Synthesis and properties of polyurethane modified with an aminoethylaminopropyl‐substituted polydimethylsiloxane. II. Waterborne polyurethanes

A series of polyurethane (PU) emulsions modified with aminosilicone were synthesized, based on 2,4‐toluene diisocyanate (TDI), poly(tetramethylene oxide) (PTMO), and dimethylolpropionic acid (DMPA) as a prepolymer which was chain‐extended with aminoethylaminopropyl polydimethylsiloxane (AEAPS) in an aqueous emulsion. Their chemical compositions, structures, bulk and surface properties, and emulsion morphologies were investigated using Fourier transform infrared spectrum analysis (FTIR), tensile and surface contact angle measurements, electron spectroscopy for chemical analysis (ESCA), water swellablity, an emulsion stability test, and transmission electron microscopy (TEM). It was shown that the PU emulsions were stable and the siloxane chains were enriched on the PU surface. The water resistance of the PU film increased but the bulk tensile properties of the PU film were not changed significantly with a small amount siloxane modification up to 6 wt %. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 79: 295–301, 2001     

Mechanical and surface properties of polysulfide‐based polyurea modified with aminoethylaminopropyl poly(dimethylsiloxane)

A series of polysulfide‐based polyureas with different siloxane contents were synthesized, and they were based on isophorone diisocyanate, liquid polysulfide oligomer, aminoethylaminopropyl poly(dimethyl siloxane) (AEAPS), and 2,5‐diamino‐3,6‐dimethylmercapto‐toluene. The mechanical and surface properties were investigated with attenuated total reflectance Fourier transform infrared spectroscopy, surface contact angles, electron spectroscopy for chemical analysis, and stress–strain analysis. Siloxane was enriched on the surfaces of these elastomers, and the tensile properties of the elastomers did not change markedly with the AEAPS modification. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 584–588, 2003     

Synthesis and properties of self‐crosslinkable polyurethane–urea with silsesquioxane formation

Based on the typical two‐step polyurethane–urea synthesis, a new series of self‐crosslinkable polyurethane (PU)–urea formulations, consisting of poly(tetramethylene oxide) and 4,4′‐diphenyl methane diisocyanate, and extended by ethylenediamine (EDA)/aminoethylaminopropyltrimethyoxysilane (AEAPS), were prepared. FTIR, ESCA, WAXD, DSC, and mechanical properties of samples were recorded. The results show that the self‐crosslinkable polyurethane–urea could be crosslinked by hydrolysis of the trimethyloxysiloxane group to form the silsesquioxane structure. These structures represent a kind of nanosize, cagelike, chemical crosslink site as well as filler, which affect the properties of PU. The morphology, varied with different ratios of EDA/AEAPS, was also discussed. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 190–195, 2004     

Morphology and surface properties of some siloxane–organic copolymers

BACKGROUND: It is well known that, due to their extremely low polarity, polysiloxanes are incompatible with almost any organic system. This incompatibility leads to phase separation in mixed siloxane–organic systems. RESULTS: Three siloxane–organic copolymers, poly[(5,5′‐methylene‐bis‐salicylaldehyde)‐imine‐(1,3‐bis(propylene)tetramethyldisiloxane)] (Paz1), poly[(2,5‐dihydroxy‐1,4‐benzoquinone)‐imine‐(1,3‐bis(propylene)tetramethyldisiloxane)] (Paz2) and poly[1,3‐bis(propylene)tetramethyldisiloxane diamide] (Pam), were prepared by the reaction of 1,3‐bis(3‐aminopropyl)tetramethyldisiloxane with appropriate organic partners (5,5′‐methylene‐bis‐salicylaldehyde, 2,5‐dihydroxy‐1,4‐benzoquinone and oxalyl chloride, respectively). The morphologies dictated by the incompatibility between siloxane and polar organic moieties were investigated using differential scanning calorimetry and scanning electron microscopy. The surface activity of the copolymers and water vapour sorption capacity were also measured. CONCLUSION: Even though the polar sequences are very short ones, the highly flexible siloxane‐containing sequence permits the self‐assembly of these into more or less polar domains. Such an organization influences the properties of the resulting materials, an important place being occupied by the surface properties. Copyright © 2009 Society of Chemical Industry     

Mixed macrodiol‐based siloxane polyurethanes: Effect of the comacrodiol structure on properties and morphology

Two series of polyurethanes were prepared to investigate the effect of comacrodiol structure on properties and morphology of polyurethanes based on the siloxane macrodiol, α,ω‐bis(6‐hydroxyethoxypropyl) polydimethylsiloxane (PDMS). All polyurethanes contained a 40 wt % hard segment derived from 4,4′‐methylenediphenyl diisocyanate (MDI) and 1,4‐butanediol (BDO), and were prepared by a two‐step, uncatalyzed bulk polymerization. The soft segments were based on an 80/20 mixture of PDMS (MW 967) and a comacrodiol (MW 700), selected from a series of polyethers and polycarbonates. The polyether series included poly(ethylene oxide) (PEO), poly(propylene oxide) (PPO), poly(tetramethylene oxide) (PTMO), poly(hexamethylene oxide), and poly(decamethylene oxide) (PDMO), whereas the polycarbonate series included poly (hexamethylene carbonate) diol (PHCD), poly [bis(4‐hydroxybutyl)‐tetramethyldisiloxy carbonate] diol (PSCD), and poly [hexamethylene‐co‐bis(4‐hydroxybutyl)‐tetramethyldisiloxy carbonate] diol (COPD). Polyurethanes were characterized by size exclusion chromatography, tensile testing, differential scanning calorimetry (DSC), and dynamic mechanical thermal analysis (DMTA). The results clearly demonstrated that the structure of the comacrodiol influenced the properties and morphology of siloxane‐based polyurethanes. All comacrodiols, except PEO, improved the UTS of the polyurethane; PHMO and PTMO were the best polyether comacrodiols, while PSCD was the best polycarbonate comacrodiol. Incorporation of the comacrodiol made polyurethanes more elastomeric with low modulus, but the effect was less significant with polycarbonate comacrodiols. DSC and DMTA results strongly supported that the major morphological change associated with incorporation of a comacrodiol was the significant increase in the interfacial regions, largely through the compatibilization with the hard segment. The extent of compatibilization varied with the comacrodiol structure; hydrophilic polyethers such as PEO were the most compatible, and consequently, had poor mechanical strength. Among the polyethers, PHMO was the best, having an appropriate level of compatibility with the hard segment for substantial improvement in mechanical properties. Siloxy carbonate comacrodiol PSCD was the best among the polycarbonates. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 1071–1082, 2000     

聚硅氧烷聚氨酯的合成与性能

氨基硅油、甲苯二异氰酸酯与相对分子质量为1000和2000左右的聚氧化丙烯二醇在无溶剂条件下制备了相应的两类氨基硅油改性聚氨酯。测试结果表明,采用无环境污染的该法制备的改性聚氨酯与文献报道的溶剂法制备的改性聚氨酯具有类似的改性效果,改性后的聚氨酯兼有有机硅和聚氨酯的特性。w(氨基硅油)=3%～15%时,有较明显的改性效果,且在w(氨基硅油)=10%时,两类改性聚氨酯都具有最佳综合性能,其伸长率较未改性的分别提高28 05%,52 38%,其表面水接触角分别提高了23°,25°,耐热性也有较大提高。     

Synthesis and characterization of poly(dimethyl siloxane) containing poly(vinyl pyrrolidinone) block copolymers

ABA‐type block copolymers containing segments of poly(dimethyl siloxane) and poly(vinyl pyrrolidinone) were synthesized. Dihydroxyl‐terminated poly(dimethyl siloxane) was reacted with isophorone diisocyanate and then with t‐butyl hydroperoxide to obtain macroinitiators having siloxane units. The peroxidic diradical macroinitiators were used to polymerize vinyl pyrrolidinone monomer to synthesize ABA‐type block copolymers. By use of physicochemical methods, the structure was confirmed, and its characterization was accomplished. Mechanical and thermal characterizations of copolymers were made by stress–strain tests and differential scanning calorimetric measurements. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 1915–1922, 1999     

Synthesis and characterization of polyamideimide‐branched siloxane and its gas‐separation

Polyamideimide‐branched siloxanes (PAIBrSs) were synthesized from 4, 4′‐(hexafluoroisopropyllidene)diphthalic anhydride (6FDA), p,p′‐oxydianiline (ODA), and aminopropyl‐terminated oligomeric dimethylsiloxane (ODMS). In this investigation, a mixture of N‐methylpyrrolidinone (NMP) and tetrahydrofuran (THF) was used as a cosolvent for the homogeneous mixing of poly(amic acid) (PA) and the ODMS solution. Thionyl chloride (SOCl₂) was used for the acylation of PA to activate the reaction between PA and ODMS. FTIR spectra showed an increase in the intensity of characteristic absorption peaks of dimethylsiloxane units with the amount of ODMS reacted. From thermogravimetric analysis (TGA), PAIBrSs showed good thermal stability, but relatively low thermal stability when compared with that of block poly(imide siloxane) (PIBlS) or poly(amideimide siloxane) (PAIBlS). A solubility test showed that dipolar aprotic solvents were relatively good solvents for the polymer. Gas separation was performed by single gas‐permeation equipment. The permeabilities of PAIBrS membranes are higher than those of PIBlS membranes and the selectivities of PAIBrS membranes are lower than those of PIBlS membranes. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 965–973, 1999     

Preparation of poly(IPDI‐PTMO‐siloxanes) and influence of siloxane structure on reactivity and mechanical properties

Siloxane‐modified polyurethanes were prepared through isophorone diisocyanates (IPDI), poly(tetramethylene oxide) (PTMO), and siloxanes. IPDI served as the hard segment in the structure. Both PTMO and siloxanes were diols and served as the soft segments. In addition, different chemical structures of siloxanes were used, in which siloxane chains would remain in the main chain of polyurethanes (PU) or become the side chain of PU. First, the reactivities of PTMO and siloxanes to react with IPDI in bulk system were studied through DSC, in which the reaction heat was related to their reactivities. Copolymerization of IPDI, PTMO, and siloxanes in bulk were also studied. The results showed that hydrophobicity and steric hindrance of siloxane diols led to their low reactivities. Next, a series of siloxane‐modified PU in toluene solvent were synthesized, and the conversion of NCO groups was determined by the method of chemical titration. In the synthesis of PU copolymers in a solution polymerization, because of low reactivity of siloxanes, a two‐step procedure was adopted. The siloxane diol was first reacted with IPDI in toluene to form NCO‐terminated prepolymer. Then PTMO was added to form final PUcopolymers. The addition of side‐chain siloxanes resulted in PU copolymers with higher molecular weight than main‐chain siloxanes. Both main‐chain and side‐chain siloxanes increased the elongation at break and tensile strength of final PU copolymers. The microphase‐separation of siloxane segments was observed by SEM, which was the main cause for the improved mechanical properties. POLYM. ENG. SCI., 47:625–632, 2007. © 2007 Society of Plastics Engineers.     

Surface structures of solvent‐cast films prepared from poly(ethylene oxide)‐segmented nylons

The surface structures of three kinds of poly(ethylene oxide)‐segmented nylon (PEO‐Ny) films prepared by the solvent‐cast method were investigated with electron spectroscopy for chemical analysis (ESCA). The PEO‐Ny's used were high‐crystalline PEO‐segmented poly(iminosebacoyliminohexamethylene), low‐crystalline PEO‐segmented poly(iminosebacoylimino‐m‐xylene), and amorphous PEO‐segmented poly(iminoisophthaloyliminomethylene‐1,3‐cyclohexylenemethylene), and the PEO contents in the bulk polymers were approximately 10 wt %. The ESCA results showed that the PEO segment was enriched on the top surfaces of all the films, and the degrees of enrichment were different. The mechanism of the PEO enrichment was examined. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 10–16, 2002     

Effects of the interaction between siloxane hydrolysate and PANI on the properties of PANI/SiO2 hybrid materials

PANI/SiO₂ Hybrids were synthesized via a sol‐gel process using tetramethoxysilane (TMOS), γ‐glycidoxypropyltrimethoxysilane (GPTMS), and 3‐(trimethoxysily1)propyl methacrylate (MSMA) as precursors, respectively. The effect of the interaction between siloxane hydrolysate and PANI on the microstructure and properties of the PANI/SiO₂ Hybrid Materials was studied using scanning electron microscopy, Fourier‐transform infrared, UV–vis, ¹H NMR, thermo gravimetric analysis, and potentiodynamic polarization analysis. Experiment results demonstrated that, an appropriate interaction between siloxane hydrolysate and PANI is useful to achieve a homogeneous and stable hybrid. The weak interaction between silanols and PANI will cause the phase separation between siloxane hydrolysate and PANI, whereas the strong interaction may lead to the formation of bulk materials and precipitation. In comparison with TMOS and MSMA, more hydrogen bonds are formed in the PANI/SiO₂ hybrid materials using GPTMS as precursor, which make it have a homogeneous and smooth surface without detectable cracks and present excellent corrosion protection properties. POLYM. COMPOS., 38:657–662, 2017. © 2015 Society of Plastics Engineers     

Surface properties of cationic ultraviolet‐curable coatings containing a siloxane structure

A polysiloxane diglycidyl ether was used as a comonomer of epoxy resins to obtain coatings through the ultraviolet curing technique. Notwithstanding its very low concentration (<1 wt %), the siloxane monomer caused a change in the surface properties of the films. Selective surface stratification was evidenced by X‐ray photoelectron spectroscopy analysis, and an interesting surface modification was achieved without changing the bulk properties of the films or the rate of polymerization. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 584–589, 2004     

Synthesis and characterization of rubbery highly fluorinated siloxane–imide segmented copolymers

The synthesis and characterization of a series of poly(siloxane–imide) block (or segmented) copolymers obtained by copolymerization of amine‐terminated polydimethylsiloxane with fluorinated aromatic compounds containing anhydride and amine functionality are reported. New fluorinated block copolymers have been synthesized to obtain organophilic polyimides potentially interesting for molecular membrane separations. The new aspects of this work relative to the literature are (1) a comparison of solution and solid‐state approaches in the imidization step to generate the target poly(siloxane–imide) copolymers and (2) exploration of new compositions involving fluorinated aromatic polymers derived from added diamine compounds. It is shown that the copolymer properties can be tailored from glassy to rubbery materials by varying the amount and the type of oligosiloxane used; the transition between glassy and rubbery properties is characterized at a siloxane content of 60 wt%. As a main result, it is shown that the solid‐state approach for inducing the cyclo‐imidization step is the more efficient one for synthesizing polymers with good mechanical properties, when the amount of siloxane block is increased in the copolymer series. Physical and chemical methods (thermogravimetric analysis, Fourier transform infrared spectroscopy, viscosity measurements) were used to characterize the copolymer properties obtained according to the two different synthesis routes. The obtained siloxane–imide copolymers are well soluble in a large variety of moderately polar solvents and exhibit very good thermal stability up to 400 °C. Hence the prepared copolyimides would seem to be promising candidates as organophilic membranes as well as gas permeation membranes. © 2012 Society of Chemical Industry     

Electrocapillary wave studies of different poly(dimethyl siloxane)s

The monolayer behavior of different end-functionalized poly(dimethyl siloxane)s (PDMSs) and a block copolymer, poly(dimethyl siloxane-co-ethylene oxide) (PDMS-co-EO) spread on an oligomeric poly(ethylene glycol) (PEG) substrates, were studied by means of electrocapillary wave diffraction (ECWD). Over a relatively small temperature range (40–70°C), the damping constant was more dependent on temperature than on the wave vector. Different surface layer properties were observed for two PDMS: one terminated with a methyl group (PDMS-CH₃) and the one terminated with a hydroxy group (PDMS-OH). PDMS-OH showed a larger reduction in surface tension compared to PDMS-CH₃ because of a higher interfacial affinity with PEG, which indicated that its monolayer surface activity was weaker. A lower surface elasticity of PDMS-OH than that of PDMS-CH₃ supported that conclusion. The block copolymer showed no surface activity, since the short siloxane moiety did not repel the strong interaction between PEG and the ethylene oxide.     

Copolymers based on poly(butylene terephthalate) and polycaprolactone‐block‐polydimethylsiloxane‐block‐polycaprolactone

A series of novel thermoplastic elastomers, based on poly(butylene terephthalate) (PBT) and polycaprolactone‐block‐polydimethylsiloxane‐block‐polycaprolactone (PCL‐PDMS‐PCL), with various mass fractions, were synthesized through melt polycondensation. In the synthesis of the poly(ester‐siloxane)s, the PCL blocks served as a compatibilizer for the non‐polar PDMS blocks and the polar comonomers dimethyl terephthalate and 1,4‐butanediol. The introduction of PCL‐PDMS‐PCL soft segments resulted in an improvement of the miscibility of the reaction mixture and therefore in higher molecular weight polymers. The content of hard PBT segments in the polymer chains was varied from 10 to 80 mass%. The degree of crystallinity of the poly(ester‐siloxane)s was determined using differential scanning calorimetry and wide‐angle X‐ray scattering. The introduction of PCL‐PDMS‐PCL soft segments into the polymer main chains reduced the crystallinity of the hard segments and altered related properties such as melting temperature and storage modulus, and also modified the surface properties. The thermal stability of the poly(ester‐siloxane)s was higher than that of the PBT homopolymer. The inclusion of the siloxane prepolymer with terminal PCL into the macromolecular chains increased the molecular weight of the copolymers, the homogeneity of the samples in terms of composition and structure and the thermal stability. It also resulted in mechanical properties which could be tailored. Copyright © 2010 Society of Chemical Industry     

Surface modification of polyethylene membranes using phosphorylcholine derivatives and their platelet compatibility

To fabricate a platelet‐compatible polymer, phosphorylcholine (PCe) was introduced onto the surface of polyethylene (PE) using a novel synthetic process. Acrylic acid was graft‐copolymerized on the surface of PE by UV irradiation, using both the peroxide preirradiation and the simultaneous methods. Benzophenone and Michler's ketone were used as an initiator and sensitizer in this investigation, respectively. To investigate the spacer effect on the platelet compatibility of the PE membrane surface, PCe with various spacer lengths was introduced onto the surface of PE by a series of chemical reactions. Ethylene glycol, butanediol, poly(propylene glycol), and poly(tetramethyl glycol) were used as spacers. The modifications of the PE membrane surface were analyzed by contact‐angle, ATR–FTIR, and ESCA techniques. The platelet compatibility of the PCe‐modified polymer was evaluated by the in vitro platelet adherent test. It was found that the platelet compatibility of the PE film surface was affected by the existence of various functional groups on the film surface. The length of the lipophilic spacer between PCe groups and the PE surface will affect the biomimetic properties of the membrane surface. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 2947–2954, 1999     

Effect of ultraviolet/ozone treatment on the surface and bulk properties of poly(dimethyl siloxane) and poly(vinylmethyl siloxane) networks

We present a comparative study aiming at comprehending the effect of ultraviolet/ozone treatment on the modification of poly(dimethyl siloxane) (PDMS) and poly(vinylmethyl siloxane) (PVMS) silicone elastomers networks (SENs). Both PDMS and PVMS SENs undergo dramatic changes in their properties when exposed to UVO. The surface chemical composition of both PDMS and PVMS at long UVO treatment times changes substantially and features a high density of hydrophilic groups. There are two major differences in behavior in the two classes of materials. First, relative to PDMS, the PVMS-based SENs get modified throughout the entire bulk. Second, the physico-chemical changes detected in PVMS take place on much shorter time scale relative to PDMS. These results are in accord with our earlier reports that indicated that when exposed to UVO, the topmost ≈5 nm of PDMS gets converted into a silica-like material, which then acts as a barrier for diffusion of atomic oxygen. In this case, the bulk of PDMS maintains its elasticity. In contrast, both the surface and bulk of PVMS films undergo substantial changes in properties when exposed to UVO. First, the surface modification of PVMS SENs takes place after only a few seconds of the UVO treatment. In addition, we register substantial modification of bulk properties, including the complete densification accompanied with increased bulk modulus. Likely, the susceptibility of the vinyl bonds to radical reactions is responsible for this effect.     

Polyether‐segmented nylon hemodialysis membrane. VII. Studies on surface structures of various poly(ethylene oxide)‐segmented nylon membranes

The relationships of the surface morphologies to the surface chemical compositions in poly(ethylene oxide)‐segmented nylon (PEO–Ny) membranes prepared by the phase‐inversion method were studied using scanning electron microscopy (SEM), electron spectroscopy for chemical analysis (ESCA), and static secondary ion mass spectrometry (SSIMS). The PEO–Ny's used were high semicrystalline PEO‐segmented polyiminosebacoyliminohexamethylene (PEO–Ny610), low semicrystalline PEO‐segmented poly(iminosebacoylimino‐m‐xylylene) (PEO–NyM10), and amorphous PEO‐ segmented poly(iminoisophthaloyliminomethylene‐1,3‐cyclohexylenemethylene) (PEO–NyBI). SEM observation showed that the surfaces of the PEO–Ny610 and PEO–NyM10 membranes were composed of crystalline spherulite and that the PEO–NyBI membrane surface had a nodular structure. ESCA analysis exhibited the enrichment of the PEO segment at the surfaces of the PEO–Ny610 and PEO–NyM10 membranes. On the other hand, the enrichment of the Ny segment was observed in the case of the PEO–NyBI membrane. SSIMS analysis revealed that the outermost surfaces of the PEO–Ny membranes except the PEO–NyBI membrane were almost covered with the PEO segment. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 517–528, 2000     

Surface behavior of dilute blends of poly(vinyl chloride) with siloxane–urethane–ethyleneoxide oligomers

X-ray photoelectron spectroscopy is used to study the surface segregation of siloxane in blends of poly(vinyl chloride) with siloxane–urethane–ethyleneoxide oligomers. At high concentration of the oligomeric additive, the surface segregation of siloxane in the blends strongly depends on the molecular architecture of the additive: the segregation is much higher when the siloxane blocks are at the ends of the oligomeric chains. At low additive concentrations, the surface segregation of siloxane is governed solely by the siloxane concentration in the bulk. © 1995 John Wiley & Sons, Inc.     

Block copolymers derived from azobiscyanopentanoic acid. XI. Properties of silicone–PMMA block copolymers prepared via polysiloxane(azobiscyanopentanamide)s

Mechanical, thermal, and surface properties of poly(dimethylsiloxane)–poly(methyl methacrylate) block copolymers (PDMS-b-PMMA) prepared by the use of polysiloxane(azobiscyanopentanamide)s were intensively investigated. The mechanical strength of block copolymers was found to decrease with an increase of siloxane contents. Dynamic mechanical analysis (DMA) of block copolymers having long siloxane chain length (SCL) and high siloxane content revealed the existence of two glass transitions attributable to microphase separation of two segments. Differential scanning calorimetry (DSC) also gave some evidence of microphase separation supporting the DMA results. It was observed that the incorporation of PDMS segments in block copolymers improved thermal stability of PMMA, as confirmed by thermogravimetric analysis. Surface analysis of the block copolymers films cast from several solutions indicated surface accumulation of PDMS segments, as revealed by water contact angle and ESCA measurements.