Synthesis of poly(urethane‐imide) using aromatic secondary amine‐blocked polyurethane prepolymer

A set of poly(urethane‐imide)s were prepared using blocked Polyurethane (PU) prepolymer and pyromellitic dianhydride (PMDA). The PU prepolymer was prepared by the reaction of polyether glycol and 2,4‐tolylene diisocyanate, and end capped with N‐methyl aniline. The PU prepolymer was reacted with PMDA until the evolution of carbon dioxide ceased. The effect of tertiary amine catalysts, organo tin catalysts, solvents, and reaction temperature were studied and compared with the poly(urethane‐imide) prepared using phenol‐blocked PU prepolymer. N‐methyl aniline blocked PU prepolymer gave a higher molecular weight poly(urethane‐imide) at a lower reaction temperature in a shorter time. Amine catalysts were found to be more efficient than organo tin catalysts. The reaction was favorable in particular with N‐ethylmorpholine and diazabicyclo(2.2.2)octane (DABCO) as catalysts, and dimethylpropylene urea as a reaction medium. The poly(urethane‐imide)s were characterized by FTIR, GPC, TGA, and DSC analyses. The molecular weight decreased with an increase in reaction temperature. The thermal stability of the PU was found to increase by the introduction of imide component. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 4032–4037, 2000     

Preparation of polyurethane elastomers (PUEs) in a high‐throughput workflow

High‐throughput experimentation (HTE) represents a promising and versatile approach for polyurethane (PU) research as a tool to rapidly screen and characterize a large number of samples in an automated way. To realize a unique HTE workflow for the research and development of PU elastomers (PUEs), the use of parallel automated formulation and coating platforms at Flamac were explored. To evaluate the applicability of HTE for PUEs, four different PU systems were investigated with different reactivities and viscosities. All prepared PUEs were evaluated by conventional physical testing methods measuring the E‐modulus, tensile‐elongation and the hardness properties revealing similar trends as conventionally prepared PUEs indicating the viability of the HTE approach. In addition, the properties of the PUEs were also investigated using downscaled microtensile bars as well as depth‐sensing indentation, again, revealing similar trends. With this proof of principle study, we demonstrated for the first time that HTE can also be extended to polymeric materials based on high reactive and viscous raw materials in combination with complex technologies. The reported results provide a basis for the use of HTE approaches for preparing, screening and characterizing large numbers of PUEs for R&D purposes. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Synthesis and characterization of poly(urethane‐benzoxazine) films as novel type of polyurethane/phenolic resin composites

Poly(urethane‐benzoxazine) films as novel polyurethane ( PU )/phenolic resin composites were prepared by blending a benzoxazine monomer ( Ba ) and PU prepolymer that was synthesized from 2,4‐tolylene diisocyanate (TDI) and polyethylene adipate polyol (MW ca. 1000) in 2 : 1 molar ratio. DSC of PU/Ba blend showed an exotherm with maximum at ca. 246 °C due to the ring‐opening polymerization of Ba, giving phenolic OH functionalities that react with isocyanate groups in the PU prepolymer. The poly(urethane‐benzoxazine) films obtained by thermal cure were transparent, with color ranging from yellow to pale wine with increase of Ba content. All the films have only one glass transition temperature (T_g ) from viscoelastic measurements, indicating no phase separation in poly(urethane‐benzoxazine) due to in situ polymerization. The T_g increased with the increase of Ba content. The films containing 10 and 15% of Ba have characteristics of an elastomer, with elongation at break at 244 and 182%, respectively. These elastic films exhibit good resilience with excellent reinstating behavior. The films containing more than 20% of Ba have characteristics of plastics. The poly(urethane‐benzoxazine) films showed excellent resistance to the solvents such as tetrahydrofuran, N,N‐dimethyl formamide, and N‐methyl‐2‐pyrrolidinone that easily dissolve PU s. Thermal stability of PU was greatly enhanced even with the incorporation of a small amount of Ba . © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 4165–4176, 2000     

Separation of ethylene‐propylene copolymers and ethylene‐propylene‐diene terpolymers using high‐temperature interactive liquid chromatography

Ethylene‐propylene‐diene terpolymers (EPDM) are generally amorphous and, therefore, do not crystallize from solution. Consequently, fractionation techniques based on crystallization, such as crystallization analysis fractionation or temperature rising elution fractionation, cannot be used to analyze their chemical composition distribution. Moreover, no suitable chromatographic system was known, which would enable to separate them according to their chemical composition. In this study, two different sorbent/solvent systems are tested with regard to the capability to separate EPDM‐terpolymers and ethylene‐propylene (EP)‐copolymers according to chemical composition. While porous graphite/1‐decanol system is selective towards ethylene and ethylidene‐2‐norbornene, carbon coated zirconia/2‐ethyl‐1‐hexanol is preferentially selective towards ethylene. Consequently, the earlier system enables to separate both EP copolymers and EPDM according to the chemical composition and the latter mainly according to the ethylene content. The results prove that the chromatographic separation in both sorbent/solvent systems is not influenced by molar mass of a sample or by its long chain branching. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Preparation and properties of polyurethane networks based on α,ω-difunctional poly(hexafluoropropylene oxide)

Poly(hexafluoropropylene oxide), poly(HFPO), networks were prepared from functional polymers by end linking via urethane groups. The prepolymers were characterized by NMR spectroscopy and GPC. The networks were characterized by determination of the number of network chains from the shear modulus, and were snown to contain both trifunctional crosslinks and difunctional links. The properties of the networks were investigated by a range of techniques. Compared with fully-fluorinated networks formed via triazine cross-links, investigated previously, the urethane-linked networks were more readily prepared but were poorer elastomers, were less thermally stable, and were less resistant to swelling by common polar solvents. © 1995 John Wiley & Sons, Inc.     

A new category of thermally stable poly(ether amide ether imide)s with increased solubility

Two new poly(ether amide ether imide)s (PEAEIs) were prepared from a new diamine (DA) containing ether, aliphatic, amide, naphthyl and pyridine functional groups that resulted flexible and thermally stable ultimate polymers. The DA was synthesized via two steps, starting from nucleophilic substitution reaction of 1,8‐diamino‐3,6‐dioxaoctane with 6‐chloronicotinoyl chloride in the presence of propylene oxide which, afforded dichloro‐diamide (DCDA) compound. In the second step for the preparation of DA, reaction of DCDA compound with 5‐amino‐1‐naphthol in the presence of K₂CO₃ was achieved. The new DA was then polycondensed with 2,2'‐bis‐(3,4‐dicarboxyphenyl) hexafluoropropane dianhydride and pyromellitic dianhydride to produce PEAEIs. The precursor, monomer and obtained polymers were entirely characterized by FT‐IR and ¹H‐NMR spectroscopy and elemental analysis techniques. The physical properties of the polymers including solubility, thermal behavior, thermal stability, inherent viscosity, morphology and mechanical properties were studied. The new PEAEIs exhibited favorable balance of physical and thermal properties, and their solubility was improved without sacrificing their thermal stability. Copyright © 2013 John Wiley & Sons, Ltd.     

Preparation and characterization of N‐methyl‐substituted polyurethane

We prepared N‐methyl‐substituted polyurethanes with different substitution degrees from sodium hydride, methyl p‐toluene sulfonate, and polyether–polyurethane containing poly(oxytetramethylene) glycol, 4,4′‐diphenylmethane diisocyanate, and 1,4‐butanediol. The chemical structures were characterized with Fourier transform infrared and ¹H NMR. To investigate the effects of the N‐substitution degree on the morphology, thermal stability, and mechanical properties, we used differential scanning calorimetry, thermogravimetric analysis, and a universal testing machine. As the substitution degree increased, the new free (1708 cm^?1) and bonded (1650 cm^?1) carbonyl peaks increased. There was no bonded carbonyl peak in fully substituted polyurethane because the urethane groups had no hydrogen. At a small substitution degree, we observed a slight increase in the glass‐transition temperature and decrease in the endotherms of soft‐segment and hard‐segment domains due to the decrease in the hard‐segment domain and the increase in the urethane groups in the soft‐segment domain. The hard‐segment domain decreased and then disappeared as the N‐methyl substitution degree increased. These changes in the morphology resulted (1) in decreased modulus and tensile strength for the films because of the decrease in physical crosslinking points and (2) improved thermal stability as the substitution degree increased. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 4077–4083, 2002     

Evidences of phase separation in moisture‐cured poly(urethane urea)s by means of temperature modulated differential scanning calorimetry

The degree of phase separation in several moisture‐cured poly(urethane urea)s (PUUs) was studied by FTIR spectroscopy, wide angle X‐ray diffraction (WAXD), and temperature‐modulated differential scanning calorimetry (TMDSC). This latter technique was shown to be particularly useful in analysing the degree of phase separation in PUU polymers. Both phase mixing and phase segregation coexisted in the PUUs and the degree of phase separation increased as the urea hard segment (HS) content in the PUU increased. The maximum solubility of urea HSs into the polyol soft segments (SSs) was achieved for 50 wt % urea HS content in diol‐based PUUs, whereas for triol‐based PUUs the highest solubility between HS and SS was reached for lower urea HS amount. Finally, the higher the urea HS content the higher the extent of phase separation in the PUU. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 3034–3045, 2007     

Kinetic study of the polymerization of aromatic polyurethane prepolymers by high‐throughput experimentation

In this contribution, high‐throughput screening experiments are reported to study the polymerization of different aromatic polyurethane (PU) prepolymers. The prepared prepolymers were synthesized from toluene diisocyanate (T80) with different molar mass polyether diols and polyether triols, respectively. The reactions were performed in solution using a Chemspeed Accelerator? SLT106 automated parallel synthesizer as well as in bulk to evaluate the high‐throughput approach for this kind of prepolymers. More than 100 samples were prepared and characterized by GPC within 1 week labor time to investigate the reaction kinetics and to compare the resulting trends obtained by high‐throughput experimentation (HTE) or by conventional, bulk prepolymerization. The synthesis of the prepared prepolymers with a linear (T80‐Diol) or a branched (T80‐Triol) structure followed a second‐order kinetic in solution but showed deviation from this phenomenon in bulk under the selected reaction conditions, although the same trends are observed in both cases. The calculation of the rate constants allowed comparing the reactivity of different prepolymer systems, which could have a significant influence on the industrial application and processing of these materials. As a result, the HTE approach was found to represent a powerful tool for the kinetic studies of PU prepolymers. Moreover, in spite of the complexity of the curing process, the results obtained by high‐throughput solution polymerization can be applied for evaluating the bulk polymerization. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 570–580, 2010     

Synthesis and properties of a novel high temperature pyridine‐containing phthalonitrile polymer

A novel pyridine‐containing aromatic phthalonitrile monomer, 2,6‐bis[4‐(3,4‐dicyanophenoxy)benzoyl]pyridine (BCBP) was synthesized from the nitro displacement of 4‐nitrophthalonitrile by the phenoxide of 2,6‐bis (4‐hydroxybenzoyl)pyridine (BHBP). 4‐(Aminophenoxy) phthalonitrile (APPH) was selected to promote the curing reaction, and the curing behavior has been investigated by differential scanning calorimetric (DSC), suggesting a wide processing window about 64 °C. Different curing additive concentrations resulted in polymers with different crosslinking degrees and subsequently influenced the performance of resins. The resulting BCBP polymer exhibited high glass transition temperatures exceeding 400 °C, outstanding thermo‐oxidative stability with weight retention of 95% at 530 °C, indicating a significant improvement in thermal properties endowed by pyridine units. Additionally, it also showed a lower overall water absorption after submersion in boiling water for 50 hours. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 3819–3825     

Synthesis and characterization of conducting poly(aniline‐co‐o‐aminophenethyl alcohol)s

Poly(o‐aminophenethyl alcohol) and its copolymers containing the aniline unit were synthesized in aqueous hydrochloric acid medium by chemical oxidative polymerization. The chemical composition of these novel polymers was determined spectroscopically, and their viscosities were measured. These polymers exhibit good solubility in organic solvents that is attributed mainly to the polar hydroxyethyl side groups. Their structures (chain conformation and morphological structure) and properties (conductivity, electrochemical characteristics, glass transition, and degradation behavior) were characterized and then interpreted on the basis of the chemical composition along with the electronic and steric hindrance effects associated with the hydroxyethyl side group. Overall, the side group has a significant effect on the polymerization and influences the structure, chain conformation, and properties of the resultant polymer. The poly(aniline‐co‐o‐aminophenethyl alcohol)s containing 20–40 mol % o‐aminophenethyl alcohol units are potential conducting materials for microelectronic and electromagnetic shielding applications because they are easier to process than polyaniline but retain its beneficial properties. These polymers can also be used as a functional conducting polymer intermediate owing to the reactivity of the side group. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 983–994, 2002     

Synthesis,characterization, and investigation of structure‐thermal cycloimidization relationship of novel poly(amide amic acid)s to poly(amide imide)s by thermogravimetric analysis

Novel diamic acids (DAAs) and poly(amide amic acid)s (PAAs) were prepared and their thermal cycloimidization to the corresponding imide form was investigated by thermogravimetric analysis under isothermal conditions at four different temperatures, that is, at 175, 200, 225, and 260 °C for 75 min. A general equation, 18NW/R_MW, where, the numerical 18 corresponds to the molecular weight of water, N is the number of water molecules, which would be eliminated per repeat unit of the PAA upon cycloimidization, W is the weight of PAA taken for TGA, and R is the molecular weight of the repeat unit of PAA, has been derived for the calculation of theoretical amount of weight loss of PAA upon complete cycloimidization. The degree of cycloimidization (DCI%) of PAAs to poly(amide imide)s (PAI) has been calculated from their isothermal TGA curves. The variation in DCI on temperature, time, and the structures of diamine and acid chloride, especially, with respect to meta‐ and para‐linkages and the presence of electron withdrawing groups has been discussed. Cycloimidization occurs at faster rate in the initial stages of about 20 min, curing and then proceeds in a gradual manner and reaches almost a plateau within an hour. The DCI was more at higher temperatures, and the final values were 22?60% at 175 °C, 34?78% at 200 °C, 50?96% at 225 °C, and 85?99% at 260 °C after 75 min of heating, depending on the nature of diamine and acid chloride in the PAA. The DCI of PAAs with meta‐linkages in either of diamine or diacid chloride was somewhat lower than those having para‐linkages. The DCI of PAAs containing electron withdrawing group like sulfone in the diamine is somewhat higher compared with those of others. The final DCI (%) values obtained from FT‐IR spectra and isothermal TGA curves were very close to each other. Further, the thermal and thermooxidative stabilities of the PAIs were discussed. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 2937–2947, 2007     

The influence of reactive organoclay on a biorenewable castor oil‐based polyurethane prepolymers toughened polylactide nanocomposites

Polylactide (PLA) is the most extensively reviewed and utilized biodegradable and renewable thermoplastic polyester, with potential to replace conventional petroleum‐based polymeric materials. To improve the toughness of PLA, castor oil‐based polyurethane prepolymer (COPUP) toughened PLA nanocomposites were prepared via the melt mixing process and investigated for its mechanical, thermal and morphological properties. X‐ray diffraction and transmission electron microscopy studies revealed the formation of polymer blend nanocomposites. Mechanical tests revealed optimum performance characteristics at PLA/COPUP ratio of 70:30. Further, loading of the organoclay showed higher tensile strength and modulus of the blend nanocomposites as compared to optimized blend. The morphological results indicated that the surface roughness increases as a function of the organoclay incorporation. Thermogravimetric measurements reveal that the thermal stability of the blend increases with the incorporation of organoclay. The improved mechanical properties along with its biodegradability might lead to new industrial and biomedical applications. Copyright © 2016 John Wiley & Sons, Ltd.     

Synthesis and properties of new soluble triphenylamine‐based aromatic poly(amine amide)s derived from N,N′‐bis(4‐carboxyphenyl)‐N,N′‐diphenyl‐1,4‐phenylenediamine

A new triphenylamine‐containing aromatic dicarboxylic acid, N,N′‐bis(4‐carboxyphenyl)‐N,N′‐diphenyl‐1,4‐phenylenediamine, was synthesized by the condensation of N,N′‐diphenyl‐1,4‐phenylenediamine with 4‐fluorobenzonitrile, followed by the alkaline hydrolysis of the intermediate dinitrile compound. A series of novel triphenylamine‐based aromatic poly(amine amide)s with inherent viscosities of 0.50–1.02 dL/g were prepared from the diacid and various aromatic diamines by direct phosphorylation polycondensation. All the poly(amine amide)s were amorphous in nature, as evidenced by X‐ray diffractograms. Most of the poly(amine amide)s were quite soluble in a variety of organic solvents and could be solution‐cast into transparent, tough, and flexible films with good mechanical properties. They had useful levels of thermal stability associated with glass‐transition temperatures up to 280 °C, 10% weight‐loss temperatures in excess of 575 °C, and char yields at 800 °C in nitrogen higher than 60%. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 94–105, 2003     

Synthesis and characterization of soluble polyimides derived from 2′,5′‐bis(3,4‐dicarboxyphenoxy)‐p‐terphenyl dianhydride

A novel bis(ether anhydride) monomer, 2′,5′‐bis(3,4‐dicarboxyphenoxy)‐p‐terphenyl dianhydride, was synthesized from the nitro displacement of 4‐nitrophthalonitrile by the phenoxide ion of 2′,5′‐dihydroxy‐p‐terphenyl, followed by alkaline hydrolysis of the intermediate bis(ether dinitrile) and cyclodehydration of the resulting bis(ether diacid). A series of new poly(ether imide)s bearing laterally attached p‐terphenyl groups were prepared from the bis(ether anhydride) with various aromatic diamines via a conventional two‐stage process that included ring‐opening polyaddition to form the poly(amic acid)s followed by thermal or chemical imidization to the poly(ether imide)s. The inherent viscosities of the poly(amic acid) precursors were in the range of 0.62–1.26 dL/g. Most of the poly(ether imide)s obtained from both routes were soluble in polar organic solvents, such as N,N‐dimethylacetamide. All the poly(ether imide)s could afford transparent, flexible, and strong films with high tensile strengths. The glass‐transition temperatures of these poly(ether imide)s were recorded as between 214 and 276 °C by DSC. The softening temperatures of all the poly(ether imide) films stayed in the 207–265 °C range according to thermomechanical analysis. For all the polymers significant decomposition did not occur below 500 °C in nitrogen or air atmosphere. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 1008–1017, 2004     

Novel method for the preparation of poly(urethane–imide)s and their properties

A polymer blend consisting of polyimide (PI) and polyurethane (PU) was prepared by means of a novel approach. PU prepolymer was prepared by the reaction of polyester polyol and 2,4-tolylenediisocyanate (2,4-TDI) and then end-capped with phenol. Poly(amide acid) was prepared from pyromellitic dianhydride (PMDA) and oxydianiline (ODA). A series of oligo(amide acid)s were also prepared by controlling the molar ratio of PMDA and ODA. The PU prepolymer and poly(amide acid) or oligo(amide acid) solution were blended at room temperature in various weight ratios. The cast films were obtained from the blend solution and treated at various temperatures. With the increase of polyurethane component, the films changed from plastic to brittle and then to elastic. The poly(urethane–imide) elastomers showed excellent mechanical properties and moderate thermal stability. The elongation of films with elasticity was more than 300%. The elongation set after the breaking of films was small. From the dynamic mechanical analysis, all the samples showed a glass transition temperature (T_g) at ca. −15°C, corresponding to T_g of the urethane component, suggesting that phase separation occurred between the two polymer components, irrespective of polyimide content. TGA and DSC studies indicated that the thermal degradation of poly(urethane–imide) was in the temperature range 250–270°C. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 3745–3753, 1997     

Surface modification of MWCNTs with glucose and their utilization for the production of environmentally friendly nanocomposites using biodegradable poly(amide‐imide) based on N‐trimellitylimido‐S‐valine matrix

In the present investigation, the preparation, characterization, and surface morphology of poly(amide‐imide) (PAI)/multi‐walled carbon nanotubes (MWCNTs) bionanocomposites (BNCs) were the main goals of the study. At first, an optically active PAI based on S‐valine as a biodegradable segment was synthesized. Then, carboxyl‐modified MWCNTs were functionalized with glucose (f‐MWCNT) as a biological active molecule in a green method to achieve a fine dispersion of f‐MWCNT bundles in the PAI matrix. The existence of S‐valine in the PAI matrix and functionalized MWCNT with glucose resulted in a series of potentially biodegradable nanocomposites. The obtained BNCs were characterized by various techniques. Field emission scanning and transmission electron microscopy micrographs of the composites showed a fine dispersion of f‐MWCNTs in the polymer matrix because of hydrogen bonding and π–π stacking interaction between f‐MWCNTs and polymer functional groups and aromatic moieties. Adding f‐MWCNTs into polymer matrix significantly improved the thermal stability of BNCs because of the increased interfacial interaction between the PAI matrix and f‐MWCNTs and also good dispersion of f‐MWCNT in the polymer matrix. Copyright © 2015 John Wiley & Sons, Ltd.     

Catalysis of poly(urethane imidine) copolymer formation from amine‐blocked isocyanate and bisphthalide

The catalysis of imidine formation between an amine‐blocked polyurethane prepolymer and bisphthalide was studied with a series of metal alkoxides, phenoxides, and organotin compounds and tertiary amines. The carbon dioxide released during the reaction was followed for monitoring of the reaction. The metal alkoxides and phenoxides catalyzed the imidine formation reaction but did not catalyze the deblocking reaction, whereas the organotin compounds and tertiary amines showed no catalytic activity in the reaction between isocyanate and phthalide. With tin catalysts, the imidine formation reaction depended on the deblocking of the blocked prepolymer, but it was independent of deblocking with amine catalysts. The resultant poly(urethane imidine) copolymers were characterized with Fourier transform infrared, ¹H NMR, ¹³C NMR, gel permeation chromatography, and thermogravimetric analysis techniques. The thermal stability of polyurethane increased significantly with the incorporation of imidine groups. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 4236–4242, 2001     

Poly(urethane‐co‐benzoxazine)s via reaction of phenol terminated urethane prepolymers and benzoxazine monomer and investigation of their properties

In the present work, a new method was developed for the combination of polyurethanes (PUs) and polybenzoxazine (PBz) to obtain novel thermoset poly(urethane‐co‐benzoxazine)s with good thermal, mechanical, and electrical properties as well as low temperature curing profile. Knowing the catalytic effect of compounds possessing free phenolic groups on ring opening polymerization of benzoxazine monomers, preparation of phenol terminated urethane oligomers (PTPU) as the macroinitiator for a benzoxazine monomer (Ba) was considered. Firstly, NCO‐terminated urethane prepolymers were prepared from the reaction of poly(tetramethyleneether glycol), and 2,4‐tolylene diisocyanate, and then end functionalized with bisphenol‐A under proper condition. DSC, DMTA, and gel content measurements were applied to find optimum ring opening polymerization condition (170°C for 1 hr and 200°C for 15 min). Various kinds of thermoset polymers were prepared by the reaction of PTPU at different molecular weights with variable contents of Ba. All of monomeric and polymeric materials were characterized by conventional spectroscopic methods and their thermal, mechanical, viscoelastic, and electrical properties were measured and properties were correlated to their structure. Due to the interesting properties of these new materials, the possibility of using them as electrical insulators with higher service temperature in comparison to common PUs were examined and their potential applicability was confirmed. Copyright © 2010 John Wiley & Sons, Ltd.     

Star‐like polyurethane hybrids with functional cubic silsesquioxanes: Preparation,morphology, and thermomechanical properties

Star‐like polyurethane (PU) hybrid films containing octafunctional cubic silsesquioxanes are prepared by polyaddition reaction between octakis(dimethylsilyloxy) silsesquioxane isopropenyldimethylbenzyl isocyanate (OS‐PDBI) and octakis(dimethylsilyloxy) hydroxypropyl silsesquioxane (HPS); and between OS‐PDBI and hexane diol (HD). The effect of incorporation of nanostructured cubic silsesquioxanes (CSSQ) on the macroscopic properties of PU film and their thermomechanical properties are investigated. The obtained hybrid films are relatively transparent. Their morphologies and properties are studied by using Fourier transform infra‐red spectroscopy (FTIR), X‐ray diffraction (XRD), atomic force microscopy (AFM), thermogravimetry (TGA), differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA) and contact angle measurements. The formation of urethane linkage disrupts the three‐dimensional ordered structure of CSSQ in the hybrid film. AFM images show clearly that no phase separation in the macroscopic level for both PU hybrid films. TGA and DMA analyzes indicate that the incorporation of octafunctional silsesquioxane in PU hybrid film provides enhanced thermal stability and increased crosslink density. Moreover, the existence of cage structure also improves oxidation resistance and mechanical strength. The incomplete reaction between OS‐PDBI and HPS due to the steric hindrance of highly branched rigid CSSQ could result in a slight decrease in initial decomposition temperature. Furthermore, hardness and out‐of‐plane compressive modulus are also investigated by nanoindentation. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 4602–4616, 2009