聚氨酯/聚苯胺抗静电涂料的制备与性能研究

先以IPDI和聚醚二元醇为原料合成聚氨酯，然后加入通过氧化还原引发聚合制备得到的聚苯胺，获得了聚氨酯／聚苯胺抗静电复合材料，研究了聚苯胺含量对共聚物材料抗静电性能和力学性能及热学性能的影响。并用红外谱图、扫描电镜、TGA和DSC对此材料进行了表征。研究表明经聚苯胺改性的聚氨酯材料的热稳定性及力学性能均有所提高，该聚氨酯-聚苯胺复合材料作为抗静电涂料完全可以满足要求。     

Polyaniline/polyurethane networks. II. A spectroscopic study

The interconnection of polyaniline (Pani) chains through polyurethane (PU) blocks of the same length but with different spacing has originated a series of new semi conducting networks of varying crosslinking density, with good mechanical properties. FTIR, UV-Vis-NIR, XPS and EPR were used to probe the molecular features of the conducting species, and to test the morphological model proposed in a previous publication, where a continuous Pani phase percolates a PU matrix, linked together by a mixed interphase. Blends with the same composition of the networks and a model structure of crosslinked Pani were also prepared for comparison purposes. The proposed morphological model was confirmed by the new findings obtained by the spectroscopic techniques. The differences between the blends and networks of the same composition were discussed in terms of the morphology presented by each of these systems.     

Dynamic mechanical properties of sandwich‐structured epoxy beam composites containing poly(ethyleneterephthalate)/poly(ethyleneglycol) copolymer with shape memory effect

To make smart vibration‐controlling composite laminate, a few poly(ethylene terephthalate) (PET) and poly(ethylene glycol) (PEG) copolymers with shape memory ability were prepared. After selecting the best composition of PET–PEG copolymer in mechanical properties, a crosslinking agent such as glycerine, sorbitol, or maleic anhydride (MA) was included for crosslinked copolymer, followed by analysis of its effect on mechanical, shape memory, and damping properties. The highest shape recovery was observed for copolymer with 2.5 mol % of glycerine, and the best damping effect indicating vibration control ability was from copolymer with 2.5 mol % of sorbitol. With the optimum copolymers in hand, sandwich‐structured epoxy beam composites fabricated from an epoxy beam laminate and crosslinked PET–PEG copolymer showed that impact strength increased from 1.9 to 3.7 times depending on the type of copolymer, and damping effect also increased as much as 23 times for the best case compared to epoxy laminate beam alone. The resultant sandwich‐structured epoxy beam composite can be utilized as structural composite material with vibration control ability, and its glass transition temperature can be controlled by adjustment of PET, PEG, or crosslinking agent composition. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3141–3149, 2003     

Electrochemical synthesis of poly(2‐iodoaniline) and poly(aniline‐co‐2‐iodoaniline) in acetonitrile

Poly(2‐iodoaniline) (PIANI) and poly(aniline‐co‐2‐iodoaniline) [P(An‐co‐2‐IAn)] were synthesized by electrochemical methods in acetonitrile solution containing tetrabutylammonium perchlorate (TBAP) and perchloric acid (HClO₄). The voltametry of the copolymer shows characteristics similar to those of conventional polyaniline (PANI), and it exhibits higher dry electrical conductivity than PIANI and lower than PANI. The observed decrease in the conductivity of the copolymer relative to PANI is attributed to the incorporation of the iodine moieties into the PANI chain. The structure and properties of these conducting films were characterized by FTIR and UV‐Vis spectroscopy and by an electrochemical method (cyclic voltametry). Conductivity values, FTIR and UV‐Vis spectra of the PIANI and copolymer were compared with those of PANI and the relative solubility of the PIANI and the copolymer powders was determined in various organic solvents. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1652–1658, 2003     

Mechanical characterization and modeling stress relaxation behavior of acrylic–polyurethane-based graft-interpenetrating polymer networks

The stress relaxation behavior of acrylic–polyurethane (PU)-based graft-interpenetrating polymer networks (IPNs) was characterized via dynamic mechanical analysis (DMA) and modeled using finite element method (FEM) analysis. Stress relaxation of glassy IPN specimens was experimentally studied under flexural testing, while rubbery IPN specimens were tested in tension. The effects of varying the styrene content in the acrylic copolymer phase, compatibility of the two phases in IPNs, and changing the concentration of acrylic copolymer and PU were studied. A higher percentage of styrene content resulted in higher homogeneity of IPN specimens, and decrease in initial modulus for acrylic copolymer specimens. Additionally, glassy IPN specimens with 90% styrene shows resistance to relaxation as high as acrylic copolymer samples. Experimental results were used to develop a numerical model to study stress relaxation response of specimens. While polymer systems have been studied computationally, numerical modeling of IPN systems is still in its infancy. A three-dimensional FEM model was developed using the Generalized Maxwell model and four-term Prony series constants, which were extracted from the stress relaxation experiments. With four terms in the Prony series, a good match was observed between experimental observations and results from the FEM model.     

New conductive thermoplastic elastomers. Part II. Physical and chemical‐physical characterization

To overcome the problems relevant to the low processbility and scarce mechanical properties of polyaniline, in a previous work we have proposed the synthesis of elastomeric conducting copolymers prepared by grafting polyaniline (EB) or sulfonated polyaniline (SPAN) chains to the backbone of a carboxylated segmented polyurethane (PEUA). In the present work the physical and chemical‐physical properties of the copolymers are investigated. As evidenced by thermal (DSC) and dynamo‐mechanical (DMTA) characterization, the introduction of EB or SPAN in the matrix enhances the hard‐soft phase segregation effect, because of the strong tendency of the conductive polymer chains to aggregate. Moreover, the EB and SPAN chains, grafted to the polyurethane backbone, acting as reinforcing filler, give rise, compared with the mechanical properties of the insulating matrix, to an increase of the Young modulus and a decrease of the tensile set. When the copolymers are HCl doped their electrical conductivity increases many orders of magnitude, reaching values of about 10^?3 Ω^?1 cm^?1. The conductivity, measured along the deformation direction, may be further increased by stretching the copolymer films. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 1259–1264, 2002     

Flame-retarding materials. II. Synthesis and flame-retarding properties of phosphorus-on-pendent and phosphorus-on-skeleton polyols and the corresponding polyurethanes

A phosphorus-on-skeleton compound was synthesized by reacting phenyl dichlorophosphate (PDCP) with 2-hydroxyethyl methacrylate (HEMA). This monomer was then copolymerized with other acrylic monomers to form a hydroxy-containing copolymer, which was then used as the polyol in the synthesis of a polyurethane. Phosphorus-on-pendent copolymers and phosphorus-free copolymers and their corresponding polyurethanes were also prepared for comparison with the phosphorus-on-skeleton material in terms of their flame-retardant properties. The flame retardancy and degradation mechanism of these copolymers and polyurethanes were analyzed with thermogravimetric analysis (TGA) and infrared spectroscopy. Although those phosphorus-on-skeleton copolymer polyols have less flame-retarding ability than that of the phosphorus-on-pendent copolymer polyol because of less phosphorus content, it was evident that the phosphorus-on-skeleton polyurethanes were more effective flame retardants than the phosphorus-on-pendent polyurethanes. This was attributed to the fact that the crosslinking arising from the phosphorus-on-skeleton copolymer polyols has a tremendous effect on the flame-retarding ability of the corresponding polyurethanes. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 343–357, 2001     

Conductive IPN based on polyaniline and silicon‐crosslinked styrene‐isoprene‐styrene triblock copolymer

A series of new conducting interpenetrating polymer networks (IPNs) are prepared by sequential crosslinking reactions of tetraethyl orthosilicate with silicon‐grafted functional styrene‐isoprene‐styrene triblock copolymer (SIS) and polyaniline (PANI) doped with dodecylbenzenesulfonic acid (DBSA). The various factors affecting the properties of conductive IPNs are investigated. The conductivity is found to increase only slightly after the IPN films are treated at 140 ° C . The thermal stability of the IPNs is much better than that of the pure polymer under nitrogen atmosphere, as shown by the results from thermal gravimetry analysis (TGA). © 1999 Society of Chemical Industry     

Conductive hybrid film from polyaniline and polyurethane-silica

In order to improve the mechanical performance and water resistance of water-borne conducting polyaniline film, conducting polyaniline/polyurethane-silica hybrid film was prepared in aqueous solution employing silanol-terminated polyurethane and methyltriethoxysilane as sol-gel precursors. The hybrid film showed surface resistivity of 10⁸ Ω even though the conducting polyaniline loading was only 10 wt% (or 1.5 wt% of polyaniline), and the mechanical performance as well as water resistance was significantly improved, making it suitable for antistatic application. Therefore, a practical route to water-borne processing of conducting polyaniline is disclosed.     

Stress–relaxation properties of segmented polyurethane rubbers

Stress–relaxation behavior of polyurethane elastomers based on two hydroxyl-terminated polyesters: poly(ethylene adipate) and poly(ethylene maleate) was studied. In addition, a polyester-diol consisting of poly(ethylene adipate) and oligo(ethylene terephthalate) blocks, a number of low-molecular-weight diols as chain extenders, and 4,4′-diphenylmethane diisocyanate (MDI) were determined. The elastomers were crosslinked by an excess of MDI and had stiff segments of differing chemical structure and length. Stress–relaxation properties of the elastomers conformed with the three-component Maxwell model, with negligibly small contribution from the fastest relaxation process. The influence of crosslinking density, chemical structure, and stiff segment content on the relative relaxation speed and the parameters of the slow and fast relaxation processes, was examined. The elucidation of the results was based on the morphological models of segmented polyurethanes.     

Characterization of electron beam crosslinked poly(styrene-block-ethylene-co-butylene-block-styrene)

A saturated triblock copolymer, poly(styrene-block-ethylene-co-butylene-block-styrene) was chemically crosslinked using trimethylol propane trimethacrylate, TMPTM, and subjected to electron beam radiation. The gel percent, Gehman ten second modulus, and stress relaxation were measured to characterize the materials as a function of crosslinker concentration and radiation level. A time-temperature super-position master curve was generated at 63°C for 3 percent TMPTM and 5 Mrads of radiation, which indicated rubbery plateau behavior at long times of measurement, as opposed to the uncrosslinked material, which continued to creep and flow. The main locus of crosslinking was within the polystyrene phase, which explains reduced creep and stress relaxation only for long times of measurement and/or high temperatures. Based on shifts of the glass transition temperatures, it was estimated that 11 to 16 percent poly(ethylene-co-butylene) was dissolved in the polystyrene phase.     

A soluble self-doped conducting polyaniline graft copolymer as a hole injection layer in polymer light-emitting diodes

We demonstrate that a novel soluble self-doped conducting polyaniline graft copolymer can be used for a hole injection layer (HIL) in polymer light-emitting diodes (PLEDs). The work function of the material (5.18 eV) was similar to that (5.20 eV) of a conventional conducting polymer dispersion, poly(3,4-ethylenedioxythiophene) (PEDOT) doped with polystyrene sulfonate (PSS). When we fabricated PLEDs by using this material, the current-voltage-luminescence characteristics were very similar to those of the device using the PEDOT/PSS. When the material was blended with PSS, the luminous efficiency was further improved up to 11.9 cd/A. Since this kind of soluble type HIL has advantages over the conventional PEDOT/PSS dispersion in terms of the solution processibility and film quality, this soluble graft-type conducting polymer can be one of the promising candidates for a HIL in PLEDs.     

Structure and relaxation properties of medical‐purposed polyacrylamide gels

By IR and NMR spectroscopy methods, thermomechanical analysis, mechanical relaxation measurements, and computational simulation the effect of production conditions of acrylamide copolymer and N,N′‐methylenebisacrylamide derived hydrogels with respect to their properties were studied. Four hydrogel samples, prepared under different production conditions (γ‐radiation dose and autoclaving), were investigated. It was found that autoclaving and γ‐radiation lead to a slight increase of the crosslinking degree in the polymeric network and formation of alkene structures in polymeric chains. Stress relaxation and creep processes under axial compression of gel cylindrical samples were studied in detail. To approximate stress relaxation and creep curves new memory functions were used, based on the analysis of entropy production in the system during the relaxation process. It was found that primary γ‐radiation of initial gels induces an increase of quasi‐equilibrium rubbery elasticity modulus, and quasi‐equilibrium compliance is decreased. The opposite situation is observed during further autoclaving at 120°C. After autoclaving, required to sterilize the gels, their treatment by γ‐radiation again induced a noticeable increase of the modulus and compliance decrease. The mechanism of relaxation processes was found to be associated with the limiting stage of physical interaction between relaxants, representing different micro‐inhomogeneities in the material. The investigation results were compared with the data obtained by histology and morphology methods. A hydrogel obtained under additional γ‐radiation treatment and autoclaving did not swell when implanted into a living organism, and the tissue reaction to implantation of such gel was minimal. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 1043–1058, 2005     

Thermal and Mechanical Properties of Polyurethanes Derived from Mono- and Disaccharides

Thermal and mechanical properties of polyurethane (PU) sheets pre-pared from the glucose/fructose/sucrose–polyethylene glycol (PEG)–diphenylmethane diisocyanate (MDI) system were examined by differential scanning calorimetry, thermogravimetry, dynamic mechanical analysis and tensile tests. The saccharide content was varied at a constant NCO: OH ratio of 1·0. The glass transition temperature (T_g) increased with increasing saccharide content. The incorporation of saccharides into the PU structure results in a higher crosslinking density and a higher content of hard segments. The thermal decomposition was dependent on the saccharide content, an increase leading to a lower thermal decomposition temperature (T_d). The dissociation of saccharide OH groups and NCO groups is a major part of the thermal decomposition of these PUs. Dynamic mechanical analysis revealed two kinds of relaxation: the high temperature relaxation corresponds to main chain motion and the other is a local mode relaxation due to non-reacted isocyanate groups. The tensile stress and Young’s modulus increased with the saccharide content. © of SCI.     

Study on polyethylene glycol/polydimethylsiloxane mixing soft‐segment waterborne polyurethane from different mixing processes

The surface structure and physical properties of polyethylene glycol series polyurethane (PEG‐PU) membranes, in which were introduced hydrophobic polydimethylsiloxane (PDMS) component by the procedure of PU blending or of soft‐segment copolymerization, were studied in this investigation. In the case of the blending process, the synthesized waterborne polyurethanes (WBPUs) of PEG–PU and of polydimethylsiloxane series polyurethane (PDMS–PU) were combined, whereas in the copolymerization process PEG and PDMS were taken as mixed soft segments to polymerize the WBPU. For the blending method, glass‐transition and melting temperatures increased rapidly when a small amount of PDMS–PU was added to PEG–PU and reached a maximum with 5% PDMS–PU mixed in. However, in the case of the copolymer method, thermal properties closely followed predicted values. From dynamic mechanical analysis studies it was found that a low PDMS–PU content ratio could increase the rubbery elasticity of PEG–PU membrane and improve its strength simultaneously in the blending method, and the copolymer method only caused PU to gain some natural complementary strength and elasticity. Electron spectroscopy for chemical analysis studies indicated that PDMS migrated to the surface much more easily in the blending method than in the copolymer method. The SEM studies also found that, in the blending method, the numbers of pores were less than those in the copolymer method. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 233–243, 2003     

高光泽耐高温硅丙树脂改性聚氨酯涂料的研究

用有机硅－ 丙烯酸酯共聚树脂对聚氨酯进行改性，以ＨＤＩ／ＴＤＩ预聚物（ＨＴＰ） 作为交联组分，可制备性能优异的高光泽耐高温硅丙聚氨酯涂料。简述了这种涂料的制备方法和影响其性能的因素     

Effects of temperature,strain rate,and cyclic loading on mechanical behavior of silane-modified polyurethane sealant

To evaluate the mechanical properties of modified polyurethane sealants in engineering applications, the influences of temperature, strain rate, and cyclic loading on the mechanical properties of silane-modified polyurethane sealant were experimentally investigated. The monotonic tensile experiments with various strain rates and temperatures were conducted, and strain rate and temperature dependent nonlinear stress–strain curves were obtained. The results showed that the silane-modified polyurethane sealant exhibited temperature dependence at constant strain rate and rate dependence at room temperature. However, it is shown no obvious rate dependence at temperature of 150°C. In addition, the multi-step cyclic loading experiments with mean strain decrease and increase at each step were carried out to analyze the influence of cyclic loading and cyclic loading history at different temperatures. The results demonstrated that the viscous behavior of the materials was evidently observed in the first step and disappeared in other steps for the four-step cyclic loading with mean strain decrease case. Moreover, the cyclic stress relaxation of the materials was not obvious due to the prior cyclic loading with higher mean strain history, while the cyclic stress relaxation of the material continued to occur for the prior cyclic loading with lower mean strain history, and the cyclic strength of the materials decreased with the increase of temperature.     

Investigation of the viscoelastic and transport properties of interfacially polymerized barrier layers using pendant drop mechanical analysis

Pendant drop mechanical analysis (PDMA) enables the mechanical and transport characterization of unsupported interfacially polymerized (IP) thin films. PDMA was used to study the viscoelastic and permeation behavior of films formed by the interfacial polymerization of m‐phenylenediamine (MPD) and trimesoyl chloride (TMC). The viscoelastic properties were obtained by stress‐relaxation experiments wherein IP films on the surface of aqueous MPD drops were deformed and the decrease in the internal pressure resulting from stress relaxation was monitored with time. The stress‐relaxation behavior was interpreted using the fractional exponential relaxation model. The two model parameters, τ and β, are related to the degrees of crosslinking and branching, respectively. Water transport was generated by an osmotic gradient across the IP films, and permeation data were obtained by monitoring the increase in the drop size with time. Whereas the network structure was relatively insensitive to MPD concentration, the TMC concentration had a significant effect on the degrees of crosslinking and branching; τ evidenced a maximum at 0.1 wt % TMC concentration and β decreased monotonically with TMC concentration. The effect of organic‐phase reactant functionality was studied by incorporating isophthaloyl chloride (difunctional) with TMC. For TMC fractions > 25 wt %, the network structure was relatively insensitive to TMC fraction in the isophthaloyl chloride–TMC mixture. The transport experiments enabled the determination of a membrane constant A. The transport results generally corroborated the trends observed in the stress‐relaxation experiments, thus demonstrating the close association between the network structure and transport behavior. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 558–568, 2004     

Electrochemical synthesis and characterisation of polyaniline/poly(2-methoxyaniline-5-sulfonic acid) composites

The potentiodynamic synthesis and subsequent characterisation of a polyaniline (PAn) grown in the presence of a water-soluble conducting polymer, poly(2-methoxyaniline-5-sulfonic acid) (PMAS) is described. The novel polymer is obtained as a water-insoluble film consisting of a PAn backbone with PMAS integrated as the molecular dopant. The electrodeposition of the polyaniline material is enhanced by the presence of the electrically conducting PMAS polyelectrolyte dopant, which functions as a molecular template providing supramolecular pre-ordering as well as simultaneously facilitating charge transport during electrodeposition.     

Fabrication and properties of solution processed all polymer thin‐film ferroelectric device

A ferroelectric device, making use of a flexible plastic, polyethylenterephtalate (PET), as a substrate was fabricated by all solution processes. PET was globally coated by a conducting polymer, poly(3,4‐ethylenedioxythiophene) poly(styrenesulfonate) acid (PEDOT/PSSH), which is used as bottom electrode. The ferroelectric copolymer, poly(vinylidenefluoride–trifluoroethylene) (PVDF–TrFE), thin film was deposited by spin‐coating process from solution. The top electrode, polyaniline, was coated by solution process as well. The ferroelectric properties were measured on this all solution processed all polymer ferroelectric thin‐film devices. A square and symmetric hysteresis loop was observed with high‐polarization level at 15‐V drive voltage on a all polymer device with 700 Å (PVDF–TrFE) film. The relatively inexpensive conducting polyaniline electrode is functional well and therefore is a good candidate as electrode material for ferroelectric polymer thin‐film device. The remnant polarization P_r was 8.5 μC/cm² before the fatigue. The ferroelectric degradation starts after 1 × 10³ times of switching and decreases to 4.9 μC/cm² after 1 × 10⁵ times of switching. The pulse polarization test shows switching take places as fast as a few micro seconds to reach 90% of the saturated polarization. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011