Synthesis and characterization of fluorinated polyurethane with fluorine-containing pendent groups

A novel fluorinated polyurethane （FPU） with fluorine-containing pendent groups was prepared by using fluorinated polyether glycol （PTMG-g-HFP） as a soft segment, 1,6-hexamethylene diisocyanate （HDI） or toluene diisocyanate （TD1） as a hard segment and 1,4-butanodiol （BDO） as a chain extender. FTIR, ^1H NMR, ^13C NMR and GPC were used to characterize the structure of the fluorinated polyurethane. Thermal stabilities of the fluorinated polyurethane and the corresponding hydrogenated polyurethane were studied by TGA. XPS analysis at two different sampling depths for the fluorinated polyurethane was used to investigate the surface compositions of FPU. The results showed the fluorine enrichment on the surface of FPU.     

A novel approach to fluorinated polyurethane by macromonomer copolymerization

For the first time, through macromonomer radical copolymerization, a novel fluorinated polyurethane (FPU) was synthesized based on partly acrylate-endcapped polyurethane macromonomers with hexafluorobutyl acrylate (HFBA). Partly acrylate-endcapped polyurethane (PU) macromonomers were synthesized using isophronediisocyanate (IPDI), dimethylol propionic acid (DMPA), polyethylene adipate glycols (PEA) etc. The novel fluorinated polymer, which bore PU side chains and fluorinated side chains, was confirmed by F¹⁹ NMR spectroscopy, X-ray photoelectron spectroscopy (XPS), elemental analysis, scanning electron spectroscopy (SEM) etc. Copolymerization of polyurethane macromonomers with hexafluorobutyl acrylate (HFBA) was briefly investigated. The surface tension of FPU solution was measured and showed sharply decrease compared to that of pure polyurethane. Results from SEM showed a uniform size distribution of phase micro-domains on the fracture surface of FPU.     

Synthesis and properties of fluorine-containing polyurethane based on long chain fluorinated polyacrylate

For the first time, a novel fluorine-containing polyurethane (FPU) was prepared by introducing long chain fluorinated polyacrylate into PU. The FPU was prepared from dodecafluoroheptyl methacrylate (DFMA), β-mercaptoethanol (β-ME), methacryloyloxyethyl isocyanate(MOI), hydroxyethyl methylacrylate (HEMA), iso-butyl acrylate(I-BA), polyether diol (N220) and toluene diisocyanate (TDI). The structure of product for every step was confirmed by Fourier transform infrared (FT-IR) spectroscopy and proton nuclear magnetic resonance (¹H-NMR) spectra. It was found that when the DFMA content increased from 0 to 12%, thermal stability was improved in some degree; the hardness, the adhesion and the tensile strength increased; the swelling degree in water, NaOH solution and HCl solution decreased; the solvent resistance in hexane and butanone improved to some degree; the contact angle of water and ethylene glycol increased; the surface free energy decreased. XPS tests indicated fluorine migrated to surface.     

Synthesis and characterization of fluorinated polyurethane containing carborane in the main chain: Thermal,mechanical and chemical resistance properties

In this study, two fluorinated polyurethanes(FPU) containing carborane groups in the main chains were firstly designed and synthesized via the reaction of hexamethylene diisocyanate trimer(HDI trimer) with fluorinated polyesters(CFPETs) having hydroxyl-terminated carborane groups at room temperature. The structures of carborane fluorinated polyesters(CFPETs) and polyurethanes(CFPUs) were characterized by gel permeation chromatography(GPC), Fourier transform infrared(FTIR) spectroscopy and nuclear magnetic resonance(NMR) measurements. The thermal stability, mechanical properties, Shore A hardness, solvent resistance and acid-alkali resistance of the carborane fluorinated polyurethane films were also studied. Thermogravimetric analysis(TGA) tests manifested that the introduction of carborane groups into the main chain of fluorinated polyurethane endowed the obtained fluorinated polyurethane with excellent thermal stability. The thermal decomposition temperature of carborane fluorinated polyurethane(CFPU) increased by 190 °C compared with that of the carborane-free fluorinated polyurethane(FPU). Even at 800 °C, CFPU showed the char yield of 66.5%, which was higher than that of FPU(34.3%). The carborane-containing fluorinated polyurethanes also showed excellent chemical resistance and prominent mechanical property even after the cured films being immersed into Jet aircraft oil or 37% HCl for 168 h or at high temperature(700 °C). It is found that the structural characteristics of carborane group and the compacted structure of CFPU effectively improve the thermal stability, mechanical property, solvent resistance and acid-alkali resistance of the carborane-free fluorinated polyurethane. These excellent properties make CFPU as the useful raw materials to prepare the high temperature resistant coatings or adhesives for automotive engines, engine or fuel tank of aircraft and other equipment working in high-temperature or high concentrations of acid-alkali environments.     

Preparation,characterization, and properties of fluorinated polyurethanes

Novel fluorinated polyurethanes (FPUs) were prepared by living radical polymerization of polyurethanes and hexafluorobutyl acrylate. The structures of the FPUs were characterized by FTIR, ¹H NMR, GPC, DSC, and XPS. The fluorinated polyurethane polymerization was investigated and showed monomer conversion, and molecular weight increased with increasing reaction time. In this way, the fluorine content in polyurethane could be easily adjusted by controlling the content of the fluorinated acrylate monomer. The mechanical evaluation shows that FPUs exhibit good mechanical properties. Morphology of FPU films was observed by scanning electron spectroscopy. The effects of the fluorine content on the surface properties and oxidative stability of FPUs were investigated. FPUs films were devoid of significant surface degradation after immersion in 20% H₂O₂ and 0.1 M CoCl₂ at 37 °C for 5 weeks. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3248–3256, 2009     

Fluorinated modification of hyperbranched polyesters used for improving the surface property of UV curing coatings

The commercial hyperbranched aliphatic polyols (Hn) were modified by thioglycolic acid (TA) and hexafluorobutyl acrylate (HFBA) or dodecafluoroheptyl methacrylate (DFHMA) to prepare a series of fluorinated hyperbranched polyesters. For comparison, a linear fluorinated polymer, poly(n-BMA-co-DFHMA), was synthesized through the copolymerization of n-butyl methacrylate (BMA) and DFHMA. The molecular structures were characterized by ¹H NMR spectroscopic analysis. The synthesized polymers were incorporated into UV-curable formulations as additives, and exposed to a UV lamp. After UV curing, the wettability of the films was investigated by contact angle measurement with water and 1-bromonaphthalene. The results showed that both the hydrophobicity and oleophobicity were greatly enhanced. Moreover, the fluorinated hyperbranched polymers possessed better water and oil repellency than the copolymer poly(n-BMA-co-DFHMA) at a very low concentration. The surface F/C ratio values of the cured films were detected by XPS analysis, and the film with TAH20-DFHMA showed the highest F/C ratio value, indicating its most efficient aggregation effect at the film surface.     

Convenient synthesis of novel fluorinated polyurethane hybrid latexes and core-shell structures via emulsion polymerization process with self-emulsification of polyurethane

Novel fluorinated polyurethane hybrid latexes in the size range of 40–50 nm, fluoroalkyl acrylate as fluorinated monomers, with various fluorine content (F% = 9∼26 wt%) were successfully prepared via emulsion polymerization process without traditional emulsifier. The waterborne polyurethane, which was synthesized by using isophronediisocyanate, dimethylol propionic acid, polyethylene glycols, etc., served not only as copolymerizable macromonomer but also as polymeric high molecular weight emulsifier. The structures of polyurethane macromonomer and fluorinated polyurethane were characterized by Fourier transform infrared and H¹-NMR. Particle size, zeta potential, micromorphology of the latex par.ticles, and surface properties were investigated by dynamic light scattering, potential particle size analyzer, transmission electron microscopy, and contact angle measurement, respectively. Results illustrated that the advantage of this process is that the size of fluorinated polyurethane hybrid particle is less sensitive to the composition. Furthermore, it was showed that fluorinated polyurethane latex particles had core-shell structures, especially when the content of fluorine was 26.08 wt%. Moreover, there was an obvious migration of fluorinated groups to the surface during the formation of fluorinated polymer films, although fluorinated groups were covered by polyurethane in latex particles.     

硬段侧链含有氟化双季铵盐的聚氨酯表面性能及抗菌性能分析

研究了硬段侧链含有氟化双季铵盐的系列聚氨酯(FQPUs)的表面性能和抗菌性能. 水接触角测试和表面自由能测试结果表明, 加入少量氟化双季铵盐扩链剂, 可以使聚氨酯表面富集氟碳链, 氟化双季铵盐聚氨酯表面自由能很低, 具有很好的抗黏附性能. 迁移到表面的两条氟碳链在常温下不会发生链反转, 使材料的抗黏附性能得以保持. 同时, 使材料表面形成一层疏水层, 减小材料的吸水率. XPS研究结果表明, 氟碳链的-CF₃位于材料的最外层, 材料的次表面是具有良好杀菌性能的双季铵盐, 这样形成了具有多重抗菌性能的表面. 另外, XPS研究结果表明, 材料表面化学结构与材料本体的微相分离结构相关. 抗菌性能测试结果表明, 氟化双季铵盐聚氨酯抗金黄色葡萄球菌的能力很强, 对于大肠杆菌的抗菌效果有所下降, 但相对于单季铵盐聚氨酯的抗菌效果有一定提高.     

Effect of soft segment length on properties of fluorinated polyurethanes

The effects of soft segment length on the variations in morphology, surface composition, and hydrophilicity have been studied in fluorinated polyurethanes (FPUs) and correlated with their preliminary blood compatibility as evidenced by in vitro platelet adhesion experiments. The fluorinated polyurethanes were obtained using hexamethylene diisocyanate (HDI) and chain extender of 2,2,3,3-tetrafluoro-1,4-butanediol (TF) as the hard segment as well as various soft segments—polytetramethyl oxides (PTMO) with molecular weights of 650, 1000, 1400, and 2000. The increased phase separation in hard-segment domains with lengthening soft segment was observed by FT-IR, which is believed to result in enhanced strength of hydrogen bonds and good hard-segment order arrangement. Thin-film XRD results indicate at least three lateral distances existing between adjacent hard segments in the crystallized hard segment. Their distribution depends strongly on the length of soft segment. Lengthening soft segment promotes the formation of dense arrangement of crystallized hard segments. Compared with the effect of phase separation, surface composition was found to exert a major influence on the preliminary blood compatibility of fluorinated polyurethanes. Increasing fluorine content by decreasing soft segment length promotes reduction in platelet adhesion and activation on polyurethane surfaces.     

Effect of soft segment length on the thermal behaviors of fluorinated polyurethanes

Differential scanning calorimetry (DSC) and temperature modulated DSC (MDSC) have been applied to investigate the thermal behaviors of fluorinated polyurethanes (FPU), which were obtained using 2,2,3,3-tetrafluoro-1, 4-butanediol as the chain extender and based on various soft segments—polytetramethyl oxides (PTMO) with molecular weights of 650, 1000, 1400 and 2000. An exothermic peak and/or multiple melting endotherms were observed during the heating to melting temperature of soft and hard segments. Attributed to the simultaneous recrystallization and melting processes during heating, these features have been confirmed via MDSC, where an endotherm and an exotherm were noted in reversing and non-reversing components of the heat flow. Separating the non-reversing components from the reversing curves, the dependencies of polyurethane morphology on the length of the soft segment could be clarified using MDSC analysis. Soft segment lengthening significantly influences the morphology of soft segment domains in FPUs. The phase separation and crystallinity of the soft segment increased with its length. However, soft segment length exerted a minor influence on the dissociation temperature of the short-range ordered hard segment domain and on the melting temperature of hard segment crystals. Examination of the heats of melting based on the quasi-isothermal MDSC experiments indicated that the crystallinity of hard segment domains declined with increasing soft segment length.     

SURFACE STRUCTURE AND BULK PROPERTIES OF FLUORINATED POLY(ETHER URETHANE)S AND POLY(ETHER URETHANE) BLENDS

INTRODUCTIONPolyurethanes (PU) have been widely used for manufacturing medical devices because of their excellentmechanical properties and moderate biocompatibility[1]. Although polyurethanes used in applications requiringall of the above properties have been successful for short-term use, the problems of long-term thromboresistanceand biostability in a biological environment still remain unsolved[2,3]. A legitimate approach to improving theproperties of polyurethanes is introduction of f…     

UV-curable low-surface-energy fluorinated poly(urethane-acrylate)s for biomedical applications

Novel UV-curable fluorinated poly(urethane-acrylate) (FPUA) oligomers have been synthesized from 1H,1H,12H,12H-perfluoro-1,12-dodecanediol (PFDDOL), either 1,6-hexamethylene diisocyanate (HDI) or 4,4′-diphenylmethane diisocyanate (MDI), and 2-hydroxyethyl methacrylate (HEMA) for end-capping with photo-crosslinkable methacrylate groups. The fluorine content and the nature of the isocyanate were investigated to determine their effects on the physical properties, surface properties, and blood compatibilities of the polymers. The introduction of hydrophobic fluorocarbon chains led to phase separation and a low total surface energy, which reduced the adhesion of blood platelets onto the materials. The HDI-type UV-curable, fluorinated poly(urethane-acrylate) exhibited a low-surface-energy and superior blood compatibility (as determined from RIPA values).     

Synthesis and characterization of copolymers based on styrene and partially fluorinated acrylates

Copolymers of styrene and fluorinated acrylate monomers with F-octylalkyl, F(CF₂)₈(CH₂)_n^′ side groups were prepared by free radical polymerization. Thermal behaviour of the resulting polymers was investigated by DSC and TGA. Even if at the macroscopic scale the polymers surfaces are homogeneous and clear, the analysis indicates that all samples exhibit two glass transitions temperatures. This discontinuity may be regarded as an indication for microphase separation of fluorine-rich and polystyrene-rich microphases. Water and hexadecane contact angles measurements show that these polymers are quite surface active in the solid state. Surface and bulk organizations were investigated by XPS analysis. A strong correlation between bulk organization and surface properties of the polymers could be established. Preferential adsorption of fluorinated segments at the material surface were more pronounced than expected in the bulk.     

Synthesis and surface properties of a series of surfactants based on O-alkyl and O-perfluoro-N,N′-diisopropylisoureas

O-Dodecyl-N,N′-diisopropylisourea and O-tridecafluorooctyl-N,N′-diisopropylisourea were synthesized by reaction of hydrogenated or fluorinated alcohols onto diisopropylcarbodiimide in quasi-quantitative yields. Adding various hydrogen halides (HCl, HBr, or HI) onto these isoureas enabled one to obtain isoureas hydrohalides with tensioactive properties. The surface properties of both series of hydrogenated and fluorinated surfactants were studied and compared. The influence of the counter-ions onto the surface properties showed that the tensioactive properties were improved in the following increasing order: I < Cl < Br. Fluorinated isourea hydrohalides exhibited better surfactant properties than their hydrogenated homologues.     

Synthesis and characterization of a new fluorinated macroinitiator and its diblock copolymer by AGET ATRP

A new fluorinated macroinitiator of poly 2,2,3,4,4,4-hexafluorobutyl methacrylate-Br (PHFMA-Br) was prepared via activator generated by electron transfer atom transfer radical polymerization (AGET ATRP), and then a series of fluorinated block copolymers with different fluorine content were successfully synthesized from the macroinitiator by the second step AGET ATRP. GPC, FTIR and ¹H NMR data obtained verified the synthesis. Contact angle measurement indicated that proper fluorine content could decrease the surface energy and increase the contact angle of the copolymer films. XPS characterization showed that the large difference in surface energy between the block and random copolymer film resulted from the difference of the fluorine content on the surface, although the fluorine content of the two copolymers in bulk was similar. The self-assembly behavior of the fluorinated block copolymer in selective solvents was evaluated by the TEM study, and the stable micelles with a core-shell structure were observed when the copolymer content was about 1 wt%.     

Thermal stability enhancement of polyurethanes by surface treatment

Both oxidation and methoxymethylation of the surfaces of a series of MDI (methylene diphenyl isocyanate) and TDI (toluene diisocyanate) polyether and polyester soft segment 1–4 butanediol polyurethanes result in increased thermal stability as measured by TG. Explosive loss of mass above the hard segment melting temperature suggests that the diffusion of the dissociated diisocyanate moiety is hindered at lower temperatures. Thus suppression of the depolycondensation reaction by chemical blockage of the surface may result in a material with an increased service life at use temperatures as thermal stability of a polyurethane may depend upon the low diffusivity of its diisocyanate comonomer. The effect of vacuum, oxygen and water vapor on the kinetics of mass-loss of several of the polyurethanes is presented. In celebration of the 60^th birthday of Dr. Andrew K. Galwey     

Synthesis of Fluorinated Polyurethane/Polyacrylate Hybrid Emulsion Initiated by 60Co γ-Ray and Properties of the Latex Film

Based on the solvent-free method, novel fluorinated polyurethane/polyacrylate hybrid emulsions, dodecafluoroheptyl methacrylate (DFMA) as fluorinated monomer, were successfully prepared via emulsion polymerization without traditional emulsifier. For the purpose of increasing the grafting ratio of polyurethane and polyacrylate, ⁶⁰Co γ-ray radiation polymerization had been adopted to enhance the hardness of latex film. The chain structure and polymerization progress were confirmed by the analysis of Fourier transform infrared spectroscopy. The grafting ratio of polymethyl methacrylate and polyurethane was obtained by calculating the ratio of N–H peak integral area and Ph(C=C) peak integral area. The effect of DFMA content on thermal stability, mechanical property and water resistance were investigated systematically by thermal weight loss analysis, tensile strength test, absorbed water ratio and water contact angle.     

Preparation of an environmentally friendly antifouling degradable polyurethane coating material based on medium-length fluorinated diols

A novel medium-length fluorinated diols and poly(L-lactide) (PLLA) were synthesized via Michael addition reaction and ring-opening polymerization, respectively. Subsequently, Synthetic medium-length fluorinated diols and PLLA were combined to prepare new polyurethane composites with degradability and low surface energy. The compositional analysis and structural characterization of synthetic materials were characterized by using fourier transform infrared spectroscopy (FT-IR) and proton nuclear magnetic resonance spectra (¹HNMR). Thermogravimetric analysis(TGA) indicated that the introduction of medium-length fluorinated diols improved the thermal stability of the polyurethane. The biodegradation and low surface energy of the polyurethane were investigated by static hydrolysis experiment and water contact angle test. It was found that the degradation rate of the polyurethane increased as measurement time went on when the PLLA content was under 40%, and the water contact angle increased from 71.12° to 108.24° with the increase of fluorine content, which indicated that the degradable and low surface energy polyurethane has a potential as a coating material for a marine antifouling coating application.     

Synthesis and characterization of chitosan-based polyurethane elastomer dispersions

Abstract  

A number of aqueous polyurethane dispersions were synthesized by the reaction of poly(ε-caprolactone) and isophorone diisocyanate, extended with different mass ratios of chitosan and dimethylol propionic acid. Their chemical structures were characterized by using FTIR, ¹H NMR, and ¹³C NMR spectroscopy, and thermal properties were determined by TGA. Incorporation of chitosan into the polyurethane backbone improved thermal stability. The hydrophilicity of the prepared polymers was also examined by contact angle measurements. For all samples, the contact angles increased by increasing the amount of chitosan. The increased contact angle is ascribed to the decrease of the hydrophilicity of the polyurethanes, which is reduced by the increasing amount of chitosan with respect to dimethylol propionic acid chain extender.     

Synthesis,characterization, thermal stability and compatibility properties of new energetic polymers

Four new cross-linked polymers poly(vinyl m-nitrobenzene)-polyglycidylazides (PVMNB-GAPs) were successfully synthesized using toluene diisocyanate as the cross-linking agent. Their structure was confirmed by their FTIR, UV–Vis, ¹H and ¹³C NMR spectroscopy. Moreover, the thermal properties of cross-linked polymers were evaluated by DTA, TGA and DSC techniques, which confirmed that synthesized polymers exhibited good resistance to thermal decomposition up to 200°C. In addition, their compatibility with the main energetic components of 2,4,6-trinitrotoluene-based melt-cast explosives were also evaluated by the non-isothermal differential thermal analysis method.