Investigation of Accelerated Degradation Methods to Cause Blisters for Non-Defective Vinyl Ester Resin Glass Flake Organic Coatings

Organic coatings are applied as a corrosion prevention measure, but their effectiveness may degrade over time. In this study, the acceleration effects of typical degradation methods in non-defective vinyl ester resin organic coatings containing glass flakes such as high-temperature immersion and immersion in chemical accelerators are clarified using physiochemical techniques. Immersion in an acetic acid (AcOH) aqueous solution causes resin swelling, and the behaviors are quantitatively evaluated through gravimetric, thickness, and electrochemical impedance spectroscopy (EIS) measurements. Furthermore, a combined process of immersion in hydrofluoric acid and an AcOH aqueous solution reduces the electrical properties and eventually blisters the thick coating surface. This result suggests that an appropriate combination of the resin swelling and the glass degradation (glass dissolution and/or formation of the gap between glass and resin) decrease mechanical properties of the glass flake coating and causes blisters. In order to help the health diagnosis of the visually non-defective aged glass flake coating, the relationship between the electrical characteristic values and the invisible degradation by accelerated tests is finally indicated.

INFLUENCE OF IPNS (VINYLESTER/EPOXY/POLYURETHANE) ON THE MECHANICAL PROPERTIES OF GLASS/CARBON FIBER REINFORCED HYBRID COMPOSITES

The main objective of this study is to compare the interpenetrating polymer networks’ (IPNs) physical strengths with different variants of fibers. In this study, E-glass, carbon, and a combination of E-glass and carbon fiber (hybrid) have been taken as the reinforcement. Similarly, three combinations of the IPNs were chosen as the matrix material, namely epoxy / polyurethane (EP), vinyl ester / polyurethane (VP) and epoxy/vinyl ester (EV) as IPN blends. In order to thoroughly understand the physical characteristics of the combination of blends and fibers, nine variants (laminates) were fabricated: combinations of epoxy / polyurethane / E-glass (EPG), epoxy / polyurethane / carbon (EPC), epoxy / vinyl ester / glass / carbon (EPGC-hybrid), vinyl ester / polyurethane / glass (VPG), vinyl ester / polyurethane / carbon (VPC), vinyl ester / polyurethane / glass / carbon (VPGC), epoxy / vinyl ester / glass (EVG), epoxy / vinyl ester / carbon (EVC), and epoxy / vinyl ester / glass / carbon (EVGC-hybrid), all with help of a hand-layup technique. Furthermore, mechanical tests such as tensile, flexural, impact, and HDT (heat distortion temperature) were performed on all the variants as per the ASTM standards. Results shows that carbon fiber reinforcement with all IPN combinations has shown extraordinary performance (double fold) over the E-glass fiber reinforcement, whereas the hybrid (combination of E-glass/carbon) laminates have shown excellent characteristics over E-glass fiber reinforcement, irrespective of IPN matrix material. All the results were compared with each other and their corresponding variations were plotted as bar charts. ABSTRAK: Objektif utama kajian ini adalah bagi membandingkan kekuatan fizikal rangkaian polimer saling menusuk (IPN) dengan pelbagai jenis gentian berbeza. Kajian ini mengguna pakai gentian kaca-E, karbon dan gabungan kaca-E dan gentian karbon (hibrid) sebagai penguat. Begitu juga, tiga kombinasi IPN dipilih sebagai bahan matrik, iaitu epoksi / poliuretan (EP), ester vinil / poliuretan (VP) dan epoksi / ester vinil (EV) sebagai campuran IPN. Bagi tujuan memahami secara mendalam ciri-ciri fizikal gabungan campuran dan gentian, sembilan varian (lamina) dihasilkan, malaui kombinasi seperti epoksi / poliuretan / kaca-E (EPG), epoksi / poliuretan / karbon (EPC), epoksi / ester vinil / kaca / karbon (EPGC-hibrid), ester vinil / poliuretan / kaca (VPG), ester vinil / poliuretan / karbon (VPC), ester vinil / poliuretan / kaca / karbon (VPGC), epoksi / ester vinil / kaca (EVG), epoksi / ester vinil / karbon (EVC), epoksi / ester vinil / kaca / karbon (EVGC-hibrid) dengan teknik susun atur lapisan menggunakan tangan. Selain itu, ujian mekanikal seperti tegangan, lenturan, hentaman dan HDT (suhu kelenturan panas) dilakukan pada semua varian mengikut piawaian ASTM. Dapatan kajian menunjukkan bahawa, penguat gentian karbon dengan semua kombinasi IPN telah menunjukkan prestasi luar biasa (dua kali ganda) daripada penguat gentian kaca-E, manakala lamina hibrid (campuran kaca-E / karbon) telah menunjukkan ciri-ciri sangat baik berbanding penguat gentian kaca-E tanpa mengira bahan matrik IPN. Semua hasil dapatan dibandingkan antara satu sama lain dan padanan variasi diplot sebagai carta bar.

Comparison of the Wear Behavior and Hardness of Vinylester Resin Reinforced by Glass Fiber and Nano ZrO2 and Fe3O4

The current trend in scientific researches is to improve the performance of mechanical and physical properties of polymeric compounds, one of these methods is to add nanoparticles to polymeric composites. In this work, the wear behaviour (pin to disc) of nanocomposites composed of vinyl ester reinforced glass fibers and nanoparticles was evaluated under three different factors, such as specimen content, load applied, and distance sliding using a sliding time constant, as well as studying the hardness shore for these nanocomposites. The (hand-lay) method was used for the purpose of preparing the nanocomposites from vinyl ester filled with 10% vf. glass fiber and (0.5%, 1%, 1.5%, and 2% vf. of nano-Fe3O4 and ZrO2). The results are tabulated and analysed using Taguchi experiments (L9) (Minitab 18) for the purpose of determining which of the factors under consideration had the greatest influence on the wear behaviour. From the results, it was found that the specimens (vinyl ester-10% vf. glass fibers-2% ZrO2) and (vinyl ester-10% vf. glass fibers-2% Fe3O4) give the best wear resistance 0.003×10-5, 0.012×10-5 mm3/Nm respectively under the factors (load 20 N, sliding distance 45 cm). It was found that the specimen content is the most important factor influencing the wear behaviour, followed by the factors of the applied load and then the sliding distance. The addition of nanoparticles (0.5-2% vf. ZrO2, Fe3O4) to the vinyl ester resin improved the hardness values. Furthermore, the findings show that the addition of nanoparticles (ZrO2, Fe3O4) had a positive effect on the (wear and hardness) tests, implying that the nanoparticles improved the bonding between the base material and reinforcing material.

FRP for Marine Application

Fiber Reinforced Plastics (FRPs) are widely used in marine sector owing to their high specific strength and resistance to marine corrosion. For naval application, additional advantages are transparency to radar wave and better vibration damping than metals. The use of various FRPs in off-shore structures and marine vessels needs analysis of desired properties considering the types of matrices and fiber. The common consideration is effect of sea water on the properties of the FRP. This chapter gives a brief on use of different FRPs in various areas such as off-shore pillars, Reinforced Cement Concrete (RCC) enclosers, primary and secondary marine components. A brief discussion is included here on diffusion models and estimation of durability by a time-temperature superposition principle applied to water ingress and corresponding change in mechanical strength of FRPs with examples. The effect of microbial activity on the damage of FRP is not very much reported in literature. It is known that sulfate-reducing bacteria (SRB) are the most damaging microbes for FRP. In conclusion, it is highlighted that vinyl-ester-based FRPs using glass and carbon fibers are best for marine application. To determine the realistic service life in marine environment, Vinyl Ester- FRP (VE-FRP) are to be simultaneously studied for damage due to sea water and the microbes such SRB.

Effect of Green Hybrid Fillers Loading on Mechanical and Thermal Properties of Vinyl Ester Composites

The need of eco-friendly materials has been attracted due to renewability, abundance availability, low cost, and so on. Therefore, the search for bio fillers for the production of bio-based composite materials is gaining more and more attention in both academic and industry circles because it promotes sustainability. The present study represents the utilization of biomass solid waste in the hybrid form of tamarind seed and date seed powder into polymer reinforced composite which has been explored for the first time by a compression molding technique. These fillers are bio-waste that can be obtained at a minimal cost from renewable sources. An attempt has been made to use these hybrid fillers to reinforce with the matrix ranging from 0 to 50 wt.%, and their physical, mechanical, and thermal properties were investigated. In general, the inclusion of hybrid fillers increases mechanical properties, although the addition of hybrid fillers had only a minor impact on thermal properties. When compared to the pure vinyl ester resin, the hybrid fillers reinforced composites revealed a significant improvement in tensile, flexural, impact, and hardness properties, with improvements of 1.51 times, 1.44 times, 1.87 times, and 1.46 times respectively, at 10 wt.% filler loading. Filler matrix interaction of fractured mechanical testing samples was analyzed by scanning electron microscope. Based on the findings, hybrid filler reinforced composites may be suitable for applications where cost is a consideration and where minor compromises in thermal qualities are acceptable.

Functional Properties of Kenaf Bast Fibre Anhydride Modification Enhancement with Bionanocarbon in Polymer Nanobiocomposites

The miscibility between hydrophilic biofibre and hydrophobic matrix has been a challenge in developing polymer biocomposite. This study investigated the anhydride modification effect of propionic and succinic anhydrides on Kenaf fibre’s functional properties in vinyl ester bionanocomposites. Bionanocarbon from oil palm shell agricultural wastes enhanced nanofiller properties in the fibre-matrix interface via the resin transfer moulding technique. The succinylated fibre with the addition of the nanofiller in vinyl ester provided great improvement of the tensile, flexural, and impact strengths of 92.47 ± 1.19 MPa, 108.34 ± 1.40 MPa, and 8.94 ± 0.12 kJ m−2, respectively than the propionylated fibre. The physical, morphological, chemical structural, and thermal properties of bionanocomposites containing 3% bionanocarbon loading showed better enhancement properties. This enhancement was associated with the effect of the anhydride modification and the nanofiller’s homogeneity in bionanocarbon-Kenaf fibre-vinyl ester bonding. It appears that Kenaf fibre modified with propionic and succinic anhydrides incorporated with bionanocarbon can be successfully utilised as reinforcing materials in vinyl ester matrix.