited an overall good biocompatibility around 80%, with limited cytotoxicity. A wide range of physico-chemical and mechanical properties were also obtained, evidencing the importance of the macromolecular architecture on the systems final properties.

Synthesis and characterization of hydrophobic properties of silicon dioxide in palm oil based bio-coating

This research aims to synthesize a biobased polyurethane coating from epoxidized palm oil (EPO) and determine the effect of different silicon dioxide (SiO2) loadings on the hydrophobicity performance of the coating. In this work, EPO was firstly undergoing an acrylation reaction and followed by the addition of isophorone diisocyanate (IPDI) to form Polyurethane (PU). Improvement was made by adding SiO2 at different loadings into the palm oil-based PU to provide hydrophobic properties to the coating materials. The sample was characterized using Fourier Transform Infrared Spectroscopy (FTIR), water sliding angle test, and water absorption test. Based on the FTIR results, PU was successfully synthesized from EPO with SiO2 addition. The results also proved that the addition of SiO2 successfully improved the hydrophobicity of the coating. The higher the SiO2 content in palm oil PU, the shorter the time taken for the water to slide down the 25° angle coated glass and lower the water absorption percentage of the coating material. Based on the analysis, 3 phr SiO2 content showed the highest hydrophobicity performance, which could be applied in further research.

Bio-Based Waterborne PU for Durable Textile Coatings.

Polyurethane (PU) coatings are often applied on high added value technical textiles. Key factor to success of PU coatings is its versatility and durability. Up to today most PU textile coatings are solvent-based or water-based. Recent advances are made in applying bio-based PU on textiles. Currently, polymers made from renewable raw materials are experiencing a renaissance, owing to the trend to reduce CO2 emissions, the switch to CO2-neutral renewable products and the depletion of fossil resources. However, the application of bio-based coatings on textiles is limited. The present paper discusses the potential of a bio-based anionic PU dispersion as an environment friendly alternative for petroleum-based PU in textile coating. Coatings were applied on textile via knife over roll. The chemical, thermal and mechanical properties of the bio-based PU coating were characterised via FT-IR, thermogravimetric analysis, differential scanning calorimetry and tensile test. The performance of the coating was studied by evaluating antimicrobial properties, fire retardancy, the resistance to hydrostatic pressure initially and after washing, QUV ageing and hydrolysis test. The developed bio-based PUD coating complied to the fire retardancy test ISO 15025 and exhibited excellent hydrostatic pressure, QUV ageing resistance, hydrolysis resistance, wash fastness at 40 °C.