Epoxy-polyamide Resin Research Articles

Rheological, Mechanical and Morphological Characterization of Fillers in the Nautical Field: The Role of Dispersing Agents on Composite Materials.

Coatings have a fundamental role in covering the external surface of yachts by acting both as protective and aesthetic layers. In particular, fillers represent the essential layer from the point of view of mechanical properties and consist of a polymeric matrix, different extenders and additives, and dispersing agents, with the latter having the role to provide good extender-matrix compatibility. In the present work, the effects of dispersing agents with an ionic or steric action on the interactions between hollow glass microspheres and an epoxy-polyamide resin are evaluated. Un-crosslinked filler materials are studied via rheological tests, whereas the mechanical and morphological properties of the crosslinked samples are assessed. The results clearly indicate that steric dispersing agents provide a much greater compatibility effect compared to ionic ones, owing to their steric hindrance capability, thus leading to better-performing filler materials with a less-marked Payne effect, which is here proved to be an efficient tool to provide information concerning the extent of component interactions in nautical fillers. To the best of our knowledge, this work represents the first attempt to deeply understand the role of dispersing agents, which are until now empirically used in the preparation of fillers.

Study of anticorrosive coatings based on high and low molecular weight polyphenols extracted from the Pine radiata bark

In this work, two primers with organic corrosion inhibitors were extracted from Pinus radiata bark, from the waste generated by the timber and paper industries. The process resulted in a water-soluble fraction (WSF) and water-insoluble fraction (WIF). The additives were incorporated in a two-component (2 K) primer based on epoxy-polyamide resin with a ratio formulation of λ = 0.85 (PVC = 34.79). Spectroscopy techniques, such as electron paramagnetic resonance (EPR), high-performance liquid chromatography (HPLC), Raman spectroscopy, and electrochemical impedance spectroscopy (EIS) were used for both the extract and coating characterizations. Coating performances were obtained in the order of 109 Ω. cm2 for the impedance, and the systems were simulated using a circuit (R1(Q1(R2(Q2(R3(R4C))))). The formation of tannin-Fe complexes was demonstrated using RAMAN spectroscopy.

Comparative Study on Polyvinyl and Polyamide (Polymers) Resins as Corrosion Resistance Coating on Low Carbon Steel

Two commonly applied corrosion resistance coatings (Polyvinyl and Epoxy Polyamide resins) in Rivers and Bayelsa areas of Nigeria, have been compared on performance properties. The coatings were applied on low Carbon Steel samples that were cut to specific sizes. These prepared samples were subjected to varying conditions of pH, temperatures and exposure to definite time periods. The corrosion rates in ML per year (MPY) were then analyzed. The results of the corresponding corrosion rate in MPY obtained at PH 2,3,4,5, and 6, for epoxy polyamid resin, were 0.566, 0.553, 0.379, 0.354 and 0.322 respectively, and that for polyvinyl resin were 0.334, 0.326, 0.314, 0.288 and 0.277 respectively. The effect of temperature at 30° C, 4 ° C, 50° C, 60° C and 70°C were compared and corresponding corrosion rate in MP obtained for epoxy polyamide were 0.158, 0.288, 0.477, .655 and 0.810 respectively, while that for polyvinyl resin gave values of 0.122, 0.21 ,0.411, 0.552 and 0.651 respectively. The time exposure in hours of 692, 1008, 1344, 1680 and 2016 for the test steel samples applied with epoxy polyamide resin coating gave a corresponding corrosion values in MPY of 0.012, 0.016, 0.030, 0.043 and 0.055 respectively, and that for polyvinyl resin coating were 0.002, 0.009, 0.020, 0.034 and 0.044 respectively. The results obtained showed that polyvinyl resin coating have better performance properties over epoxy polyamide resin. Therefore polyvinyl resin coating can be recommended as a good corrosion resistance coating on low carbon steel pipes used in crude oil exploration in Petroleum industries

Synthesis and characterization of layer-by-layer assembled magnesium zinc molybdate nanocontainer for anticorrosive application

Magnesium zinc molybdate nanoparticles which has been synthesised by conventional method, used as core of nanocontainer. In the present work, a novel approach for the loading and responsive release of corrosion inhibitor (benzotriazole) on the magnesium zinc molybdate nanocontainer by layer by layer (LbL) assembly has been presented. The synthesized nano particle coated with corrosion inhibitor i.e. benzotriazole and polyelectrolyte layer, provides enhanced corrosion protection. The thickness of the layer, surface charge and functional groups present on each layer has been achieved by using particle size distribution (PSD), zeta potential and Fourier transform infrared spectroscopy (FTIR) analysis respectively. The X-ray diffractograms (XRD) and thermogravimetric analysis (TGA) gives the development of nanoparticle as well as nanocontainer. The morphological studies shows the variation in the size of magnesium zinc molybdate nanoparticles and the nanocontainer. The release of benzotriazole from the magnesium zinc molybdate nanocontainer has been quantitatively evaluated in water at different pH. The anticorrosive performance of nanocontainers has been studied by incorporating it in epoxy based coating and evaluating by DC polarization measurement. The current density has been found to be decrease significantly with the addition of 1wt.% of magnesium zinc molybdate nanocontainers in neat epoxy-polyamide resin. Additionally, corrosion potential values are shifted to positive side with the addition of 1wt.% of magnesium zinc molybdate nanocontainers. The corrosion results from Bode plots and Salt spray test shows the significant improvement in anticorrosive performance for epoxy-polyamide-nanocontainer coatings. The results shows the successful application of magnesium zinc molybdate nanoparticles as a core of nanocontainers by giving rise to dual corrosion inhibition mechanism due to combination of magnesium, zinc, molybdate ions and inhibitor loaded on inorganic core.

Improvement of adherence and anticorrosion properties of an epoxy-polyamide coating on steel by incorporation of an indole-3 butyric acid-modified nanomagnetite

In this study, synthesized magnetite (Fe3O4) nanoparticles were treated with a corrosion inhibitor, indole-3 butyric acid (IBA) and incorporated in an epoxy-polyamide coating. The coating was applied on a carbon steel substrate. For comparison, coatings without particles or with nontreated Fe3O4 particles were also prepared. The IBA-modified nanomagnetite (IBA–Fe3O4) was characterized by infrared spectroscopy and Zeta potential measurements. The inhibitive action of IBA was shown by electrochemical measurements (polarization curves) performed for a bare carbon steel in 0.1 M NaCl solution containing Fe3O4 or IBA–Fe3O4 nanoparticles. Adherence and anticorrosion properties of the epoxy-based coatings containing Fe3O4 or IBA–Fe3O4 were compared to those of the pure epoxy-polyamide resin by dry and wet adherence measurements and by salt spray test. The results showed significant improvement of the film adherence and higher corrosion protection of the carbon steel in the presence of IBA–Fe3O4. It was concluded that the IBA effect was restricted to the metal/coating interface.

Nano alumina–zirconia blended epoxy polymeric composites for anticorrosive applications

Amorphous alumina–zirconia (Al2O3–ZrO2) nanoparticles were produced by hot-air spray pyrolysis method. Two and six layers of anticorrosive coating of epoxy polyamide (EP) resin and mixture of amorphous Al2O3–ZrO2 nanoparticles in epoxy polyamide resin (NEP), respectively, were applied on SS 316L specimens. The performance of EP and NEP coated samples was comprehensively characterized. The results show that the sample with six layers of NEP coating (SSNEP6) has enhanced thermal, elastic properties and chemical resistance than that with six layers of EP coating (SSEP6). Thermo gravimetric analysis reveals that EP sample decomposed at 523 °C whereas NEP sample has extended thermal stability up to 750 °C with minimum residual mass. The thermal conductivity of EP sample is 0.124 while for NEP is about 0.263 W/mK. The hardness and reduced elastic modulus of SSNEP6 sample were, respectively, 318.32 MPa and 5.98 GPa whereas those of SSEP6 sample were 233.69 MPa and 4.17 GPa. Further, in-situ scanning probe microscopy (SPM)-nanoindentation and atomic force microscopy (AFM) images were obtained to explore the formation of Al2O3–ZrO2 nano filler in EP matrix. The samples coated with multilayers of EP and NEP was exposed to acid immersion (10 % of H2SO4) for 48 h. The SPM and AFM microstructure images show that the NEP coated sample maintains its original surface feature with existing passive layer formation, whereas EP coated sample shows surface deterioration and deformation. In addition, stability of EP and NEP coated samples was measured in terms of surface roughness with respect to nano filler in epoxy matrix. This observation shows that Al2O3–ZrO2 nanofiller can be used to improve the desirable properties in host epoxy matrix.

Efficacy of Resinous Polypropylene (PP) Fibers on Strength Behavior of Reinforced Soils

In the current study, Laboratory uniaxial compression tests are carried out in order to determine the strength and mechanical behavior of silty sand reinforced with randomly distributed short resinous Polypropylene (PP) fibers. The stress-strain behavior of composite materials is investigated through varying the number and length of PP fibers. In order to study the effects of the length and weight percent of fibers on the results of the uniaxial compressive strength, tests were accomplished on specimens with three different lengths and weight percentages of fibers. The results demonstrate increasing weight percent of fibers, in a constant length, leads to increase the maximum strength. Meanwhile, increasing the length of fibers, in a constant weight percent, reduces the maximum strength. Moisture absorbency of fibers which was about 120% at first, however, could be reduced to just 9% by using the epoxy polyamide resin. Moreover, the resin causes more interaction between sand aggregates and fibers leading to a higher internal friction angle.

Corrosion protection of magnesium alloys by cerium, zirconium and niobium-based conversion coatings

A new Ce, Zr and Nb-based conversion coating was designed for AZ91 and AM50 magnesium alloys. The corrosion protection provided by this coating was evaluated by electrochemical measurements (polarization curves, electrochemical impedance spectroscopy) in Na 2SO 4 electrolyte, and accelerated atmospheric corrosion tests (humid, SO 2 polluted air, and salt spray). Its chemical composition was characterized by X-ray photoelectron spectroscopy (XPS). Electrochemical measurements showed that Mg alloys treated during 24 h in the Ce–Zr–Nb conversion bath exhibit: (i) increased corrosion potential, (ii) decreased corrosion and anodic dissolution current densities, and (iii) increased polarization and charge transfer resistances. The accelerated corrosion tests revealed excellent atmospheric corrosion resistance for all Ce–Zr–Nb-treated samples, with or without an additional layer of epoxy–polyamide resin lacquer or paint. XPS analysis showed that the coating includes CeO 2, Ce 2O 3, ZrO 2, Nb 2O 5, MgO, and MgF 2 as main components. No significant modification of the chemical composition was observed after cathodic and anodic polarization in Na 2SO 4. This new coating provides improved corrosion resistance, and excellent paint adhesion. It offers an alternative to the chromate conversion coating for magnesium alloys.

The study of epoxy polyamide and polyvinyl resins as corrosion protective coatings on low carbon steel

The corrosion resistance of two commonly used protective coatings (epoxy polyamide and polyvinyl resins) in the Niger Delta area of Nigeria has been assessed. The coatings on low carbon steel were subjected to varying conditions of pH, temperature and exposure time and the corrosion rates calculated. At a pH of 2, 3, 4, 5 and 6 the corresponding calculated corrosion rates in mpy for epoxy polyamide resin were 0.677, 0.660, 0.392, 0.345 and 0.336 respectively and that for polyvinyl resin were 0.345, 0.336, 0.315, 0.298 and 0.272 respectively. At temperatures of 30oC, 40oC, 50oC, 60oC and 70oC, the corresponding calculated corrosion rates in mpy for epoxy polyamide resin were 0.169, 0.399, 0.572, 0.856 and 0.971 respectively and that for polyvinyl resin were 0.112, 0.227, 0.402, 0.572 and 0.741 respectively. At an exposure time in hours of 672, 1008, 1344, 1680 and 2016, the corresponding calculated corrosion rates in mpy of epoxy polyamide resin were 0.014, 0.018, 0.034, 0.044 and 0.059 respectively and that for polyvinyl resin were 0.0001, 0.009, 0.021, 0.44 and 0.046 respectively. The results showed polyvinyl resin to have a better coating performance than epoxy polyamide resin. KEY WORDS: Corrosion, coatings, temperature, polyamide, polyvinyl. Global Jnl Pure & Applied Sciences Vol.10(2) 2004: 301-305

Application of electrochemical impedance spectroscopy to study efficiency of anticorrosive pigments in epoxy-polyamide resin

AbstractThe anticorrosive properties of six non-toxic pigments have been compared with those of zinc chromate. Following incorporation in an epoxy-polyamide resin} the pigments were applied to cold rolled steel and galvanised steel substrates. The painted panels were exposed to total immersion in 0·5M NaCl solution. Coating deterioration was monitored by electrochemical impedance spectroscopy (EIS) complemented by visual evaluation and adhesion tests. Water permeability into the paints was monitored by a single frequency impedance method. A most probable equivalent circuit for the polymer coated metal system is proposed. Good correlation was observed between the delaminated area obtained by EIS measurements and that obtained by visual observations of the specimens after exposure. The performance of zinc phosphate on cold rolled steel in immersion tests was superior even to that of zinc chromate. All pigments except zinc chromate fared worse on galvanised steel than on cold rolled steet probably owing to p...

Application of electrochemical impedance spectroscopy to study efficiency of anticorrosive pigments in epoxy-polyamide resin

Application of electrochemical impedance spectroscopy to study efficiency of anticorrosive pigments in epoxy-polyamide resin

Reactions of rabbit brain and peripheral vessels to plastics used in coating arterial aneurysms.

M ANY techniques have been applied to the surgical treatment of intracranial aneurysm. Hypothermia, hypotensive drugs, and hypertonic solutions for reducing brain volume have helped the surgeon, but some aneurysms cannot be clipped, ligated, or trapped because of their configuration. Muscle and gauze wrapping techniques have been used for a long time, but are now being replaced with synthetic adhesives.4,6, s, 9,12,17.21--27 Many different types of adhesives have been used experimentally and clinically. Ideally they require ease of application, rapid setting, and security of adhesiveness even in a moist environment. They should withstand elevated blood pressure and should be nontoxic. Untoward effects of Eastman 910 adhesive and monomer (methyl 2-cyanoactylate) have been reported on various occasions;3~ nevertheless there have been a number of reports of their successful use in the treatment of intracranial aneurysms. ~8,17 Histologic preparations have revealed epineural inflammation, increased vascularity and giant cells, destruction of neural tissue, thrombosis of small vessels, necrosis of arterial wall, as well as aneurysm formation. Other clinically applied synthetic adhesives include Selverstone's mixture (polyvinyl polyvinyledene chloride and epoxy polyamide resin), 21,24 Pudenz's mixture (Silastic RTV.502), 2~,27 Aneuroplastin (methyl methacrylate), 1~ Ad/Here (methyl alpha-cyanoacrylate), is and Biobond (EDH adhesive; a mixture of polyisocyanate and nitrile rubber with a small amount of methyl 2-cyanoacrylate monomer in a nitro-methane solution).l~, 25 Investigations of separate adhesives have been noted in individual reports. Our current investigation was directed toward comparison of seven such adhesives under similar conditions.