Effect of crosslink density on transport of industrial solvents through polyether based polyurethanes

Polyurethanes based on PPG 2000 with variable concentrations of TDI and TMP were prepared and used for sorption studies, employing homologous series of hydrocarbons such as benzene, toluene and xylene. The sorption was observed to be non-Fickian in nature. The solubility parameter of the polyurethane series was observed to be 9·7(calcm^-3)^1/2. The polymer solvent interaction parameter χ was found to be lowest in benzene, suggesting higher interaction with it. The sorption and diffusion coefficients were observed to increase with a decrease in the degree of crosslinking. Molecular weights between crosslinks were calculated using the Flory–Rehner equation and compared with those obtained theoretically. © 1998 Society of Chemical Industry     

Biodegradation of pyridine‐based polyether polyurethanes by the Alternaria tenuissima fungus

The scope of the present work is to study the biodegradability behavior of several novel heterocyclic poly(ether urethanes) when their hard segments are subjected to exposure to the Alternaria tenuissima fungus. The heterocyclic poly(ether urethanes) were chain‐extended with various pyridine derivatives that had different functional groups placed in different positions on the pyridine rings. Different ratios of the reactive components were also used. The measurements obtained by the use of the attenuated total reflectance–Fourier transform infrared spectroscopy revealed the different structural changes that occurred after exposure to fungi. The degradation process was analyzed through measurement of the mechanical properties and surface morphology evolution by scanning electron microscopy. The obtained results show that the nature and design of the functional groups on the pyridine ring determine the strength of the cohesion linkages that in turn influence different degradation behaviors under exposure to fungi. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46096.     

The effects of the molecular weight and structure of polycarbonatediols on the properties of waterborne polyurethanes

A series of waterborne polyurethanes (WPUs) were synthesized by a pre-polymer process from isophorone diisocyanate, 1,6-hexamethylene diisocyanate and polycarbonatediol with varying molecular weight (1000–2000 Da) and molecular structure (copolycarbonate and homopolycarbonate). The effect of polycarbonatediols on the performance of the emulsion was studied by means of apparent viscosity, particle size distribution and Zeta potential analysis. Fourier transform infrared spectroscopy, thermal gravimetric analysis, differential scanning calorimetry, X-ray diffraction, dynamic mechanical analysis, physical and mechanical measurements and water droplet contact angle tests were employed to characterize the thermal stability, crystallinity, low temperature flexibility, physical and mechanical properties and wettability of the films derived from the emulsions. The results indicated that WPU dispersions with mean particle size in the range of 50–70 nm and Zeta potential value about −50 mV displayed excellent storage stability. It was found that the mean particle size, thermal stability, crystallinity, low temperature flexibility, mechanical properties and hydrophobicity increased and the particle distribution decreased with the increase of molecular weight of the polycarbonatediols. Moreover, copolycarbonate-based WPUs showed higher crystallinity of hard segments, thermal stability and wettability than the homopolycarbonate-based ones.     

聚氨酯和聚醚改性环氧树脂分子结构和性能的探讨

分子复合结构设计是将一种树脂的特性赋予其他种类树脂，来达到改性和提高固化物性能的目的。本文对聚氨酯和聚醚改性环氧树脂的分子结构及性能作了简要的论述。     

Experimental and theoretical characterization of the morphologies in fluorinated polyurethanes

On the analyses of modulated differential scanning calorimetry, Fourier transform infrared spectra and quantum chemical calculations of fluorinated and corresponding unfluorinated polyurethanes, we investigated the effects of fluorination on the intermolecular hydrogen bonds and resulted morphological changes in polyurethanes. The B3LYP/6-31G(d′,p′) calculated values supported the experimental results suggesting that the fluorinated hard segment facilitates hydrogen bond interactions towards soft segment polyether, while reducing the strengths within self-associated hard segments.     

Synthesis and electrochemical properties of redox active polyurethanes with ferrocene units in polyether soft segments

Electrochemical active segmented polyurethane with ferrocene units in polyether soft segments (PU‐S‐Fc) has been originally synthesized and identified by ¹H‐NMR spectra. Electrochemical behaviors of PU‐S‐Fc blending with lithium perchlorates were investigated by cyclic voltammetry. In N,N′‐dimethyl formide solution, PU‐S‐Fc exhibited normal cathodic and anodic peaks of the ferrocene/ferricinium (Fc/Fc⁺) couple. Compared with that of ferrocene molecules blended in ordinary polyurethane (PU‐B‐Fc), redox peaks of ferrocene units in PU‐S‐Fc were found to be broader, which may be ascribed to the weak adsorption of the polyurethane on the electrode surface. The influence of lithium perchlorate concentration on peak potentials indicated that supporting electrolytes played an important role in electrochemical redox of PU‐S‐Fc. In the solid state, PU‐S‐Fc/Li⁺ showed discernible redox peaks at temperatures higher than 60°C, and an exponential increase curve of electrochemical response with an increase of temperature was found. Temperature variations of the solid‐state ionic conductivity for PU‐S‐Fc/Li⁺ can be interpreted by the Arrhenius equation. The similarity between the temperature dependence of ionic conductivity and electrochemical response revealed that transport mechanism of ionic and redox species in the polyurethane matrix was controlled by the mobility of polyether chains. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 2674–2680, 1999     

Relationship between carbon dioxide transport,free volume and morphology of polyolefin‐based polyurethanes

A series of polyurethane (PU) films, produced from toluene diisocyanate, 1,4‐butane diol and either hydroxyl‐terminated polybutadiene (HTPB), hydroxyl‐terminated polybutadiene/acrylonitrile (HTBN) or hydroxyl‐terminated polybutadiene/styrene (HTBS), was synthesized by solution polymerization. Differential scanning calorimetry (DSC), Fourier‐transform infrared (FT‐IR) spectroscopy, and positron annihilation lifetime (PAL) spectroscopy were used to investigate the morphologies and free volumes of these polyolefin‐based polyurethanes. The free volumes were closely related to the morphologies of such PUs. HTBN‐based PUs showed the lowest degree of phase separation, the smallest fraction of free volume and smallest hole radius among the three types of polyolefin‐based PUs, while the HTPB‐based PUs displaying the largest values. The diffusion and permeation coefficients decreased with decreasing degree of phase separation and increasing content of hard segments. The transport data were in relation to the free volume and fitted the Fujita free‐volume model. Copyright © 2004 Society of Chemical Industry     

Thermal stability of polyurethanes based on vegetable oils

A series of polyurethanes from polyols derived from soybean, corn, safflower, sunflower, peanut, olive, canola, and castor oil were prepared, and their thermal stability in air and nitrogen assessed by thermogravimetric analysis, FTIR, and GC/MS. Oil‐based polyurethanes generally had better initial thermal stability (below 10% weight loss) in air than the polypropylene oxide‐based polyurethane, while the latter was more stable in nitrogen at the initial stage of degradation. If weight loss at a higher conversion is taken as the criterion of stability, then oil polyurethanes have better thermal stability both in air and in nitrogen. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 1723–1734, 2000     

The effect of fluorinated side chain attached on hard segment on the phase separation and surface topography of polyurethanes

It has been well established that polyurethanes exhibit a two-phase micro-structure due to the thermodynamic incompatibility between the soft segments and hard segments. In this work, we reported the effect of fluorinated side chain attached on hard segment on the phase separation and surface topography of polyurethanes. Two sets of fluorinated polyurethanes, namely, poly(ether urethane)s and poly(carbonate urethane)s containing various amounts of chain extender of fluorinated side chains, were investigated by DSC, XPS, DMA, AFM and FTIR. It was found that the phase separation in both bulk and surface increases in fluorinated poly(carbonate urethane)s and the phase mixing increases in fluorinated poly(ether urethane)s, with increasing amounts of fluorinated side chain. The increased degree of hydrogen bonding between hard segments and soft segments was observed by FTIR for fluorinated poly(ether urethane), which is believed to result in the enhanced phase mixing, and the enhanced association of domains with long-range order (hydrogen bonding) between hard segments was evident for fluorinated poly(carbonate urethane)s, which may correspond to the enhanced phase separation. The result is new and provides direct connection between surface topography and bulk phase separation of polyurethanes.     

Diffusion and sorption of benzene vapor through polybutadiene‐, polybutadiene/styrene‐, and polybutadiene/acrylonitrile‐based polyurethanes

A series of polyurethane (PU) films made from toluene diisocyanate (TDI), 1,4‐butanediol (BDO), and hydroxyl‐terminated polybutadiene (HTPB), hydroxyl terminated polybutadiene/styrene (HTBS), or hydroxyl terminated polybutadiene/acrylonitrile (HTBN) was synthesized by solution polymerization. The absorption of benzene vapor was found mainly in the soft phase. The equilibrium adsorption (M_∞) was reduced with increasing hard segment content for all the PUs. The values of M_∞ were in the sequence of HTBN‐PUs > HTBS‐PUs > HTPB‐PUs, which could be explained by the different interaction parameters between soft segments and benzene. The HTBN‐PU film showed the lowest degree of phase segregation and had more hard segments intermixed in the soft phase, restricting the movement of soft segments, and therefore resulted to non‐Fickian behavior, while the HTPB‐PU is antithetical. FTIR and atomic force microscopy were utilized to identify the hydrogen bonding behavior and morphology change of the PU films before and after the absorption of benzene vapor. The tensile strength of the HTBN‐PUs showed a greater decrease than that of HTBS‐PUs and HTPB‐PUs after absorbing benzene vapor. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 2984–2991, 2004     

超分子聚氨酯的合成及应用研究进展

综述了超分子聚氨酯的合成方法,利用氢键相互作用、电子供体-受体相互作用、离子相互作用等分子间非共价键的键合作用而制得超分子聚氨酯,并介绍了超分子聚氨酯主要在液晶材料、涂层材料、形状记忆材料的应用。     

Phase behavior and hydrogen bonding in biomembrane mimicing polyurethanes with long side chain fluorinated alkyl phosphatidylcholine polar head groups attached to hard block

To achieve a good biocompatibility, two sets of novel segmented polyurethanes, namely, poly(ether urethane)s and poly(carbonate urethane)s, with long side chain fluorinated alkyl phosphatidylcholine polar head groups attached to hard block have been synthesized recently in our laboratory by using a new diol with a long side chain fluorinated alkyl phosphatidylcholine polar head group 2-[2-[2,2,3,3,4,4,5,5,6,6,7,7,8,8,9,9-hexadecafluoro-10-ethoxy-decyloxy]-N-(2-hydroxy-1-hydroxymethyl-1-methyl-ethyl)-acetamide] phosphatidylcholine, HFDAPC as an extender. These novel polyurethanes have shown a potential to be used as bio-membrane mimicry. In this article we investigated the phase behavior of these materials by Instron, DSC, DMA, and AFM because the phase behavior has a great effect on the surface properties thus the biological-related perspective. T_g decreases first then increases for the poly(carbonate urethane)s, but increases first then decreases for the poly(ether urethane)s with an increasing in fluorinate phosphatidylcholine content. On the other hand, the tensile modulus was found decrease for the poly(carbonate urethane)s but increase for the poly(ether urethane)s with an increasing in fluorinate phosphatidylcholine content. It was found via AFM that the phase separation increases in poly(ether urethane)s but phase mixing increases in poly(carbonate urethane)s, with increasing content of fluorinated phosphatidylcholine side chain. The interaction between hard and soft segment, particularly, the hydrogen bonding was investigated by FTIR. The effect of fluorinated phosphatidylcholine side group on the phase separation of polyurethane was discussed and compared with that of fluorinated polyurethanes containing only fluorinated side chains. Our result demonstrated how the phase behavior of polyurethanes could be controlled by tailoring the interaction between hard and soft segment.     

Properties of crosslinked polyurethanes synthesized from 4,4′‐diphenylmethane diisocyanate and polyester polyol

Polyurethanes were synthesized using the high functional 4,4′‐diphenylmethane diisocyanate (MDI), polyester polyol, and 1,4‐butane diol. The synthesized polyurethanes were analyzed using differential scanning calorimeter (DSC), dynamic mechanical thermal analysis (DMTA), Fourier transform infrared (FTIR) spectrometer, and swelling measurement using N,N′‐dimethylformamide. From the result of thermal analysis by DSC and DMTA, single T_gs were observed in the polyurethane samples at all the formulated compositions. From this result, it is suggested that the polyurethanes synthesized in this study have crosslinked structure rather than the phase‐separated segmented structure because of the high functionality (f = 2.9) of the MDI. By annealing the polyurethane samples using DSC, the T_gs were increased by 4.7∼16.0°C at the various annealing temperatures. From the results of FTIR and swelling measurement of polyurethanes, it is suggested that the increase of T_g of the polyurethanes by annealing is not due to increase of the hydrogen bond strength but mainly due to the increase of the crosslink density. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 624–630, 2000     

Lithium sulfonate promoted compatibilization in single ion conducting solid polymer electrolytes based on lithium salt of sulfonated polysulfone and polyether epoxy

Polymeric lithium salts of sulfonated polysulfone (SPSU(X)Li) were synthesized via post sulfonation route followed by ion exchange. A novel single ion conducting solid polymer electrolyte (SPE) was prepared by curing poly(ethylene glycol)diglycidyl ether (PEGDGE) with 4,4′ diaminodiphenyl sulfone (DDS) in SPSU(X)Li matrix. The ionic conductivity, thermal stability and tensile properties were investigated as a function of degree of sulfonation and PEGDGE concentration. The introduction of lithium sulfonate groups in polysulfone promoted compatibility of SPSU(X)Li and PEGDGE in SPE. AFM analysis demonstrated heterogeneous phase morphology and reduction in size of dispersed PEGDGE phase with increasing degree of sulfonation. The interactions between lithium sulfonate and polyether epoxy improved thermal stability of the epoxy network. The enhanced compatibility also caused improvement in elongation at break compared to neat SPSU(X)Li. The higher Li⁺ ion concentration and the segmental mobility of the polymer chains above T_g contributed to the high ionic conductivity at high temperature in the single ion conducting SPE.     

The effect of different palm oil‐based bio‐polyols on foaming process and selected properties of porous polyurethanes

Rigid polyurethane foams were successfully prepared by blending up to 70 wt% of two different palm oil‐based bio‐polyols with a petrochemical polyether polyol. The bio‐polyols were synthesized by epoxidation–oxirane ring‐opening process using water (PP102) and diethylene glycol (PP147), respectively. Due to the high viscosity of both bio‐polyols the reactive mixture was heated to start the foaming reaction at about 50 °C. Under these conditions, the gelling reactions speed up as the amount of PP147 increases but slow down to a great extent when PP102 is used. The thermal conductivity of modified foams is higher and the closed cell content lower compared to reference ones, even when the bio‐foams present a lower apparent density. However, all foams exhibit reduced water absorption, excellent dimensional stability and better thermal stability at temperatures up to 400 °C than the control foam. Conversely, their mechanical and dynamic mechanical properties become poorer as the PP147 concentration increases and even more so if PP102 is used instead. PP147 foams containing up to 50% bio‐polyol could be used as a green replacement of petroleum‐based ones in applications where excellent behaviour in compression (the most affected properties) is not fundamental, with the additional advantages of reduced density and increased content of bio‐derived components. © 2017 Society of Chemical Industry     

咪唑类离子液体高效吸收二氯甲烷

合成了一系列常规离子液体1-丁基-3-甲基咪唑四氟硼酸盐([Bmim][BF4])、1-丁基-3-甲基咪唑六氟磷酸盐([Bmim][PF6])、1-丁基-3-甲基咪唑双三氟甲磺酰亚胺盐([Bmim][NTf2])、1-丁基-3-甲基咪唑双氰胺盐([Bmim][DCA])、1-丁基-3-甲基咪唑硫氰酸盐([Bmim][SCN])、1-乙基-3-甲基咪唑硫氰酸盐([Emim][SCN])和N-丁基吡啶硫氰酸盐([BPy][SCN]),用智能重量分析仪(IGA)测定不同温度和分压下离子液体吸收二氯甲烷(DCM)的容量。结果表明,[Bmim][SCN]具有最高的二氯甲烷吸收容量(1.46 g/g, 303.15 K, 60 kPa),5次循环后吸收能力无明显下降,[Bmim][SCN]基本可完全再生,能循环使用。量化计算结果表明[SCN]?可与二氯甲烷形成氢键,增强其对二氯甲烷的吸收能力。     

Temperature dependent microphase mixing of model polyurethanes with different intersegment compatibilities

In this paper we explore the temperature dependence of segregation of hard and soft segments of selected segmented polyurethane copolymers using synchrotron small-angle X-ray scattering (SAXS). The copolymers are composed of the same hard segments but three different soft segment chemistries, of particular interest in biomedical device applications. Hard segments are formed from 4,4′-methylenediphenyl diisocyanate and 1,4-butanediol, and soft segments from an aliphatic polycarbonate [poly(1,6-hexyl 1,2-ethyl carbonate)], poly(tetramethylenoxide), or a mixed soft segment synthesized from hydroxyl-terminated poly(dimethylsiloxane) [PDMS] and poly(hexamethylenoxide) macrodiols. The changes in SAXS relative invariants and interdomain spacings are indicative of gradual dissolution of phase separated hard and soft segments with increasing temperature. All copolymers investigated herein, even those containing PDMS soft segments, transform to the single-phase state at a temperature determined by the soft segment chemistry (and hard segment content). The SAXS findings, along with those from parallel temperature-controlled Fourier Transform infrared spectroscopy measurements, also facilitate assignment of the origin of the thermal events observed in the DSC thermograms of these materials.     

水性聚氨酯改性研究新进展

由于水性聚氨酯的广泛使用,对于水性聚氨酯的改性研究也越来越多。从改性的次数方面对水性聚氨酯改性进行了综合评述,并介绍了一些新型的改性原料。     

Effect of hydrogen donors on polymer degradation

The thermal decomposition of hydrocarbon macromolecules, including polymers in solution, is influenced by the presence of hydrogen donors. Depending on the particular polymer, hydrogen donors may increase, decrease, or have no effect on degradation rate. We investigated the concentration effect of the hydrogen- (H-)donor, 6-hydroxy tetralin, on degradation of polystyrene (2 g/l) dissolved in mineral oil at 275°C. The time evolution of the molecular weight distribution (MWD) was determined by gel permeation chromatography of samples from the batch reactor. The data indicated that the H-donor decreases the polystyrene degradation rate. This is in contrast to the H-donor (tetralin) enhancement of degradation for poly(styrene–allyl alcohol) dissolved in a 1-butanol solution at 150°C. Because the reaction mechanism for polymer degradation involves radicals, we have developed continuous-distribution mass balances for polymers and radicals in the elementary reactions by treating molecular weight as a continuous variable. Based on reactions for initiation–termination, propagation–depropagation and H-abstraction, the model describes the various H-donor effects through relative values of rate coefficients.     

聚醚多元醇新型催化剂的技术经济分析

概述了聚醚多元醇新型催化剂的研制背景 ,描述了新技术的创新点及优势 ,对年产 5 0t新型催化剂装置进行了经济分析