Noor Najmi Bonnia

Polyester-Kenaf Composites: Effects of Alkali Fiber Treatment and Toughening of Matrix Using Liquid Natural Rubber

In this study, polyester-kenaf fiber composites were prepared by adding various percentages of kenaf fiber in unsaturated polyester resin and subsequently cross-linked using methyl ethyl ketone peroxide and the accelerator cobalt octanoate. Liquid natural rubber (LNR) (3%) was added as a toughening agent. Kenaf fibers were treated with sodium hydroxide solution to improve the interfacial bonding between the fiber and the matrix. The mechanical properties of the composites were evaluated by impact and flexural testing. Environmental stress cracking resistance (ESCR) of composites in acid and base medium was also studied. Bonding mechanisms were assessed by scanning electron microscope and Fourier transform infrared analysis. It was found that the addition of LNR increased the impact strength and fracture toughness. Alkali fiber treatment was found to provide better impact and flexural strengths to the composites. Measurement of ESCR shows that the composite with acid medium has the fastest diffusion rate, followed by that with base medium, and then without medium.

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.

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.

Permeability properties of thermoplastic natural rubber (TPNR) nanocomposites

Linear low-density polyethylene (LLDPE)/natural rubber (NR)/liquid natural rubber (LNR) with organomontmorillonite (OMMT) were prepared using melt blending method and denoted as TPNR nanocomposites. The melt blending of LLDPE/NR/LNR with a composition of 70:20:10 formed blends. For better dispersion of nanoclay in the TPNR blend, maleic anhydride grafted polyethylene (MA-PE) was used as a coupling agent. The nanoclay dispersion was investigated by X-ray diffraction (XRD), and a novel method using permeability measurements data in a permeability model. The measured d-spacing data proved a good dispersion of nanoclay at low clay contents. The permeability model for flake-filled polymer was used to estimate the aspect ratio of nanoclay platelets in the blend nanocomposites. The oxygen barrier property of the TPNR blend improved about two-fold by adding only 2 wt% of organoclay. Differential scanning calorimetry showed an increase in cystallinity up to 20% suggesting an increase in spherulite growth, by the increased in melting temperature. The increase in the barrier property of the blend with the induction in crystallinity indicates the dominant role of organoclay platelets in barrier improvement. The transmission electron micrograph, showed an intensive intercalation structure and exfoliation structure with the presence of MA-PE.

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.

Thermal properties and crystallisation behaviour of thermoplastic natural rubber (TPNR) nanocomposites

The effect of preparation technique on the crystallisation behavior and thermal properties of TPNR filled nanoclay nanocomposites was investigated. The nanocomposites were prepared via melt blending method using internal mixer (Haake 600P). Two types of nanocomposites preparation technique were employed which is method A and B. In method A, the nanoclay was pre-mixed with liquid natural rubber (LNR) before it was charged into the other materials. For method B, the nanoclay was directly charged into the molten TPNR matrix. The result shows, preparation methods were significantly affect the crystallinity and thermal properties of TPNR nanocomposites. DSC thermogram revealed that nanocomposites crystallinity was increased when prepared by method A but decreased with method B. An increment in polypropylene crystallinity was attributed by the nanoclay which is believed to be as a nucleating agent. DMA thermogram suggested that the preparation method has affected the storage modulus and tan δ but not the glass transition temperature (tg).

Nanofibers from oil palm trunk (OPT): Preparation & chemical analysis

Oil palm trunk (OPT) is one type of agricultural waste material from palm oil industries. The material has big potentials in biocomposite industries. Nanocellulose was extracted from OPT fibers by a chemi-mechanical technique. Chemical characterization of OPT nanofibers confirmed that cellulose content was increased after alkali and acid treatment. FTIR result demonstrated that chemical treatment also led to partial removal of hemicelluloses and lignin from the structure of the fibers. The structure of the cellulose was investigated by scanning electron microscope (SEM).

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.

Flexural & Impact Properties of PLA/Kenaf Fibers Bio-Composites

Polylactic acid (PLA) reinforced kenaf fibres composites were fabricated using melt compounding and compression moulding. Kenaf bast and core fibres had undergone chemi-mechanical treatment before use. The mechanical properties of kenaf bast composites (KBC) and kenaf core composites (KCC) were studied by performing flexural and impact testing. KBC and KCC treated with 1.0M acid treatment at 60 rpm speed shows highest flexural and impact properties. The fibre surface treatment had an efficient effect on the flexural strength at 1.0M concentration, with improvement of approximately 27% of strength.