Ing Kong

The effect of fermentation and addition of vegetable oil on resistant starch formation in wholegrain breads.

Resistant starch has potential health benefits but the factors affecting its formation in bread and baked products are not well studied. Here, the formation of resistant starch in wholemeal bread products was evaluated in relation to the processing conditions including fermentation time, temperature and the inclusion of palm oil as a vitamin source. The effects of each the factor were assessed using a full factorial design. The impact on final starch content of traditional sourdough fermentation of wholemeal rye bread, as well as the bulk fermentation process of wheat and wheat/oat blends of wholemeal bread, was also assessed by enzyme assay. Palm oil content was found to have a significant effect on the formation of resistant starch in all of the breads while fermentation time and temperature had no significant impact. Sourdough fermentation of rye bread was found to have a greater impact on resistant starch formation than bulk fermentation of wheat and wheat blend breads, most likely due the increased organic acid content of the sourdough process.

Hybrid Fibre Polylactide Acid Composite with Empty Fruit Bunch: Chopped Glass Strands

Hybrid polylactide acid (PLA) composites reinforced with palm empty fruit bunch (EFB) and chopped strand E-glass (GLS) fibres were investigated. The hybrid fibres PLA composite was prepared through solution casting followed by pelletisation and subsequent hot compression press into 1 mm thick specimen. Chloroform and dichloromethane were used as solvent and their effectiveness in dissolving PLA was reported. The overall fibre loading was kept constant at volume fraction, , of 20% while the ratio of EFB to GLS fibre was varied between of 0 : 20 to 20 : 0. The inclusion of GLS fibres improved the tensile and flexural performance of the hybrid composites, but increasing the glass fibre length from 3 to 6 mm has a negative effect on the mechanical properties of the hybrid composites. Moreover, the composites that were prepared using chloroform showed superior tensile and flexural properties compared to those prepared with dichloromethane.

Manufacturing of Natural Fibre-Reinforced Polymer Composites by Solvent Casting Method

Globally increasing environmental concern of petroleum-based material leads to finding the alternative renewable natural sources. Natural fibre-based composite is gaining immense interest not only because of its positive environmental impact but also its economic advantages. One of the very first and simplest processing techniques that have been used for preparing natural fibre-reinforced polymer composites is solvent casting method. In practice, the major advantage of solvent casting is its ease of fabrication without the need of specialized equipment. There are several factors that may influence solvent casting method and hence, the performance of the overall polymer composites. The present chapter provides a comprehensive overview on the manufacturing of natural fibre-reinforced polymer composites by solvent casting method. It comprises information on the factors that influence the method and the properties of the natural fibre-reinforced polymer composites prepared by this method as well as the possible applications.

Synthesis and Characterization of Red Mud and Sawdust Based Geopolymer Composites as Potential Construction Material

The aim of this study was to synthesize the geopolymer composites formed by two industrial wastes, namely red mud (RM) and saw dust (SD). SD was chemically treated with alkali for the removal of lignin and subsequently bleached, before forming composite with acid-modified RM. The composites were then characterized by using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), thermogravimetic analysis (TGA) and universal testing machine to study the morphology, chemical, thermal and mechanical properties. The FTIR spectrum showed that Si and Al from the raw materials played the major role in forming aluminosilicate geopolymer composites. The SEM images revealed that SD and RM particles aggregated to form fully condensed geopolymer matrices with high compressive strength of 8.3-138 MPa, which were comparable to Portland cement (compressive strength of 9-20.7 MPa).

Phase Formation and Electrical Transport Properties of Nano-Sized SnO 2 Added (Tl 0.85 Cr 0.15 )Sr 2 CaCu 2 O 7-δ Superconductors

In this work, the effect of nano-sized SnO2 addition on the phase formation and electrical transport properties of (Tl0.85Cr0.15)Sr2CaCu2O7-δ (Tl-1212) superconductor was investigated. Thallium-based high temperature superconductor (HTS) with nominal starting composition (Tl0.85Cr0.15) Sr2CaCu2O7-δ was prepared using high purity oxide powders via solid state reaction method. Nano-sized SnO2 with 0.01 – 0.05 wt.% were added into Tl-1212 superconductors. The characteristic of the samples were determined by powder X-ray diffraction method (XRD), scanning electron microscopy (SEM), energy dispersive X-Ray analysis (EDX), electrical resistance measurements and transport critical current density measurements. Nano-sized SnO2 added (Tl0.85Cr0.15)Sr2CaCu2O7-δ showed Tc-zero between 93 and 95 K. All of the samples indicated a dominant phase of Tl-1212 with a minor phase of Tl-1201. The highest Jc (at 77 K) was shown by sample with 0.03 wt.% at 3260 mA/cm2. SnO2 has significantly enhanced the transport critical current density of Tl-1212 superconductor by acting as flux pinning centers. However, further addition of nano-sized SnO2 in Tl-1212 superconductor caused degradation in Jc. The SEM micrographs with energy dispersive X-Ray analysis (EDX) showed that SnO2 were well distributed in all the samples.

Effects of organophosphorus and mineral based flame retardants on combustibility and mechanical performances of natural fiber reinforced composites

Purpose The study aimed to investigate epoxy composites reinforced with mechanical performances, thermal decomposition and ignitibility of natural fiber (NF) and doped with 5 wt.% of varying flame-retardant (FR) compounds. The incorporation of ammonium polyphosphate (APP) and zinc borate (ZB) showed improvement in modulus and elongation to break compared to the empty fruit bunch-filled epoxy (control). However, slightly lower tensile and impact strengths were recorded in all FR-containing composites. Design/methodology/approach Among the FR-loaded specimens, enhancement in flexural property was observed in composites with APP, whereas the addition of ZB and alumina trihydrate (ATH) resulted in the reduction of flexural strength. Thermogravimetric analysis results indicated that the introduction of APP and ATH negatively impacted the thermal degradation temperature (Td) of the NF-filled composites. Greater mass residue with FR-filled composites, where increment was in the range from 32-80 per cent compared to the control, was observed, with the greatest being the ZB-containing formulation. Vertical Bunsen burner experiment revealed that the addition of ZB and APP led to a zero dripping flame system, whereas such a phenomenon was absent in both the control and NF composites loaded with ATH. The bomb calorimeter results revealed that addition of NF into neat epoxy significantly enhanced the FR behavior of the composite, and the gross heat of combustion was greatly reduced when FRs were incorporated into the control sample. Findings Results from the current study concluded that non-halogenated FRs including APP, ZB and ATH were able to enhance the fire retardancy of EFB epoxy composite without significantly deteriorate the mechanical behaviors. Originality/value It can be shown from scanning electron microscopy micrographs that the fabrication technique produced composites with good interfacial adhesion between NF and epoxy matrix, and homogenous distribution of FRs were achieved.

The Effects of Graphene and Flame Retardants on Flammability and Mechanical Properties of Natural Fibre Reinforced Polymer Composites

The effects of incorporating three different types of flame retardant (FR) and two variants of graphene into 10 %wt palm EFB natural fibre (NF) filled epoxy composites were investigated in term of the flammability, thermal and mechanical properties through standard Bunsen burner experiment, bomb calorimetry, TGA and tensile tests. The types of FR employed include zinc borate (ZB), ammonium polyphosphate (APP) and alumina trihydrate (ATH) while a lab synthesised and a commercial form of graphene were used in the current work. Compared to the neat NF filled epoxy composite, specimens loaded with 15 %wt of either ZB or APP demonstrated a drip-free condition as observed from the Bunsen burner tests, which could be attributed to the strong char forming characteristic of the compositions. In specimens containing 15 %wt of either ZB or ATH, results from Bomb calorimetry revealed that these specific formulations produced the lowest mean gross heat release amongst others, suggesting better resistant to flame. Relative to the graphene incorporated composites, the post TGA measured mass residue was observed to be greater in FR rich formulations, suggesting that FR additives capable of yielding a much superior flame retardancy compared to graphene. While a slight increases in Young’s modulus was recorded in composites loaded with FR, such formulations produced several main drawbacks whereby reduction in ultimate tensile strength and elongation to break were being measured in large proportion of the specimens.

The Synergistic Effect of Flame Retardants on Flammability, Thermal and Mechanical Properties of Natural Fiber Reinforced Epoxy Composite

Epoxy was effectively resin infused with 15 %wt intumescing Alumina Trihydrate (ATH) flame retardant (FR) formulations into a 10 %wt palm EFB natural fiber (NF) mat. The effects of ATH and its intumescing blend with Zinc Borate (ZB) and Ammonium Polyphosphate (APP) on flammability, thermal and mechanical properties of the composites were investigated. Compared to neat NF filled epoxy composites, specimens loaded with intumescing blend of FR formulations demonstrated an improved thermal properties, showing greater mass residual which can be attributed to the formation of cross-linked network amongst the NF, FRs and epoxy matrix upon combustion at elevated temperature tested within a TGA instrument. Incorporation of fibers drastically enhanced the mass residue and lowered the heat release compare to the pure epoxy. Addition of the intumescing blend of FR formulations also drastically reduces the combustion heat release, total mass loss and zero drip flame in the NF composites. The optimum FRs formulation with 5 %wt ATH and 10 %wt APP exhibited self-extinguishing property, achieved lowest mass loss and no drip flame under Bunsen burner tests, signifying the synergistic effects between ATH and APP within the NF epoxy composites. APP reacts with the carbonaceous network of NF throughout the ignition period, such interaction formed a thick char layer acting as gas and thermal barrier against the fire mechanism. This reaction does not take place in NF composite specimens without APP. In terms of mechanical properties, NF composites loaded with FRs broadly showed poorer tensile strength, mainly due to the existence of FRs, which acted as a nucleating agent affected the physico-mechanical characteristics of the composites. Amongst the FR rich formulations, specimens with APP or ZB blends seem to possess a more superior tensile strength compared with the neat ATH filled formulation. In addition, composites loaded with FRs showed enhanced Young’s modulus relative to those without addition of FRs.

Comparison of magnetic and microwave absorbing properties between multiwalled carbon nanotubes nanocomposite, nickel zinc ferrite nanocomposite and hybrid nanocomposite

Three types of fillers were incorporated in the thermoplastic natural rubber by melt blending process. They are NiZn ferrite, multiwalled carbon nanotubes, and hybrid NiZn ferrite/multiwalled carbon nanotubes followed by weight ratio of 1:1. Their magnetic properties and microwave absorbing properties were investigated. The ball-milled techniques, resulted good filler dispersion in hybrid nanocomposite, proven by the matching saturation magnetization experimental values with the theory calculation. It was found that the magnetic property strongly depends on the amount of magnetic particles in the nanocomposites. The mixing of two different types of filler (multiwalled carbon nanotubes and NiZn ferrite) showed an enhancement of the microwave properties at lower filler loading.