Effects of Poly(acrylic acid) on Rheological and Dispersion Properties of Aqueous TiO2 Suspensions

The poly(acrylic acid) was used as dispersant to prepare aqueous TiO₂/poly(acrylic acid) suspensions. The poly(acrylic acid) was adsorbed on the surface of the TiO₂ particles. The zeta potential of the TiO₂ particles in TiO₂/poly(acrylic acid) suspensions was higher than that of the TiO₂ particles in TiO₂ suspensions, and the zeta potential of the TiO₂ particles increased with increasing poly(acrylic acid) content. At the same shear rate, the viscosity of TiO₂/poly(acrylic acid) suspensions was lower than that of TiO₂ suspensions, and the liquidity was improved. The dispersion of TiO₂ particles in TiO₂/poly(acrylic acid) suspensions was improved compared with that of TiO₂ particles in TiO₂ suspensions.     

In situ polymerization of titanium isopropoxide in polycaprolactone: Properties and characterization of the hybrid nanocomposites

In this study, tetra isopropyl ortho titanate (TTIP) and polycaprolactone (PCL) were chosen as the ceramic precursor and the continuous phase, respectively, for the preparation of novel nanocomposites by using an in situ sol‐gel process. In addition, acrylic acid grafted polycaprolactone (PCL‐g‐AA) was investigated as an alternative to PCL. The hybrids (PCL/TiO₂ and PCL‐g‐AA/TiO₂) were characterized via Fourier transform infrared (FTIR) spectroscopy, dynamic mechanical thermal analysis (DMA), X‐ray diffraction (XRD), differential scanning calorimetry (DSC), thermogravimetry analysis (TGA), and Instron mechanical testing. It was found that the carboxylic acid groups of acrylic acid acted as coordination sites for the titania phase to form chemical bonds, thus improving the properties of the acrylic acid grafted composite compared with its acrylic‐acid‐free counterpart. The TiO₂ content also determined the strength of interfacial bonding between the polymer chains and the ceramic phase, as shown by changes in glass transition temperature (T_g) with TiO₂ content. The maximum values of tensile strength and T_g were obtained with the PCL‐g‐AA/TiO₂ composite at 10 wt % TiO₂. At TiO₂ contents above this, excess particles led to segregation between the organic and inorganic phases. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1749–1757, 2004     

Copper nanowire/PA6 composites prepared by in situ polymerization and its properties

Most magnetic composite materials have a serious sedimentation problem because of their large density. When the nanomaterials are combined with magnetic materials, the density would become larger. In this article, polystyrene (PS) beads were used as core to synthesize raspberry-like PS-Fe₃O₄@TiO₂ particles (PFTPs) by a facile method, which could float on the water. The loaded Fe₃O₄@TiO₂ particles were characterized by X-ray diffraction (XRD), which could confirm the anatase phase TiO₂ coated on Fe₃O₄ nano-particles. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) confirmed the presence of acrylic acid in reaction media could effectively tune the morphology of resulting composite particles between “core-shell” and “raspberry-like”. The data of Vibrating sample magnetometer (VSM) indicated the change in saturation magnetization before and after TiO₂ coated, the introduction of PS could further influence the saturation magnetization of Fe₃O₄. Lastly, we proved the sedimentation stability of PFTPs via capturing the photographs of them in water and oil.     

Tio2‐ or tio2/fe3o4‐containing PVA‐based microgels for controlled photocatalytic degradation of methyl orange

An inverse emulsion radical reaction was adopted to prepare poly(vinyl alcohol) (PVA)‐based microgels that contained titanium oxide (TiO₂) or TiO₂/Fe₃O₄, and the obtained microgels were applied to catalyze the degradation of methyl orange. First, well‐defined PVA was used to synthesize a PVA‐based macromonomer (PVAM) that contained carbon–carbon double bonds of tunable contents. Then, the composite microgels were prepared via the crosslinking reaction between PVAM and acrylic acid in the presence of TiO₂ or TiO₂/Fe₃O₄. Thermogravimetric analysis (TGA) and scanning electron microscope observation confirmed that the inorganic nanoparticles were well encapsulated within the microgels. TGA results showed that the loading efficiency of TiO₂ was able to be controlled by varying the structure of PVAM. It was found that the microgels can efficiently catalyze the degradation of methyl orange. Moreover, the composite microgels possessed controllable and returnable catalysis ability. In addition, the separation of the composite microgels from aqueous solution could be quite easily accomplished by incorporating magnetic particles. POLYM. COMPOS., 38:132–137, 2017. © 2015 Society of Plastics Engineers     

Preparation of titanium dioxide/poly(methyl methacrylate‐co‐n‐butyl acrylate‐co‐methacrylic acid) hybrid composite particles via emulsion polymerization

Titanium dioxide core and polymer shell composite poly(methyl methacrylate‐co‐n‐butyl acrylate‐co‐methacrylic acid) [P(MMA‐BA‐MAA)] particles were prepared by emulsion copolymerization. The stability of dispersions of TiO₂ particles in aqueous solution was investigated. The addition of an ionic surfactant, sodium lauryl sulfate, which can be absorbed strongly at the TiO₂/aqueous interface, increases the stability of the TiO₂ dispersion effectively by increasing the absolute value of the ζ potential of the TiO₂ particles. The adsorption of the nonionic surfactant, Triton X‐100, on the surface of TiO₂ particles is less than that of the ionic surfactant. Fourier transform IR spectroscopy was used to measure the content of MAA composite particles. Dynamic light scattering characterized the composite particle size and size distribution. The field‐emission scanning electron microscopy results for the composite particles showed a regular spherical shape, and no bare TiO₂ was detected on the entire surface of the samples. The composite particles that were produced showed good spectral reflectance compared to bare TiO₂. Thermogravimetric analysis results indicated the encapsulated TiO₂ and estimated density of composite particles. There was up to 78.9% encapsulated TiO₂ and the density ranged from 1.76 to 1.94 g/cm³. The estimated density of the composite particles is suitable at 1.73 g/cm³, which is due to density matching with the suspending fluid. The sedimentation experiment indicates that reducing the density mismatch between the composite particles and suspending fluid may enhance the stability. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 72–79, 2005     

Preparation of hollow TiO2 nanoparticles through TiO2 deposition on polystyrene latex particles and characterizations of their structure and photocatalytic activity

In a mixed solvent of water and ethanol, polystyrene/titanium dioxide (PSt/TiO₂) composite particles of core-shell structure were prepared by hydrolysis of tetrabutyl titanate in the presence of cationic PSt particles or anionic PSt particles surface-treated using γ-aminopropyl triethoxysilane. Hollow TiO₂ particles were obtained through calcination of the PSt/TiO₂ core-shell particles to burn off the PSt core or through dissolution of the core by tetrahydrofuran (THF). An alternative process constituted of preheating the PSt/TiO₂ particles at 200°C to allow partial crystallization followed by calcination or PSt dissolution by THF. The outcome TiO₂ particles thus prepared were examined by TEM, and hollow TiO₂ particles were observed. The crystalline phase structure and phase transformation were characterized, which revealed that preheating before the removal of the PSt core was useful to achieve the desired hollow TiO₂ particles, and the calcination process was beneficial to the formation of anatase and rutile structures. The tests of TiO₂ particles as catalyst in the photodegradation of Rhodamine B demonstrated that a much higher catalytic activity was observed with the TiO₂ hollow particles prepared through calcination combined with preheating.     

Preparation of TiO2-loaded nanocapsules and their sun protection behaviors

Titanium dioxide (TiO₂) sol (TS) or TiO₂ nanoparticles with chitosan shell were encapsulated to enhance their sun protection abilities. Nanocapsules loaded with TiO₂ were evaluated for their ultraviolet (UV) absorption and UV protection rate. The effect of eicosapentaenoic acid (EPA) incorporation into the nanocapsules was examined in relation to UV absorption. The particle size of TiO₂ crystallites in TS was below 30 nm, which was considerably smaller than that of a commercial TiO₂ (P25 TiO₂) particles. In the encapsulation of TiO₂ with chitosan, the loading efficiencies of TS were higher than those of P25 TiO₂. The sizes of the nanocapsules loaded with TiO₂ particles ranged from 30 to 80 nm. The absorption range of irradiation wavelength was enlarged by the incorporation of EPA into the nanocapsules. The TS-loaded nanocapsules exhibited a high UV protection rate of up to 95% to both UV-A and UV-B.     

Molecular dynamics study of TiO2/poly(acrylic acid‐co‐methyl methacrylate) and Fe3O4/polystyrene composite latex particles prepared by heterocoagulation

All‐atom molecular dynamics simulations were used to study the morphology of polymer/inorganic composite particles prepared by heterocoagulation. The results were also compared to those of our previous study of the preparation of TiO₂/poly(acrylic acid‐co‐methyl methacrylate) and Fe₃O₄/polystyrene composite particles. In the simulation system, polymer or inorganic particles were simulated by surface‐charge‐modified C₆₀ or Na atoms. Through a combination of analysis of the radial distribution functions of charged atoms and snapshots of the equilibrated structure, three kinds of particle distributions were observed under different conditions. When the polymer and inorganic particles had opposite surface charges and their sizes were very different, the composite morphology showed a core–shell structure with small particles adsorbed onto the surfaces of large particles. Furthermore, when the polymer and inorganic particles had opposite surface charges but comparable sizes, the polymer and inorganic particles aggregated domain by domain. Finally, when the polymer and inorganic particles were endowed with the same surface charge, the distribution of these two types of particles was homogeneous, regardless of their size difference. The simulation results were in agreement with the experimental results. The electrostatic interaction and the size of the particles dominated the final morphology of the composite particles when the heterocoagulation method was used. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

High PVC film‐forming composite latex particles via miniemulsification,part 1: Preparation

Miniemulsification technology was used to encapsulate TiO₂ particles inside a styrene/n‐butyl acrylate copolymer with high loading levels (11 to 70% PVC (pigment volume concentration)). In this approach, a St/BA copolymer dissolved in toluene in the presence of a costabilizer (hexadecane) was mixed with a dispersion of TiO₂ particles in toluene and sonified, and then emulsified in an aqueous surfactant solution by sonification. The effect of sonification time on both the dispersibility of the TiO₂ particles in the presence of the copolymer and hexadecane and on the encapsulated particle size was investigated. Particle size analysis by dynamic light scattering showed that these composite latexes are quite stable. It was also found that as the TiO₂ loading increased from 11 to 43% PVC, the particle size of the TiO₂ dispersion decreased while the polymer‐encapsulated TiO₂ particle size increased. The effect of surfactant concentration (sodium lauryl sulfate, SLS) on the encapsulated particle size was investigated using four different SLS concentrations in the 11% PVC system. The results showed that as the SLS concentration increased the particle size decreased, as expected. Also it was found that the minimum surfactant concentration that gives stable encapsulated TiO₂ particles is above 10 mM SLS. The role of HD in the recipe was studied for an artificial latex containing no TiO₂ and one prepared at 11% PVC, in terms of particle size before and after solvent stripping, and its effect on the T_g. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 4504–4516, 2006     

Trilayer Composite Poly(styrene/butyl acrylate/acrylic acid) Terpolymer Microspheres with Fe2O3 Middle Layer: Synthesis and Characterization

Fe₂O₃ particles with diameter of 3–5 nm were encapsulated in polymer spheres (styrene/butyl acrylate/acrylic acid terpolymer latex) by emulsion polymerization. Control of the pH value of the medium and modification of the latex prior to the second polymerization were of importance in determining the microstructure and morphology of the composite particles. The interaction between Fe₂O₃ and seed latex was confirmed by IR spectral changes of the surface groups of the latex particles. Mossbauer spectra gave evidence for the changes of electric density and electric field symmetry around Fe₂O₃, and surface photovoltage spectra indicated that the Fe₂O₃ particles were encapsulated in polymer. It was shown by all the results that the composite microspheres of size 80 nm had a core–shell structure with trilayers of seed latex core, Fe₂O₃ nanoparticles middle layer and polymer shell. © 1997 SCI.     

Influence of MWCTs and nanometal oxide/MWCTs hybrids on the thermal conduction of their acrylic-based nanocomposites

In this study, acrylic-based nanocomposites containing different contents of multi-walled carbon nanotubes (MWCNTs) and metal oxide nanoparticles (i.e., TiO₂, CuO and Fe₂O₃) were fabricated by solvent mixing method. The thermal conductivity of these samples was evaluated. The results indicated that the thermal conductivity of all fabricated samples was significantly improved even at small loading of MWCNTs. It was found that the thermal conductivity was enhanced by increase in MWCNTs content up to 5 wt%. Similarly, the metal oxide nanoparticles caused up to 75 % increment in thermal conductivity at 1.5 wt% of their loading in acrylic film. Contrary to expectations, the thermal conductivity of acrylic film was more increased by nanometal oxides (i.e., TiO₂, CuO and Fe₂O₃) than MWCNTs. The effect of hybridizing of nanometal oxide particles (1.5 wt%) and MWCNTs (1.5 wt%) on thermal conduction was investigated as well. It was found that hybridizing improved thermal conductivities by about 85, 94 and 97 % for Fe₂O₃, TiO₂ and CuO, respectively. Finally, the effects of TiO₂ pigment and CaCO₃ extender on the thermal conductivity of acrylic polymer and nano-TiO₂ acrylic composites were studied. It was found that TiO₂ could increase considerably thermal conduction of its acrylic films and acrylic nanocomposites.     

Preparation and characterization of porous titanium dioxide sulfonated polystyrene composite microspheres with amphiphilicity

Porous particles with amphiphilicity were prepared by a nonpolymeric pore‐formation process with the sulfonation of polystyrene microspheres. Nano titanium dioxide (TiO₂) particles were then grafted onto the surface via a sol–gel method to finally form the composite particles. The effects of the mass ratio of ethanol (EtOH) to water, temperature, and solubility parameter on the pore‐formation process is discussed in detail. The morphology, porous structure, and wetting properties of the particles were studied by scanning electron microscopy, transmission electron microscopy, Fourier transform infrared (FTIR) spectroscopy, and contact angle measurement. The results show that porous sulfonated polystyrene (SP) microspheres could be fabricated at 60°C with a 1 : 1 mass ratio of EtOH–water and a solubility parameter of 29.69 MPa^1/2. The TiO₂ particles were determined to be grafted onto the SP microspheres by physical‐bond interaction on the basis of FTIR analysis. The contact angles for both water (aqueous‐phase) and various organic solvent (oil‐phase) droplets with different polarities on the surface of compressed tablets of TiO₂–SP powder were all lower than 30°; this indicated excellent amphiphilicity in the composite particles. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Synthesis of copper–polystyrene nanocomposite particles using water in supercritical carbon dioxide medium and its antimicrobial activity

Copper‐encapsulated polystyrene nanocomposite particles were prepared through ex situ dispersion of Cu nanoparticles into monomer droplets and subsequent polymerization using water in supercritical carbon dioxide (water‐in‐sc‐CO₂) at 70°C. First, colloidal dispersion of copper nanoparticles was synthesized by chemical reduction of copper chloride (CuCl₂) using sodium borohydrate (NaBH₄) as reducing agent. Colloidal dispersion of copper nanoparticles was added slowly during the polymerization of styrene using water‐in‐sc‐CO₂ medium at 70°C and 20.68 MPa. Cu nanoparticle encapsulated polymer particles were characterized by UV, X‐ray diffraction, thermogravimetric analysis, SEM, and TEM. Cu nanoparticles were uniformly distributed inside the polymer matrix during the polymerization process. This work represents a simple way to prepare a variety of metal nanoparticles encapsulated polymer particles using water‐in‐sc‐CO₂ medium. The Cu/polystyrene nanocomposite particles exhibit antimicrobial activity against a number of bacteria. The current work represents a simple, cheap and universal way to prepare a variety of metal–polymer nanocomposite materials. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Facile method to prepare Pd/Polystyrene composite microspheres and investigation on their catalytic properties

Nano-sized Pd/polystyrene composite nanoparticles were prepared via surfactant-free emulsion polymerization. The as-prepared composite particles were used as a catalyst for Suzuki reaction, and they showed excellent catalytic properties in the conversion and recyclability. First, polystyrene (PS) latex particles bearing carboxyl groups on the surfaces were synthesized via one-stage surfactant-free emulsion polymerization employing acrylic acid as the functional monomer. Thus, made the PS particles negatively charged and could attract positively charged Pd²⁺ ions. By adding PdCl₂ solution to this functional polystyrene emulsion, Pd²⁺ ions were attached to the surfaces and reduced to zero valent particles by the reducing agent, NaBH₄. Nano-sized Pd/PS composite particles could be synthesized via this facile method. The amount of the functional monomers, the Pd²⁺ content and the amount of the initiator played important roles to the final morphologies of the composite particles. The resulting composite microspheres were observed by TEM. Furthermore, catalytic properties of the as-prepared Pd/PS composite particles were studied via Suzuki reaction, and the results were characterized by FTIR and ¹H-NMR. The Pd/PS composite particles showed excellent conversion and could be recycled easily for reuse. After each round of Suzuki reaction, the Pd/PS composite particles could be separated just by filtration, the conversion still remained as high as 70.2?%, even when used 5 times.     

Synthesis of conductive PSt-g-PANi/TiO2 nanocomposites by metal catalyzed and chemical oxidative polymerization

Well-defined polymer-TiO₂ nanocomposites of core–shell structure were prepared by two-steps, surface-initiated atom transfer radical polymerization (ATRP) of styrene and in situ chemical oxidative polymerization of aniline monomers from the surfaces of the TiO₂ nanoparticles. The methods used include the following: initially, the ATRP initiator was covalently attached to the surface of TiO₂ nanoparticles by esterification of 2-bromo-2-methyl propionic acid with hydroxyl group. The metal-catalyzed radical polymerization of styrene with modified TiO₂ nanoparticles was performed using a copper catalyst system to give the TiO₂-based core hybrids linking PSt segments (TiO₂-PSt hybrids). Next, the TiO₂-PSt reacted with HNO₃/H₂SO₄ to produce a nitro group containing polystyrene to form TiO₂-PSt-NO₂, and obtained TiO₂-PSt-NO₂ was treated with hydrochloric acid/SnCl₂, and converted to an amine group containing polystyrene (TiO₂–PSt-NH₂). Finally, surface oxidative graft copolymerization of aniline, using the –NH₂ moieties of TiO₂/PSt-NH₂ as the anchoring sites. Characterization of these well-defined nanocomposites included FTIR, thermogravimetric analysis, transmission electron microscopy, and X-ray diffraction.     

Pulmonary toxicity screening studies in male rats with TiO2 particulates substantially encapsulated with pyrogenically deposited, amorphous silica

The aim of this study was to evaluate the acute lung toxicity in rats of intratracheally instilled TiO₂ particles that have been substantially encapsulated with pyrogenically deposited, amorphous silica. Groups of rats were intratracheally instilled either with doses of 1 or 5 mg/kg of hydrophilic Pigment A TiO₂ particles or doses of 1 or 5 mg/kg of the following control or particle-types: 1) R-100 TiO₂ particles (hydrophilic in nature); 2) quartz particles, 3) carbonyl iron particles. Phosphate-buffered saline (PBS) instilled rats served as additional controls. Following exposures, the lungs of PBS and particle-exposed rats were evaluated for bronchoalveolar lavage (BAL) fluid inflammatory markers, cell proliferation, and by histopathology at post-instillation time points of 24 hrs, 1 week, 1 month and 3 months.     

Macroporous Polytetrafluoroethylene Film with a Reusable Matrix and Its Application as the Microreactors

This work reports a simple and efficient preparation method of an inverse‐opal‐like macroporous polytetrafluoroethylene (IO‐PTFE) film with a reusable matrix. At first, the pH‐responsive poly(acrylic acid) (PAA) is grafted on the PTFE latex particles induced by γ‐ray radiation. The stability of PAA grafted PTFE latex particles (PTFE‐g‐PAA) in water decreases in acid aqueous solution. As a result, PTFE‐g‐PAA particles can coprecipitate with monodispersed polystyrene (PS) microspheres from the acidic aqueous dispersion to form a composite particulate film. After the composite particulate film is etched with toluene to remove PS microspheres, a self‐stand inverse‐opal‐like macroporous PTFE film can be successfully obtained. The macroporous PTFE film can be applied as the microreactor to synthesize uniform TiO₂ particles. The separation of TiO₂ microparticles and the recycle of PTFE‐g‐PAA particles can be simultaneously achieved simply in water by means of ultrasonification. The prepared TiO₂ microparticles also show good photocatalytic performance. This work opens a new thought to prepare special macroporous polymeric materials, and expands the microsynthesis of inorganic or organic microparticles by taking advantage of polymeric macroporous materials.

     

Chemical modification of TiO2 nanoparticles as an effective way for encapsulation in polyacrylic shell via emulsion polymerization

Encapsulation of inorganic nanoparticles by polymers is one of the interesting research topics that lead to the synthesis of nanocomposites. These nanocomposite materials comprise the properties of both organic polymer and inorganic nanoparticles. Here, hybrid latex particles with core–shell nanostructure were prepared via semi-batch emulsion polymerization. Copolymers of (methyl methacrylate-butyl acrylate) and (dimethylaminoethyl methacrylate-butyl acrylate-acrylic acid) were formed as the inner and outer layers, respectively on the surface of modified TiO₂ nanoparticles as the core. In order to create compatibility between inorganic and polymeric phases, modification of TiO₂ nanoparticles was performed with glycidyl methacrylate with an optimized procedure for the first time and then emulsion polymerization was carried out. The products of each step were fully characterized. The results of dynamic light scattering, TEM and SEM analyses proved the formation of encapsulated hybrid latex particles. DLS and SEM data revealed that the sizes of nanocomposite particles vary between 85 and 120 nm for 0–5 wt% of the modified TiO₂ nanoparticles. Physico-mechanical properties of the obtained nanocomposite films were studied by DMTA. It was found that using only 3 wt% of modified TiO₂ improved those properties of resulting films remarkably.     

Encapsulation of titanium dioxide in styrene/n‐butyl acrylate copolymer by miniemulsion polymerization

Miniemulsion copolymerization of styrene/n‐butyl acrylate was investigated as a means of encapsulating hydrophilic titanium dioxide (TiO₂) in a film‐forming polymer. Dispersion studies of the TiO₂ were first carried out to determine the choice of stabilizer, its concentration, and the dispersion process conditions for obtaining stable TiO₂ particles with minimum particle size. Through screening studies of various functional stabilizers and shelf‐life stability studies at both room and polymerization temperatures, Solsperse 32,000 was selected to give relatively small and stable TiO₂ particles at 1 wt % stabilizer and with 20–25 min sonification. The subsequent encapsulation of the dispersed TiO₂ particles in styrene/n‐butyl acrylate copolymer (St/BA) via miniemulsion polymerization was carried out and compared with a control study using styrene monomer alone. The lattices resulting from the miniemulsion encapsulation polymerizations were characterized in terms of the encapsulation efficiencies (via density gradient column separations; DGC) and particle size (via dynamic light scattering). Encapsulation efficiencies revealed that complete encapsulation of all of the TiO₂ by all of the polymer was not achieved. The maximum encapsulation efficiencies were 79.1% TiO₂ inside 61.7% polystyrene and 63.6% TiO₂ inside 38.5% St/BA copolymer. As the density of the particles collected from the DGC increased from one layer to another, both the average particle size and the number of the TiO₂ particles contained in each latex particle increased. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3479–3486, 2006     

Assessment of Novel Water-Borne Coatings Obtained from Composite Latex Particles and Reinforced with TiO2 Nanotubes

Novel, environmentally friendly waterborne coatings were obtained from the filmification of nanostructured latex particles reinforced with inorganic nanotubes. The latex used to form the coatings consists of core-shell particles with a shell functionalized with different amounts of acrylic acid (AA). This external polymer layer was doped, in some cases, with TiO₂ nanotubes at three different concentrations: 100, 500 and 1000 ppm. The composite particles were synthesized in two steps by semi-continuous emulsion polymerization at 75°C. A series of films was prepared by employing core-shell particles with different sizes, core cross-linking and shell functionalization. The coatings obtained were characterized by infrared spectroscopy (FTIR), tapping mode atomic force microscopy (TM-AFM), scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and thermogravimetrical analysis (TGA). Drying rates and tests were also performed to further evaluate these films. It was observed that the addition of small amounts of TiO₂ nanotubes contributes to improve the application properties, mainly adhesion to metallic substrates and water impermeability. The resistance to thermal degradation was also strongly increased, as showed by the DSC and TGA analyses.