TEM, XPS and thermo-mechanical properties of novel sustainable hybrid coatings (original) (raw)
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Polyimide–silica hybrid coatings: morphological, mechanical, and thermal investigations
Polymers for Advanced Technologies, 2007
In this study, polyimide-silica (PI-silica) based hybrid coating compositions were prepared from tetraethoxysilane (TEOS), g-glycidyloxypropyl trimethoxy silane (GOTMS), and polyamic acid (PAA) via a combination of sol-gel and thermal imidization techniques. PAA was synthesized from 3,3(,4,4(-benzophenone tetracarboxylic dianhydride (BTDA) and 3,3'-Diaminodiphenyl sulfone (DDS) in N-Methyl-2-pyrrolidone (NMP). The silica content in the hybrid coatings was varied from 0 to 20 wt%. The structural characterization of the hybrid coatings was performed using FTIR and 29 Si-NMR spectroscopies. Results from both pendulum hardness and micro indentation test show that the hardness of hybrid coatings improves with the increase in silica content. The tensile tests also demonstrated that the mechanical properties at low silica content are rather striking. Their surface morphologies were characterized by scanning electron microscopy (SEM). SEM studies revealed that inorganic particles were distributed homogenously through the PI matrix. It was also found that, incorporation of the silica domains increased the thermal stability of the hybrid coatings.
Journal of Applied Polymer Science, 2018
This study prepared fluorine and SiO 2 particles containing organic-inorganic hybrid polyimide nanocomposite coatings (PISFs) with inorganic content in the range of 5-20% in pure polyimide solutions via the sol-gel process. Polyimide hybrid structures containing fluorine and SiO 2 particles were synthesized by using perfluorooctyltriethoxysilane and tetraethyl orthosilicate. These formulations were applied on aluminum sheets by using a 75 μm wire wound applicator, and the coatings were cured for 8 h at room temperature and then 24 h at 100 C. Increased inorganic contents caused slight decreases in the initial decomposition temperatures, but the char yield values increased for PISF15 and PISF20. All samples exhibited hydrophobic properties. When all samples were compared, PISF5 and PISF10 exhibited hydrophobicity, high wear resistance and thermal properties. Additionally, PISF5 and PISF10 showed high adhesion, hardness, and methyl ethyl ketone solvent resistance.
Journal of Materials Science, 2009
The mechanical properties of various inorganic organic films were studied and compared in order to investigate the relation between structural modifications and the mechanical behavior. Films were prepared by a sol-gel process and spin-coated on silicon substrate. The organicinorganic hybrid is composed of a mixture of colloidal silica and organosiloxane precursors. The functionality of the organosiloxane and the nature of its organic part have been modified to obtain a structural change. Mechanical properties were studied using nanoindentation. Analysis of the strength evolution as a function of depth of indentation shows the layer hardness and elastic modulus. Moreover, coating and interface toughness and residual stresses were determined by a time resolved study of energy dissipation during indentation. The structural changes were determined using liquid and solid 29 Si NMR spectroscopy. Quantity of partially and fully condensed species in the deposited sol and final solid are discussed in relation to the mechanical properties.
Progress in Organic Coatings, 2012
For the first time, polyurethanefattyamide/silica [PULFAS] based organic-inorganic hybrid coatings were prepared at ambient temperature to combat the corrosion of mild steel. The coating material was synthesized in situ by the reaction of Linseed diol fattyamide (HELA) and tetraethoxy orthosilicate (TEOS, 20-30 phr) at 80 • C, followed by the addition of calculated amount of toluene-2,4-diisocyanate (TDI) in the reaction setup at room temperature. The formation of PULFAS was confirmed by FTIR spectral technique while morphology of the same was observed by optical micrography. The physico-mechanical properties of PULFAS coatings such as scratch hardness, impact resistance, bend test and gloss along with coating thickness were evaluated by standard methods. Thermal stability of PULFAS was investigated by thermogravimetric analysis (TGA). Curing behavior of PULFS was studied by differential scanning calorimetry (DSC). Corrosion resistance performance of the hybrid coatings was evaluated by potentio dynamic polarization (PDP) measurements in different corrosive environments at room temperature. Salt spray test of PULFAS coatings was carried out in 3.5 wt% NaCl solution. The corrosion protection mechanism of the same was also investigated. The results showed that PULFAS coatings exhibit good physico-mechanical properties with excellent performance against the corrosive environments.
Polymer International, 2012
Hyperbranched polyurethane-urea)/[(3-aminopropyl)triethoxysilane]-ZnO (HBPUU-APTES-ZnO) hybrid coatings were synthesized using an inexpensive mixing technique by varying the APTES-modified ZnO concentration. The mechanical and surface properties of the hybrid coating films were studied and compared with unmodified and modified ZnO. The corrosion, solvent and abrasion resistance show significant enhancement in HBPUU-APTES-ZnO hybrids and their properties are increased with increasing APTES-ZnO concentration. This hybrid coating has opened up an opportunity for automotive topcoat application.
Independent Control of Adhesive and Bulk Properties of Hybrid Silica Coatings on Polycarbonate
ACS Applied Materials & Interfaces, 2013
Transparent polymers are widely used in many applications ranging from automotive windows to microelectronics packaging. However, their intrinsic characteristics, in particular their mechanical properties, are significantly degraded with exposure to different weather conditions. For instance, under humid environment or UV-irradiation, polycarbonate (PC) undergoes depolymerization, leading to the release of Bisphenol A, a molecule presumed to be a hormonal disruptor, potentially causing health problems. This is a serious concern and the new REACH (Registration, Evaluation, Authorization and Restriction of Chemical substances) program dictates that materials releasing Bisphenol A should be removed from the market by January 1st, 2015 (2012-1442 law). Manufacturers have tried to satisfy this new regulation by depositing atop the PC a dense oxide-like protective coating that would act as a barrier layer. While high hardness, modulus, and density can be achieved by this approach, these coatings suffer from poor adhesion to the PC as evidenced by the numerous delamination events occurring under low scratch constraints. Here, we show that the combination of a N 2 /H 2-plasma treatment of PC before depositing a hybrid organicinorganic solution leads to a coating displaying elevated hardness, modulus, and density, along with a very high adherence to PC (> 20 J/m 2 as measured by double cantilever beam test). In this study, the sol-gel coatings were composed of hybrid O/I silica (based on organoalkoxysilanes and colloidal silica) and designed to favor covalent bonding between the hybrid network and the surface treated PC, hence increasing the contribution of the plastic deformation from the substrate. Interestingly, doublecantilever beam (DCB) tests showed that the coating's adhesion to PC was the same irrespective of the organoalkoxysilanes/ colloidal silica ratio. The versatility of the sol-gel deposition techniques (dip-coating, spray-coating, etc.), together with the excellent mechanical properties and exceptional adherence of this hybrid material to PC should lead to interesting new applications in diverse fields: optical eyeglasses , medical materials, packaging, and so forth.
Express Polymer Letters, 2015
Silica nanoparticles were modified with aromatic amino groups and modified-silica/polyimide composite films were prepared using them. 3,3!,4,4!-Benzophenone tetracarboxylic dianhydride (BTDA) and 4,4!-oxydianiline (ODA) were used as precursors for polyimide matrix. The structures of the modified nanoparticles and hybrid nanocomposites were identified using Fourier Transform Infrared (FTIR) spectrometry. The hybrid composite films were evaluated for mechanical, thermal and morphological characteristics. Morphological results describe a uniform dispersion of silica particles in the polymer matrix. The thermal stability and mechanical properties of polyimide composite were improved, and the decomposition temperature was increased when the amount of silica nanoparticles was increased.
The novel use of organo alkoxy silane for the synthesis of organic–inorganic hybrid coatings
Journal of Non-crystalline Solids, 2006
UV-curable, organic-inorganic hybrid coatings based on a UV-curable epoxyacrylate resin (EA) and methacryloxypropyl trimethoxysilane were prepared by the sol-gel method. 2,2 0 -Bis(4-b-hydroxy ethoxy) phenyl propane was modified by a coupling agent, 3-isocyanato propyl triethoxy silane, to improve the compatibility of the organic and inorganic phases. The formulations were applied onto Aluminum panels and cured by UV light to obtain a hard and clear coating with a good adhesion. The structural characterization of cured hybrid materials was performed using solid state 29 Si NMR spectroscopy. The real time infrared technique was used to follow the degree of double bond conversion and photopolymerization rate. The thermal properties of the coatings are improved depends on the 'component A' composition in hybrid mixture which was composed of methacryloxy propyl trimethoxysilane (MAPTMS) and trimethoxysilane terminated HEPA urethane (TMSHU). The char yield of pure epoxy acrylate resin was 0.7 wt% and that of 30 wt% of component A containing hybrid coating was 4.6 wt% at 900°C in air atmosphere. The morphology of the hybrid materials was examined by scanning electron microscopy. The hybrids were nanocomposites.
Design, processing and characterization of flexible hybrid coatings: A comparative evaluation
Materials and Design, 2014
Visual appearance as well as mechanical and chemical resistance of a phenyl methyl silicone resin deposited on cylindrical aluminum substrates by dipping and spraying is investigated. The morphological features of the coatings were analyzed by contact gauge profiler and scanning electron microscopy. Scratch and wear endurance was tested by progressive load scratch and dry sliding linear reciprocating tribological tests. The chemical resistance was tested by contact tests during which the coatings were dipped in acid, solvent-based and surfactant-rich solutions. The machinability of the coated substrates was tested by three-point bending and tensile static tests. Performance of the phenyl methyl silicone resin was also evaluated by comparison with two organic coating systems based on epoxy and polyurethane resins, widely used in several industrial domains as for their outstanding properties of chemical insulation and ductility. The experimental findings highlight significant performances of silicone resins as for protective and decorative purposes. Yet, the characteristics of flexibility showed by pure organic materials remain unparalleled, thus making epoxy and/or polyurethane good choice as far as the machinability of the coated substrate is concerned.
A series of sol-gel derived organic-inorganic hybrid coatings consisting of organic poly(methyl methacrylate) (PMMA) and inorganic silica (SiO 2 ) were successfully synthesized by using 3-(Trimethoxysilyl)propyl methacrylate as a coupling agent. In this work, MSMA is first copolymerized with methyl methacrylate monomer at specific feeding ratio by using benzoyl peroxide (BPO) as initiator. Subsequently, the asprepared copolymer (i.e., sol-gel precursor) is then cohydrolyzed with various contents of tetraethyl orthosilicate (TEOS) to afford chemical bondings to the forming silica networks, giving a series of hybrid sol-gel coatings. Transparent organic-inorganic hybrid sol-gel coatings with different contents of silica are always achieved. The as-synthesized hybrid sol-gel materials were subsequently characterized by Fourier-Transformation infrared (FTIR) spectroscopy and transmission electron microscopy (TEM).