Properties Of Polyurethane Research Articles

Synthesis and Characterization of Biopolyol-Based Waterborne Polyurethane Modified through Complexation with Chitosan.

In this study, a series of castor oil-based anionic waterborne polyurethane (CWPU) systems, which it has been suggested may be suitable for use as green elastomers with diverse applications in films and coatings, was prepared by modified with O-carboxymethyl chitosan (CS) as not only a reinforcing filler, but a chain-extender of polyurethane prepolymer to enhance the properties of polyurethanes. Moreover, not only was the system obtained with castor oil-based polyol in the absence of a catalyst, but it was maintained with low viscosity by using acetone instead of toxic methyl ethyl ketone (MEK) during the synthesis process. The sizes, zeta potential, chemical formation, and morphology of the CWPU-CS composites had been investigated by dynamic light scattering (DLS), infrared spectroscopy (IR), and scanning electron microscopy (SEM). Moreover, the results show that the modification allows to enhance storage/loss modulus, tensile properties, thermal stability at high temperature, and biocompatibility of CWPU and CWPU/CS nanocomposites according to various contents of CS.

Preparation and Characterization of Intrinsically Compatibilized Thermoplastic Polyurethane and Silicone Rubber

AbstractTo combine the excellent properties of thermoplastic polyurethane (TPU) with methyl vinyl silicone rubber (VMQ), thermoplastic dynamic vulcanizates (TPVs) are synthesized. An essentially compatibilized method is used to resolve the thermodynamic incompatibility between TPU and VMQ. The principle is that the hydroxybutane‐terminated polydimethylsiloxane (PDMS) block on the TPU will increase the microphase separation of the matrix, but it will also increase the phase compatibility through similar compatibility with VMQ. Moreover, a series of effects of PDMS on the microstructure and macroscopic properties of TPV have been explored to find the influence law of PDMS, which will guide the application of TPV in various environments.

Influence of the chain extender of a segmented polyurethane on the properties of polyurethane-modified asphalt blends

This paper reviews the influence of the hard segment (HS) chemical structure on the properties of thermoplastic polyurethanes based on dimer fatty acid soft segments, and on their resulting blends with bitumen. Three types of hard segments were used which consist in 4,4′-methylene bis(phenyl isocyanate) (MDI) reacted either with 1,4-butanediol (BDO), 1,4:3,6-dianhydro D-sorbitol (isosorbide) or 2-ethyl-1,3-hexanediol (EHDO). The characterization of thermoplastic polyurethanes (TPUs) containing 13 wt% HS was conducted by differential scanning calorimetry, dynamic mechanical analysis, Hansen solubility parameters measurements and morphology analysis. The use of Hansen solubility parameters combined with thermal and swelling analyses provides information about the quality of phase separation occurring in the neat TPUs. Phase separation depends on the hard segments used and on their ability to self-organize within crystalline structures. Morphology analysis and swelling measurements of the TPU blended with bitumen by fluorescence microscopy show that the swelling of the polymer is highly dependent on the quality of phase separation between soft and hard segments in the pure polymer as well as on the compatibility of these segments with bitumen. Highly phase separated TPUs offer elasticity improvement to the bituminous blend.

The Effect of Ash Silanization on the Selected Properties of Rigid Polyurethane Foam/Coal Fly Ash Composites

According to the assumptions of the European Union, by 2050 it is planned to achieve climate neutrality. For this purpose, a document called the “European Green Deal” was established, which is a set of policies of the European Commission. One of the assumptions is a circular economy that takes into account the use of waste in subsequent production cycles. In order to meet the latest trends in environmentally friendly materials and use of waste in the production of building materials, composites of rigid polyurethane foam with 10 wt.% of waste were produced. Fly ash from coal combustion after modification was used as a filler. Three types of modifications were used: silanization, sieving, and both processes together. The silanization process was carried out for 1 and 2% silane ([3-(2-aminoethylamino)propyl]trimethoxysilane) concentration in relation to the fly ash mass. The sieving was aimed at reaching a fraction with a particle diameter below 75 µm. Six composites with modified fillers were compared and one material containing unchanged fly ash was used as a reference. A comparative analysis was carried out on the basis of surface analysis, thermal stability and physical properties. It turned out that the polyurethane materials modified fly ash silanized with 1% and 2% silane solution proved the best results in performed tests. On the other hand, the polyurethane foam containing sieved ash was characterized by the lowest flammability and the lowest emission of smoke and CO. The use of modified fly ash in technology of polyurethane foams can be a good method of its disposal and can increase the applicability of the composites.

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.

Interface Properties of Epoxy and Polyurethane Mutually Sized Carbon Fiber Reinforced Composites

Interface Properties of Epoxy and Polyurethane Mutually Sized Carbon Fiber Reinforced Composites

Synergy of titanium dioxide nanotubes and polyurethane properties for bypass graft application: Excellent flexibility and biocompatibility

A flexible, porous and biocompatible titanium dioxide nanotubes (TNT) - polyurethane (PU) film has been produced as a new scaffold for artificial vascular grafts. Synergistic improvements in the properties of vertical TNT and PU was reached, including enhancements in their biocompatibility, mechanical strength, flexibility and porosity. Open-ended (OE) TNT-PU and close-ended (CE) TNT-PU films were synthesized and their mechanical and biological properties were compared with their pure PU counterparts. TNT were attached to PU with a new strategy. The resulting flexible structure was hydrophilic and super hydrophilic in OE-TNT-PU and CE-TNT-PU scaffolds, respectively. The gas leakage during the attachment of polymers and nanotubes led to an interconnected porous structure of the polymer. The results revealed that the rate of endothelialization of the OE-TNT-PU scaffold vs pure PU scaffolds was 2 times greater after 5 days of in vitro cell culture. In addition, the number of platelets and their agglomeration on the newly designed scaffolds were much lower than those of PU scaffolds. In OE-TNT-PU film, the elongation at break was 881% and the ultimate tensile strength was more than 3 times greater compared to PU. The Young modulus of these scaffolds was greater than150 MPa.

Modification of asphalt using polyurethanes synthesized with different isocyanates

To study the effect of isocyanates on the properties of polyurethane (PU) modified asphalt, three kinds of polyurethane with different hard segments were synthesized, by the reaction of polyethylene adipate (PEA) with diphenylmethane diisocyanate (MDI), toluene diisocyanate (TDI) and polyaryl polymethylene isocyanate (PAPI), respectively. These three kinds of polyurethane were used to modify the asphalt and study the effects of isocyanate on the performance of polyurethane modified asphalt by experiments. The Fourier transform infrared spectrometer (FTIR), and the gel permeation chromatography (GPC) were used to analyse PU samples. The dynamic shear rheology (DSR), bending beam rheology (BBR), multiple stress creep test (MSCR), Fourier transform infrared spectroscopy (FTIR), atomic force microscope (AFM), and differential scanning calorimetry (DSC) were used to research rheological properties, modification mechanism and microstructure of the asphalts, respectively. The results show that isocyanates influence the structure of polyurethane molecules, the distribution of soft and hard segments and the content of hard segments, and affect the distribution of asphaltenes in asphalt, resulting in different modification effects on asphalt. Of the three isocyanates, the PU synthesized by TDI provides the best improvement to the asphalt in terms of resistance against permanent deformations, low-temperature property and storage stability. Improvement effects of PU synthesized by PAPI on resistance against the permanent deformations and storage stability are better than that of MDI, but the effects on low-temperature property are worse with that of MDI.

Microstructure and viscoelastic behavior of waterborne polyurethane/cellulose nanofiber nanocomposite

Cellulose nanofiber (CNF) has been widely used to reinforce the mechanical properties of waterborne polyurethane (WPU). There are, however, few works that focus on structure, rheological behavior, and creep resistance of WPU/CNF composites. To fill this research gap, in this work, the m-CNF was obtained by γ-aminopropyltriethoxysilane modification to improve the interfacial strength of CNF and WPU, and then it was introduced into the polyurethane matrix. Structure characterization of WPU/m-CNF nanocomposites is performed using Fourier-transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), Scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The obtained results show that with the increase of m-CNF, the hydrogen bonding index (HBI) increased, which meant a significant improvement in the mechanical properties. The tensile strength improved by 480%. Moreover, with the increase of m-CNF content, the viscosity, storage modulus, and loss modulus of the dispersions increased and showed more obvious shear-thinning behavior. In addition, m-CNF improved the thermal stability and creep resistance of WPU. The creep strain of WPU decreased from 3% to 0.2%. This work offers a simply feasible way to prepare environmental friendly green nanocomposites.

Semi-Crystalline Polyoxymethylene-co-Polyoxyalkylene Multi-Block Telechels as Building Blocks for Polyurethane Applications.

Hydroxy-terminated polyoxymethylene-co-polyoxyalkylene multi-block telechels were obtained by a new methodology that allows for the formal substituting of ether units in polyether polyols with oxymethylene moieties. An interesting feature is that, unlike carbonate groups in polycarbonate and polyethercarbonate polyols, homopolymer blocks of polyoxymethylene moieties can be formed. The regular nature of polyoxymethylene blocks imparts a certain crystallinity to the polymer that can give rise to new properties of polyurethanes derived from such telechels. The synthesis, reaction sequence and kinetics of the formation of oligomeric hydroxy-terminated multi-block telechel polyoxymethylene moieties are discussed in this paper and the preparation of a polyurethane material is demonstrated.

Improvement of the structural, thermal, and mechanical properties of polyurethane adhesives with nanoparticles and their application to Al/Al honeycomb sandwich panels

Abstract Understanding the relationship between core/face adhesive interface and performance of MWCNT added nanoadhesives are essential for better designing and fabrication of aluminum honeycomb sandwich panels. In this study, we used multi-walled carbon nanotubes (MWCNTs) to prepare enhanced interfacial adhesion between honeycomb core and aluminum facesheet. MWCNTs are first introduced to isocyanate, and then MWCNTs/isocyanate blend poured into polyol to produce MWCNTs reinforced polyurethane (PU) nanoadhesives. The relationship between core/face adhesive interface and performance of MWCNT added nanoadhesives are investigated in detail in terms of thermogravimetric analyses (TGA), Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy, edge-wise compression tests, flat-wise tensile tests and three-point bending tests The experimental results showed that the MWCNT addition to PU adhesive led to enhanced thermal stability, flat-wise tensile strength and edge-wise compression strength for sandwich structures. This study gives a significant reference indicator on the fabrication of an improved core/face interface for obtaining sandwich panels with desired mechanical properties.

Study on Corrosion Behavior of Waterborne Polyurethane Coating with High Thermal Conductivity

In this paper, the effects of mixture fillers on the thermal conductivity of a coating are studied, and the optimal addition proportion was obtained. Then, the corrosion behavior of the modified waterborne polyurethane coating with high thermal conductivity is investigated by salt spray experiments, pull-off tests, EIS and SKP measurements. The result shows that the coating with 2 wt % composite fillers exhibits the most excellent thermal conductivity (1.222 W·m−1·K−1). In terms of corrosion resistance, there is an absence of obvious corrosion phenomenon for the modified coating, and the polarization resistance is still as high as 1.31 × 107 Ω·cm2 at the final stage, which indicates that the incorporation of 2 wt % composite fillers also markedly enhances the corrosion resistance property of waterborne polyurethane coating. This is mainly attributed to the more compact structure and more excellent shielding action to the electrolyte. The surface Kelvin potential results further confirm the advantageous effects of mixture fillers on the corrosion protective performance. The corresponding protective mechanism of the composite coating is also proposed.

Nano-ceria and nano-zirconia reinforced polyurethane nanocomposite-based coated textiles with enhanced weather resistance

This work reports the effect of nano-ceria or cerium oxide (CeO2) nanoparticles and nano-zirconia or zirconium oxide (ZrO2) nanoparticles on the weather resistance property of polyurethane (PU) based coatings. The concentrations of ceria and zirconia nanoparticles (NPs) were varied in the PU coating formulation to obtain optimum weather resistance property. The prepared PU/ceria and PU/zirconia nanocomposite-based formulations were coated on a high strength polyester fabric by a knife coater. Coated fabrics were exposed in a weather-o-meter up to 300 h, in accelerated weathering conditions by controlling UV irradiance, humidity, temperature and dry/wet state. The weather resistance performance was analyzed by studying the UV protection factor (UPF) and the change in tensile properties (tensile strength and breaking extension). The chemical change after UV exposure was analyzed by Fourier Transform Infrared Spectroscopy (FTIR). The surface morphology was investigated before and after exposure by observing the tropology of the coated surface under SEM. Both the nanoparticles (ceria and zirconia) showed a great potential in enhancing the weather resistance property of PU-coated fabrics, while the weather resistance improved gradually with increasing the concentration of nanoparticles up to a certain percentage (5 wt%). After 300 h UV exposure, the change in carbonyl index (CI) was 25%, 8.6% and 12.8% for the fabrics coated with neat PU, PU/ceria (5 wt%) nanocomposite and PU/zirconia (5 wt%) nanocomposite, respectively. The photooxidative index (PI) of PU/ceria nanocomposite was also much lower than the PU/zirconia nanocomposites, especially at higher concentration of nanoparticles (5 wt% and 10 wt%). In case of PU/ceria nanocomposites, this significantly low CI and PI values indicated their better weather resistance potential compared to the PU/zirconia nanocomposites. As a consequence, after 300 h UV exposure, the percentage retention in tensile strength was significantly high for the fabric coated with PU/ceria nanocomposite (72%) in comparison to the neat PU (only 30%) and PU/zirconia nanocomposite (48%) coated fabric.

Synthesis and Characterization of Palm Kernel Oil Polyol Based Shape Memory Polyurethane: Effect of Different Diisocyanates

Shape memory polyurethane (SMPU) is a very versatile material that has a broad array of applications. The selection of soft segments and hard segments play critical roles in determining the structure-property behaviors of SMPU. This research was conducted to evaluate the role of distinct types of diisocyanate on the final properties of polyurethane (PU). Palm kernel oil polyol (PKO) based PU were produced by using two-step bulk polymerization method with variations of diisocyanates. Isophorone diisocyanate (IPDI), 4,4-methylenebis (cyclohexyl isocyanate) (HMDI) and hexamethylene diisocyanate (HDI) were used in the preparation of PU and the soft segment crystallinity, thermal and shape memory properties of the PU were evaluated. Based on the analyses, it was found that different types of diisocyanate and combination of diisocyanates had huge impact on the properties of the synthesized PU. The Fourier transformation infrared (FTIR) analysis revealed that IPDI based PU achieved the highest hydrogen bonding index value which promoted the phase separation. This is in accordance with differential scanning calorimetric (DSC) and x-ray diffraction (XRD) analysis which showed that IPDI based PU exhibited crystalline soft phase, hence resulted in an excellent shape fixity behavior. On the other hand, HDI and HMDI based polyurethane prepared showed absence of crystalline soft phase based on the DSC thermogram and XRD diffractogram. These results suggest the phase mixing phenomenon between soft and hard segments which contributed to low shape memory behavior of the resulting polyurethane.

Fabrication and assessment of a novel hybrid scaffold consisted of polyurethane-gellan gum-hyaluronic acid-glucosamine for meniscus tissue engineering

The meniscus has inadequate intrinsic regenerative capacity and its damage can lead to degeneration of articular cartilage. Meniscus tissue engineering aims to restore an injured meniscus followed by returning its normal function through bioengineered scaffolds. In the present study, the structural and biological properties of 3D-printed polyurethane (PU) scaffolds dip-coated with gellan gum (GG), hyaluronic acid (HA), and glucosamine (GA) were investigated. The optimum concentration of GG was 3% (w/v) with maintaining porosity at 88.1%. The surface coating of GG-HA-GA onto the PU scaffolds increased the compression modulus from 30.30 kPa to 59.10 kPa, the water uptake ratio from 27.33% to 60.80%, degradation rate from 5.18% to 8.84%, whereas the contact angle was reduced from 104.8° to 59.3°. MTT assay, acridine orange/ethidium bromide (AO/EB) fluorescent staining, and SEM were adopted to assess the behavior of the seeded chondrocytes on scaffolds, and it was found that the ternary surface coating stimulated the cell proliferation, viability, and adhesion. Moreover, the coated scaffolds showed higher expression levels of collagen II and aggrecan genes at day 7 compared to the control groups. Therefore, the fabricated PU-3% (w/v) GG-HA-GA scaffold can be considered as a promising scaffold for meniscus tissue engineering.

Surface, structural, and thermal properties of polydimethylsiloxane-based polyurethanes and their blends with thermoplastic polyurethane elastomer

Surface, structural, and thermal properties of polydimethylsiloxane-based polyurethanes and their blends with thermoplastic polyurethane elastomer

Preparation and properties of self-healing polyurethane without external stimulation

Preparation and properties of self-healing polyurethane without external stimulation

Synthesis, Characterization and Properties of Antibacterial Polyurethanes.

Novel physically crosslinked polyurethane (PUII), based on isophorone diisocyanates, was prepared by a conventional two-step method. The chemical structures of the PUII were characterized by fourier transform infrared (FTIR), proton nuclear magnetic resonance (1H NMR), gel permeation chromatography (GPC), scanning electron microscopy (SEM) and DSC. The PUII hydrogels were subjected to solvent-induced self-assembly in THF + water to construct a variety of morphologies. The self-assembly morphology of the PUII was observed by scanning electron microscopy (SEM). The PUII films with different amounts (0.2%, 0.4%, 0.6%, 0.8%, 1.0%) of 1,3,5-Tris(2-hydroxyethyl)hexahydro-1,3,5-triazine (TNO) were challenged with Escherichia coli, Staphylococcus aureus, Bacillus subtilis and Gray mold. The results showed that when a small amount of antibacterial agent were added, the antibacterial effect of films on Botrytis cinerea was more obvious. The mechanical evaluation shows that the antimicrobial polyurethane films exhibit good mechanical properties.

Leaf vein-inspired engineering of MXene@SrSn(OH)6 nanorods towards super-tough elastomer nanocomposites with outstanding fire safety

The progress of super-robust, high ductile polymeric nanocomposite with superior safety have been caught increasing eyesight for the application in electronic products. In this article, strontium hydroxystannate (SSO) nanorods were in-situ fabricated on the surface of titanium carbide (Ti 3 C 2 T x ) MXene nanosheets (MSSO) for improving fire safety and mechanical property of thermoplastic polyurethane (TPU) to further applications of portable devices. With biomimetic method, the tensile robustness and toughness of TPU-2.0MSSO was enhanced by 46% and 126%, respectively. In addition, the TPU-MSSO nanocomposites performed leaf vein-inspired hierarchical structure during the stretching behavior, resulting 55% enhancement of elongation at break. Furthermore, the fire safety was systematically evaluated, and the peak heat release rate (pHRR) decreased by 37.31%. Above all, hazardous pyrolysis products of TPU during the combustion were also efficiently reduced, especially the generation of carbon oxide (CO) and carbon dioxide (CO 2 ) were decreased by 96.04% and 89.85% when the additive of MSSO was only 2 wt%. As a result, ternary catalytic effect and labyrinth structure improved the safety of TPU in modern electronic products. Hence, this leaf vein-inspired TPU-MSSO nanocomposites not only exhibit superior toughness but also reinforce fire safety while facing thermal runaway, which was significant to destroy the formation of thermal disaster chain and maintain further applications of additional products for portable devices, and package materials for flexible electronics. • Leaf vein-inspired nanostructure was prepared via SSO nanorods in-situ growing on Ti 3 C 2 T x . • TPU-2.0MSSO nanocomposite shows up exceeding improvement of toughness reaching 126%. • The pHRR of TPU-2.0MSSO was reduced by 37.31% with a low heat release. • The production of CO and CO 2 were reduced by 96.04% and 89.85% using 2 wt% MSSO. • MSSO offers a method for enhancing toughness and safety for flexible electronics.

Novel technique of controlled laser air-force detection for rheological properties of polymers

A novel controlled laser air-force detection (CLAFD) technique was developed to detect the rheological properties of polymers with the characteristics of non-destruction and cross-contamination free. Dynamic testing and static testing were carried out in the technique. Back propagation neural network algorithm was used to establish the air-force control model. The replicability of CLAFD system was analyzed, the viscoelastic properties of polyurethane were investigated using alternating load testing. A comparative analysis of performances was made between the CLAFD and the texture analysis (TA) on the testing of creep-recovery and stress relaxation. The results demonstrated that the CLAFD system had good replicability. The lagging phase angle was between 0°-90° in the testing of alternating load. This illustrated that the CLAFD technique could be used to detect viscoelasticity. The parameters of response speed and the precision of the CLAFD entirely surpassed the TA on the creep-recovery testing. The CLAFD technique will provide a new real-time, non-destruction and cross-contamination-free detection method for material science, especially for those materials such as artificial biological tissue and function food products. Keywords: controlled laser air-force detection (CLAFD) technique, biological tissues, rheological properties, statics analysis, dynamic analysis DOI: 10.25165/j.ijabe.20221501.6494 Citation: Xu H B, Hu R Z, Lin Y Z, Juan H, Tang X Y. Novel technique of controlled laser air-force detection for rheological properties of polymers. Int J Agric & Biol Eng, 2022; 15(1): 62–70.