Polyurethane Composite Films Research Articles

Modified cellulose nanocrystals enhancement to mechanical properties and water resistance of vegetable oil‐based waterborne polyurethane

ABSTRACTEnvironmentally friendly and lightweight silylated cellulose nanocrystal (SCNCs)/waterborne polyurethane (WPU) composite films that exhibit excellent mechanical properties and water resistance were prepared. The cellulose nanocrystals (CNCs) of the filamentous structure were surface‐modified by γ‐aminopropyltriethoxysilane (APTES) and then introduced into a castor oil‐based aqueous polyurethane (WPU) matrix by in situ polymerization. The morphology and silylation degree of CNCs were characterized by scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and Fourier infrared transform spectroscopy at different APTES concentrations. The results showed that the surface of the nanocellulose crystal has the best silylation morphology and thermal stability with incorporation of 6 wt % APTES. The thermal stability, mechanical properties, surface morphology, and water resistance of the nanocomposites were investigated by TGA, tensile test, SEM and optical contact angle, water absorption test, and mechanical property test after immersed in water. It was found that the effective introduction of modified CNCs resulted in a significant increase in tensile strength at high levels, and the thermal stability and hydrophobicity of the material were improved simultaneously, reaching the percolation threshold at a 0.50 wt % SCNCs as determined theoretically. This study provided an approach to the design and development of surface‐modified CNCs/vegetable oil‐based polymer composites by using an appropriate concentration of silane coupling agent to modify CNCs and improve the compatibility between nanocellulose and vegetable oil‐based polymer matrices. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 48228.

High conductive and mechanical robust carbon nanotubes/waterborne polyurethane composite films for efficient electromagnetic interference shielding

Highly conductive multi-walled nanotubes (MWCNT)/waterborne polyurethane (WPU) composites were prepared using facile latex technology without surfactant, in which the solid composites were achieved by filtration process to prevent the re-aggregation of MWCNT during drying process. MWCNT was distributed along the interfaces of polyurethane particles, constructing segregated structure without insulating surfactant. Therefore, high conductivity of 362.6 ± 23.1 S m−1 was obtained at CNT content of 10.6 wt%, resulting in excellent electromagnetic interference (EMI) shielding effectiveness (SE) of 24.7 dB at thin film thickness of 0.4 mm in X-bands. Considering lightweight and thin thickness, outstanding specific shielding effectiveness (SSE) of 537 dB cm2 g−1 was achieved, higher than most values of CNT composites ever reported. Furthermore, the composites exhibited desirable mechanical properties with high elongation at break of 62%, demonstrating promising applications for commercial EMI shielding, especially for flexible and stretchable devices.

Structural and dielectrical characterization of low-k polyurethane composite films with silica aerogel

In this study, a hydrophobic silica aerogel was synthesized via one-step surface modification and polymer composite films based on a polyurethane (PU) matrix were prepared by doping with silica aerogel powder (at 2%, 3%, 5%, and 7% by weight = w/w%). The structural, thermal, morphological, and surface properties of the silica aerogel and PU composite films containing aerogel were investigated by Fourier transform infrared spectroscopy, thermogravimetric analysis, differential scanning calorimetry (DSC), scanning electron microscopy, and tensiometry. The dielectric properties of the silica aerogel and PU composite films containing the aerogel were determined over a temperature range of 293–423 K and a frequency range of 1–106 Hz. The contact angle of the silica aerogel was 106°. Moreover, the PU composite film with 7% aerogel had the highest contact angle (θ = 105°) among the composite samples, which was similar to contact angle of the silica aerogel. The dielectric constants and dielectric losses decreased with the frequency for all of the samples, whereas they increased with the temperature. The polarization regions and relaxation times were determined for all of the samples using the Cole–Cole equation. The glass-transition temperatures (Tg) were determined for the silica aerogel and PU composite films containing aerogel by dielectric spectroscopy and compared with the DSC results. The dielectric constants were lower for the PU composite films than the PU film. The dielectric constant for the PU composite film doped with 2% silica aerogel was 2.9 at 10 MHz. Thus, the PU composite with a low dielectric constant and dielectric loss factor (tanδ) could be regarded as a potential dielectric constant candidate, with possible applications as a dielectric material in the microelectronics industry.

Layered structural design of flexible waterborne polyurethane conductive film for excellent electromagnetic interference shielding and low microwave reflectivity

A highly efficient electromagnetic interference (EMI) shielding waterborne polyurethane (WPU) composite film with low microwave reflectivity is designed by constructing an FeCo alloy decoration reduced graphene oxide (FeCo@rGO) /nano silver (Ag) layered structure. The FeCo@rGO layer formed by natural sedimentation at the bottom of the WPU film acts as a microwave absorption layer, and the ultra-thin Ag layer covered on the top surface serves as a highly efficient shielding layer. This unique layered structure combines the microwave-reflecting characteristic of nano Ag and the microwave-absorbing characteristic of rGO@FeCo to achieve strong microwave shielding effectiveness (SE) with low microwave reflection. The obtained Ag/rGO@FeCo/WPU composite film (10 wt% rGO@FeCo and Ag layer of 500 nm in thickness), which is only 300 μm in thickness, possesses an outstanding EMI SE of 50.5 dB and the microwave reflection coefficient is as low as 0.49 (average SER of 3.2 dB). This flexible and highly efficient shielding film with extremely low reflectivity is suitable for application in portable and wearable smart electronics, and this strategy offers a new method for designing the flexible electromagnetic interference shielding materials with low reflection characteristic.

Large-scale fabrication of boron nitride nanotubes and their application in thermoplastic polyurethane based composite for improved thermal conductivity

The large-scale manufacture of inexpensive boron nitride nanotubes (BNNTs) has proven difficult in recent decades. In this study, BNNTs are fabricated on a massive scale by ball-milling a mixture of boron oxide (B2O3), amorphous boron powder (B), and magnesium diboride (MgB2) and then annealing the resulting product in NH3, which follows a vapor-liquid-solid growth mechanism. MgB2 serves as a catalyst in the growth process, and the vaporous B2O3 and diboron dioxide (B2O2) produced from the reaction of B2O3 and B are efficient sources of boron. The obtained BNNTs can be dispersed well in dimethyl formamide, possibly as a result of some cracked structures in the BNNTs and impurities that form during the synthesis process. Taking advantage of the good dispersity, the uniform BNNT/thermoplastic polyurethane composite films are prepared via solution blending. The incorporation of BNNTs apparently enhances the thermal conductivity of the neat thermoplastic polyurethane. This article contributes to the low-cost fabrication of BNNTs and their potential application as fillers in polymers.

Gradient Structure Design of Flexible Waterborne Polyurethane Conductive Films for Ultraefficient Electromagnetic Shielding with Low Reflection Characteristic.

Highly efficient electromagnetic shielding materials entailing strong electromagnetic wave absorption and low reflection have become an increasing requirement for next-generation communication technologies and high-power electronic instruments. In this study, a new strategy is employed to provide flexible waterborne polyurethane composite films with an ultra-efficient electromagnetic shielding effectiveness (EMI SE) and low reflection by constructing gradient shielding layers with a magnetic ferro/ferric oxide deposited on reduced graphene oxide (rGO@Fe3O4) and silver-coated tetraneedle-like ZnO whisker (T-ZnO/Ag) functional nanoparticles. Because of the differences in density between rGO@Fe3O4 and T-ZnO/Ag, a gradient structure is automatically formed during the film formation process. The gradient distribution of rGO@Fe3O4 over the whole thickness range forms an efficient electromagnetic wave absorption network that endows the film with a strong absorption ability on the top side, while a thin layer of high-density T-ZnO/Ag at the bottom constructs a highly conductive network that provides an excellent electromagnetic reflection ability for the film. This specific structure results in an "absorb-reflect-reabsorb" process when electromagnetic waves penetrate into the composite film, leading to an excellent EMI shielding performance with an extremely low reflection characteristic at a very low nanofiller content (0.8 vol % Fe3O4@rGO and 5.7 vol % T-ZnO/Ag): the EMI SE reaches 87.2 dB against the X band with a thickness of only 0.5 mm, while the shielding effectiveness of reflection (SER) is only 2.4 dB and the power coefficient of reflectivity ( R) is as low as 0.39. This result means that only 39% of the microwaves are reflected in the propagation process when 99.9999998% are attenuated, which is the lowest value among the reported references. This composite film with remarkable performance is suitable for application in portable and wearable smart electronics, and this method offers an effective strategy for absorption-dominated EMI shielding.

Size‐Dependent Electrical and Thermal Properties of Onion‐Like Carbons/Polyurethane Composites

Results of dielectric/electrical studies of onion‐like carbon (OLC)/polyurethane composite films in very broad frequency (20 Hz–3 THz) and temperature (26–300 K) ranges are presented. We show that the percolation threshold in these composites strictly depends on OLC aggregate size and is lower for composites having smaller OLC aggregates. The electrical conductivity in the composites is mainly due to electron tunneling between OLC clusters and quasi‐one‐dimensional hopping inside the clusters. The thermal diffusivity increases with OLC concentration and, as for electrical conductivity, is the highest for composites having the smallest OLC aggregates. POLYM. COMPOS., 39:E1834–E1840, 2018. © 2018 Society of Plastics Engineers

High self-dispersibility carbon black particles prepared via hydroxylation and urethane chains encapsulation for enhancing properties of waterborne polyurethane composite films

Carbon black (CB) is a preferred nano-reinforcer for conventional polymers, but it exhibit poor dispersibility, which makes it difficult for further application in the coating industry. Here we prepared hydroxylated carbon black (OCB) by a mild oxidation process and then covalently encapsulated with a urethane chains shell via in situ polymerization, and thus encapsulated carbon black (EOCB) particles were achieved. Surface chemical composition of the EOCB particles was thoroughly characterized by FT-IR, TGA, XPS, and EA techniques, and its dispersion properties in aqueous medium were studied by DLS, natural sedimentation, and TEM analyses. It was found that EOCB possessed a high encapsulation percentage, and showed excellent self-dispersibility and prominent stability in aqueous medium. Furthermore, intensive investigation demonstrated that PUB/EOCB composite, that prepared by blending EOCB particles with a polyurethane binder (PUB), exhibited improved mechanical property, water resistance and matting appearance, which probably due to the strong hydrogen bonds between the EOCB particles and the PUB matrix. This work provides a potential avenue for designing CB-based microcapsules and makes it promising application in waterborne coatings.

Preparation of smooth, flexible and stable silver nanowires- polyurethane composite transparent conductive films by transfer method

Silver nanowires (AgNWs)-polyurethane (PU) composite transparent conductive films were fabricated via transfer method using AgNWs conductive inks and polyurethane as starting materials, and the effects of post-treatments including heat treatment, NaCl solution bath and HCl solution bath for AgNWs film on the sheet resistance and transmittance of the composite films were respectively investigated in detail. AgNWs networks are uniformly embedded in the PU layer to improve the adhesion and reduce the surface roughness of AgNWs-PU composite films. Heat treatment can melt and weld the nanowires, and NaCl and HCl solution baths promote the dissolution and re-deposition of silver and the dissolving of the polymer, both which form conduction pathways and improve contact of AgNWs for reducing the sheet resistance. Smooth and flexible AgNWs-PU composite film with a transmittance of 85% and a sheet resistance of 15 Ω · sq−1 is obtained after treated in 0.5 wt% HCl solution bath for 60 s, and the optoelectronic properties of the resultant composite film can maintain after 1000 cycles of bending and 100 days.

Calcium copper titanate/polyurethane composite films with high dielectric constant, low dielectric loss and super flexibility

Calcium copper titanate(CCTO)/polyurethane composite films with high dielectric constant, low dielectric loss and super flexibility were fabricated by incorporating CCTO ceramic powders into millable polyurethane elastomer (MPU) matrix using a rubber milling combined with hot compression molding method. The composite films show uniform microstructures and the dielectric constant is as high as 35.2 while the dielectric loss is only 0.041 when CCTO content reaches 40vol% at 100Hz and room temperature (RT). Moreover, it is important to note that this film has stable dielectric constant and dielectric loss in a relatively wide temperature range (from 0°C to 70°C), which is significantly import to the practice use of electronic devices based on CCTO composites. In addition, the flexibility of the film could be retained even when the CCTO content is up to 40vol% and the elongation at break of this composite film is as high as 159.1%. Theoretical analysis indicates that the experimental data are in good conformity to the effective medium theory (EMT) model with a derived n = 0.21, suggesting more close association of the dielectric constant with the CCTO filler size and shape.

In Situ Photogeneration of Palladium Nanoparticles in Thermoplastic Polyurethane: Photopatterning and Enhanced Oxygen Barrier Property

AbstractA solid phase synthesis of sub 5 nm palladium nanoparticles (Pd NP) by in situ photogeneration in thermoplastic polyurethane (TPU) composite films containing metal precursor and organic photoreducing agent is reported. The technique is highly facile, controllable, and potentially scalable to production quantities. Selective reduction and photopatterning can also be afforded using a shadow mask. The TPU films with Pd NP significantly enhance the barrier property by 64%. This photochemical approach shows promise for the fabrication of oxygen scavenging packaging systems for food, pharmaceutical, and electronics applications as well as for other products that require low oxygen storage atmosphere.

Polyurethane/esterified cellulose nanocrystal composites as a transparent moisture barrier coating for encapsulation of dye sensitized solar cells

ABSTRACTThis research work aims to investigate the effects of types and concentration of cellulose nanocrystals (CNCs) prepared from bacterial cellulose (BC) and nanofibrillated cellulose (NFC) on structure properties of polyurethane (PU) composites. Feasibility of applying the polymer composite for encapsulation of dye sensitized solar cells was of interest. Both CNCs were pretreated via esterification before mixing with the polyurethane by a solution process. Tensile strength and thermal stability of the PU/esterified CNCs were found to be superior to those of the systems reinforced with untreated CNCs. With the introduction of both untreated and esterified CNCs, water vapor transmission rates through the PU composite films were lowered while their visible light transmittance values were maintained to be above 80%. Also, better efficiency and stability of the solar cell were obtained when the PU was reinforced with CNCs, indicating its longer lifetime usage. The most suitable cell, described in terms of durability, was obtained when the PU was mixed with 2 wt % of esterified CNCs obtained from BC. Overall, this study shows that the surface modification of the CNCs is an important factor, affecting the reinforcing efficacy. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45010.

Shape-controllable and -tailorable multi-walled carbon nanotube/MnO2/shape-memory polyurethane composite film for supercapacitor

A new shaped memory, energy storage and all-solid-state supercapacitor is manufactured by incorporating the prepared multi-walled carbon nanotube/MnO2 (MWCNT/MnO2) composite film into the shape memory polyurethane (SMPU) substrate. The resultant multi-walled carbon nanotube/MnO2/shape-memory polyurethane (MWCNT/MnO2/SMPU) hybrid film can be changed into various shapes under an external force and maintained them after removing the external force. And it would recover to its original state within one second once the temperature is above the glass transition temperature of SMPU. Furthermore, the MWCNT/MnO2/SMPU hybrid film used as the electrode maintains a high areal specific capacitance (69.1mF cm−2) and cycles stability (3000 cycles with only 4.7% loss), making it attractive for supercapacitor. In addition, when the hybrid film was tailored into arbitrary shapes, the capacitance was well proportional to the area. For these properties, the hybrid film can be used in wearable electronics, in which the shapes need to be controlled or tailored.

Polyurethane encapsulated carbon black particles and enhanced properties of water polyurethane composite films

Abstract Polyurethane-encapsulated carbon black (ECB) particles were synthesized successfully through a facile method by encapsulating carbon black (CB) particles in the presence of an amphiphilic isocyanate-terminated polyurethane pre-polymer. Fourier transform infrared spectroscopy demonstrated the existence of a polyurethane layer on the surface of encapsulated CB, and thermo-gravimetric analysis indicated the encapsulation percentage reached 15.77 wt.%. The results of dynamic light scattering, transmission electron microscopy, and UV–vis spectroscopy analyses revealed that the ECBs exhibited better dispersibility and stability in water in comparison with the dispersant-dispersed carbon black (DCB) prepared by simply dispersing CB particles using a polymer super-dispersant. In particular, scanning electron microscope observation of PUB/ECB composite films obtained by blending ECB particles with a waterborne polyurethane binder (PUB), showed enhanced dispersibility and compatibility of the ECBs in the PUB matrix. Therefore, as test results demonstrated, PUB/ECB composite films showed better mechanical, water resistance, and color properties compared with those of PUB/DCB composite film. It is expected that this effective encapsulation method for preparing functional CB dispersions will be used to make waterborne coatings in the leather and textile finishing fields.

A comparative study on anti-UV non-spherical methacrylate polymer particles and anti-UV PVA nanofibers

Three types of anti-UV non-spherical polymer particles (AUNSPP) based on methacrylate and anti-UV PVA nanofiber were synthesized to study and compare their UV protection properties. In the first type of AUNSPP, polystyrene seeds were swollen with dichloromethane solution of 2-(2H-benzotriazol-2-yl)-4,6-bis(1-methyl-1-phenylethyl) phenol (TINUVIN® 234, which hereafter is called TINUVIN), styrene, divinylbenzene, and 2,2′-azobisisobutyronitrile (AIBN). In the other two types of AUNSPP, poly(methyl methacrylate) seeds were swollen with dichloromethane solution of TINUVIN, methyl methacrylate, lauryl methacrylate, ethylene glycol dimethylacrylate, and AIBN. Subsequently, dichloromethane was evaporated from the swollen microspheres, and polymerization was accomplished by elevating the temperature of swollen particles to 70 °C. The final particles were assigned as P(S)/TINUVIN, P(S-DVB)/TINUVIN, P(LMA–EGDMA)/TINUVIN, and P(MMA–EGDMA)/TINUVIN composite microspheres. Anti-UV PVA nanofibers were prepared by dispersing P(S-DVB)/TINUVIN microparticles in PVA aqueous solution. Finally, this mixture was electrospun under ambient conditions. Particle size, size distribution, and morphology of the particles were investigated by SEM micrograph and image analyzer software (Image J). The presence of TINUVIN in P(S-DVB)/TINUVIN composite particles was confirmed by FTIR and phosphorescence spectroscopy. The UV protective properties of microcomposite particles and anti-UV nanofibers were studied by UV–Vis spectra of their polyurethane (PU) composite film. Comparatively, similar cutoff wavelength effects were observed in the range of 200–400 nm in all the samples. The obtained results showed consistent drop in the UV-blocking efficiency as the UV irradiation time increased. PU/PS/TINUVIN and PU/anti-UV nanofiber composite films showed the worst and best UV-blocking efficiency, respectively. After 200, 400, 600, 800, and 1000 h of UV irradiation time, the blocking efficiency of the PU–PS/TINUVIN composite films dropped from 80 to 72, 68, 65, and 59 %, and that of the PU/anti-UV nanofiber composite films dropped from 98 to 97, 94, 86, and 83 %.

The “Wear and Measure” Approach: Linking Joint Stability Measurements from a Smart Clothing System to Optical Tracking

Joint stability is essential for maintaining normal everyday function. However, assessment of stability often still relies on subjective or obtrusive methods. An unobtrusive approach would be to have our clothes assess our joint stability.Methods. A new application consisting of an attachable clothing sensing system (ACSS), constructed from a flexible carbon black and polyurethane composite film, was tested against an optical tracking system to assess if the ACSS placed across the knee could provide stability results that correlate with the optical tracking outcomes. Stability was challenged by reducing the base of support and by removing vision generating different experimental conditions.Results. Bland and Altman plots indicated a general proportional error between the measurement systems within each stability condition. However, across all conditions a Spearman correlation coefficient of 0.81 (p<0.001) was found between the displacement values and ACSS, showing a good association between stability measurements. Electromyography (EMG) also indicated that joint stability was challenged between the different conditions. The ACSS was experienced by users as comfortable and hardly noticeable.Conclusions. This study indicates that smart clothing can measure important physiological parameters in an unobtrusive manner. This “wear and measure” approach might change how we gather relevant clinical data in the future.

Functionalized Low Defect Graphene Nanoribbons and Polyurethane Composite Film for Improved Gas Barrier and Mechanical Performances

A thermoplastic polyurethane (TPU) composite film containing hexadecyl-functionalized low-defect graphene nanoribbons (HD-GNRs) was produced by solution casting. The HD-GNRs were well distributed within the polyurethane matrix, leading to phase separation of the TPU. Nitrogen gas effective diffusivity of TPU was decreased by 3 orders of magnitude with only 0.5 wt % HD-GNRs. The incorporation of HD-GNRs also improved the mechanical properties of the composite films, as predicted by the phase separation and indicated by tensile tests and dynamic mechanical analyses. The improved properties of the composite film could lead to potential applications in food packaging and lightweight mobile gas storage containers.

Improved nanoindentation and microwave shielding properties of modified MWCNT reinforced polyurethane composites

Acid modified multiwalled carbon nanotubes (a-MWCNT) reinforced polyurethane (PU) composite films have been fabricated using a solvent casting technique with 0–10 wt% of a-MWCNTs. A nanoindentation study has been carried out on these films in order to investigate the mechanical properties. Incorporation of a-MWCNTs in a PU matrix led to a drastic increase in the hardness and elastic modulus. The maximum nanoindentation hardness of 217.5 MPa for 10 wt% a-MWCNT loading was observed as compared to 58.5 MPa for pure PU (an overall improvement of 271%). The nanoindentation elastic modulus for a 10 wt% a-MWCNT loaded sample was 1504.2 MPa as compared to 385.7 MPa for pure PU (an overall improvement of 290%). In addition to hardness and elastic modulus, other mechanical properties i.e. plastic index parameter, elastic recovery, ratio of residual displacement after load removal and displacement at the maximum load and plastic deformation energy have also been investigated. The enhancement in the mechanical properties was correlated with spectroscopic and microscopic investigations using Raman spectroscopy, SEM and TEM. Dispersion of a-MWCNTs in the PU matrix was studied using Raman mapping. Besides the improvement in mechanical properties, the electromagnetic interference shielding properties were also investigated in the 8.2–12.4 GHz (X-band) frequency range. A value of ∼29 dB for the 10 wt% MWCNT loaded sample having a thickness of 1.5 mm was obtained. Therefore, these polyurethane composite films shall not only be useful for hard and scratchless coatings but also for protection from electromagnetic radiation in making electromagnetic shielding bags for packaging of electronic circuits and for scratchless tape for laminating circuit boards.

Photostability and photobactericidal properties of porphyrin-layered double hydroxide-polyurethane composite films.

The photostability and photobactericidal properties of PdTPPC (Pd(ii)-5,10,15,20-tetrakis(4-carboxyphenyl)porphyrin)-Zn2Al/PU (polyurethane) composite films have been studied in order to investigate their applicability as new photodynamic surfaces. These films comprise a PdTPPC porphyrin photosensitizer intercalated between the lamella of Zn2Al layered double hydroxide and dispersed (1 wt%) into a polyurethane matrix. The study of the photophysical behaviour shows that the Zn2Al LDH host enhances the chemical stability of the PdTPPC guest by minimizing photobleaching and quenching aggregation effects. The singlet oxygen production under irradiation of PdTPPC-Zn2Al/PU composite films is confirmed by the observation of an O2(1Δg) emission band centered at 1274 nm. Furthermore, the value of the rate constant kq for the PdTPPC phosphorescence quenching by oxygen kq = (8.2 ± 0.3) 10-2 s-1 Pa-1 indicates a slow diffusion of oxygen into and out of the PU polymer. In a second step, accelerating light ageing tests are conducted to determine the effect of singlet oxygen production on the chemical and mechanical stability of the PU matrix. Oxygen uptake experiments coupled with ATR-IR measurements indicate the probable formation of hydroxylated photoproducts but with no detrimental effects on the microstructure and the viscoelastic properties of the PU matrix as evidenced by dynamical mechanical analysis. Finally, in vitro preliminary antimicrobial tests show that PdTPPC-Zn2Al/PU composite films are able to inhibit S. aureus growth with no release of PdTPPC biocide from the PdTPPC-Zn2Al/PU composite film. We also observe a total inhibition of P. aeruginosa growth suggesting an efficacy against biofilm formation.

Low pressure plasmachemical processing of multi-walled carbon nanotubes for the production of polyurethane composite films with improved mechanical properties

Multiwalled carbon nanotubes (CNTs) were modified in low pressure capacitively coupled discharges (13.56 and 27.12MHz) in Ar/NH3 and oxygen-containing gas mixtures. A direct functionalization by nitrogen groups was not possible but 1–3 percentage of carbon–oxygen bonds increased with the total oxygen content on the expenses of sp2C almost independently on the plasma conditions. The plasma modified CNTs were used as fillers for polyurethane (PU) composites prepared by in situ polymerization. The composites were investigated by depth sensing indentation that revealed the existence of surface harder layer caused probably by different polymerization process in the bulk and at the surface that was in a contact with air. The significant improvement of the hardness and elastic modulus was observed when plasma-modified CNTs with high amount of oxygen were added to PU. It also improved the creep resistance of the PU, whereas the ability to recover from a deformation, i.e. anelastic recovery, did not change much.