Prepare Polyurethane Research Articles

Zwitterionic functional layer modified electrospun polyurethane nanofiber membrane incorporating silver nanoparticles for enhanced antibacterial applications

Nanofiber materials, with their porous nature and high specific surface area, can effectively adsorb and capture bacteria. Additionally, their antibacterial properties can be enhanced by incorporating substances with antibacterial effects and by surface modification with special chemical functional groups. Therefore, this study uses the electrospinning method to prepare polyurethane (PU) nanofiber antimicrobial membranes. Silver nanoparticles (AgNPs) will be incorporated into the PU nanofiber membranes through a green reduction method, followed by atmospheric plasma treatment to graft the zwitterionic material (2-methacryloyloxyethyl phosphorylcholine, MPC) with quaternary ammonium functional groups onto the surface. This process will result in the production of PMPC@PU/AgNPs nanofiber antimicrobial membranes. The results show that MPC grafted onto the surface of PU/AgNPs nanofiber membranes exhibits better antibacterial capability against Escherichia coli than the pristine PU/AgNPs nanofiber antimicrobial membranes, with an antibacterial efficiency reaching 99.68 ± 0.07 %. This is attributed to the synergistic effect provided by the combination of AgNPs within the PU nanofibers and the surface grafting of zwitterionic materials, leading to an antibacterial effectiveness close to 100 %. Therefore, the prepared PMPC@PU/AgNPs nanofiber antimicrobial membrane demonstrates the potential for applications in public health, specifically in areas such as food packaging materials, membrane filters and the biomedical field.

Efficient degradation of amine cured epoxy resin via the cleavage of C-N bond by amphiphilic dodecylbenzenesulfonic acid

Amine-cured epoxy resin (EP) is often compounded with carbon fiber (CF) used for wind power blades due to its excellent performance. However, the insolubility and infusibility of service-life-expired carbon fiber reinforced epoxy resin (CFREP) hinder its sustainable recycling. We reported a new strategy for efficient degradation of EP and CFREP with 0.5 mol% amphiphilic dodecylbenzenesulfonic acid (DBSA) in aqueous system. It was found that the strong lipophilicity of DBSA accelerated its enrichment on EP surface, and further promoted the diffusion of DBSA and H2O to the resin bulk phase. As a result, the degradation ratio of the EP powder reached 100 % at 190 °C only in 10 h. The characterization of FT-IR and NMR proved that the degradation mechanism of EP was the selective cleavage of C-N bond catalyzed by H+. The resin degradation products (RDP) containing active hydrogen were used to prepare polyurethane (PU) with good mechanical properties. This method achieves complete recycling of waste CFREP in aqueous systems.

Self-Healing Polyurethane Elastomers with High Mechanical Properties Based on Synergistically Thermo-Reversible and Quadruple Hydrogen Bonds

It is still challenging and attractive to prepare polyurethane (PU) materials with excellent self-healing ability while improving their mechanical properties and high ductility. Here, a multifunctional linear PU supramolecular elastomer was successfully prepared by introducing a cross-linking network of quadruple hydrogen bonds and thermo-reversible Diels–Alder bonds and rigid ring structure to the linear backbone. The results exhibited that the obtained PU elastomer displayed a high tensile strength (6.30 MPa), elongation (1957.84%), toughness (84.48 MJ/m3), and excellent repair efficiency (93.33%). The quadruple hydrogen bonds from 5-(2-hydroxyethyl)-6-methyl-2-aminouracil and thermo-reversible Diels–Alder bonds from the conjugated reaction of 4,4′-bismaleimide diphenylmethane with furfuryl alcohol, due to its synergetic dual reversible bonds, formed the PU elastomer that possessed excellent mechanical, self-healing, shape recovery, and reprocessing properties. The prepared multifunctional PU can be used as a substrate for flexible conductive materials or as conductive composite material with conductive materials, which can self-repair many times when the surface is damaged, can be recycled, and greatly improve the service life of the material. Therefore, the prepared multifunctional high-performance self-healing PU materials have potential applications in several fields.

Ultra-robust, self-healable and recyclable polyurethane elastomer via a combination of hydrogen bonds, dynamic chemistry, and microphase separation

Flexibility, robustness, transparency, and recyclability are critical to the application of self-healing polymer materials in the field of flexible electronics. However, integrating all the above properties remains a huge challenge to date. In this work, we put forward a facile strategy to prepare polyurethane (PU) elastomer with ultra-high strength and self-healing performance based on hydrogen bonds, disulfide dynamic chemistry, and microphase separation at the same time. Three different self-healing PUs were obtained by introducing disulfide bonds and different types of hydrogen bonds. A robust, transparent, and recyclable PU with amino-terminated chain extender (PUA) with fast and efficient self-healing performance was prepared. The mechanical and self-healing properties of the PUA were effectively balanced by the synergistic effect of reversible interaction of disulfide bonds and the formation of microphase separated structure. The results indicated that the PUA exhibited high transparency up to 90% and excellent mechanical property, e.g. the tensile strength and elongation at break can reach 37.10 MPa and 1080%, respectively. Meanwhile, it can achieve a high self-healing efficiency of 96.8% at 80 °C for 4 h and maintain 84% of the initial mechanical strength even after four times of recycling. Moreover, the colloid graphite/PUA flexible strain sensor was prepared by the combination of colloid graphite and PUA, which can accurately detect both large and tiny scale deformations.

Development of shoe insert for Diabetic Foot Ulcer Patients in case of Ethiopia

Foot ulcer is mainly developing due to diabetic disease. It is an open sore on the foot. The aim of this research is to develop polyurethane memory foam in sock/shoe insert in Ethiopia by replacing costly material silicon surfactant by locally available and affordable input materials castor oil as surfactant and tap water instead of distilled water for the diabetic foot ulcer patients. Under this research, it was able to prove the severity of foot ulcer in Ethiopia and enhance the high demand of orthotic appliance. Three memory foams in sock with different surfactant ratios were manufacture at AMAGA P.L.C foam factory, Bahir Dar Ethiopia using standard Polyols and diisocynates. The shoe insert /in sock was prepared by using materials used in the factory to prepare polyurethane (PU) memory foam mattress with 5g, 9.5 g and 10.36g of castor oil surfactant amount as a new replaced material instead of costly silicon surfactant from the three the first (castor oil 5g is not form a foam and hence no further investigation is conducted on it). Physical properties such as thickness, density, hardness, compression set, water absorption and abrasion resistance of developed in sock were tested. Further the new developed in sock was compared with that of existed commercial polyurethane in sock and the SATRA standards. The new developed in sock has showed an equivalent mechanical property with the standard.

Small diameter blood vessels with controllable micropore structure induced by centrifugal force for improved endothelialization.

The micropore structure is prerequisite for fast and durable endothelialization of artificial small diameter blood vessels (ASDBVs). Although some methods, such as salt leaching, coagulation, and electrospinning, have been developed to construct micropores for ASDBVs, the uncontrollability of the structure and the complicated procedures of the process are still the issues to be concerned about. In this study, a compact device based on the principle of centrifugal force is established and used to prepare polyurethane (PU) ASDBVs with micropore structures by blasting different porogens. It is found that the glass beads could construct micropores with regular round shape, uniform distribution, and controllable size (60–350 µm), which significantly improves the endothelialization of PU‐based ASDBVs, especially when the pore size is about 60 µm. This method is easy‐accessible and wide‐applicable, which provides a new pathway for the research and development of ASDBVs.

Large Improvement in the Mechanical Properties of Polyurethane Nanocomposites Based on a Highly Concentrated Graphite Nanoplate/Polyol Masterbatch.

In this study, a highly concentrated graphite nanoplate (GNP)/polyol masterbatch was prepared by the exfoliation of natural graphite in an aqueous system using cetyltrimethylammonium bromide and the replacement of aqueous solution with a polyol, viz. poly(tetramethylene ether glycol), and it was subsequently used to prepare polyurethane (PU) nanocomposites by simple dilution. The polyol in the masterbatch efficiently prevented the aggregation of GNPs during the preparation of PU nanocomposite. In addition, the dispersed GNPs in the masterbatch exhibited rheological behavior of lyotropic liquid crystalline materials. In this study, the manufacture and application methods of the GNP/polyol masterbatch were discussed, enabling the facile manufacture of the PU/GNP nanocomposites with excellent mechanical properties. In addition, the manner in which the GNP alignment affected the microphase separation of PU in the nanocomposites was investigated, which determined the improvement in the mechanical properties of the nanocomposites. High-performance PU/GNP nanocomposites are thought to be manufactured from the GNP/polyol masterbatch by the simple dilution to 0.1 wt% GNP in the nanocomposite.

Anticoagulant polyurethane substrates modified with poly(2-methacryloyloxyethyl phosphorylcholine) via SI-RATRP.

A novel catalyst system of Reverse Atom Transfer Radical Polymerization (RATRP) to prepare Polyurethane (PU) films modified by poly(2-methacryloyloxyethyl phosphorylcholine) (pMPC) was studied in this article. In this system, PU film was pretreated by LaCl3/CA ethanol solution to obtain a hydrated surface allowing more initiators to be immobilized on it. Moreover, complexes composed of silane coupling agent 3-chloropropyltrimethoxysilane (CPTM), chlorhexidine acetate (CA) and lanthanum(III) worked as ligands of copper ions as a whole during RATRP process. PU films before and after modification were characterized by X-ray photoelectron spectroscopy (XPS) and static contact angle (SCA) to confirm that pMPC chains were successfully grafted from the substrates. Results of Plasma recalcification time assay, platelet adhesion test indicated excellent blood compatibility. Furthermore, the antibacterial activity of the material have been improved which proved by adhesion test of E.coil.

Chemical functionalization of graphene oxide for improving mechanical and thermal properties of polyurethane composites

Abstract Graphene oxide (GO) was chemically functionalized to prepare polyurethane (PU) composites with improved mechanical and thermal properties. In order to achieve a well exfoliated and stable GO suspension in an organic solvent (dimethylformamide, DMF), 4, 4′-methylenebis(phenyl isocyanate) and polycaprolactone diol, which were the two monomers for synthesizing PU, were selectively used to functionalize GO. The obtained functionalized GO (FGO) could form homogeneous dispersions in DMF solvent and the PU matrix, as well as provide a good compatibility with the PU matrix. The most efficient improvement of mechanical properties was achieved when 0.4 wt.% FGO was added into the PU matrix, showing increases in the tensile stress, elongation at break and toughness by 34.2%, 27.6%, and 64.5%, respectively, compared with those of PU. Regarding the thermal stability, PU filled with 1 wt.% FGO showed the largest extent of improvement with T 2% and T 50% (the temperatures at which 2% and 50% weight-loss happened) 16 °C and 21 °C higher than those of PU, respectively. The significant improvement in both mechanical properties and thermal stability of FGO/PU composites should be attributed to the homogeneous dispersion of FGO in the PU matrix and strong interfacial interaction between them.

Effects of functional groups on the graphene sheet for improving the thermomechanical properties of polyurethane nanocomposites

Dispersibility of graphene sheets in polymer matrices and interfacial interaction are challenging for producing graphene-based high performance polymer nanocomposites. In this study, three kinds nanofillers; pristine graphene nanoplatelets (GNPs), graphene oxide (GO), and functionalized graphene sheet (FGS) were used to prepare polyurethane (PU) composite by in-situ polymerization. To evaluate the efficacy of functional groups on the graphene sheets, PU reinforced with GNPs, GO, and FGS were compared through tensile testing and dynamic mechanical thermal analysis. The Young's moduli of 2 wt% GO and FGS based PU nanocomposites were found significantly higher than that of same amount of GNPs loading as an evidence of the effect of functional groups on graphene sheets for the mechanical reinforcement. The strong interaction of FGS with PU was responsible to exhibit notably high modulus (25.8 MPa) of 2 wt% FGS/PU composite than the same amount of GNPs and GO loading even at elevated temperature (100 °C).

Inorganic–organic hybrid biodegradable polyurethane resin derived from liquefied Sakura wood

Prunus cerasus (Japanese cherry blossom: Sakura) was liquefied in polyethylene glycol—glycerol co-solvent with sulfuric acid (H2SO4) as a catalyst. The liquefied wood was blended with poly-4,4′-diphenylmethane diisocyanate to prepare polyurethane (PU) resin. In addition, inorganic–organic hybrid biodegradable polyurethane resin was prepared by adding tetraethoxysilane into liquefied-wood-derived polyurethane. It was found that the thermal stability of liquefied-wood-derived polyurethane is better than general polyurethane. Furthermore, it was ensured that Si was introduced in PU at a molecular level, while maintaining the urethane structure.

Influence of cellulose nanofibrils on soft and hard segments of polyurethane/cellulose nanocomposites and effect of humidity on their mechanical properties

Cellulose nanofibrils (CNFs) were prepared by sulfuric acid hydrolysis from cotton microfibers, and used to prepare polyurethane (PU) nanocomposites by mixing CNFS and PU water suspensions. CNFs as nanofillers improved the tensile strength of PU significantly up to 10 wt% content. With an increase in the CNF content, the glass transition temperature of PU and the temperature onset of the soft segment increased compared with those of neat PU. However, the crystalline phase present in soft domains and its melting temperature decreased. The influences of humidity on the mechanical properties of PU/CNF nanacomposites were also investigated. The tensile strength at different elongations of PU/CNF nanocomposites decreased substantially after being exposed to 60% relative humidity for 24 h; for 10 wt% loading, the tensile strength at 500% dropped from 10.64 to 2.34 MPa. This behavior was attributed to the formation of hydrogen bonds of PU and CNFs with water.

Polyurethane Foams from Cellulosic Waste and Natural Oil-based Polyols – a Modified Approach

A modified approach was used to prepare polyurethane (PU) foams employing natural oil-based polyols. Functionalized polyols with different hydroxyl values were synthesized from glycoside obtained from waste paper and reacted with natural oils viz. castor oil and soy oil. The obtained polyols were used to prepare the TDI-adduct based foams. Their physical and thermal properties were studied and compared using compression tests and thermogravimetric analysis; their cellular structures were also investigated using scanning electron microscopy. Processing parameters such as cream, rising and gel times were determined for the reactivity of the prepared polyols. Confirmation of PU linkage was performed by FTIR. The prepared PU foams demonstrated compressive properties ranging from 0.2 to 1.2 MPa and microscopic studies of the foam cell structure indicated its possible use for insulation purposes.

Fabrication Polyurethane/Expanded Graphite Powder Composite Antistatic Sponge by <i>In Situ</i> Polymerization

This document explains and demonstrates how to prepare Polyurethane(PU)/Expanded Graphite powder(EGp) composite antistatic sponge by in situ polymerization. The morphology、mechanical、electrical and thermal properties of the PU/EGp composite antistatic sponge have been investigated. PU/ EGp composite sponge have better mechanical properties than that of CB composite. The resistivity of PU/EGp composite antistatic sponge can reach at about 108Ω•cm at the content around 5wt% of the EGp. EGp can stably exist in PU sponge and has little influence to the polymeric matrix while being heated.

Influence of the morphology of barium sulfate nanofibers and nanospheres on the physical properties of polyurethane nanocomposites

Barium sulfate spherical agglomerates and fibers in the nanometric size range were used to prepare polyurethane (PU) nanocomposites (with 1wt.% concentration) via melt extrusion. A detailed analysis on the effect of the morphology of the barium sulfate phase upon the mechanical, rheological and optical properties was carried out. Results show that the inclusion of the dispersed phase (with various morphologies and sizes) in the polymer matrix does not decrease the polymer mechanical properties, as is observed when particles in the micrometric size range are included. Rheological studies show that the nanocomposite containing spherical particles presents a slightly higher shear viscosity than that of the polymer matrix, in contrast to the nano-fibers viscosity which presents lower values. This is reflected in the effect of the particle morphology on the processability of the material; in contrast, the morphology has no effect on the radio-opacity of the samples. The structure and dispersion of the particles were analyzed using scanning and transmission electron microscopy. The sample with 1wt.% nanofibers presents better processability than the system with spherical agglomerates maintaining the X-ray opacity properties.

Oleic Acid-based Polyurethane and its Biocomposites with Oil Palm Trunk Fiber Dust

The main objectives of the present research are (i) to obtain a monoglyceride from oleic acid through a direct esterification process, (ii) utilization of the obtained monoglycerides to prepare polyurethane (PU) sheet, and (iii) the preparation of a series of biocomposites using prepared PU and different amounts of oil palm trunk (OPT) fiber dust. The tensile strength of OPT fiber dust incorporated PU biocomposites is found to be increased with the increase in the OPT fiber dust content up to 20% in the composites. The tensile strengths of PU and its biocomposites with 20% OPT fiber dust were 0.6 and 2.15 MPa, respectively. The thermal properties of PU and its biocomposites having varied amounts of OPT fiber dust of 0—40% have been investigated using dynamic mechanical analyzer (DMA) and thermogravimetric analyzer (TGA). TGA studies revealed that PU and its biocomposites have undergone two- and three-step degradation, respectively. From DMA studies, a shift in the tan δ value was noticed for the biocomposites containing 30 and 40% OPT fiber dust. The morphology of the tensile fractured composite specimens was analyzed using scanning electron microscope.

The Influence of Macrodiol Type on the Mechanical Properties of Polyurethane Materials

A one-step bulk polymerization procedure was used to prepare polyurethane (PUR) materials based on hexamethylene diisocyanate, 1,4-butanediol, and a macrodiol. Polycarbonate diol, polyoxypropylene diol, and polybutadiene diol were used as the macrodiols (MW ca 2000), with dibutyltin dilaurate as the catalyst. To evaluate the mechanical properties of the PUR materials, a common tensile test was performed at room temperature and dynamic mechanical analysis (DMA) in the temperature range of −100°C to +150°C. The effect of macrodiol type on mechanical behavior is discussed, together with the influence of the shape of the prepared materials (bulk, film) on the tested properties.

Preparation and application of polyurethane adhesives made from polyhydric alcohol liquefied Taiwan acacia and China fir

AbstractTaiwan acacia (Acacia confusa) and China fir (Cunninghamia lanceolata) were liquefied in polyethylene glycol (PEG)–glycerol cosolvent, with sulfuric acid (H2SO4) as a catalyst. The liquefied woods were blended with three kinds of isocyanate, such as poly‐4,4′‐diphenylmethane diisocyanate (PMDI), Desmodur L (adduct of toluene diisocyanate with trimethylol propane), and Desmodur N (trimer of hexamethylene diisocyanate), to prepare polyurethane (PU) resins. From the results, China fir had better liquefaction effect than Taiwan acacia. Those PU resins prepared from liquefied wood blending with isocyanate could cure at room temperature. Their gel property was influenced by the type of isocyanate, the molar ratio of the functional group of isocyanate to liquefied wood [NCO/(OH+COOH)], and the rate of catalyst added. PU resins prepared from Desmodur L had an appropriate gel time for processing. But those prepared from PMDI had too short gel time to process. Contrary, the PU resins prepared from Desmodur N would take a longer time to gel. However, addition of catalyst could shorten the gel time significantly. FT‐IR analysis showed that a urethane bond had formed between the liquefied wood and isocyanate. When these PU resins were used as wood adhesives, liquefied wood blended with Desmodur L had better dry and wet bonding strength than others. Increasing the molar ratio of NCO/(OH+COOH) could increase the bonding strength. On comparing liquefied Taiwan acacia and China fir, the former had better bonding strength than the latter. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008

Synthesis and characterisation of polyurethane coatings based on trimer of isophorone diisocyanate (IPDI) and monoglycerides of oils

Monoglycerides (MGs) of four oils (castor, linseed, soybean and sesame) were prepared. They were reacted with a trimer in definite proportions to prepare polyurethane (PU) coatings. These coatings were applied in the form of thin films on tin plates and analysed for various coating properties such as gloss, scratch resistance, flexibility properties and physicochemical tests. A highly cross-linked product was obtained due to the higher functionality associated with MGs compared with their molecular weight. The trimer also imparted cross-linking due to its trifunctionality, and a hard yet flexible, tough, glossy polyurethane coating was obtained.

Index to Volume 26, 2004

Cellulose nanofibrils (CNFs) were prepared by sulfuric acid hydrolysis from cotton microfibers, and used to prepare polyurethane (PU) nanocomposites by mixing CNFS and PU water suspensions. CNFs as nanofillers improved the tensile strength of PU significantly up to 10 wt% content. With an increase in the CNF content, the glass transition temperature of PU and the temperature onset of the soft segment increased compared with those of neat PU. However, the crystalline phase present in soft domains and its melting temperature decreased. The influences of humidity on the mechanical properties of PU/CNF nanacomposites were also investigated. The tensile strength at different elongations of PU/CNF nanocomposites decreased substantially after being exposed to 60% relative humidity for 24 h; for 10 wt% loading, the tensile strength at 500% dropped from 10.64 to 2.34 MPa. This behavior was attributed to the formation of hydrogen bonds of PU and CNFs with water.