Mechanical characterization of unsaturated polyester composite filled modified kenaf fiber / Suzana Ratim, Rahmah Mohamed and Siti Norasmah Surip

Lignecellulosic fibers such as jute, ramie, kenaf, coir have attracted consideration as alternative materials to replace synthetic fiber and other conventional reinforcements. These natural fiber composite combine good mechanical properties with low specific mass ad offer alternative materials for glass fiber reinforced plastics in some technical application (Gassan 2002). Despite the attractiveness of natural fiber reinforced polymer matrix composites, they suffer from lower modulus, lower strength and relatively poor moisture resistance compared to synthetic fiber reinforced composites (Thwe and Liao, 2002). One difficulty that has prevented the use of natural fibers is the lack of good adhesion with polymeric matrices (Bessadok et al. 2008). According to Gassan 2002, their high level of moisture absorption, poor wettability by non-polar plastic and insufficient adhesion between untreated fibers and polymer matrix lead to debonding with age. The presence of hydroxyl and other polar groups in natural fiber, moisture uptake can lead to weak interfacial bonding between the fibers and hydrophobic polymer matrices (Thwe and Liao, 2002). In particular, the great moisture sorption of natural fibres adversely affects adhesion with hydrophobic matrix leading to premature ageing by degradation and loss of strength reactions (Bessadok et al. 2008). Previous study shown that degradation of mechanical properties caused by higher moisture uptake of natural fiber (Karmaker 1997). Interfacial adhesion and resistance to moisture absorption of natural-fibre composites can be improved by treating these fibres with suitable chemical reactions (Bessadok et al. 2008). It is necessary to enhance the hydrophobisity of natural fiber by chemical treatments with suitable coupling agents or coating with appropriate resin to develop better mechanical properties and environmental performance (Thwe and Liao, 2002)

A comparative study on the mechanical properties of clay-modified epoxy adhesive by using different clay types

A comparative study on the mechanical properties of clay-modified epoxy adhesive by using different clay types was ascertained. The effects on different clay types which are micron-sized clay and nano-sized clay that modified the epoxy adhesive were determined. The clay (5 wt. %) along with hardener (10%) was dispersed in the epoxy adhesive (90%) in order to investigate the mechanical properties of epoxy adhesive after added the clay. The adherend used for shear and tensile test are wood. The optimum loading was determined to investigate the differences between neat epoxy adhesive with epoxy adhesive added with clay. The results shows that the tensile strength was increase by using micron clay while shear and impact strength was increase by using nano clay. The function of clay to enhance the properties of epoxy adhesive is more effective when the clay is well dispersed in the epoxy adhesive. FESEM shows that the nano clay was well dispersed in the epoxy adhesive while micron-sized sized clay was partially intercalated

Synthesis of SiO2 nanostructures using sol-gel method

Sol-gel method is the simplest method and has the ability to control the particle size and morphology through systematic monitoring of reaction parameters. The objective of this research is to synthesize silica nanostructures by sol-gel method and to characterize the synthesized silica nanostructures. Silica nanoparticles were synthesized via the sol-gel method using Tetraethyl orthosilicate as a precursor. The acetic acid and distilled water were used as the catalyst and the hydrolyzing agent. Varied parameters of the study were the aging time in the range of 2 to 6 h and the calcination temperature in the range of 600–700 ◦C. The obtained silica nanopowder was characterized using FESEM, and Nano-Particle Size Analyzer. The results show that the silica nanospheres were successfully synthesized by using sol-gel method with the optimum parameters of 700 ◦C of calcination temperature and 2 h of aging time. The average size of silica nanoparticles was in the range of 79.68 nm to 87.35 nm

Evaluation of elastic modulus and hardness of polylactic acid-based biocomposite by nano-indentation

This study focuses on the micromechanical properties of polylactic acid (PLA) reinforced with kenaf fiber (KF) and organo-montmorillonite (OMMT) hybrid biocomposite by using nanoindenter. Nanoindenter is an analytical device that can record small load and depth with high accuracy and precision which can be used to determine the modulus, hardness and other mechanical properties of nanomaterials. The result shows that the optimum properties of the hardness and elastic modulus were dominated by PLA-KF-OMMT hybrid composite

Mechanical properties of toughened polyester reinforced with untreated and treated kenaf hybird carbon composite

This research focusing on mechanical properties of rubber toughened polyester filled carbon black (RPCB) reinforced with untreated kenaf (RPCBUK) and treated kenaf (RPCBTK). The samples were fabricated via compression moulding technique in which 3 % of LNR was added as toughening agent in this composite. Percentages of carbon black (CB) is 4 % and kenaf used vary from 5,10,15,20 and 25wt %. The mechanical properties were evaluated by impact and fracture toughness testing. The result for each test was discussed to determine the most optimum loading of kenaf fibre used to produce the best properties of composite. Untreated hybrid composite showed improvement on impact strength as compared to RPCB composite. RPCBTK with 25% of kenaf and RPCBUK with 5% of kenaf loading give the highest impact strength among the hybrid composites, approaching the strength of neat polyester. Same trend shows by fracture toughness testing. The microstructures of the composites’ fracture surface images from scanning electron microscope (SEM) prove the mechanical properties of the hybrid composites

Effect of solid particles concentration to the size of graphene oxide liquid crystals pickering emulsion

Graphene oxide (GO) sheets have been used as a colloidal surfactant in a Pickering emulsion system due to their amphiphilic property. They also show a liquid crystals behavior, which make them suitable to synthesize graphene oxide liquid crystals Pickering emulsion (GOLCsPE). Desired GOLCsPE sizes and stability can be obtained by controlling several parameters, especially the concentration of graphene oxide colloidal surfactant. This paper focused on the preparation of GOLCsPE with linseed oil as an internal phase. The GO concentration was varied in order to study their effect on GOLCsPE size and stability. The stability of the emulsion was observed through phase separation observation. Polarized optical microscope (POM) and particle size analyzer (PSA) were employed to characterize the size distribution of the GOLCsPE. POM analysis shows that increased in GO concentration led to the finer emulsion with the smallest droplet size around 8μm. However, the PSA analysis revealed otherwise. It was found that by increasing the amount of GO sheets, the GOLCsPE size will also increase, which could be caused by too many GO sheets laden around the oil droplets. The coefficient of variation (Cv) of the liquid crystals based on POM images showed a decreased, indicates the GO concentration improves the droplet size distribution. It also suggested that GO concentration plays a more important role in maintaining the stability of the GOLCsPE, rather than their sizes. By comparing both POM and PSA results, liquid crystals prepared with 3.7 mg/ml produced satisfied GOLCs diameter (around 8.5μm, Cv = 0.31) and stability. The shining halos around the droplets are proof that the GO acts as a colloidal surfactant and assembled themselves around the linseed oil droplets, forming a shell-like structure

ZnO nanoparticles for anti-corrosion nanocoating of carbon steel

Nanostructured coatings offer great potential for various applications due to their superior characteristics that are not typically found in conventional coatings. This research aimed at developing a new and improved coating that employs zinc oxide nanopowder as the agent to achieve corrosion resistant properties for a coating. The research project discusses on its corrosion behaviour of epoxy-zinc oxide in different media by measuring its corrosion rate. Mild carbon steel was used as the substrate for the epoxy-zinc oxide coating. The corrosion behavior mechanism of mild steel was investigated in different media, namely fresh water, NaCl solution, HCl solution and NaOH solution. Immersion test was conducted and studied for a period of 60 days, with daily and weekly weighing and immersing. The corrosion rate was calculated and mild steel corrodes in the different environment and degrades in the following trend; HCl → NaCl → NaOH → H2O

Mechanical properties and environmental stress cracking resistance of rubber toughened polyester/clay composite

Crosslinked polyester clay nanocomposites were prepared by dispersing originically modified montmorillonite in prepromoted polyester resin and subsequently crosslinked using methyl ethyl ketone peroxide catalyst at different clay concentration. Cure process and the mechanical properties of rubber toughened polyester clay composite have been studied. Rubber toughened thermoset polyester composite were prepared by adding 3 per hundred rubber (phr) of liquid natural rubber (LNR) was used in the mixing of producing this composite. Modification of polyester matrix was done due to the brittle problem of polyester composite. Addition of LNR will increase the toughness of composite and produce ductile polyester. Two types of composites were produced which is clay-lnr polyester composite and clay polyester composite. Addition of liquid natural rubber significantly increased the impact strength and flexural properties. Result shows that addition of 6% of clay-lnr composite give good properties on impact, strength and flexural. From the ESCR test, both composites showed good resistance to environmental

Effect of PEG on tensile properties of PLA-Based biocomposite

Hybridization of polylactic acid (PLA), kenaf fibre (KF) and montmontmorillonite (MMT) is expected to contribute to new class of biodegradable materials. In light with this, three types of composites were developed namely PLA-KF biocomposite, PLA-MMT nanocomposite and PLA-KF-MMT hybrid biocomposite. On the basis of sustainable and green material, this paper aims to investigate the effect of plasticizer on the tensile properties of PLA composites. PLA and its composites were compounded using twin screw extruder and then injection moulded for tensile characterization. PLA with different content of 0, 1, 3 and 5 wt% polyethylene glycol (PEG) 600 molecular weight (Mw) was prepared to determine the optimum content of plasticizer. From tensile test, it was found that PEG content at 3 wt% produced the highest tensile strength. Thus, 3 wt% PEG was added during extrusion process to produce PLA-based biocomposites. The presence of PEG significantly amplified the tensile strength of PLA-KF biocomposite by about 114% as compared to unplasticized PLA-KF biocomposite. Addition of PEG slightly increased the tensile modulus for all PLA-based composites. This suggested that compatibility in the structure of PLA and PEG enhanced the processability and subsequently improved the properties of PLA-based composites

Physical and mechanical properties of Thermoplastic Natural Rubber (TPNR) nanocomposites

Thermoplastic natural rubber (TPNR) nanocomposites were prepared by melt blending method with the optimum mixing parameters (140oC, 100 rpm, 12 min) using internal mixer (Haake 600 P). The aim of this work is to study the effects of organo-montmorillonite (OMMT) on the physical and mechanical properties of TPNR with and without coupling agent (maleic anhydride grafted polyethylene, MA-PE). Significant improvement in tensile strength and modulus of TPNR nanocomposites were obtained with the presence of MA-PE