Polyether Polyurethane Research Articles

Preparation and properties of carbon fiber/polyether polyurethane composites

A series of carbon fiber (CF)/polyether polyurethane (PU) composites were prepared by in situ polymerization and a casting compression molding technique. The influence of CF content and its pretreatment with a coupling agent and oxidation by 65%-68% (mass fraction) nitric acid on the mechanical performance, thermal properties and morphology of the composites was investigated by TGA, SEM and mechanical tests. Results showed that coupling agents improve the mechanical performance of the CF/PU composites, especially for silane coupling agents KH5501, KH602 and the titanate coupling agent TCA-K44. Nitric acid oxidation also improved the mechanical performance and thermal stability of the composites. The adhesion between PU and nitric acid-oxidized CFs was better than that between PU and fibers treated with silane coupling agents. [New Carbon Materials 2014, 29(6): 454–460]

DisBa-01 inhibits angiogenesis, inflammation and fibrogenesis of sponge-induced-fibrovascular tissue in mice

Integrins are involved in a number of physio-pathological processes including wound healing, chronic inflammation and neoplasias. Blocking its activity is potentially of therapeutic value in these conditions. We investigated whether DisBa-01, a recombinant His-tag RGD-disintegrin from Bothrops alternatus snake venom, could modulate key events (inflammatory cell recruitment/activation, neovascularization and extracellular matrix deposition) of the proliferative fibrovascular tissue induced by polyether polyurethane sponge implants in mice. The hemoglobin content (μg/mg wet tissue), blood flow measurements (laser Doppler perfusion imaging) and number of vessels in the implants, used as indices of vascularization, showed that the disintegrin dose-dependently reduced angiogenesis in the implants relative to the Saline-treated group. DisBa-01 inhibited neutrophil and macrophage content as determined by the myeloperoxidase (MPO) and N-acetyl-β-D-glucosaminidase (NAG) activities, respectively. Similarly, down regulation of the fibrogenic component studied (collagen deposition) was observed in DisBa-01-treated implants. VEGF, bFGF, TNF-α, CXCL1 and CCL2 levels were also decreased by the disintegrin. The inhibitory effect of this αvβ3-blocking disintegrin on the angiogenic, inflammatory, and fibrogenic components of the fibrovascular tissue induced by the synthetic matrix extends the range of DisBa-01 actions and may indicate its therapeutic potential in controlling angiogenesis in fibroproliferative diseases.

Vinyl-modified hyperbranched polyether cross-linked hydroxyl-terminated polybutadiene-based polyurethane membrane for pervaporation recovery of butanol

Hyperbranched polyether was synthesized and vinyl modified using the one-pot method and characterized by Fourier transform infrared spectroscopy (FTIR), hydrogen nuclear magnetic resonance spectroscopy, and thermogravimetric analysis (TGA). The as-obtained polyether was used to cross-link hydroxyl-terminated polybutadiene-based polyurethane (PU). The PU was characterized by FTIR, TGA, scanning electron microscopy, water contact angle, tensile tests, and swelling properties. The PU was used in pervaporation (PV) recovery of butanol from its dilute aqueous solution. The PV performance was determined using the separation factor ( α) and permeate flux ( Fp). With a membrane thickness of 31 μm, the separation factor of the membrane was up to 10.2 with a total flux of 320.7 g m−2 h−1 at 70°C.

A direct quantitative agar-plate based assay for analysis of Pseudomonas protegens Pf-5 degradation of polyurethane films

A quantitative assay was developed for the direct measurement of polymer film degradation from bacterial colonies on agar plates. Small (1 mm diameter) colonies of Pseudomonas protegens Pf-5 (formerly Pseudomonas fluorescens Pf-5) were used for this work. Interactions between the Pf-5 colonies and thin polyurethane (PU) coatings on ZnSe coupons were evaluated for degradation using infrared spectroscopy. Three different coatings were analyzed and were formed from 1) a colloidal, aqueous – based polyester PU (Impranil® DLN); 2) an organic solvent – based polyester PU (Irogran); and 3) an organic solvent – based polyether PU (AS-P108). Over a 24 h time period at 30 °C, citrate exposed Pf-5 cultures rapidly degraded Impranil coatings, consistent with analogous zone clearing assays. However, the Irogran and AS-P108 PU's, which are not directly compatible with zone clearing assays, showed no measureable degradation by the coating assay under identical conditions. These results demonstrated the capability to evaluate any variety of polymer formulation as solid films under identical biological conditions. The results also show that rapid microbial degradation of colloidal polyurethanes such as Impranil are not necessarily representative of activity towards other PU materials.

Natriuretic peptide clearance receptor ligand (C-ANP4-23 ) attenuates angiogenesis in a murine sponge implant model.

Natriuretic peptide receptor-C activation by the synthetic ligand C-ANP-4-23, a specific agonist for this receptor, has been shown to inhibit key events of the angiogenic cascade, such as migration, proliferation and vascular endothelial growth factor (VEGF) production. In the present study we investigated whether C-ANP4-23 could also inhibit angiogenesis in the sponge model in vivo. To this end, we evaluated the effects of C-ANP4-23 on inflammatory and angiogenic components of the fibrovascular tissue induced by polyether polyurethane sponge implants in mice. Measurements of the haemoglobin content (μg/mg wet tissue) and blood flow (laser Doppler perfusion imaging) of the implants, used as an index of vascularization, revealed that single (200ng) or multiple (200ng/day, 5days) doses of C-ANP4-23 reduced angiogenesis in the implants relative to the phosphate-buffered saline-treated group. The peptide exerted an inhibitory effect on nitric oxide production (nitrite levels) and had a dual effect on VEGF levels, depending on the number of doses (i.e. stimulation at 4days after one dose; inhibition at 7days after five doses). Histological analysis corroborated the biochemical and functional parameters indicative of inhibition of neovascularization (decreased vessel number) by C-ANP4-23 . The peptide failed to modulate inflammation in our system. The inhibitory effect of C-ANP4-23 on the angiogenic component of the fibrovascular tissue induced by the synthetic matrix extends the range of the its actions and may indicate its therapeutic potential in controlling angiogenesis in fibroproliferative diseases.

Deletion of the chemokine receptor CCR2 attenuates foreign body reaction to implants in mice

Subcutaneous implantation of synthetic materials and biomedical devices often induces abnormal tissue healing – the foreign body reaction – which impairs their function. Here we investigated the role of the chemokine receptor CCR2 in this reaction to subcutaneous implants in mice. We measured angiogenesis, inflammation and fibrogenesis induced by implantation, for 1, 4, 7 and 14days, of polyether–polyurethane sponges in mice with genetic deletion of CCR2 (KO) and WT mice. Blood flow was determined by dye diffusion and laser Doppler perfusion techniques. Cytokines (VEGF, TNF-α, CCL2, TGF-β1) were measured by ELISA. Histochemical methods were used to assess collagen deposition and macrophage-derived giant cells in the implants. Skin and implant blood flow was lower in CCR2 KO than in WT mice, as were other aspects of neo-vascularization of the implants. Neutrophil accumulation was increased in KO implants but macrophage accumulation was decreased. Implant content of CCL2 was higher in KO implants, but TGF-β1, collagen deposition and the number of foreign body giant cells were lower than in WT implants. Deletion of CCR2 decreased blood flow in normal skin and inhibited neo-vascularization, chronic inflammation and fibrogenesis in subcutaneous implants. The chemokine receptor CCR2 plays an important role in both normal skin and in the reaction elicited by subcutaneous implantation of a foreign body.

Formulation and characterization of a porous, elastomeric biomaterial for vocal fold tissue engineering research.

Biomaterials able to mimic the mechanical properties of vocal fold tissue may be particularly useful for furnishing a 3-dimensional microenvironment allowing for in vitro investigation of cell and molecular responses to vibration. Motivated by the dearth of biomaterials available for use in an in vitro model for vocal fold tissue, we investigated polyether polyurethane (PEU) matrices, which are porous, mechanically tunable biomaterials that are inexpensive and require only standard laboratory equipment for fabrication. Rheology, dynamic mechanical analysis, and scanning electron microscopy were performed on PEU matrices at 5%, 10%, and 20% w/v mass concentrations. For 5%, 10%, and 20% w/v concentrations, shear storage moduli were 2 kPa, 3.4 kPa, and 6 kPa, respectively, with shear loss moduli being 0.2 kPa, 0.38 kPa, and 0.62 kPa, respectively. Storage moduli responded to applied frequency as a linear function. Mercury intrusion porosimetry revealed that all 3 mass concentrations of PEU have a similar overall percentage porosity but differ in pore architecture. Twenty-µm diameter pores are ideal for cell seeding, and a range of mechanical properties indicates that the lower [corrected] mass concentration PEU formulations are best suited for mimicking the viscoelastic properties of vocal fold tissue for in vitro research.

Limitations of predictingin vivobiostability of multiphase polyurethane elastomers using temperature-accelerated degradation testing

Polyurethane biostability has been the subject of intense research since the failure of polyether polyurethane pacemaker leads in the 1980s. Accelerated in vitro testing has been used to isolate degradation mechanisms and predict clinical performance of biomaterials. However, validation that in vitro methods reproduce in vivo degradation is critical to the selection of appropriate tests. High temperature has been proposed as a method to accelerate degradation. However, correlation of such data to in vivo performance is poor for polyurethanes due to the impact of temperature on microstructure. In this study, we characterize the lack of correlation between hydrolytic degradation predicted using a high temperature aging model of a polydimethylsiloxane-based polyurethane and its in vivo performance. Most notably, the predicted molecular weight and tensile property changes from the accelerated aging study did not correlate with clinical explants subjected to human biological stresses in real time through 5 years. Further, DMTA, ATR-FTIR, and SAXS experiments on samples aged for 2 weeks in PBS indicated greater phase separation in samples aged at 85°C compared to those aged at 37°C and unaged controls. These results confirm that microstructural changes occur at high temperatures that do not occur at in vivo temperatures. In addition, water absorption studies demonstrated that water saturation levels increased significantly with temperature. This study highlights that the multiphase morphology of polyurethane precludes the use of temperature accelerated biodegradation for the prediction of clinical performance and provides critical information in designing appropriate in vitro tests for this class of materials.

Impregnated electrospun nanofibrous membranes for water vapour transport applications

Membranes with high water vapour permeance and selectivity find many end uses including protective clothing, dehydration, and humidification. One application for water vapour transport membranes is in energy recovery ventilators (ERVs) for buildings. These devices improve building energy efficiency by transporting heat and moisture between incoming and outgoing air streams in building ventilation systems, effectively ‘recycling’ the energy used to condition the indoor air. Membranes for these devices must have high vapour permeance, and selectivity for water vapour over other gases and contaminants that may be present in the exhaust indoor air. Due to the high rates of water vapour transport required in these gas to gas devices, boundary layer and internal resistances within the membrane contribute significantly to performance. Commercially available membranes suffer from high water vapour transport resistance in the microporous substrate support layer. In this study we report the fabrication of novel impregnated electrospun nanofibrous membranes (IENM) for water vapour transport applications. Electrospun nanofibre layers are impregnated with a polyether–polyurethane solution and cured to create continuous thin impregnated fibre loaded film layers which are bound to a non-woven support layer. These membranes have high water vapour permeance and selectivity while eliminating the requirement for a microporous support layer which has high vapour transport resistance. Here we report initial studies on how controllable factors in the membrane fabrication (namely fibre loading and impregnated solution polymer solids concentration) affect structural and permeation properties of IENMs created. Membranes with adequate permeance and selectivity are demonstrated and direction for optimization is identified. We find that the nanofibre loading has a significant impact on water vapour permeability as the membrane thickness decreases. Future work will study how modifications to the geometric and structural properties of the fibres affect the membrane performance.

Determination of gold in ore samples by energy dispersive X-ray fluorescence after separation and preconcentration on polyurethane foam

A sensitive and selective method to determine gold in ore samples was developed. It was based upon gold extraction from hydrochloric acid medium by unloaded polyether type polyurethane foam (PUF). After that direct measurement on the solid sorbent by energy dispersive X-ray fluorescence (EDXRF) was done. The main parameters that control the gold sorption on PUF were evaluated. HCl concentration, sorption kinetic, amount of PUF and influence of foreign ions are some examples of these parameters. No variation in the gold system sorption was observed in the concentration range of 10−2 to 1mol L−1 of HCl. A 0.3mol L−1 HCl concentration was selected. The sorption kinetics of Au (III) is rapid with a half-life of adsorption (t1/2) of 0.83min. The curve fitted by EDXRF measurement of gold Lα intensity signal on PUF was linear in the mass range of 0 to 25μg. The calibration sensitivity was 0.0860 CPS μg−1. The detection and quantification limits of gold in ore samples were 1.36 and 4.53μg .g−1, respectively. It was observed that Al, Cu (II), Fe (III), Mn (II) and Ni have no significant effect on gold sorption. The method was successfully applied to determine gold in ore reference materials. The results are in good agreement with the certified gold values at a 95% confidence level. The average relative standard deviation (RSD) was 6%.

In vitro Endothelialization and Platelet Adhesion on Titaniferous Upgraded Polyether and Polycarbonate Polyurethanes.

Polycarbonateurethanes (PCU) and polyetherurethanes (PEU) are used for medical devices, however their bio- and haemocompatibility is limited. In this study, the effect of titaniferous upgrading of different polyurethanes on the bio- and haemocompatibility was investigated by endothelial cell (EC) adhesion/proliferation and platelet adhesion (scanning electron microscopy), respectively. There was no EC adhesion/proliferation and only minor platelet adhesion on upgraded and pure PCU (Desmopan). PEUs (Texin 985, Tecothane 1085, Elastollan 1180A) differed in their cyto- and haemocompatibility. While EC adhesion depended on the type of PEU, any proliferative activity was inhibited. Additional titaniferous upgrading of PEU induced EC proliferation and increased metabolic activity. However, adherent ECs were significantly activated. While Texin was highly thrombotic, only small amounts of platelets adhered onto Tecothane and Elastollan. Additional titaniferous upgrading reduced thrombogenicity of Texin, preserved haemocompatibility of Elastollan, and increased platelet activation/aggregation on Tecothane. In conclusion, none of the PUs was cytocompatible; only titaniferous upgrading allowed EC proliferation and metabolism on PEUs. Haemocompatibility depended on the type of PU.

Comparison between properties of polyether polytriazole elastomers and polyether polyurethane elastomers

In order to explore the application of click chemistry in the field of elastomer materials, the comparison between the properties of polyurethane and polytriazole elastomers has been carried out. Propargyl-terminated ethylene oxide-tetrahydrofuran copolymer (PTPET) has been prepared from the ethylene oxide-tetrahydrofuran copolymer (PET) by end modification. Using polyisocyanate N100 and polyazide compounds as cross-linkers, PET polyurethane and PTPET polytriazole elastomers have been prepared through urethane and copper-catalyzed azide-alkyne huisgen [3 + 2] dipolar cycloaddition reactions, respectively. Mechanical properties indicate that, to be different from those of polyurethane elastomers, the modulus E and stress σb of polytriazole elastomers increase at first, and then decrease with the increase in R. At around the stoichiometric ratio, the modulus E and stress σb reach a maximum, and the strain εb reaches a minimum. Swelling tests demonstrate that the Mc of polytriazole elastomers has a minimum value at the stoichiometric ratio. The dynamic mechanical analysis indicates that both polyurethane and polytriazole elastomers have the same glass transition temperature of −64°C, although polytriazole elastomers exhibit lower dissipation factor tan δ. Thermal analysis shows that polytriazole elastomers have better thermal stability than polyurethane elastomers. Copyright © 2014 John Wiley & Sons, Ltd.

用于染料敏化太阳能电池的聚醚型聚氨酯凝胶电解质的研究

用于染料敏化太阳能电池的聚醚型聚氨酯凝胶电解质的研究

Aging Behavior of the Polyether Polyurethane Films Irradiated by UV

The failure behavior of polyether polyurethane films irradiated by UV depends on its molecular structures evolvement. The molecular structure evolvement of the polyether polyurethane films under UV irradiation were studied by in-situ FTIR spectra in this paper. It has been found that some oxygen contained groups such as hydroxyl group and carbonyl group increase; on the contrary, ether bond and CH2 decrease with the UV irradiation time. The aromatic ring maintains changeless. However, -NH group has not be determined due to the interference of the-OH and O-C=O. Results from FTIR and SEM have shown that UV photodegradative processes participated by oxidization occur mostly in ether segments and is accompanied by crosslinkage. Using the absorbance band of aromatic ring as the base the service life of polyether polyurethane can be determined by the change rate of C-O-C and-CH2 during UV irradiation. After UV irradiation, the polyether polyurethane film has higher color difference value and lower UV light transparence.

Holland Colours launches new product line for PU foam

Holland Colours Europe has launched a new product line for polyether polyurethane (PU) foams, slabstock and rigid foam. The company says that the need for a more competitive range of colours for the coloration of PU foams resulted in the development of a new series based on a sustainable carrier: a hydroxy functional vegetable oil.

Existence and uniqueness of solutions of a differential equation system modeling the thermal decomposition of polymer materials

The present study focuses on analyzing the solution of differential equation systems modeling the thermal decomposition kinetics of polymer materials at the matter scale. The kinetic parameters that allow reproduction of the mass loss rate are estimated by solving the system of equations using an inverse method. The methodology relies on a robust optimization technique using genetic algorithms, which is a research tool based on the principle of Darwinian evolution that is used to seek an optimal solution to a problem having a large number of adjustable parameters. However, a major disadvantage of the inverse problems dealt with here is that the uniqueness of the solution (the kinetic-parameter set) cannot be guaranteed. Even if the numerical approach is widely used, surprisingly there has been no attempt in the literature to provide a general proof of the equilibrium existence and uniqueness of systems modeling the thermal decomposition of polymer materials. This is a potentially important omission. This work seeks, therefore, to prove there is one and only one solution of the system satisfying the initial conditions. The Picard–Lindelöf theorem is used to ensure the existence of solutions to certain initial value problems. The analyses were performed on equation systems modeling the thermal decomposition of polyether–polyurethane foam. The results are presented and discussed. They show that, under some conditions, only one solution of the system satisfying the initial conditions exists.

Synergistic Aging Effect of Polyether Polyurethane Coatings

Synergistic Aging Effect of Polyether Polyurethane Coatings

Use of Rice Husk as Filler in Flexible Polyurethane Foams

AbstractSummary: In this study, flexible polyether polyurethane foams were synthesized by using two kinds of fillers: Inorganic filler and vegetal fiber obtained from agricultural waste. Structural, thermal and mechanical properties of the obtained foams were analyzed.

Reinforcement of Polyether Polyurethane with Dopamine-Modified Clay: The Role of Interfacial Hydrogen Bonding

Dopamine-modified clay (D-clay) was successfully dispersed into polyether polyurethane (PU) by solvent blending. It is found that the incorporation of D-clay into PU gives rise to significant improvements in mechanical properties, including initial modulus, tensile strength, and ultimate elongation, at a very low clay loading. The large reinforcement could be attributed to the hydrogen bonds between the hard segments of PU and stiff D-clay layers that lead to more effective interfacial stress transfer between the polymer and D-clay. Besides, the interactions between D-clay and PU are also stronger than those between Cloisite 30B organoclay and the PU chains. Consequently, at a similar clay loading, the PU/D-clay nanocomposite has much higher storage modulus than the PU/organoclay nanocomposite at elevated temperatures.

Quantitative estimation of the strength of specific interactions in polyurethane elastomers, and their effect on structure and properties

Two sets of segmented polyurethane (PU) elastomers were prepared from crystalline MDI, butanediol and a polyester or a polyether polyol, respectively. The molar mass of both polyols was 1000g/mol. The –OH functional group ratio of polyol/total diol was kept constant at a value of 0.4, while the ratio of the isocyanate and hydroxyl groups (NCO/OH) changed between 0.90 and 1.15 in the polyester, and 0.94 and 1.15 in the polyether polyurethanes, respectively. One step bulk polymerization was carried out in an internal mixer and the samples were compression molded for testing. Advanced molecular modeling was used to estimate the strength of various specific interactions quantitatively in the polymers studied. Fifteen different specific interactions were identified in polyester while thirteen in polyether PU considering only hydrogen bonds. Estimated binding enthalpy changes between 11 and 26kJ/mol. The results proved that hard–soft and not hard–hard segment interactions control phase separation of linear segmented polyurethanes. A new model was developed to quantify the relative importance of specific interactions acting between the two types of segments. The calculations predicted better solubility of the soft phase in hard domains in polyester than in polyether polyurethanes. Besides the mutual solubility of the phases, their size and mechanical properties also depend on these interactions shown by the study of phase structure using a novel combination of various methods in a wide length scale. Properties are determined by different aspects of morphology. Transparency depends on the amount of ordered hard phase, stiffness and hardness on phase composition, while ultimate properties on stoichiometry, which determines molecular weight and the number of physical cross-link points.