Polycarbonate-based Polyurethane Research Articles

Evaluation of properties for Carbothane™ 3575A–based electrospun vascular grafts in vitro and in vivo

Bioengineered vascular grafts have emerged as a promising alternative to the treatment of damaged or occlusive vessels. It is thought that polyurethane-based scaffolds possess suitable hemocompatibility and biomechanics comparable to those of normal blood vessels. In this study, we investigated the properties of electrospun scaffolds comprising various blends of biostable polycarbonate-based polyurethane (Carbothane™ 3575A) and gelatin. Scaffolds were characterized by scanning electron microscopy, infra-red spectroscopy, small-angle X-ray scattering, stress-loading tests, and interactions with primary human cells and blood. Data from in vitro experiments demonstrated that a scaffold produced from a blend of 5% Carbothane™ 3575A and 10% gelatin has proven to be a suitable material for fabricating a small-diameter vascular graft. A comparative in vivo study of such vascular grafts and ePTFE grafts implanted in the abdominal aorta of Wistar rats was performed. The data of intravital study and histological examination indicated that Carbothane-based electrospun grafts outclass ePTFE grafts and represent a promising device for preclinical studies to satisfy vascular surgery needs.

Comparing the resilience of macromolecular coatings on medical-grade polyurethane foils

Foils made from elastomeric polymers, such as polycarbonate-based polyurethane (PCU), can combine desirable properties including flexibility, durability, and compliance. Still, their usage is often limited by their strongly autohesive behavior. To overcome this issue, surface coatings can be applied. Here, dopamine-based (dopa) and carbodiimide-mediated (carbo) coatings are compared by assessing their tribological performance and surface properties after long-term sliding tests, and after storage or sterilization. Even though both coating strategies achieve very good lubricity, the dopa-coatings are less resilient than the carbo-coatings. Thus, for such applications where extended sample storage or sterilization is required, covalent coatings should be preferred.

Preparation of PCU/PPy composites with self-healing and UV shielding properties

Polycarbonate-based polyurethanes (PCU) are frequently used in airship envelope materials because of its outstanding mechanical performances and aging resistance. However, the surface of PCU is likely damaged during processing and operating and the emerged minuscule cracks will lead to deterioration of perfomances for airship’s envelope materials. Herein, self-healing PCU/polypyrrole nanoparticles (PPy) composites were prepared by solution blending and quick healing of specific area for PCU was realized due to the high photo-thermal conversion merit of PPy. The results show that, the mechanical properties of PCU/PPy composites can be restored to more than 80% and the gas barrier properties can also be basically repaired when irradiating the destroyed surface using near-infrared light for only 60s. In addition, the ultraviolet visible (UV-vis) shielding performance of the PCU/PPy composites was enhanced significantly and the UV-vis transmittance was less than 14% and 2% with 0.25wt% and 0.5wt% PPy, respectively. Meanwhile when 0.25wt% PPy was added, the tensile strength increased from 17.9MPa to 21.7 MPa and the elongation at break increased from 647% to 829%. Besides, the thermal decomposition temperature at 5wt% loss increased from 277.8°C to 300.7°C and 304.88°C with 0.25 wt% and 0.5 wt% PPy, respectively. The prepared composites show promising application in aerospace domain.

Superior anti-biofouling properties of mPEG-modified polyurethane networks via incorporation of a hydrophobic dangling chain

PEG-modification is a proven method to enhance the hydrophilicity, protein resistance, and anti-biofouling properties of polymer coatings. It is considered as the gold standard interfacial modification technique such that the higher PEG content, the higher hydrophilicity, and lower protein adsorption, i.e., the initial stage of the biofouling process. Nevertheless, increasing the PEG content causes a higher water uptake, which declines the polymer mechanical strength and increases its hydrolytic degradation rate. Thus, an effective strategy to produce a limited-water-absorbing PEG-modified polymer is to force the majority of PEG molecules to migrate towards the interfacial region while the modification takes place. In the current paper, we report the synthesis and characterization of crosslinked polycarbonate-based polyurethanes (PU) containing methoxy polyethylene glycol (mPEG) dangling chains. We show that the simultaneous incorporation of a limited amount of a low-surface-energy dangling chain, i.e., 1-octadecanol (oDEC), along with mPEG, results in a considerably higher mPEG surface concentration, according to X-ray photoelectron spectroscopy (XPS), and a significantly lower water contact angle (WCA), up to 45° lower. We also put forward a reasonable mechanism for our outstanding observation and verified it through extensive experiments, e.g., dynamic WCA, Atomic force microscopy (AFM), and XPS. Moreover, we outline a delicate dynamic WCA experimental protocol, by which the smart and responsive behavior of our coatings is illustrated. Eventually, we examined the mixed hydrophobic/hydrophilic dangling chains strategy for low-protein adsorption applications, in which a great potential has been discovered.

Effect of the cyclic structure content on aliphatic polycarbonate-based polyurethane

Aliphatic polycarbonate-based polyurethanes were successfully synthesized using two aliphatic polycarbonate polyols and hexamethylene diisocyanate (HDI) with 1,4-butanediol (1,4-BD) as the chain extender. One of the aliphatic polycarbonate polyols, named PBC-diol, was prepared from dimethyl carbonate (DMC) and 1,4-BD, while the other, named PCHC-diol, was derived by reacting DMC with 1,4-cyclohexanedimethanol (CHDM). The results of the thermogravimetric analysis (TGA) indicated that the cyclic structure improved the thermal stability of the polyurethanes. In addition, the differential scanning calorimetry (DSC) curves showed that the cyclic structure increased the glass transition temperature (Tg) of the polyurethanes but slowed their crystallization. Furthermore, the mechanical properties of the polyurethanes with different cyclic structure contents were analyzed using Instron. Although the elongation at break decreased, the tensile strength increased from 32.6 to 844.0 MPa when the PBC-diol was replaced with PCHC-diol in the polyurethanes. Finally, Fourier transform infrared (FTIR) analysis was conducted to investigate the formation of hydrogen bonds. The relationship between the hydrogen bonds and cyclic structure content was also shown in this study. A series of aliphatic polycarbonate-based polyurethanes with different content of cyclic structure was synthesized. There were more hydrogen bonds between soft and hard segments formed as the content of cyclic units increased. The mechanical and thermal properties of the environment-friendly polycarbonate-based polyurethanes can be enhanced and controlled by varying the content of the cycloaliphatic structures. These polyurethanes can be considered as high potential materials that can be used in different applications in the future.

Degradation of polycarbonate-based polyurethane via selective cleavage of carbamate and urea bonds

Deep eutectic solvents (DESs) have attracted broad attention due to their low cost and toxicity, easy preparation, good biological compatibility and similar characteristics to those of ionic liquids. In this study, a DES system composed of choline chloride and urea has been applied for the controllable degradation of polyurethane (PU). By the combination of Fourier transform infrared spectroscopy (FT-IR), nuclear magnetic resonance spectroscopy (NMR) and matrix-assisted laser analytical ionization time-of-flight mass spectrometer (MALDI-TOF-MS), the selective cleavage of carbamate and urea bonds with little damage on carbonate bonds was achieved in the DES system by the regulation of reaction conditions, which favored the recovery of both valuable polycarbonate diol (PCDL) and 3,3′-Dimethyl-[1,1′-biphenyl]-4,4′-Diamine (o-toluidine). The degradation rate of PU and the yield of PCDL reached 100% and 57.4% respectively under mild conditions (1 atm, 170 °C, 8 h). A possible degradation mechanism was proposed based on the experimental results, in which the synergistic effect of choline chloride and urea activated largely the carbamate bond and thus led to a controlled degradation of PU.

Effect of oxalate unit on polycarbonate-based polyurethane and biodegradation by fungi

A series of aliphatic oxalate-polycarbonate polyols (AOPC) was synthesized from dimethyl carbonate, 1,6-hexanediol, and diethyl oxalate, made from oxalic acid that is a kind of bio-based material, via melting polycondensation. The aliphatic polycarbonate-based polyurethanes with oxalate units (AOPCUs) were successfully prepared using the AOPCs and hexamethylene diisocyanate (HDI) with 1,4-butanediol (1,4-BD) as the chain extender. The results of the 1H NMR analysis showed that the Mn of AOPCs was approximately 2900. Whereas, the Mw of the AOPCUs was ca. 48,200–53,000 from the gel permeation chromatography (GPC) measurement. The oxalate unit effectively impeded the crystallization of the AOPCUs as shown in the Differential scanning calorimetry (DSC) analysis. Based on the stress-strain curves, the AOPCUs with 10 M ratio of oxalate unit had best strength and elongation at break; however, their Young's modulus decreased from 130 MPa to 26 MPa. In addition, the biodegradation of the AOPCUs was studied using the fungi, Aspergillus sp. and Fusarium sp. The more oxalate units in the AOPCUs, the better biodegradability they presented after the 84-day degradation test. The characteristics of the biodegradation analysis for the AOPCUs presented the bulk erosion, and the oxalate unit played an important role in their biodegradability.

Polycarbonate-based polyurethane - attractive materials for adhesives, binders and sealants production

In the last few years, a very wide range of oligocarbonate diols, oligomers of carbonic acid esters terminated on both sides with hydroxyl groups, have appeared on the chemical market. They are mainly used for the production of flexible segments in precious grades of polyurethanes used in biomedical engineering. Poly(carbonate-urethane) due to high resistance to oxidizing and hydrolytic agents is also an attractive material for the production of adhesives and coatings with increased resistance to weather conditions. This paper presents the current state of knowledge on the methods of synthesis and main producers of oligomerols with carbonate groups, methods of poly(carbonate-urethane) synthesis and examples of its commercial applications.

The effect of TiO2 particles on thermal properties of polycarbonate-based polyurethane nanocomposite films

In this work, aliphatic starting reactants were used to prepare a series of polycarbonate-based polyurethane (PC-PU) nanocomposite films with a low amount of titanium dioxide (TiO2) nanoparticles (0.5, 1.0 and 2.0%) by one-step technique. The influence of nanoparticles on the structure and hydrogen bonding, as well as the microphase and topography of the obtained hybrid materials was followed by Fourier transform infrared spectroscopy, Atomic force microscopy and Scanning electron microscopy coupled with energy-dispersive X-ray Spectroscopy, respectively. Thermogravimetry was performed to study the effect of TiO2 on the thermal stability and the decomposition pattern of the obtained PC-PU films. The impact of TiO2 on the glass transition temperature, relaxation of soft domains as well as the melting of hard segments was determined by modulated differential scanning calorimetry. The significant enhancement of thermal stability and degradation of prepared hybrid materials were achieved, due to increased hydrogen bonding by addition of TiO2. The glass transition temperatures of all PC-PU films were found independent on the titanium dioxide mass fraction. The starting of physical cross-linking disruption of the obtained hybrids was registered at significantly higher temperatures, as a consequence of the achieved interaction between uniformly dispersed TiO2 nanoparticles and hard phase.

Self-Healing Polycarbonate-Based Polyurethane with Shape Memory Behavior

A self-healing polycarbonate-based shape memory polyurethane (PCPU) comprising of polycarbonate diol, 4,4′-diphenylmethane diisocyanate (MDI) and 1,4-Butanediol (1,4-BDO) was synthesized. Through a series of shape memory tests, PCPUs showed 100% shape fixation rate, and a shape recovery rate of over 95% within 15 s. PCPUs exhibit excellent mechanical properties compared to common shape memory polymers, such as a tensile strength of up to 38.10 MPa and elongation at break of 616%. Additionally, after being damaged, polyurethane can self-heal within 60 s at 80 °C without any external force, which makes it applicable in many fields.

Robust and stretchable self-healing polyurethane based on polycarbonate diol with different soft-segment molecular weight for flexible devices

The self-healing polyurethane films have received significant attention due to their unique shape memory behaviors and the hydrogen bonding arising from the urethane linkages. However, it is still a challenge to develop self-healing polyurethane with transparent, high impact resistance, and excellent shape recovery and mechanical properties. In particular, polycarbonate-based polyurethane shows transparency, weatherability and excellent mechanical properties. In this work, transparent self-healing polyurethane film with robust mechanical properties (breaking stress of 26 MPa and elongation at break of 630%) was synthesized by controlling the different molecular weight of the polycarbonate diol and incorporating dynamic disulfide bonds for reversibility. As a result, the self-healing polyurethane film showed an excellent self-healing ability with 98% healing efficiency and excellent shape memory ability with a recovery efficiency of ˃92%. In addition, we have identified a potential application for the self-healing flexible substrate in flexible electronics because of their stable electrical resistance even upon mechanical deformation.

Zinc-oxide nanoparticles act catalytically and synergistically with nitric oxide donors to enhance antimicrobial efficacy.

The development of infection-resistant materials is of substantial importance as seen with an increase in antibiotic resistance. In this project, the nitric oxide (NO)-releasing polymer has an added topcoat of zinc oxide nanoparticle (ZnO-NP) to improve NO-release and match the endogenous NO flux (0.5-4 × 10-10 mol cm-2 min-1 ). The ZnO-NP is incorporated to act as a catalyst and provide the additional benefit of acting synergistically with NO as an antimicrobial agent. The ZnO-NP topcoat is applied on a polycarbonate-based polyurethane (CarboSil) that contains blended NO donor, S-nitroso-N-acetylpenicillamine (SNAP). This sample, SNAP-ZnO, continuously sustained NO release above 0.5 × 10-10 mol cm-2 min-1 for 14 days while samples containing only SNAP dropped below physiological levels within 24 h. The ZnO-NP topcoat improved NO release and reduced the amount of SNAP leached by 55% over a 7-day period. ICP-MS data observed negligible Zn ion release into the environment, suggesting longevity of the catalyst within the material. Compared to samples with no NO-release, the SNAP-ZnO films had a 99.03% killing efficacy against Staphylococcus aureus and 87.62% killing efficacy against Pseudomonas aeruginosa. A cell cytotoxicity study using mouse fibroblast 3T3 cells also noted no significant difference in viability between the controls and the SNAP-ZnO material, indicating no toxicity toward mammalian cells. The studies indicate that the synergy of combining a metal ion catalyst with a NO-releasing polymer significantly improved NO-release kinetics and antimicrobial activity for device coating applications. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 00A: 000-000, 2019.

Structure—Functional property relationship of aliphatic polyurethane-silica hybrid films

The novel aliphatic polyurethane-silica hybrid films were prepared using prepolymerization method in the presence of spherical, submicron amorphous SiO2 Sidistar T120 particles (0, 1, 2, 5 and 10 wt%). The study of the influence of silica distribution on the structure–functional property relationship of polyurethane (PU) composites was performed using FT-IR, SEM, AFM, TGA, DSC, DMTA, tensile testing and immersion test. It was found that the presence of low SiO2 content is acting as dispersing agent between soft- and hard-segments. Achieved uniform distribution of 1 and 2 wt% of silica caused the formation of additional hydrogen bonds between organic matrix and inorganic filler, and remarkably improved thermal stability, thermal and mechanical properties of obtained polyurethane composites. The agglomerates, formed at higher SiO2 loading (5 and 10 wt%), caused the change of thermal degradation mechanism as well as the change of physical crosslinking disruption mechanism. Despite significantly deteriorated mechanical properties of polyurethanes with heterogeneously incorporated silica particles, the onset temperature of elastomers and the starting of melting of hard domains were registered at higher temperature compared to pure PU. Optimal thermal characteristics (onset, decomposition and melting temperatures) and remarkable tensile properties (especially high elongation-at-break and tensile strength, and extraordinary energy-to-break) compared to pure polyurethane have been determined for the polycarbonate-based polyurethanes containing 1 wt% and especially 2 wt% of SiO2. It allows them to be utilized as mechanically strong and durable coatings or films in biomedical applications or as packaging materials. The solvent-resistance data are well described using novel proposed model covering two swelling and dissolution phenomena. The presence of silica decreased the rate and the amount of swelling in water, acetone, toluene and hexane. The rate and mass reduction of swollen sample in acetone, toluene and hexane also decreased by the addition of SiO2 particles.

Polycarbonate-based polyurethane as a polymer electrolyte matrix for all-solid-state lithium batteries

Four kinds of polycarbonate-based polyurethane with 8–14 wt% hard segments content are synthesized via reactions of polycarbonatediol, hexamethylene diisocyanate and diethylene glycol. The mechanical strength of the polyurethanes increase with the increase of hard segments content. Solid polymer electrolytes composed of the polycarbonate-based polyurethanes and LiTFSI exhibits fascinating characteristics for all-solid-state lithium batteries with a high ionic conductivity of 1.12 × 10−4 S cm−1 at 80 °C, an electrochemical stability window up to 4.5 V (vs. Li+/Li), excellent mechanical strength and superior interfacial stability against lithium metal. The all-solid-state batteries using LiFePO4 cathode can deliver high discharge capacities (161, 158, 134 and 93 mAh g−1 at varied rates of 0.2, 0.5, 1 and 2 C) at 80 °C and excellent cycling performance (with 91% capacity retention after 600 cycles at 1 C). All the results indicate that such a polyurethane-based solid polymer electrolyte can be a promising candidate for all-solid-state lithium batteries.

The impact of conditions mimicking physiological environment on the thermal stability of aliphatic polycarbonate-based polyurethane elastomers

Thermal stabilities of all-aliphatic thermoplastic polyurethane (PU) films, either three-component (made from polycarbonate-based macrodiol, diisocyanate-1,6-hexane and butane-1,4-diol) or four-component (containing in addition oligomeric d,l-lactide-based linker in PU backbone), were studied by using thermogravimetric analysis (TG), Fourier transform infrared spectroscopy (FTIR), auto-stepwise TG and TG coupled with FTIR (TG-FTIR). The evaluation of the influence of PU composition and time of the sample exposure to the environment mimicking physiological conditions (phosphate buffer saline at 37 °C) on the thermal characteristics was the main task of the study. The shapes of the mass loss curves of all studied PUs are almost identical, and the differences in thermal stabilities are relatively small. While the three-component PUs are thermally stable up to 280 °C in the minimum, the four-component PU starts to decompose at about 250 °C, due to the presence of the thermal-unstable d,l-lactide component. In all PU materials tested, the thermal stability is only slightly affected by the hydrolytic process. The safe technological processability till 200 °C together with the evolving of relatively safe main volatile compounds makes the polycarbonate-based PUs as suitable candidates for medical, bio-, package and similar applications.

Synthesis of fluorinated polycarbonate-based polyurethane acrylate for UV-curable coatings

Fluorinated polycarbonate-based UV-curable polyurethane acrylate (F-PCUA) was synthesized by incorporating 1H, 1H, 2H, 2H-Perfluoro-1-octanol to the end of polycarbonate-based PUA chains. The structure of F-PCUA was determined by 1H-NMR, 19F-NMR, and FTIR analyses. The physical, surface, and thermal properties of F-PCUA were also examined. The F-PCUA was used as a hydrophobic additive in PUA coatings, and the water and oil wettability of the UV-cured film was investigated by contact angle measurements. The results showed that the coating system had great hydrophobicity. Furthermore, X-ray photoelectron spectroscopy research confirmed that a hydrophobic fluorine-enriched surface was obtained in the coating system. Moreover, the mechanical and chemical properties of the hydrophobic coatings did not show deterioration with the introduction of elemental F.

Hydrolytic stability of polycarbonate-based polyurethane elastomers tested in physiologically simulated conditions

The hydrolytic stability of all-aliphatic polyurethane (PU) films made from polycarbonate-based aliphatic macrodiols (MD), diisocyanate-1,6-hexane and butane-1,4-diol (BD) were tested at 37 °C in phosphate buffer for a period up to 12 months. Two macrodiols, differing in composition and chain regularity and two MD-to-BD ratios were chosen for PU synthesis. The isocyanate-to-total hydroxyl ratio was kept constant and equal to 1.05. The functional properties of the original polyurethane films and films being immersed for 1, 3, 6 and 12 months in model physiological environment (37 °C at pH = 7.4) were studied on segmental up to macroscopic levels. The combination of SEM, AFM, FTIR, DSC, tensile and swelling analyses were used. It was found that prepared PU films are very good elastomeric materials with outstanding mechanical and suitable thermal properties keeping these properties practically unchanged for a period of up to 12 months. They can be practically used for example as strong and durable topcoats.

Thermal and mechanical properties of multiple‐component aliphatic degradable polyurethanes

ABSTRACTMacroscopic thermal and mechanical properties of complex aliphatic polycarbonate‐based polyurethane (PU) films containing degradable ester units in PU backbone were studied by a combination of several experimental techniques. Differential scanning calorimetry (DSC) revealed that the synthesized oligomeric diol (DL‐L) contributes (in addition to polycarbonate diol) to the formation of soft‐segment domains, while the hard‐segment domains are formed from 1,6‐diisocyanatohexane (HDI) and butane‐1,4‐diol (BD). Three main phase transitions were detected by DSC and by dynamic mechanical thermal analysis. Thermogravimetric analysis (TGA) of two‐component PUs showed that the PU made from DL‐L and HDI is the least thermostable product, while the PU made from polycarbonate diol and HDI is the most stable one. The differences in the thermal stability of different four‐component PUs are not important. Tensile properties very sensitively reflect the changes in composition and in microstructure of PU samples; the best tensile properties exhibits the degradable sample containing the equimolar ratio of hydroxyl groups of macrodiol, oligomeric diol DL‐L and butane‐1,4‐diol. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41872.

The influence of ZnO nanoparticles on thermal and mechanical behavior of polycarbonate-based polyurethane composites

In this work a series of thermoplastic polycarbonate-based polyurethane (PC-PU) nanocomposites were prepared by addition of ZnO nanoparticles (0.5, 1 and 2wt.%) in one-step procedure using all aliphatic starting reactants. The influence of zinc oxide on the structure and hydrogen bonding of PC-PU hybrid materials was studied by Fourier transform infrared spectroscopy (FT-IR). Thermal stability and thermal properties of obtained nanocomposites were studied by thermogravimetry (TGA) and differential scanning calorimetry (DSC), respectively. The effect of phase separation on the mechanical performances was determined by tensile measurements. It was found that the addition of ZnO particles may cause the disruption of phase separation and, hence, affect thermal and mechanical behavior of segmented polycarbonate-based polyurethane nanocomposites.

Modification of epoxy resins with thermoplastic segmented polycarbonate-based polyurethanes

In this work, epoxy hybrid materials were synthesized by addition of thermoplastic segmented aliphatic polyurethanes with good elastic properties. The modified epoxy samples were obtained by curing of previously homogenized mixture of prepared polyurethane melts, epoxy resin and crosslinking agent Jeffamine D-2000. The influence of different weight content of polyurethanes (5, 10 and 15 wt. % compared to pure epoxy resin) as well the influence of different hard segments of elastomers (20, 25 and 30 wt. %) on the curing of modified epoxy systems was studied. The curing was followed by differential scanning calorimetry (DSC), in dynamic regime from 30 to 300?C, at three heating rates (5, 10 and 20?C/min). With the increase of hard segments content of polyurethanes added in higher concentration (10 and 15 wt. %) into epoxy matrix, the temperature of maximum ratio of curing was shifted to lower values (from 205 to 179?C). Obtained DSC data were analyzed using two integral methods (Ozawa-Flynn-Wall and Kissinger-Akahira-Sunose) and one differential kinetic model (Friedman). The significant differences were observed in the second part of the epoxy curing (for the reaction degrees higher than 60 %), where the values of activation energies remarkably increase. The addition of polyurethane elastomers retarded the curing process due to decreased mobility of reactant molecules caused by higher viscosity of reaction mixture. By detailed analysis of determined kinetic parameters, it is concluded that the influence of slow diffusion is more pronounced in the presence of thermoplastic polycarbonate-based polyurethanes, which confirmed their effect on the mechanism of epoxy curing. The highest tensile strength and hardness showed the DGEBA modified with the polyurethane with highest hard segment content. Increasing the hard segment content of polyurethane and its concentration in matrix, the tensile strength of modified epoxy was increased. The elongation at break of modified epoxy samples was significantly improved by addition of polycarbonate-based polyurethanes with low hard segment content, due to higher content of flexible soft segment chains.