Photochromism of polyurethane cationomers with pendent azo groups

A new polyurethane cationomer with pendent azo groups bounds to quaternary nitrogen atoms has been synthesized by polyaddition reaction between poly(tetramethylene oxide) (PTMO), 4,4′-bibenzyldiisocyanate and N-methyldiethanolamine, followed by quaternization of tertiary nitrogen with 4-(3-chloropropionyloxy)azobenzene. E–Z photoisomerization of azo chromophores by UV irradiation with a high pressure mercury lamp and Z–E thermal relaxation were studied both in solution and film. An azo urethane model and a synthetic mixture of polyurethane cationomer with azobenzene were used for comparison.     

Polyurethane cationomers with nitroazoaromatic groups

Novel polyurethane cationomers bearing p-nitroazoaromatic groups covalently incorporated in the polymer chain were synthesized. Their photobehavior in polymer films and solutions was investigated by electronic absorption spectroscopy and was also evaluated comparatively with an ionic azodiol model. Under UV irradiation, in the first stage of the photoprocess the trans-cis isomerization occurs, followed then by a photobleaching reaction in the second stage of the process.     

Synthesis of polyurethane cationomers with anil groups: intramolecular proton transfer in salicylideneanil structures

Three new o‐hydroxy Schiff bases, 2‐chloromethyl‐N‐(2‐hydroxybenzilidene)aniline, 3‐(11‐bromoundecanoyloxymethyl)‐N‐(2‐hydroxybenzilidene)aniline and 4‐chloromethylphenyl (carbamoyloxymethyl‐2‐hydroxybenzylidene)aniline, used as quaternization agents for a polyetherurethane precursor based on poly(tetramethylene oxide) diol of 2000 g mol^?1 average molar mass (PTMO), 2,4‐toluene diisocyanate and N‐methyldiethanolamine (1:3:2 molar ratio), have been synthesized in order to obtain polymeric films with fluorescent properties. The structure and the photochromic mechanism of the salicylideneanil units were investigated. The excited state intramolecular proton‐transfer process (ESIPT) with the cis‐ and trans‐keto isomers formation as intermediate compounds and the formation of a keto tautomer were evidenced by a large Stokes shifted emission (100 nm). Copyright © 2005 Society of Chemical Industry     

Solution properties of hexamethylene diisocyanate based polyurethane cationomers

Summary Viscosity measurements of hexamethylene diisocyanate based cationomer in various polarity solvents and in water/solvent were performed. For the un-ionized sample in pure MEK and DMF, the reduced viscosities of both solutions follow the Huggins relation. For ionized samples in pure MEK and DMF, aggregation of the ionized hard segments still exist in the MEK and DMF solution in the high polymer concentration range, whereas chain expansion occurs in the DMF solution in the low polymer concentration range. For ionized samples in water/solvent mixtures, at a mixing ratio (by weight) of 0.12, the reduced viscosity indicates an aggregation behavior in MEK/water and a polyelectrolyte behavior in DMF/water. At a mixing ratio (by weight) between 0.24 and 4.44, the reduced viscosity indicates a polyelectrolyte behavior. The polymer particles change from a clear elastic gel to microspheres. For emulsions of the ionized samples, the reduced viscosity exhibits polyelectrolyte behavior.     

Phase inversion and its effect on the properties of polyester polyurethane cationomers

Polyester polyurethane cationomers are prepared using polyester polyol of molecular weight 2000 as soft segments, N-methyl diethanolamine as chain extender, glycolic acid as quaternization agent, methyl ethyl ketone as solvent, and 4,4'-diphenylenemethylene diisocyanate (MDI) as diisocyanate. Properties of the films cast from solutions and emulsions are studied by infrared spectroscopy, dynamic mechanical analysis, thermogravimetric analysis, differential scanning calorimetry, and tensile-elongation testing. Ionization can cause phase separation and produces increased cohesion in the hard domains. The dispersion process can be divided into three stages involving a separation of hard segment aggregates due to adsorption of water on their surface, water entering into hard segment microionic lattics, and finally a rearrangement of agglomerates to form microspheres. The dispersion can disrupt the order in the hard domains and an increased phase separation.     

New polyurethane cationomers with naphthyl and phenyltriazene pendants: Synthesis and properties

Two new diols bearing triazene moiety, 1‐(α‐naphthyl)‐3,3‐di(2‐hydroxyethyl) triazene‐1 (NT‐D) and 1‐phenyl‐3,3‐di(2‐hydroxyethyl) triazene‐1 (PT‐D), were synthesized from aromatic amines and diethanolamine. These monomers were used as chain coextenders in the two‐step addition reaction between poly(tetramethylene oxide) diol, 2,4‐tolylene diisocyanate, and N‐methyldiethanolamine to obtain photosensitive polyurethanes of elastomer type. Triazene polyurethane cationomers with chlorine counterions were prepared via a quaternization reaction of the above polymers with benzyl chloride. All polyurethanes had a quantity of triazene units between 7.02 and 8.93 wt % polymer, and the content of ammonium quaternary groups in the cationic ones was of 30.56 meq/100 g naphthyl triazene polyurethane cationomer (PUC‐NT) and 30.19 meq/100 g phenyl triazene polyurethane cationomer (PUC‐PT), respectively. Photobehavior of the triazene units in all polymers under continuous Hg‐lamp irradiation was similar to that found for monomers, when both chromophores were transformed during UV irradiation. It is concluded that the PT‐D acts as a more efficient sensitizer in the UV light‐induced reaction but the photolysis in elastomeric films was lower than that observed in solution. The presence of quaternary ammonium structure on the same polymer backbone decreases the constant rates of photolysis. Because the triazene polyurethanes become crosslinked during UV irradiation could be assessed as potential negative‐resist polymers. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2599–2605, 2004     

Synthesis and properties of new polyurethane ionomers. I. Photosensitive cationomers with triazene units

New bifunctional triazene compounds 1‐(m‐ hydroxymethyl)phenyl‐3‐(2‐hydroxyethyl)‐3‐methyltriaz(1)ene and l‐p‐nitrophenyl‐3,3‐di(2‐hydroxyethyl)triaz(1)ene as intermediates in polyurethane synthesis were prepared. Photosensitive polyetherurethane cationomers based on poly(tetramethylene oxide) diol of 2,000 average molecular weight, tolylene‐2,4‐diisocyanate, and N‐methyldiethanolamine/triazene diols, as cochain extender, followed by a quaternization with benzyl chloride, were synthesized and characterized. Upon UV irradiation, feniltriazene chromophore in monomer and both polymers (ionomeric or nonionomeric type) is irreversibly cleaved, as evidenced in photolytic and kinetic studies. The rate constant of photolysis in ionomer film was lower than for the corresponding nonionic film. A positive pattern can then be developed by treatment with CHCl₃ that dissolves the exposed zone, while the unexposed area remains resistant and insoluble. By incorporating side nitrofeniltriazene groups, photostable polyurethanes were obtained. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1203–1210, 2003     

Synthesis and characterization of film-forming poly(urethaneimide) cationomers containing quaternary ammonium groups

In a recent work, we have described an original family of poly(urethaneimides) containing tertiary amine groups from a polytetramethylene oxide diol (PTMO1000), N-methyldiethanolamine (MDEA), 4,4′-methylene-bis-phenylisocyanate (MDI) and 4,4′-hexafluoroisopropylidene-bis-phthalic anhydride (6FDA). This paper reports their quaternization with various alkylating agents to give the cationic quaternary ammonium groups. An optimization of the experimental conditions led to three new families of PUI cationomers with a good structural control and high quaternization degrees. These polymers differed in the number of their cationic groups (0 < x ≤ 0.7 equiv.), the type of their counter-ions X⁻ (methyl sulfate, tosylate, triflate, chloride, bromide, iodide) and their steric hindrance by the length of their n-alkyl side chain (C₁-C₆). Complementary NMR techniques, including HSQC and COSY two-dimensional NMR, enabled to characterize the control of the polymer structure and to determine quantitatively the quaternization degree of the PUI cationomers. Properties in solution (solubility and viscosity) and in the solid state (film-forming ability and density) were then examined in relation with the membrane separation application targeted for these new PUI cationomers.     

Polyurethanes from novel 1,3-propyleneoxide co-telechelics having pendant hydantoin and methoxymethyl groups

We report the synthesis of a new oxetane monomer 5,5-dimethyl-3-(2-((3-methyloxetan-3-yl)methoxy)ethyl)-imidazolidine-2,4-dione (Hy4Ox, 1), an oxetane with a hydantoin-containing moiety in the 3-position. This hydantoin-oxetane monomer is stable to cationic ring-opening polymerization. Copolymerization of Hy4Ox with another new monomer, 3-methyl-3-methoxymethyloxetane (MOx, 2) provided a series of hydroxy terminated poly(2,2-substituted-1,3-propanediol) co-telechelics (P(Hy4Ox:MOx)) with low T_gs for polyurethane synthesis. ¹H NMR spectroscopy was used for establishing stoichiometry and M_n by end group analysis. DSC for P(Hy4Ox:MOx) telechelics shows a single T_g that increases in breadth as the fraction of hydantoin increases suggesting inter- or intrachain hydrogen bonding. The telechelics were incorporated into polyurethanes with HMDI and 1,4-butanediol as the hard block. Characterization of polyurethane composition and bulk properties by ¹H NMR, MDSC, and GPC is described. The new monomers and telechelics have promise in optimizing effectiveness of biocidal polyurethane polymeric surface modifiers.     

Preparation of polysiloxane oligomers bearing benzoxazine side groups and tunable properties of their thermosets

A new pathway for the preparation of polysiloxane oligomers bearing benzoxazine side groups were reported via the hydrolysis and co‐polycondensation of benzoxazinyl siloxane (SBZ) with dimethyldiethoxysilane (DEDMS). The structures of SBZ and oligomers were characterized by Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR) spectroscopy. The average molecular weights of the obtained oligomers were estimated from size exclusion chromatography and ¹H‐NMR to be in the range of 2000–4000. The oligomers gave transparent films by casting in THF solution. The films were further thermally treated to produce crosslinked films via the ring opening polymerization of benzoxazine side group. The effects of siloxane content on polymerization behavior, glass transition temperature, and mechanical properties of the polybenzoxazine thermosets were investigated. Tensile test of the films revealed that the elongation at break increased with increasing siloxane content. The elongation at break of poly(I‐50) was up to 12.1%. Dynamic mechanical analysis of the thermosets showed that the T_gs were in the range of 119–165°C. Thermogravimetic analysis also revealed a better thermal stability as evidenced by the 5% weight loss temperatures in the range of 363–390°C. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40960.     

Synthesis of cationic manganese porphyrin bearing alkylsulfonio groups and evaluation of their antioxidant activities

A water-soluble cationic 5, 10, 15, 20-tetrakis(2-dimethylsulfoniophenyl)-porphinatomanganese(III) ion (MnT2M(2)SuP) and a 5, 10, 15, 20-tetrakis(4-dimethylsulfoniophenyl)porphinatomanganese(III) ion (MnT4M(2)SuP) were synthesized as superoxide dismutase (SOD) mimics which were introduced into PEG-liposome composed of dimyristoylphosphatidylcholine (DMPC) and Pluronic F-68 to examine the effect of the liposome on the capacity for use as drug delivery system (DDS) to maintain and perpetuate blood circulation. Fluorescence spectra in pseudo blood circulation experiments indicated that MnT4M(2)SuP continued to be bundled in PEG-liposome, while fluorescence from cross-section of cell observed by confocal laser scanning microscope indicated that PEG-liposome was ingested into a cell. SOD activity was determined by stopped-flow analysis, which allowed the determination of k(cat) values for the reaction of the metalloporphyrins with superoxide anion radical (.O(2)(-)). Solution of PEG-liposome loaded with MnT2M(2)SuP or MnT4M(2)SuP were the most effective catalyst as a SOD mimic to decompose .O(2)(-) at second-order rate constants of 3.5-4.5 x 10(7) M(-1)s(-1).     

Surface functionalization of polypropylene‐bearing isocyanate groups in solid state and their cyclotrimerization with diisocyanates

Solid‐state graft polymerization of 3‐isopropenyl‐α,α′‐dimethylbenzene isocyanate (TMI) onto the surface of polypropylene beads was carried out in a triethylborane/oxygen redox system. Chemical structures were characterized using attenuated total reflectance–Fourier transform infrared spectroscopy. Results showed that TMI was successfully grafted because of the appearance of an ? NCO absorption peak at 2255 cm^?1. The emergence of oxygen and nitrogen elements detected by EDS and XPS also demonstrated the existence of isocyanate group on PP‐grafted. The grafting ratio of TMI to polypropylene was examined using 9‐(methylamino‐methyl)anthracene (MAMA) as an intermediate substance. The fluorescent property of MAMA before and after reaction was characterized to guarantee interaction between MAMA and isocyanate. Thermal properties were examined using differential scanning calorimetry–thermogravimetric analysis. Results indicated that melting temperature (T_m) of pure PP was 168^oC, while the PP‐grafted decreased to 164^oC. Meanwhile, decomposition temperature (T_d) decreased with increased grafting ratio for about 8 to 15^oC; however, when styrene was introduced, T_m increased probably because of the stabilizing effect on macromolecular radicals and the suppression effect on chain degradation. Besides, the cyclotrimerization of isocyanates on the grafted polymer chain was further conducted to prepare thermally stable isocyanurate composite materials, remedying the T_d loss of PP‐g‐TMI by improving for 10^oC appropriately. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42186.     

含有磺酸基团的水性聚氨酯的制备

本文以聚氧化丙烯二醇(N210)和2,4-甲苯二异氰酸酯(TDI)为原料,通过逐步聚合反应,合成了聚氨酯预聚体;再以羧酸型亲水扩链剂二羟甲基丙酸(DMPA)和自制的磺酸型亲水扩链剂1,2-二羟基-3-丙磺酸钠(DHPA),通过扩链反应,制备了兼有磺酸盐和羧酸盐的水性聚氨酯乳液,并对胶膜进行力学性能的测试和分析;测定了乳液的固含量,重点研究了反应温度、亲水基团含量(DMPA和DHPA在预聚体中的百分含量)和DHPA在亲水基团中的含量对胶膜力学性能的影响。研究结果表明,通过逐步聚合和扩链反应,可成功地制得固含量高达70%,兼有磺酸和羧酸的水性聚氨酯乳液;且当R值(NCO/OH)为2,亲水基团含量为5%,DH-PA在亲水基团中的含量为20%时,胶膜的断裂伸长率达2135%。     

Novel polyaryletherketones bearing pendant carboxyl groups and their rare earth complexes, Part I: Synthesis and characterization

A series of novel polyaryletherketones bearing pendant carboxyl groups were synthesized via solution nucleophilic polycondensation reaction, and the rare earth (Re³⁺ = Sm³⁺, Eu³⁺, Dy³⁺ and Tb³⁺) coordinated polymers were prepared using the polymer as macromolecular ligand and 1,10-phenanthroline (Phen), dibenzoylmethane (DBM) or 8-hydroxyquinoline (HQ) as co-ligands. Their structures were confirmed by means of FT-IR, ¹H NMR and WAXD methods. WAXD results showed that the rare earth-coordinated polymer had similar amorphous structure to the polymer matrix, whereas the diffraction peaks corresponding to rare earth salts were completely absent, indicating a homogeneous distribution of rare earth ions within the polymer hostess due to the formation of coordination bonds between rare earth ions and the carboxyl groups on the polymer backbone. The rare earth coordination polymers were soluble in polar solvents such as DMSO, DMAc, DMF and NMP, and could be easily cast into transparent tough thin films. The polyaryletherketones synthesized had high glass transition temperatures above 210 °C, and showed fairly good thermal stability with 5% thermal decomposition loss above 402 °C.     

Preparation and photochromic properties of waterborne polyurethane containing spirooxazine groups

Two novel photochromic spirooxazines, SO 1 and SO 3, were successfully prepared and characterized by Fourier transform infrared spectroscopy (FTIR), ¹H-NMR, and mass spectrometry with electrospray ionization (ESI-MS). SO 1 was doped and grafted with waterborne polyurethane (WPU) to afford D₁-WPU and G₁-WPU. D₃-WPU was prepared by doping SO 3 with waterborne polyurethane. FTIR spectra indicated that SO 1 was grafted onto waterborne polyurethane successfully. Scanning electron microscopy proved that spirooxazines of D-WPU can be effectively dispersed in a waterborne polyurethane matrix, and spirooxazines of G-WPU are evenly distributed in the copolymer. The results showed that the light transmittance of modified waterborne polyurethane films decreased compared with pure waterborne polyurethane films, but the water resistance and tensile strength were better. Ultraviolet–visible spectra demonstrated that the thermal stability of spirooxazine derivatives improved significantly after being modified. The fading rate constant of the D₃-WPU film (k = 0.0079 s^-1) during the discoloration process decreased 9.77 times in contrast to SO 3 in ethanol, which showed that the thermal stability of spirooxazine in WPU film was obviously enhanced. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47067.     

Graft copolymerization of vinyl monomers bearing positive charges or episulfide groups onto loofah fibers and their antibacterial activity

Ion exchange fibers with quaternary ammonium groups, phosphonium groups, or thiol groups etc., were prepared by graft copolymerization of vinyl monomers on loofah fiber which is one of the natural fibers. Methacryloyloxyethyl trimethyl ammonium chloride (METAC), tributyl‐4‐vinylbenzyl phosphonium chloride (TRVB), and epithiopropyl methacrylate (ETMA) were used as vinyl monomers. Graft copolymerization of METAC on loofah could be carried out in water using ammonium cerium (IV) nitrate. Graft copolymerization of TRVB and ETMA on loofah could be performed in water and water‐dimethylsulfoxide mixed solution using hydrogen peroxide as an initiator, respectively. The optimum conditions for each graft copolymerization were investigated in detail. Ion exchange fibers (LE‐TTA) having both thiol groups and triethylenetetramine side chains were obtained by treatment of L‐g‐ETMA (LE) with triethylenetetramine. LE and LE‐TTA had high adsorption ability for silver ions. LE‐TTA‐Ag exhibited high antibacterial activity against E. Eoli and S. aureus, but LE‐Ag did not. On the other hand, L‐g‐METAC and L‐g‐TRVB also exhibited high antibacterial activity against E. Eoli and S. aureus. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 1077–1086, 2000     

阻燃型可生物降解聚氨酯

通过对淀粉的磷酸酯化改性,并以磷酸酯化淀粉为反应性阻燃剂,合成出既具生物降解特性,又具阻燃特性的聚氨酯弹性片材,为开拓聚氨酯“绿色”产品探索新的途径。     

Carboxylated polyurethane anionomers and their composites with polypyrrole

Some polyurethane anionomers synthesized by a two‐step substitution postreaction of urethane hydrogen atoms with CH₂COONa groups were studied. The influence of ionic structures on the mechanical and electrical properties of polymers was followed. The carboxylated polyurethane anionomers were used to obtain electroconductive composites with polypyrrole, by immersion of polyurethane films in aqueous solution of pyrrole and oxidative chemical polymerization of the heterocyclic monomer with FeCl₃. The proportion of polypyrrole in the composites increased by introduction of ionic groups. Stress–strain behavior and electrical conductivity of composites were compared with those of the anionomers. Incorporation of polypyrrole significantly enhanced the electrical conductivity but diminished mechanical properties. Some composites possess both satisfactory conductivity and mechanical properties. The results were explained by the morphological changes induced by ionic group and polypyrrole presence. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 75: 1385–1392, 2000     

Thermophysical properties of polyurethane foams and their melts

The thermal conductivity (λ) and the specific heat (c_p) of seven polyurethane foam formulations and their melts are obtained using a transient plane source technique called the Hot Disk experiment. In the experiment, the Hot Disk sensor is sandwiched by the samples and acts as both a heat source and a temperature sensor. The fundamental assumption is that throughout the experiment, the heat from the sensor does not penetrate beyond the boundaries of the sample. The suitable sample dimensions and sensor radius are determined from the preliminary calculations. Through sensitivity analysis, the appropriate measuring time and output power for the experiments are established. For polyurethane foams, λ ranges from 0.048 to 0.050 W/m K, and c_p ranges from 2359 to 2996 J/kg K. For melts, λ ranges from 0.186 to 0.200 W/m K, and c_p ranges from 1958 to 2076 J/kg K. When foam decomposes into melts, the changes in thermophysical properties shows λ increases by approximately 300%, whereas c_p decreases by approximately 20%. On the basis of these changes, the collapse of the foam structure into melt appears to improve the heat transfer through the material. Copyright © 2013 John Wiley & Sons, Ltd.