The effect of adding natural materials waste on the mechanical properties and water absorption of epoxy composite using grey relations analysis

Recently, there has been a tendency for scientific studies to deal with natural materials as fillers and reinforcement for polymer composites, which are used in many different applications due to their environmentally friendly properties when compared to synthetic materials. The current study aims to preserve the environment by dealing with natural materials and their influence on the mechanical properties and water absorption property of the polymer composites. In this study, epoxy composites were produced from local natural sourced non-hazardous raw natural materials using grey relational analysis (GRG). The materials used for fabrication include micro-filler of pollen palm 50 μm, seashell 75 μm and epoxy resin. Nine different composites were prepared using pollen palm and seashell as reinforcement material by varying the wt % of the micro-filler. Rule of the mixture was used for formulation and wt % of (0.5, 1 and 1.5) % reinforcement and 99.5, 99 and 98.5 % epoxy (binder) were used for composites. Grey relational analysis was conducted in order to scale the multi-response performance to a single response. The results indicate that optimum performance can be achieved with the addition of 1.5 wt % micro-filler of seashell, which achieved the first rank, while the second rank achieved by 0.5 wt % micro-filler of palm pollen and seashell when compared to other composites. The addition of micro-fillers has improved greatly the mechanical properties of epoxy composites. The loading of micro-fillers has influenced the water absorption property of composites based epoxy in ascending order

Mechanical Characteristic and Water Absorption Property of Bio Composite from Sago Starch and Jute Fiber (Boehmeria Nivea) as the filler

Environmentally friendly plastics can be degraded biologically in an anaerobic environment. This plastic is synthesized from starch such as sago starch which is available in abundance. In the form of bioplastics, its mechanical properties are still not compared to conventional plastics derived from crude oil, so its application is limited. The incorporation of filler material increases its mechanical properties, one of the selected fillers is hemp fiber as used in this study. Thermoplastic starch from sago with flax fiber as a filler and the addition of Polypropylene to improve mechanical properties with a certain composition to maintain its natural biodegradability. The mechanical properties analyzed were tensile strength, elongation and modulus of elasticity. Water absorption tests were also carried out to observe the water resistance properties. The results of the tensile strength test showed that the best tensile strength value of 9.32 Mpa was obtained at the addition of 35% fiber with a TPS: PP ratio of 1:1.5. The same conditions were obtained for the percent elongation with the results of 10.16% and the modulus of elasticity was 91.73 Mpa. Water absorption showed that 55% filler gave the lowest water absorption, namely 4.41% at a ratio of TPS: PP 1:0.5. The addition of fiber filler into the bio-composite affects the tensile strength, elongation and modulus of elasticity, the higher the volume of filler entering the bio-composite, the lower the value of tensile strength, elongation and modulus of elasticity, or vice versa. The ratio of addition of polypropylene matrix is also influential, the higher the ratio contributes to the tensile strength, elongation and higher modulus of elasticity. High water absorption capacity will reduce the performance of biocomposite, so the lower the water absorption ability, the better the quality of the biocomposite product and the wider its application

Variations in the mechanical properties of bionanocomposites by water absorption

The present study aims to investigate the water absorption property and its effect on the mechanical properties (i.e. tensile, flexural, and impact) of bionanocomposites. The epoxy-based bionanocomposites were prepared by reinforcing the epoxy with 1, 2, 3, 4, and 5 wt% of nanocellulose using in situ polymerization method. The maximum water uptake by bionanocomposites was measured; however, the water absorption behavior was not found in accordance with Fickian’s diffusion model. In the present study, very low water absorption in the range of 0.17–0.34% was offered by bionanocomposites. The results obtained from the present experimental study suggested that there were a maximum degradation of 14.96% in tensile strength, 26.44% in flexural strength, and 55.66% in impact strength for bionanocomposites reinforced with 5 wt% of nanocellulose by water uptake.

Effects of Two Pre-Treatment Methods on Water Absorption Property of Polyester-Fibre Composites

The use of plant fibres as reinforcement in composite materials is finding increasing interest in the automotive and building industry, and the properties of plant fibre composites have been addressed in numerous research studies. The replacement of synthetic fibres with natural fibres in composites is based on their renewable and environmentally friendly nature. The aim of this work is to investigate the effects of two chemical pre-treatment methods on the water absorption property of polyester-fibre composites. Fully grown kenaf (hibiscus cannabalis) bast fibres were manually retted from the stalk, washed, and cut into short fibre lengths of about 10 cm. One portion of the fibres was pre-treated with 5% pbw NaOH solution before immersing it in glacial acetic acid and then in acetic anhydride. The second portion was pre-treated with 5%pbw of NaOH and 0.125% of KMnO4 in acetone. The third portion of fibres was untreated to serve as control. The ground fibre was incorporated into ortho unsaturated polyester and cast with Teflon square shaped mould. The cured samples were weighed and immersed in water at room temperature until no further gain in weight was observed. The SEM of the fibres and the composites was taken. The results showed that the acetylation pre-treatment method reduced the water absorption property of the composites by a minimum of 46.0% across all fibre volume fractions while the permanganate pre-treatment reduced it by at least 25.5%. Chemical pre-treatment of fibres can therefore

Surface Absorption Characteristics of Recycled Concrete

Recycled aggregate is known to have higher water absorption produced due to the porosity of the cement paste adhered to the old concrete in the recycled aggregate, this in turn affects the durability. This study attempts to investigate the surface water absorption properties of recycled concrete when fly ash is added to concrete mix. In the mix proportion considered for study, 25% of natural coarse aggregate is replaced by recycled aggregate and 30 % Cement is replaced by fly ash. Surface water absorption property is studied experimentally by Initial Surface Absorption Test. Results indicate that pozzolanic properties of fly ash helps in reducing the water permeability of recycled concrete to a great extent.

Preparation and characterization of a high strength self-repairing galactomannan hydrogel

Autonomous self-repairing properties can prolong the service life of materials. In this paper, galactomannan hydrogel with high mechanical strength was prepared by graft copolymerization of galactomannan with acrylamide and octadecyl methacrylate in aqueous solution. The microstructure, water absorption property, self-healing behavior, and mechanical properties of the hydrogels were investigated using Fourier transform infrared spectroscopy (FTIR) and scanning electron microscope (SEM), etc. The galactomannan hydrogel had the highest tensile strength of 49 KPa and strain of 3000%. The water absorption reached 2340%, and the removal rate of methylene blue was more than 80%. Galactomannan hydrogels demonstrated significant self-healing properties. The cut hydrogel was quite effective in self-repairing in a few minutes, and the self-repairing strength increased with increasing contact time of hydrogel cut surfaces. The healing efficiency of fracture strain could reach 92.7% of the original sample in 10 h. The maximum water absorption of hydrogel reached 2340%. The maximum removal rate of methylene blue by hydrogel reached 80.5%, and the maximum adsorption capacity was 19.3 mg/g. The novelty of the work lies in octadecyl methacrylate being used for galactomannan cross-linking with the ability to self-repair after fracture. The galactomannan self-healing hydrogel has potential in water treatment and sealing technology.

Development of Modified Recycled Aggregate for the Production of Sustainable Concrete

This paper deals with the treatment methods of recycled aggregate (RA) for its high water absorption which is due to the old mortar and micro-cracks on the surface of the recycled aggregate. Geopolymer paste which is made using class C & F fly ash are used for coating the recycled aggregate in order to reduce the water absorption (WA). The parameters which influence the coating of RA are fly ash content, molarity of alkaline solution, Liquid alkaline to ash ratio (LA/ash). The effect of each parameter on coating RA are analysed using Response surface methodology. It is observed that all the parameters has influenced the water absorption property of RA. LA/ash ratio depends on the molarity of the alkaline solution in reducing the WA of recycled aggregate. Coating of recycled aggregate with class C fly ash performed better than class F and uncoated recycled aggregate concrete. The optimal content of fly ash content, LA/ash ratio and molarity of solution are arrived using the statistical analysis are 4%, 0.35 and 9M respectively

Properties of Cement Brick with Partial Replacement of Sand and Cement with Oil Palm Empty Fruit Bunches and Silica Fume

Oil palm empty fruit bunches (EFB) and silica fume (SF) are the by-products of the oil palm plantation and the ferroalloy smelting industries, respectively. Improper disposal of these materials leads to negative implication to the environment. This study was carried out to investigate the potential application of EFB and SF in cement bricks. EFB fibre and SF replaced up to 25% of sand and cement in the mix, respectively, in several groups of specimens that distinguished the normal, EFB-, SF- and EFB-SF-cement bricks. The specimens were tested for the compressive strength, density and water absorption property. The results reveal that SF, at an optimum amount of 10% cement replacement, increased 10% of the strength of the cement brick. EFB fibre reduced the strength and density but increased water absorption property of the cement brick. For application in the construction industry, SF and EFB fibre contents should be kept within 10% and 20% respectively.

Modelling of Hydration Characteristics of Five Varieties of Cowpea Grains

Introduction: The hydration of grains is a process that consists of soaking them in water in order to increase their moisture content and this is a crucial step in industrialized processing and provides several beneficial effects on their physicochemical and nutritional qualities. Aims: This study focused on modeling of hydration characteristics of five varieties of cowpea which are: Gombe, Oloyin white, Drum, Oloyin brown and Sokoto cultivated in Nigeria. Methodology: The experiments were carried out using electronic water bath at five temperatures (30, 40, 50, 60, and 70°C) in three replications. The amount of water absorption by five selected varieties of cowpea grains was calculated by measuring the increase in the mass of soaked grains per time. Five standard models of water absorption were fitted to the experimental data. Coefficient of determination (R2), chi-square (x2) and root mean square error (RMSE) were used to evaluate the models. Results: The initial moisture content of the saturated cowpea was estimated as 13.56 ±1.15, 15.05 ±2.27, 13.30 ±0.37, 10.85 ±0.13, 12.40 ±0.13 for Gombe, Oloyin white, Drum, Oloyin brown and Sokoto varieties respectively. The water uptake of the cowpea was faster at the initial stage and gradually slow down until the equilibrium moisture content was attained for all the varieties. Conclusions: Weibull model was adjudged as the best fitted model for describing the water absorption property of all the varieties of the cowpea and the Activation energy of Gombe, Oloyin white, Drum, Oloyin brown and Sokoto varieties are 42.26 ± 4.65, 40.36 ±8.90, 39.47 ±8.62, 43.08 ±5.25 and 39.66 ±6.72 respectively.