Welding Metallurgy of

Characterization and Properties of Natural Fiber Polymer Composites: A Comprehensive Review

Recently published research indicates that natural fibre based polymer composites have limited applications in advanced structural systems due to their low impact performance. However, natural fibres have great potential for reducing the product weight, lowering material cost, and renewability. Hybrid composites made from a combination of natural/synthetic fibres, natural/natural fibres, or synthetic/synthetic fibres are also receiving attention from both researchers and the industry for structural applications owing to the tailored mechanical and impact properties of these materials. The hybridisation process is one of the paramount and more efficient ways to strengthen and improve the performance of composite materials. This review paper examines the impact properties of hybrid composites manufactured with the aim of improving their structural characteristics, and in particular, is focused on the impact resistance and penetration behaviour of hybrid composites reinforced with natural and synthetic fibres as well as their suitability for modern structural applications.

Impact behaviour of hybrid composites for structural applications: a review

Four different types of amine-attached MCM-48 silicas were prepared and investigated for CO(2) separation from N(2). Monomeric and polymeric hindered and unhindered amines were attached to the pore surface of the MCM-48 silica and characterized with respect to their CO(2) sorption properties. The pore structures and amino group content in these modified silicas were investigated by XRD, FT-IR, TGA, N(2) adsorption/desorption at 77 K and CHN/Si analysis, which confirmed that in all cases the amino groups were attached to the pore surface of MCM-48 at 1.5-5.2 mmol/g. The N(2) adsorption/desorption analysis showed a considerable decrease of the pore volume and surface area for the MCM-48 silica containing a polymeric amine (e.g., polyethyleneimine). The CO(2) adsorption rates and capacities of the amine-attached MCM-48 samples were studied employing a sorption microbalance. The results obtained indicated that in addition to the concentration of surface-attached amino groups, specific interactions between CO(2) and the surface amino groups, and the resultant pore structure after amine group attachment have a significant impact on CO(2) adsorption properties of these promising adsorbent materials.

Tailoring pore properties of MCM-48 silica for selective adsorption of CO2

WHEN metals are submitted to stress, the stress/swain relation is generally regarded as consisting of two parts, the elastic region and the region bfsplastiwin which a permanent set remains upon the remova of the stress. In the elastic region the absence of a permanent set does not necessarily imply that the relation between stress and strain is linear of even single-valued. Prof. Zener uses the term ‘anelasticity’ to describe the properties of solids, as a result of which stress and strain are not uniquely related. Examples are the elastic after-effect, the dependence of elastic constants on the method of measurement, and the dissipation of energy during vibration, which is often referred to as the damping capacity or internal friction of a solid. These effects have aroused much interest in recent years, largely owing to Prof. Zener's own work, and a good book on the subject is much to be desired. Elasticity and Anelasticity of Metals By Clarence Zener. Pp. x + 170. (Chicago: University of Chicago Press, London: Cambridge University Press, 1948.) 4 dollars.

Elasticity and Anelasticity of Metals

Thermal behaviour and dynamic mechanical analysis of Pennisetum purpureum /glass-reinforced epoxy hybrid composites

Dynamic mechanical analysis and effects of moisture on mechanical properties of interwoven hemp/polyethylene terephthalate (PET) hybrid composites

Increased energy consumption due to industrial growth has increased the levels of carbon dioxide (CO2) emission being released into the atmosphere. CO2 emission is a type of greenhouse gas which is a major cause of global warming. Since the issue of CO2 emissions has drawn much attention in recent years, the development of CO2 capture technology has become a necessity. Although CO2 adsorbents are still at the early development stage, it has been suggested that CO2 adsorbents are the most effective technology in controlling CO2 emissions. Solid adsorbents have great potential as an alternative method to conventional adsorbents in adsorbing CO2. In this paper, low cost adsorbents including activated carbon, zeolites, mesoporous silica and clays are discussed in terms of adsorbent preparation methods and CO2 adsorption capacity. The low cost adsorbents are mainly derived from waste materials such as fly ash, steel slag, red mud, bagasses wastes and wood wastes. Besides that, natural resources such as clays have also been applied as low cost CO2 adsorbents. Surface modifications have also been applied to the low cost adsorbents, including metal ion exchange and amine impregnation to enhance CO2 adsorption capacity. In the last section, the current status of CO2 adsorbents is summarized and future trends are discussed briefly to predict the potential materials which can be applied as CO2 adsorbents.

The development of low cost adsorbents from clay and waste materials: a review

The porous composites of clay and fly ash have the potential to be used in many fields, such as catalyst support and gas adsorbents. In this study, various ratios of fly ash (1–2) with different percentage of suspension (50–70 wt%) were applied to produce porous clay-fly ash composites via polymeric replica technique. Fabrication process starts by mixing clay and fly ash in distilled water to form slurry. The process is followed by fully immersing polymer sponge in slurry. The excess slurry is then removed through squeezing. Finally, the sponge coated with slurry is sintered at 500 and 1250 °C for 1 h. It is found that the compressive strength of porous composites improves significantly (0.178–1.28 MPa) when the amount of clay-fly ash suspension mixture (50–70 wt%) increases. The compressive strength of porous composites is mainly attributed to the mullite, quartz and amorphous phase formations. These results are supported by X-ray diffraction analysis. On the other hand, increase in the amount of suspension reduces the apparent density (from 2.44 to 2.32 g/cm3) and porosity (from 97 to 85 %). The reduction in apparent density is believed to be caused by the presence of high fly ash content in porous composites. The melted fly ash cenospheres have closed the internal pores and increased density of samples. Higher suspension level not only reduces porosity, but also increases close pores of the porous composites. The results are justified through the observation from the structures of porous clay-fly ash composites.

Effects of fly ash addition on physical properties of porous clay-fly ash composites via polymeric replica technique

Joining of stainless steel type 304 to mild steel was carried out using a gas tungsten arc welding (GTAW). Samples were welded using stainless steel welding electrode: (AWS: E308l-16) and mild steel welding electrode: (AWS: E6013). The mechanical properties of welded joint were investigated by tension test. It was observed that, the yield strength and tensile strength of welded samples using mild steel welding electrode were slightly lower than welded samples using stainless steel welding electrode. All welded samples fractured at mild steel base metal indicated that the regions of stainless steel base metal, fusion zone and heat affected zone are stronger than mild steel base metal.

Mohd Noor Mazlee

Papers

Thermal behaviour and dynamic mechanical analysis of Pennisetum purpureum /glass-reinforced epoxy hybrid composites

Dynamic mechanical analysis and effects of moisture on mechanical properties of interwoven hemp/polyethylene terephthalate (PET) hybrid composites

The development of low cost adsorbents from clay and waste materials: a review

Effects of fly ash addition on physical properties of porous clay-fly ash composites via polymeric replica technique

Mechanical properties of dissimilar welds between stainless steel and mild steel