PU Films Research Articles

Preparation and characterization of thermoplastic water‐borne polycarbonate‐based polyurethane dispersions and cast films

ABSTRACTStable water‐borne polyurethane dispersions (PUDs) were prepared from bifunctional aliphatic polycarbonate‐based macrodiol, 2,2‐bis(hydroxymethyl)propionic acid (DMPA), 1,6‐diisocyanatohexane, 1,4‐butanediol (BD), and triethylamine. Water‐borne dispersion particles are thus solely formed from self‐assembled linear PU chains. Both PUDs and PUD‐based films were characterized with regards to the concentration of DMPA (ionic species content) and BD (hard‐segment content). Average particle size of PUDs decreased and their long‐term stability increased with increasing DMPA and decreasing BD concentration. Functional properties of cast films made from PUDs are substantially influenced by the character of the original colloidal particle dispersions. The swelling behavior of the films, their surface morphology, and mechanical properties are more influenced by DMPA than BD contents. At DMPA concentrations higher than 0.2 mmol g−1of the solid mass of polyurethane, distinct self‐organization of individual nanoparticles into fibril‐like structures was detected by atomic force microscopy and scanning electron microscopy. PU films made from PUD containing high BD as well as high DMPA concentrations have the best utility properties namely sufficient tensile properties and a very low swelling ability. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci.2015,132, 42672.

Synthesis and characterization of a new biodegradable polyurethanes with good mechanical properties

Abstract In the paper, a new biodegradable polyurethane (PU, PU-I) was prepared: the prepolymer was synthesized via bulk ring-opening polymerization with poly(ethylene glycol) (Mn = 600) (PEG600) as an initiator and l -lactide ( l -LA), ɛ-caprolactone (CL) as monomers, and the prepolymer was chain-extended with an isocyanate-terminated urethane triblock (macrodiisocyanate) to prepare the PU. The macrodiisocyanate, prepolymer and PUs were characterized by 1H NMR, 13C NMR, FT-IR, high resolution mass spectrometry (HR-MS), gel permeation chromatography (GPC), thermo gravimetric analysis (TGA), and differential scanning calorimetry (DSC). The corresponding PU films showed excellent mechanical properties with a tensile strength of 27.5 MPa and an elongation at break of 996%, and also maintained mechanical properties in physiological saline at 37 °C for more than three weeks, which appeared to be more suitable for biomedical applications.

Investigations on the Structural and Mechanical Properties of Polyurethane Resins Based on Cu(II)phthalocyanines

This work report was reported on the effect of the addition of organic filler, that is, 2(3),9(10),16(17),23(24)-octahydroxycopper(II)phthalocyanine [(OH)8CuPc] (3), on the thermal, tensile, and morphological properties of a polyurethane matrix. The mechanical and dynamic mechanical thermal tests together with microstructural characterization of CuPc/PU composites were performed. The three PU composite films containing up to 1, 15, and 30 wt% of CuPc have different behaviors in terms of their morphological issues, thermal properties, and tensile behavior in comparison with the PU film as the reference material. Very high elongations at break from 910% to 1230%, as well as high tensile strengths, illustrate excellent ultimate tensile properties of the prepared samples. The best mechanical and thermomechanical properties were found for the sample filled with 30 wt% of CuPc.

Microwave-assisted immobilization of heparin onto polyurethane surface for improving blood compatibility

Heparin was covalently immobilized onto polyurethane surface via a PEG spacer by a microwave-assisted approach to improve blood compatibility. Firstly, amino-terminated poly(ethylene glycol) (APEG) was rapidly grafted onto PU surface within 20 min by a two-step method involving microwave-assisted MDI-functionalization and subsequent microwave-assisted APEG coupling. Then, heparin was covalently immobilized through an amide linkage by the direct coupling of the carboxylic acid of heparin with the amino group of APEG on PU surface using carbodiimide coupling reaction. The surface structure and properties were characterized by X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM) and water contact angle measurements. The results revealed that heparin-immobilized PU surface had slightly increased roughness and significantly improved hydrophilicity in comparison to the original PU surface. The anticoagulant activity of films was evaluated by whole blood clotting time (CT) and prothrombin time (PT). Complement activation was assessed by detecting complement fragment 3a concentrations of serum exposed to the films. The results revealed that the microwave-assisted heparin-immobilized PU films had excellent antithrombogenicity and suppressed complement activation, indicating improved blood compatibility.

Enhanced microwave absorbing properties of lightweight films based on polyaniline/aliphatic polyurethane composites in X band

ABSTRACTPolymer blends based on nanostructured polyaniline (PANI) doped with hydrochloric acid (HCl) and para‐toluene sulfonic acid (PTSA) introduced into aliphatic polyurethane matrix (PU) are synthesized to produce flexible thin composite films for microwave absorbers. The effects of dopant type, PANI content and film thickness on morphologies, dielectric and microwave absorption properties in the X‐band are studied. It reveals that real and imaginary parts of the complex permittivity are proportional to filler concentrations and type of doped PANI. The PANI‐PTSA/PU films show higher permittivity and better microwave absorbing properties than PANI‐HCl/PU for the same weight fraction of PANI. The minimum reflection loss RL(dB) values for the PANI‐PTSA/PU are −37 dB at (20% PANI and 11.6 GHz) and −30 dB at (15% PANI and 11.3 GHz) for thicknesses of 1.2 and 1.6 mm, respectively. These high values of reflection losses make the obtained lightweight and flexible composites promising radar absorbing materials (RAM). © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40961.

Fatty acids based transparent polyurethane films and coatings

• Synthesis of polyesteramide from palmitic acid and dimer fatty acid. • Biobased transparent PU films and coatings. • Eco-friendly PU coatings. • Dimer fatty acid as a substitute to conventional dicarboxylic acids or anhydrides. Renewable resources used in the preparation of polymers are falling in the class of biomaterials which are rich in hydrocarbons and most of the times obtained from parts of profusely available agriculture feedstock. Use of non-edible vegetable oils and their fatty acids are currently the raw materials focused in synthesizing polymeric materials as renewable sources due to increasing economic and environmental concerns of petroleums. The current oil based polymers are prepared by consuming petroleum based anhydrides and dicarboxylic acids. With this investigation, we tried to substitute almost all components of petroleum feed stock by renewable sources in preparation of polyol. Initially palmitic acid was used as a renewable source to prepare palmitamide by amidation reaction. Further amide was converted into the polyesteramide resin (PEPAD) by reacting it with another renewable resource, i.e. dimer fatty acid which is the dimerized product of unsaturated fatty acids of vegetable oils. Structure of the prepared resin was confirmed by spectroscopic techniques and resin was also characterized by end group analysis like hydroxyl and acid values. The molecular weight of PEPAD was ranged between 2590 and 2760 g mol −1 . Palmitic acid based polyesteramide was used to prepare polyurethanes by varying amount of diisocyanate. The transparent polyurethane films and coatings were obtained and examined for water absorption, contact angle, hardness, coating properties, solvent, acid and alkali resistances. The thermal properties of the polyurethane films were estimated by TGA and discussed. It was found that change in NCO content affected on transparency as well flexibility of the prepared films. It also noticed that thermal stability was shifted toward higher range by increasing mole (NCO/OH) ratios due to formation of urea linkages.

Poly(methyl methacrylate)-functionalized graphene/polyurethane dielectric elastomer composites with superior electric field induced strain

Poly(methyl methacrylate)-functionalized graphene/polyurethane (MG–PU) dielectric elastomer composites were synthesized. MG was prepared by atom transfer radical polymerization (ATRP) and used as conducting filler. The microstructure of MG and MG–PU was characterized by SEM, TEM and XRD. The thermal degradation, mechanical, dielectric and electromechanical properties were investigated. The three-dimensional (3D) electric field induced displacement and strain of dielectric elastomer surface was observed and measured for the first time. Comparing with pure PU elastomer, the dielectric properties and electric field induced strain performance of MG–PU dielectric elastomer composites were significantly improved. The 1.50wt% MG–PU film had high relative permittivity and electric field induced strain of 28.21 and 32.8%, respectively.

Electromechanical study of polyurethane films with carbon black nanoparticles for MEMS actuators

Pure polyurethane and nanocomposite carbon black (CB) polyurethane solutions were deposited by spin-coating on a silicon substrate using gold as the adhesion layer and electrode. Different test structures were achieved for electrical and mechanical characterizations. The incorporation of CB nanoparticles in the polyurethane matrix has a significant influence on the dielectric permittivity of the material with an increase of about one third of its value. The Young's modulus of PU and nanocomposite PU films was determined by different characterization methods. Nanoindentation experiments have pointed out a Young's modulus gradient through the film thickness. By performing mechanical tests (tensile, bulge, point deflection) on freestanding films, an average Young's modulus value of about 30 MPa was found as well as a residual stress value of about 0.4 MPa. However, no influence of the presence of the nanoparticles was found. Finally, several MEMS actuators were realized and characterized. At their fundamental resonance frequency, the actuation of the nanocomposite membranes is more efficient than that of pure polyurethane. However, the time constant of the material seems to provide a major barrier for the development of high-frequency PU-based micro-actuators.

Thermo‐Mechanical and Antibacterial Properties of Soybean Oil‐Based Cationic Polyurethane Coatings: Effects of Amine Ratio and Degree of Crosslinking

AbstractSoybean‐oil‐based cationic polyurethane coatings with antibacterial properties have been prepared with a range of different molar ratios of hydroxyl groups from an amine diol. A second series of polyurethane coatings were prepared from soy polyols with different hydroxyl numbers. All of the cationic PU dispersions and films exhibit inhibitory activity against three foodborne pathogens: Salmonella enterica ssp. enterica ser. Typhimurium, Listeria monocytogenes, and Staphylococcus aureus. It is generally observed that increases in the ratio of ammonium cations improve the antibacterial performance. Reduction of the crosslink density by decreasing the hydroxyl number of the soy polyol also results in slightly improved antibacterial properties. Higher glass transition temperatures and improved mechanical properties are observed with corresponding increases in the molar ratios of the amine diol and the diisocyanate. These results show that the mechanical properties of these coatings can be tuned, while maintaining good antibacterial activity.

Polyurethane-based scaffolds for myocardial tissue engineering

Bi-layered scaffolds with a 0°/90° lay-down pattern were prepared by melt-extrusion additive manufacturing (AM) using a poly(ester urethane) (PU) synthesized from poly(ε-caprolactone) diol, 1,4-butandiisocyanate and l-lysine ethyl ester dihydrochloride chain extender. Rheological analysis and differential scanning calorimetry of the starting material showed that compression moulded PU films were in the molten state at a higher temperature than 155°C. The AM processing temperature was set at 155°C after verifying the absence of PU thermal degradation phenomena by isothermal thermogravimetry analysis and rheological characterization performed at 165°C. Scaffolds highly reproduced computer-aided design geometry and showed an elastomeric-like behaviour which is promising for applications in myocardial regeneration. PU scaffolds supported the adhesion and spreading of human cardiac progenitor cells (CPCs), whereas they did not stimulate CPC proliferation after 1-14 days culture time. In the future, scaffold surface functionalization with bioactive peptides/proteins will be performed to specifically guide CPC behaviour.

Biodegradable Electrospun Scaffolds for Annulus Fibrosus Tissue Engineering: Effect of Scaffold Structure and Composition on Annulus Fibrosus CellsIn Vitro

Electrospinning technology is an attractive process for the fabrication of a scaffold with an annulus fibrosus (AF)-like architecture for tissue engineering. Oriented and nonoriented electrospun scaffolds were prepared from poly(ester-urethane) (PU) and poly(ɛ-caprolactone) (PCL) as well as corresponding homogeneous films. Scaffolds' characteristics and mechanical properties were characterized by scanning electron microscopy, static water contact measurements, and dynamic mechanical analysis, respectively. The effect of scaffold architecture and polymer composition on bovine AF cells was investigated. PU and PCL films and scaffolds supported AF cell growth and extracellular matrix production and accumulation. Electrospun scaffolds increased the retention of collagen and glycosaminoglycan compared with films. Fiber orientation of the scaffolds promoted the AF cell phenotype with a trend toward an upregulation of matrix gene expression for oriented relative to nonoriented scaffolds. The higher yield strain of an oriented electrospun PU scaffold, compared with other scaffolds, will be advantageous for AF tissue engineering under a dynamic mechanical environment.

Técnicas FT-IR (PAS, UATR e Objetiva ATR) Aplicadas à Caracterização de EPDM Modificada com Plasma

Tecnicas FT-IR (UATR, PAS e MIC, com objetiva ATR) foram escolhidas para a caracterizacao da superficie da borracha de EPDM vulcanizada, apos tratamento em plasma de Ar/O2 e N2/H2/Ar gerado em micro-ondas. Apos tratamento, grupos oxigenados foram detectados por UATR e MIC/FT-IR, com objetiva ATR para as duas misturas gasosas, e possiveis grupos nitrogenados foram inseridos na superficie das amostras tratadas com plasma de N2/H2/Ar. A analise MIC/FT-IR sugeriu a formacao de grupos em uma camada mais externa, para as amostras tratadas com plasma de N2/H2/Ar, sendo possivel observar a reducao na intensidade das bandas da absorcao do CH2 e CH3, o que pode estar relacionado ao fato de o nitrogenio ser um gas menos permeavel que o oxigenio. Diferentes velocidades, 0,05 cm.s-1 e 0,2 cm.s-1, foram utilizadas na analise PAS para avaliar a superficie apos tratamento, e apenas para a velocidade 0,05 cm.s-1 com plasma de Ar/O2 alteracoes espectroscopicas foram detectadas. A reducao na medida de ângulo de contato e o aumento na resistencia ao descascamento da colagem indicaram melhoras nas propriedades adesivas da superficie. Falhas de adesao foram observadas entre a interface do filme de adesivo de PU e da borracha de EPDM, e confirmados por UATR/FT-IR.

Synthesis and swelling behavior of pH‐responsive polyurethane/poly[2‐(diethylamino)ethyl methacrylate] hybrid materials

ABSTRACTPolyurethane (PU)/poly[2‐(diethylamino)ethyl methacrylate] hybrids, having a chemical bond between the PU and acrylic moieties and with different compositions, were prepared by the dispersion polymerization of 2‐(diethylamino)ethyl methacrylate (DEA) in the presence of preformed PU chains with polymerizable terminal vinyl groups. The PU dispersion was synthesized according to a prepolymer mixing process by the polyaddition of isophorone diisocyanate, poly(propylene glycol), 2‐hydroxyethyl methacrylate, and dimethylol propionic acid (DMPA). Then, it was dispersed in water by the prior neutralization of the carboxylic acid groups of DMPA with triethylamine, chain‐extended with ethylenediamine. The effect of the DEA content on the swelling properties (water uptake and dynamic swelling degree) at different pHs and at 37°C was determined. The samples were also characterized by Fourier transform infrared spectroscopy and modulated differential scanning calorimetry. The experimental results indicate a higher water uptake when the DEA content was increased on the hybrid materials and a significant change in the kinetics of swelling at pH 4 compared to those at pH 7. The water content of the hydrogels depended on the DEA content, and it was inversely proportional to the pH value. The pure PU film did not show important changes over the pH range examined in this study. The synthesized hybrids were useful as drug‐delivery, pH‐sensitive matrices. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 39799.

Mechanical and Thermal Properties of Polyurethane Films from Peroxy-acid Wheat Straw Lignin

In the present work, a type of PU film was made from peroxy-acid-derived wheat straw lignin by reacting varying amounts of lignin ranging from 10 to 50 wt% (with respect to PEG), polyethylene glycol (Mn = 1000), and tolylene 2,4-diisocyanate without catalyst. The effects of lignin content on the tensile property and thermostability of the lignin polyurethane films obtained were investigated. The thermal conductivity of lignin polyurethane films was also studied. Results showed that when the lignin content increased, the glass transition temperature (Tg) and tensile strength of the lignin polyurethane film increased, but the onset decomposition temperature and elongation at break decreased. When the lignin content was 40 wt%, the lignin polyurethane film had the best overall properties. In addition, compared with PU films, lignin PU films showed better heat-insulating properties.

Polyurethane Films with Antimicrobial Properties, Intended for the Development of Coatings Preventing Catheter-Associated Bloodstream Infections

An investigation was made of the production and properties of a system based on polyurethane of grade Elastollan 1154 D (BASF, West Germany) (PU) containing antiseptic chlorhexidine (1,6-di-(p-chlorophenyl-guanido)-hexane) (CH), intended for the development of an antimicrobial coating for catheters. It was shown that the release of CH into water from PU films of 70 μm thickness occurs over a period of 70–190 h, depending on the quantity of CH introduced. The obtained data on the release of CH were correlated with data on the antimicrobial activity of films, assessed by the modified Kirby–Bauer test. For the series of obtained systems, antimicrobial activity against Staphylococcus aureus (golden staph) was retained for 15 days.

Composition, thermal and tensile properties of polyurethane-urea-silica hybrids

Polyurethane-Urea-Silica (PUUS) hybrid solutions were synthesized by a two-stage process, based on the use of polyoxypropylene glycol (PPG), 4,4′-dicyclohexyl methane diisocyanate (H12MDI), 1,4-butane diol, 3-aminopropyl-trimethoxysilane (APrTMOS) and a suitable amount of solvent. Following knife-coating and curing reaction, polyurethane/urea/silica hybrid films were prepared with different crosslinkages and silica contents through the in situ sol–gel process. The intermolecular bonding of hydrogen bonding between N–H, CO groups of PU and area and Si–O–Si crosslinked structure of APrTMOS was determined via FTIR analysis, and was correlated with thermal/tensile properties. FTIR and ESCA results indicate that the carbonyl, N–H and Si–O groups distribution contained in PU and hybrid films characterized as CO group absorption peak area ratio, N/C and Si/C atomic ratio were changed from the film's surface to the bulk with APrTMOS content. Intermolecular bonding, composition, thermal property and tensile strength of films were functions of the APrTMOS contents and PPG's molecular weight. All hybrid films exhibit a more significant change in glass transition temperature (Tg), decomposition temperatures (Td), coefficients of thermal expansion (CTEs) and stress-strain properties than that with pure PUs. The correlation between intermolecular bonding, composition, thermal and tensile properties were investigated.

Effect of oleic acid content and chemical crosslinking on the properties of palm oil‐based polyurethane coatings

AbstractPolyurethanes (PU) were prepared by reacting palm oil‐based polyols and aromatic diisocyanate (toluene 2, 4 diisocyanates). The content of oleic acid was varied in the polyester polyols and the hydroxyl value was fixed to be 140 mg KOH g−1. The NCO/OH ratios were varied to 1.2, 1.4, and 1.6. Crosslinking density of the PU was measured by swelling in toluene at room temperature. It was found that the crosslinking increased with decreasing oleic acid content and increasing NCO/OH ratio. The samples were assessed by thermogravimetric analysis, differential scanning calorimetric, and short‐term creep measurements. The highest rupture strength of the PU films was 36 MPa and thermostability improved as the oleic acid content and the NCO/OH ratios were increased in the sample. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

Characterization of polyurethane scaffold surface functionalization with diamines and heparin

Polyurethane scaffolds (PUs) have a good biocompatibility but lack cell recognition sites. In this study, we functionalized the surface of a PU, P(D/L)LA and PCL (50:50) containing urethane segments, with heparin. The first step in this functionalization, aminolysis, lead to free amine groups on the surface of the PU. Free amine content was determined to be 6.4 nmol/mL/mg scaffold, a significant increase of 230%. Subsequently, heparin was crosslinked. Immunohistochemistry demonstrated the presence of heparin homogeneous throughout the 3D porous scaffold. Young's modulus decreased significantly till 50% of the native stiffness after aminolysis and did not change after heparin crosslinking. Contact angle on PU films significantly decreased from 82.7° to 64.3° after heparin crosslinking, indicating a more hydrophilic surface. This functionalization beholds great potential for tissue engineering purposes. When used in a load-bearing environment, caution is necessary due to reduction in mechanical stiffness.

Synthesis and characterization of polyurethanes containing glucose for selective determination of epinephrine in the presence of a high concentration of ascorbic acid

AbstractPolyurethane (PU) films were prepared from glucose, ethylene glycol and diphenylmethane diisocyanate and used to construct a novel polymer electrode for the detection of epinephrine (EP) in the presence of a high concentration of ascorbic acid (AA). The NCO:OH molar ratio was kept constant at 1 and the saccharide content was varied. The PUs were characterized using Fourier transform infrared spectroscopy, differential scanning calorimetry and differential thermal and thermogravimetric analyses, with intrinsic viscosity and adhesive properties also being evaluated. The PUs exhibited high glass transition temperature, good thermal stability and good adhesive properties. The incorporation of saccharides into the PU structure resulted in a higher crosslinking density and a higher content of hard segments. Medium‐ to high‐molecular‐weight polymers were obtained, with inherent viscosities near or higher than 0.98–2.14 dL g−1. The solubility of the PUs was much better than that of aromatic PUs. The modified polymer electrodes were then used to determine EP in the presence of a high concentration of AA using differential pulse voltammetry. From the amperometric results for the PU electrode, it is concluded that a PU film containing 5 wt% glucose can be used as a membrane for EP detection in the presence of a large concentration of AA, because of its strong adherence to the electrode surface, easy preparation, chemical stability, selectivity and very high statistical confidence (R = 0.9994). © 2012 Society of Chemical Industry

전기분사를 이용한 양성담관 협착 치료용 약물방출 스텐트 개발

최근에 내시경 관련기술의 진보에 따라서 시술 편리성, 회복시간 단축, 환자 고통 경감 등의 장점으로 인해 스텐트 삽입술이 빠르게 진보하였다. 본 연구에서 양성담관 협착 치료를 목적으로 파클리탁셀을 이용한 약물방출 스텐트를 전기분사 방법에 의해 제조하였으며, 이 때 사용된 고분자는 polyether-based polyurethane(상표명 : PELLETHANE 2363-80AE<TEX>$^{(R)}$</TEX>)과 첨가제로서 Pluronic F127, 약물로서 파클리탁셀을 사용하여 금속스텐트 표면에 코팅하였다. 그 결과로서, 약물이 코팅된 고분자 필름의 물리적 특성은 SEM, FTIR, 접촉각 측정기, XRD에 의해 확인하였으며, 약물방출속도는 약물함량이 높을수록 감소하였음을 알 수 있었다. Recently, along with technology development of endoscopic equipment, the stent technology has been developed for the convenience of operation, shortening of recovery times, and reduction of patient's pain. In this study, paclitaxel-eluting metal stents for treatment of biliary benign stenosis were developed through an electrospray-coating method. Polyether-based polyurethane (PELLETHANE 2363-80AE<TEX>$^{(R)}$</TEX>)) and paclitaxel were coated onto the surface of a metallic stent and Pluronic F127 was used as an additive. As a result, physicochemical characterization of paclitaxel via SEM, FTIR, contact angle and XRD techniques revealed the information of solid state of paclitaxel-loaded PU film. The in vitro release profile showed a slower release rate with a higher content of paclitaxel.