Kinetic study of polyurethane synthesis using different catalytic systems of Fe,Cu, Sn,and Cr

This work presents a comparative study between alternative catalytic systems, metal‐β‐diketones complexes (iron, copper, chromium, and tin), and the commercial catalyst dibutyltin dilaurate, DBTDL, in the polyurethanes synthesis obtained from isophorone diisocyanate (IPDI) and polyols as polypropyleneglycol/diethyleneglycol and 1,6‐hexanodiol polyadipate (polyester A‐Mn = 2000 g/mol and polyester B‐Mn = 1000 g/mol) reactions. The polyurethanes synthesis was followed by the IPDI consumption in time, verified by infrared spectroscopy (FTIR) through the decrease of free NCO characteristic band at 2300–2200 cm^?1. The FTIR data was used to determine the polyurethanes formation kinetic behavior. It was verified that for the reactions with polyethers excess, DBTDL catalyst was more effective when compared to metal‐β‐diketones complexes, while for the reactions with polyester, A and B, the metal‐β‐diketones complexes were more effective. © 2009 Wiley Periodicals, Inc. JAppl Polym Sci, 2010     

The chain extension of anionic prepolymers in the preparation of aqueous poly(urethane–urea) dispersions

Anionic polyurethane prepolymers end‐capped with isocyanate groups were dispersed and chain‐extended in aqueous media using three different extension agents: hydrazine, 1,2‐ethylene diamine (EDA) and 1,2‐propylene diamine (PDA). Two types of prepolymer were used. The first was prepared from isophorone diisocyanate (IPDI), α,α‐dimethylol propionic acid (DMPA) and poly(propylene oxide) diol (PPO) and the second from α,α,α′,α′‐tetramethyl‐1,3‐xylylene diisocyanate (m‐TMXDI), poly(caprolactone) diol (PCL) and DMPA. The colloidal particles which formed in the dispersion process and the constituent poly(urethane–urea) chains were characterised by a combination of dynamic and static light scattering, gel permeation chromatography and FTIR spectroscopy. Using EDA as the extender, a study was made of how the degree of extension depended on the molar ratio of amine to isocyanate groups, [NH₂]/[NCO] (= R_{A, I}). It was found that using a stoichiometric balance of isocyanate and amine groups did not lead to high degree of extension, and better chain extension was obtained at lower R_{A, I} values. In a comparative study using stoichiometric balances of isocyanate and amine groups, the degrees of extension obtained using PDA and EDA were approximately the same, while hydrazine was the least effective. Force–extension studies were carried out on samples prepared from films cast from the aqueous poly(urethane–urea) dispersions in order to assess the influence of chain‐extender type and stoichiometry on bulk properties; values of Young's modulus, tensile strength and maximum extension are reported. Copyright © 2003 Society of Chemical Industry     

Kinetics of glycidyl azide polymer‐based urethane network formation

Reactions between hydroxyl‐terminated glycidyl azide polymer (GAP) and different isocyanate curatives such as toluene diisocyanate (TDI), isophorone diisocyanate (IPDI), and methylene diicyclohexyl isocyanate (MDCI) at various temperatures viz. 30, 40, 50, and 60°C were followed by Fourier transform infra red spectroscopy. The reactions were found to follow second‐order kinetics. With TDI and IPDI at 30°C, a two‐stage reaction was observed. For GAP‐TDI system, the second stage was slower than the first while for GAP‐IPDI system, the second stage was faster than the first indicating dominance of autocatalytic effect. The stage separation occurred due to the difference in reactivity of the isocyanate groups and was found to narrow down with increase in temperature. The viscosity build up due to the curing reaction was followed for GAP‐TDI system for comparison. The stage separation was evident in the viscosity build up also. Rheokinetic analysis done based on data generated showed a linear correlation between viscosity build up and fractional conversion. The kinetic and activation parameters evaluated from the data showed the relative difference in reactivity of the three diisocyanates with GAP. Both the approaches suggested that the reactivity of the isocyanates employed for the present study could be arranged as TDI > IPDI ? MDCI. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Monitoring of chemical reactions during polymer synthesis by real‐time attenuated total reflection (ATR)–FTIR spectroscopy

The present study demonstrates in situ real‐time attenuated total reflection (ATR)–FTIR spectroscopy as a powerful tool for monitoring and analyzing different polymerization and polymer modification reactions. Thus, a metallocene catalyzed copolymerization of propene and 10‐undecene‐1‐ol, a polycondensation reaction towards polysulfone, and a modification reaction of OH end groups of hyperbranched poly(urea‐urethane) were investigated successfully. The interpretation of the development of FTIR spectra was carried out on the basis of typical vibration bands of chemical groups of the corresponding monomers and polymers in each case, e.g. of the C?C double bond of 10‐undecene‐1‐ol during the copolymerization, the new C? O? C group of polysulfone, and the new urethane end group of poly(urea‐urethane). Kinetics prediction is also under consideration. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 1374–1380, 2006     

混合聚醚配比对聚氨酯脲结构和性能的影响研究

以PPG600和PPG2000混合聚醚、异佛尔酮二异氰酸酯（IPDI）和异佛尔酮二胺（IPDA）为原料合成溶剂型聚氨酯脲（Puu）树脂,通过改变PPG600和PPG2000配比调节树脂硬段含量。利用FTIR．DSC．TG等研究PPG600和PPG2000配比对聚氨酯脲微观结构、耐热性及力学性能的影响。结果表明,随着混合聚醚中PPG600含量增加,聚氨酯脲软段的玻璃化转变温度（Tg）升高,软硬段的相容性增强,脲羰基氢键化程度降低,树脂的定伸强度增大。     

Synthesis and characterization of isocyanic acid,m‐phenylenediiso‐propylidene based poly(urethane‐urea) dispersions containing different amount of 2,2‐Bis(hydroxyl methyl)propionic acid

Isocyanic acid, m‐phenylenediiso‐propylidene (m‐TMXDI)‐based anionic poly(urethane‐urea) dispersions were prepared by the prepolymer mixing process. The equivalent ratio of NCO/OH was kept constant at 1.8, while 2,2‐bis(hydroxyl methyl) propionic acid (DMPA) used was varied from 3 to 10 wt %. The colloidal stability of poly(urethane‐urea) dispersions arose entirely from the presence of ionized carboxylic acid groups. The chemical structure of poly(urethane‐urea) dispersions with various amount of DMPA were identified by FTIR and ¹³C NMR analysis. The test results showed that the hydrophilicity of poly(urethane‐urea) dispersions were increased with increase in DMPA content. The degree of chain extension was much lower than the values predicted theoretically due to the side reaction of a small amount of hydrophilic isocyanate‐terminated prepolymer with water. The average particle size of poly(urethane‐urea) dispersions were decreased with an increase in DMPA content, and this lead to an increase in viscosity. Also, the thermal degradation behavior were measured and was shown that the initial degradation temperature shifted to lower temperature with an increase in DMPA content. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 5737–5746, 2006     

Crosslinked acrylic pressure‐sensitive adhesives. II. Effect of humidity on the crosslinking reaction

The effect of humidity during storage on the crosslinking reactions of isocyanate groups was investigated with attenuated total reflectance Fourier transform infrared spectroscopy with pressure‐sensitive adhesives composed of poly[ethyl acrylate‐co‐(2‐ethylhexyl acrylate)‐co‐(2‐hydroxyethyl methacrylate)] as a base resin and polyisocyanate as a crosslinker. A peak‐resolving analysis of the amide II region revealed four bands. According to an analysis of the Fourier transform infrared spectra of the model compounds, these four bands were assigned to free urethane linkages, hydrogen‐bonded urethane linkages, free urea linkages, and hydrogen‐bonded urea linkages. As expected, storage under humid conditions led to the formation of free and hydrogen‐bonded urea linkages corresponding to the promotion of isocyanate consumption. Peak resolution of the amide II region was found to be a reasonable way of monitoring urethane and urea linkages during crosslinking reactions. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3039–3045, 2003     

Interphase Reaction of Isocyanates with Epoxy Resins Containing Functional Groups of Different Reactivity

Interphase reactions between cured epoxy resins and isocyanates are investigated. The epoxy resins contain secondary hydroxyl groups as reactive groups only or secondary hydroxyl plus amine. The isocyanate diffuses into the epoxy resin forming an interphase with a thickness of some micrometers. Depending on the functional groups available in the epoxy resin, urethane and urea groups are formed in the interphase. If a monofunctional isocyanate is used, no difference between both kinds of epoxy resin could be detected regarding the formation of urethane. If the epoxy resins react with bifunctional isocyanates a crosslinked interphase is formed. Due to the higher reactivity between amine and isocyanate compared to hydroxyl and isocyanate, the urea is formed first. The resulting cross‐links restrict the further diffusion of isocyanate into the epoxy resin. The consequence is a lower urethane content in the interphase and a thinner interphase compared to the epoxy resin containing hydroxyl only. If a prepolymer with isocyanate end groups is used as isocyanate the formation of the interphase is slower compared to the low molecular weight isocyanate. This is due to the reduced mobility of the prepolymer.     

Reactions of phenolic ester alcohol with aliphatic isocyanates—transcarbamoylation of phenolic to aliphatic urethane: A 13C‐NMR study

Reactions of aliphatic isocyanates with a phenolic ester alcohol (PHEA) were investigated using ¹³C‐NMR spectroscopy. PHEA has two reactive sites: a phenolic  OH group and a secondary aliphatic  OH group. Both  OH groups react with the isocyanate groups. With an organotin catalyst, dibutyltin dilaurate (DBTDL), the aliphatic  OH group reacts first. With a tertiary amine catalyst, 1,4‐diazabicyclo[2.2.2]octane (DABCO), or triphenylphosphine (Ph₃P) or even in the absence of a catalyst at room temperature (RT) the phenolic  OH group reacts first. With the organotin catalyst, the reactions are generally complete in a day at RT. With DABCO or triphenylphosphine or DNNDSA catalysts, the reactions are almost complete only in 3–4 days at RT in ethyl acetate or acetonitrile. Uncatalyzed reactions are slower. With an acid catalyst such as dinonylnaphthalenedisulfonic acid (DNNDSA), both  OH groups react with the isocyanate. When equimolar quantities of PHEA and hexamethylenediisocyanate (HDI) polymerize at RT or reflux in the presence of a catalyst, both  OH groups react, with the phenol reacting slowly. Upon refluxing, the phenolic  OH‐based urethane slowly rearranges (transcarbamoylation) to the aliphatic  OH‐based urethane. DABCO and Ph₃P catalysts effect this rearrangement at a much slower rate than does the acid catalyst. In the presence of a catalytic amount of DBDTL in a refluxing solvent, this rearrangement is complete in 2 h. By refluxing the phenolic–OH‐based urethane in isopropanol, the mechanism of transcarbamoylation was found to be intermolecular. The mechanism is likely to involve deblocking of the phenolic urethane and subsequent reaction of the isocyanate generated, with the aliphatic  OH group. This conclusion was confirmed by differential scanning calorimetry (DSC) experiments. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 2212–2228, 2000     

Synthesis and application of hyperbranched poly(urethane‐urea) finishing agent with amino groups

The isocyanate‐terminated linear polyurethane prepolymer (LPPU) was successfully synthesized via step‐by‐step polymerization, with isophorone disocyanate (IPDI) and polytetramethylene ether glycol (PTMG, M_n = 2000 g/mol) used as raw materials, dibutyltin dilaurate (DBTDL) as the catalyst, 1,4‐butanediol (BDO) as the chain extender and anhydrous ethanol (EtOH) as the blocking agent. Then the hyperbranched poly (urethane‐urea) (HBPU) containing amino groups was synthesized by grafting LPPU on amino‐terminated hyperbranched polymers (NH₂‐HBP). The molecular structure of LPPU and HBPU were characterized by means of FT‐IR and ¹H‐NMR. It was founded that LPPU and HBPU were successfully synthesized as anticipated. The thermal stability and crystalline morphology of LPPU and HBPU were characterized and analyzed by TG and XRD. Additionally, it was also found that, after addition of 10% HBPU, the water absorption rate, water vapor transmission rate, and water vapor permeability increased markedly by 162.02%, 400.00%, 260.00%, respectively. The tensile strength of membrane decreased by 24.57% and the elongation at break increased by 26.92%. Compared with the leather finished by commercial PU finishing agent, the leather finished by HBPU presented better properties. The water vapor permeability of the leather finished by increased by 13.0%, and the dry‐ and wet‐rub resistances and the physical and mechanical performances were excellent. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44139.     

The kinetics of the reaction of isophorone di-isocyanate with mono-alcohols

Isophorone di-isocyanate (IPDI) is used to react with hydroxyl containing prepolymers in the preparation of polyurethane elastomers, particularly with hydroxy-terminated polybutadiene (HTPB) in composite propellant systems. In the present work, the kinetics of the reaction of IPDI with monoalcohols are studied, as a model for the polyurethane systems. A gas chromatography method is used to follow the reaction, which allows direct measurement of the reaction of individual isocyanate groups. The rates of individual isocyanate groups are described by a second order equation modified to include catalysis by the urethane products. The rates of primary and secondary isocyanate groups in the two isomers of IPDI are compared. Differences between the various isocyanate groups are relatively small, and are offset by the urethane catalysis effect, so that the overall disappearance of isocyanate is roughly second order. The reaction rate of IPDI with HTPB is faster than with the model compounds, and it is suggested that this arises because there is tendency for the isocyanate to complex with the hydroxyl end groups of the polymer.     

Moisture curing kinetics of isocyanate ended urethane quasi‐prepolymers monitored by IR spectroscopy and DSC

The study of the kinetics of the curing of isocyanate quasi‐prepolymers with water was performed by infrared spectroscopy and differential scanning calorimetry. The influence of the free isocyanate content, polyol functionality, and of the addition of an amine catalyst (2,2′‐dimorpholinediethylether) in the reaction kinetics and morphology of the final poly(urethane urea) was analyzed. A second‐order autocatalyzed model was successfully applied to reproduce the curing process under isothermal curing conditions, until gelation occurred. A kinetic model‐free approach was used to find the dependence of the effective activation energy (E_a) with the extent of cure, when the reaction was performed under nonisothermal conditions. The dependence of E_a with the reaction progress was different depending on the initial composition of the quasi‐prepolymer, which reveals the complexity of the curing process. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2008     

13C NMR investigation of the reaction in water of UF resins with blocked emulsifiable isocyanates

A solid state ¹³C NMR study of hardened networks obtained by the reaction of blocked and nonblocked isocyanates (pMDI) with urea‐formaldehyde (UF) resins in water showed different results according to the temperature of the reaction. At high temperature, in water, both a nonblocked or an emulsifiable, blocked isocyanate, appear to crosslink with UF resins through the formation both of traditional methylene bridges connecting urea to urea and of urethane bridges. The latter have been confirmed by ¹³C NMR to form in water by reaction of the isocyanate ? N?C?O group with the hydroxymethyl groups of the UF resin. At ambient temperature, UF/pMDI resins where the pMDI is a emulsifiable blocked isocyanate, do not appear to form urethanes to any great extent but rather to crosslink through the usual UF resin urea to urea methylene bridges. Even in this case, when urethane bridges appear to be absent, evidence of crosslinking in water through reaction of the isocyanate with the ? NH₂ and ? NH? amide of the UF resin has not been observed. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 589–596, 2006     

Kinetic evaluation of tin‐POMS catalyst for urethane reactions

We report the activity for a new tin‐polyhedral oligomeric metal silsesquioxane (POMS) catalyst in 1‐butanol and 2‐butanol model reactions with 4,4′‐methylenebis(cyclohexylisocyanate) (H₁₂MDI) in toluene and N,N‐dimethylformamide (DMF). Kinetic rate constants for varying levels of tin‐POMS ranging between 100 ppm and 1000 ppm tin are reported. We observed urethane reactions in toluene to follow second order reaction kinetics, whereas similar reactions in DMF followed first order reaction kinetics. We determined tin‐POMS is an efficient catalyst system for urethane reactions and found the new catalyst to be easy to handle, soluble, and very effective for catalyzing urethane reactions. By direct comparison of a model reaction between tin‐POMS and dibutyltin dilaurate (DBTDL), tin‐POMS was found to be quite similar to DBTDL for urethane catalytic activity. In addition, we show the efficacy for tin‐POMS to be an excellent polyurethane reaction catalyst through a model reaction of H12MDI with 2000 g/mol poly(ε‐caprolactone) diol. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Preparation of segmented, high molecular weight, aliphatic poly(ether-urea) copolymers in isopropanol. In-situ FTIR studies and polymer synthesis

The use of isopropanol (IPA) as the reaction solvent for the preparation of high molecular weight segmented polyether-urea copolymers based on cycloaliphatic diisocyanates was investigated. Reactivity of IPA with bis(4-isocyanatohexyl)methane (HMDI) and isophorone diisocyanate (IPDI) was studied between 0 and 40 °C using in-situ FTIR spectroscopy. HMDI, which has secondary isocyanate groups, shows a very slow reaction with a large excess of IPA at 0 and 23 °C. Analysis of the kinetic data indicates an activation energy of 51 kJ/mol for the reaction between HMDI and IPA. As expected, IPDI, which has both a primary and a secondary isocyanate (NCO) group, reacts faster with IPA compared with HMDI, which only has secondary NCO groups. However, the rate of reaction of IPDI with IPA at 0 °C is extremely slow (approximately 1% consumption of isocyanate in 60 min) thus allowing the use of IPA as the reaction solvent for polyether-urea synthesis. Preparation of high molecular weight, high-strength HMDI and IPDI based polyether-urea segmented copolymers in IPA has been demonstrated. Thermal analysis and stress-strain analyses were used to characterize the products.     

Preparation and properties of poly(urethane acrylate) films for ultraviolet‐curable coatings

Four different UV‐curable poly(urethane acrylate)s were prepared through the reaction of two diisocyanates [i.e., toluene‐2,4‐diisocyanate (TDI) and isophorone diisocyanate (IPDI)] and two polyols [i.e., polycaprolactone triol (PCLT) and polycaprolactone diol (PCLD)], and they were characterized with Fourier transform infrared spectroscopy. The mechanical properties, thermal properties, and water sorption of the cured poly(urethane acrylate)s were also investigated with respect to the chemical structures of the polyols and diisocyanates. In comparison with linear PCLD–TDI and PCLD–IPDI, crosslinked PCLT–TDI and PCLT–IPDI with trifunctional PCLT showed relatively high thermal decomposition temperatures. The hardness and modulus of the UV‐cured poly(urethane acrylate) films, which were measured by a nanoindentation technique, were in the following increasing order: PCLD–IPDI ～ PCLD–TDI < PCLT–IPDI ～ PCLT–TDI. The pencil hardness was 3H for PCLT–IPDI and PCLT–TDI and HB for PCLD–IPDI and PCLD–TDI. Two urethane acrylates prepared from the trifunctional polyol showed better acid and alkali resistances than those made from the bifunctional polyol. These mechanical properties and chemical resistances may have been strongly dependent on the chain flexibility of the molecules and crosslinking density. Regardless of the functionality in the polyol, the change in the yellowness index showed a lower value in the poly(urethane acrylate) coating containing the aliphatic diisocyanate IPDI in comparison with the corresponding poly(urethane acrylate) with the aromatic diisocyanate TDI. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Studies on urethane–allophanate networks based on hydroxyl‐terminated polybutadiene: Modeling of network parameters and correlation to mechanical properties

Hydroxyl‐terminated polybutadiene (HTPB)‐based allophanate–urethane networks were prepared by reacting HTPB with di‐isocyanates, such as toluene–di‐isocyanate (TDI), isophorone–di‐isocyanate (IPDI), and 4,4′‐di(socyanatocyclohexyl)methane (H₁₂MDI) at stoichiometric ratios (r‐values) ranging from 1.0 to 1.5. The networks were characterized for mechanical and swell properties. The network parameters, such as “X,” which is the fraction of urethane groups involved in the allophanate formation, and effective chain length (L_x) were calculated from experimental crosslink density values determined from swell data, using α‐model equations developed by Marsh. Excellent linear correlations were obtained between mechanical properties and the calculated network parameters. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2986–2994, 2006     

Rheo‐kinetic evaluation on the formation of urethane networks based on hydroxyl‐terminated polybutadiene

Rheo‐kinetic studies on bulk polymerization reaction between hydroxyl‐terminated polybutadiene (HTPB) and di‐isocyanates such as toluene‐di‐isocyanate (TDI), hexamethylene‐di‐isocyanate (HMDI), and isophorone‐di‐isocyanate (IPDI) were undertaken by following the buildup of viscosity of the reaction mixture during the cure reaction. Rheo‐kinetic plots were obtained by plotting ln (viscosity) vs. time. The cure reaction was found to proceed in two stages with TDI and IPDI, and in a single stage with HMDI. The rate constants for the two stages k₁ and k₂ were determined from the rheo‐kinetic plots. The rate constants in both the stages were found to increase with catalyst concentration and decrease with NCO/OH equivalent ratio (r‐value). The ratio between the rate constants, k₁/k₂ also increased with catalyst concentration and r‐value. The extent of cure reaction at the point of stage separation (x_i) increased with catalyst concentration and r‐value. Increase in temperature caused merger of stages. Arrhenus parameters for the uncatalyzed HTPB‐isocyanate reactions were evaluated. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 79: 1869–1876, 2001     

Properties of polythiourethanes prepared by thiol–isocyanate click reaction

Polythiourethane networks with systematic compositional variations of thiol [ethoxylated trimethylol‐propane tri(3‐mercapto‐propionate), ETTMP1300 and pentaerythritol tetra(3‐mercapto‐propionate), PETMP] and isophorone diisocyanate (IPDI), i.e., IPDI/ETTMP1300/PETMP = 100/100/0, 100/80/20, 100/60/40, 100/40/60, 100/20/80, and 100/0/100, were prepared by base catalyzed thiol–isocyanate click type reaction where the base catalyst (tributylamine, TBA) was photolytically generated using photolatent amine (TBA·tetraphenylborate salt, TBA·HBPh₄). The kinetics of the polythiourethane network formation investigated using real‐time infrared indicates that the thiol–isocyanate coupling reaction was successfully triggered photolytically and the conversion of both thiol and isocyanate reached near 100% in a matter of minutes. The T_g of the polythiourethane networks progressively increases (–8 to 143 °C by DMTA) as a function of the PETMP content due to the higher extent of crosslinks, also resulting in enhanced rubbery modulus. Very narrow full width at half maximum (15–28 °C) of tan δ peak was obtained for all six sets of polythiourethane networks, which is induced by the highly uniform and dense structures of thiol‐based polymeric network. Energy damping performance of polythiourethane networks measured by nondestructive impact testing exhibited remarkably high (～95%) and the relationship with temperature was in accordance with tan δ peak. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46070.     

Thermal and surface characterization of polyurethane–urea clay nanocomposite coatings

This paper reports synthesis and characterization of polyurethane–urea (PU‐urea) and the nanocomposites derived from the PU‐urea with silicate clays. Organophilic montmorillonite cotreated by cetyl trimethyl ammonium bromide (CTAB) was synthesized and used to prepare PU‐urea/montmorillonite nanocomposites coatings. PU‐ureas were prepared from polyethylene glycol (PEG), polypropylene glycol (PPG), trimethylol propane (TMP), and 4,4′‐diphenylmethane diisocyanate (MDI) by reacting excess diisocyanate with polyether glycols. The excess isocyanate of the prepolymers was cured with atmospheric moisture. The synthesized moisture cured PU‐urea and nanocomposites were characterized by Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), differential scanning calorimetric (DSC), and angle resolved X‐ray photoelectron spectroscopy (AR‐XPS). The thermal stability of the PU‐urea nanocomposites was higher relative to the mother PU‐urea films. DSC results showed a slight enhancement in the soft segment glass transition temperature after 3 wt % clay loading. The surface properties showed an enrichment of the soft segment toward the surface. An enhancement in the hard segment composition in the nanocomposite coatings has resulted in enhancing the phase mixing process. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 2393–2401, 2006