Now showing 1 - 4 of 4
No Thumbnail Available
Publication

Effect of dispersibility of graphene nanoplatelets on the properties of natural rubber latex composites using sodium dodecyl sulfate

2022-01-01 , Che W.M. , Teh Pei Leng , Yeoh Cheow Keat , Jalilah Abd Jalil , Lim Bee Ying , Rasidi M.S.M.

Natural rubber latex/graphene nanoplatelet (NRL/GNP) composites containing GNP-pristine and GNP-SDS were prepared by a simple mechanical mixing method. The main objective was to study the effect of dispersibility of GNP on the properties in NRL. X-ray diffraction confirmed the adsorption of sodium sulfate dodecyl (SDS) on the GNP surface. The results showed that high filler loading diminished the physical and mechanical properties of the composites but successfully endured to satisfy electrical conductivity to the NRL/GNP composites. Besides, the SDS surfactant-filled system demonstrated better physical, tensile, electrical, and thermal stability properties than the GNP-pristine. The intercalated and dispersed GNP-SDS increased the number of routes for stress and heat transfer to occur and facilitated the formation of conductive pathways as well, leading to the improvement of the properties as compared to NRL/GNP-pristine composites. However, as the GNP-SDS loading exceeded 5 phr, the GNP-SDS localized in the interstitial layer of NRL, restricted the formation of crosslinking, and interfered with the strain-induced crystallization ability of the composites.

Thumbnail Image
Publication

Preparation and Characterization of Tensile Properties of PMMA/SiC Nanowhiskers Nanocomposite Films: Effect of Filler Loading and Silane Treatment

2023-10-01 , Lim Bee Ying , Voon Chun Hong , Lee L.Y. , Teh Pei Leng , Foong P.Y.

The preparation of nanocomposites through melt mixing was challenging as the nanofillers tend to form agglomeration. The silicon carbide nanowhiskers (SiCNWs) filled poly (methyl methacrylate) (PMMA) thin film in this study was prepared by means of solution casting. Acetone with low toxicity was used as solvent to dissolve the PMMA pellets. A coupling agent, silane was used to enhance the properties of composite films. Besides, the untreated and treated SiCNWs were filled into PMMA matrix, respectively with the filler loading varied from 0.2 to 0.8 wt%. The universal testing machine was used to investigate the tensile properties of composites. It was found out that the tensile strength of the PMMA was reduced in the presence of SiCNWs. However, the tensile strength had increased with the rise of filler loading. At 0.8 wt% of SiCNWs, the composites’ tensile strength was comparable to virgin PMMA. Meanwhile, the SiCNWs had reduced the elongation at break but increased the elastic modulus of PMMA/SiCNWs nanocomposite films. In addition, silane surface treatment on SiCNWs had improved the tensile strength and ductility but lowered the elastic modulus of the nanocomposites. The improvement was due to the enhancement of interfacial adhesion between SiCNWs and PMMA.

Thumbnail Image
Publication

The effect of coated calcium carbonate using stearic acid on the recovered carbon black masterbatch in low-density polyethylene composites

2023-01-01 , Leow V.J. , Teh Pei Leng , Yeoh C.K. , Nor Azura Abdul Rahim , Wong W.C. , Voon Chun Hong , Mohamed Rasidi M.S. , Lim Bee Ying

This research focuses on recycling rubber tire waste through pyrolysis to produce recovered carbon black (rCB). The rCB is combined with recycled low-density polyethylene (rLDPE), calcium carbonate (CaCO3), fatty acid, metallic stearate, and polyethylene (PE) wax to create an rCB masterbatch for household packaging. Surface modification of CaCO3 particles using stearic acid improves the compatibility with LDPE. The study investigates mechanical properties, morphology, melt flow index (MFI), X-ray diffraction, and thermogravimetric analysis in three systems: uncoated, coated, and a hybrid combination of coated and uncoated CaCO3 in LDPE/rCB masterbatch composites. The coated system demonstrates higher mechanical properties and improved compatibility between CaCO3 and LDPE. All three systems exhibit enhanced thermal stability and MFI compared to virgin LDPE, with the coated system showing the most significant improvement. The study showcases the potential of LDPE/rCB masterbatch composites for household packaging, with the coated system displaying the optimum performance across various characteristics.

Thumbnail Image
Publication

Feasibility Study of Microwave Welding of Polypropylene Using Silicon Carbide Nanowhiskers as Microwave Susceptor

2023-01-01 , Foong P.Y. , Voon Chun Hong , Lim Bee Ying , Teh P.L. , Mohd Afendi Rojan

Currently, welding is the most efficient way for joining of plastic. Due to its rapid heating, efficiency in term of time and energy, and ability to be applied on components of any shape, microwave welding stands out from other welding methods. Additionally, SiCNWs was proposed as the microwave susceptor for the microwave welding of thermoplastic in this work due to its high dielectric loss and biocompatibility. To produce microwave welded joint, SiCNWs was first mixed with acetone to obtain a SiCNWs suspension. After that, SiCNWs was drop casted onto the targeted area of PP, allowed to dry and then microwave irradiated. In this work, the microwave heating time studied ranged from 15 s to 20 s. SEM and single lap shear test were used to characterise the microwave welded joint. From the findings, the tensile strength increased as the microwave heating duration increased from 15 s to 18 s, due to formation of SiCNWs/PP nanocomposite welded joint layer with increasing thickness. Yet, when the microwave heating time was prolonged to 20 s, the tensile strength decreased to 0.85 MPa. Besides, a void was observed at the welded joint and it is believed that the presence of void causes the welded joint to weaken when force is applied. Under properly regulated of microwave heating time, a strengthened nanocomposite welded joint can be produced which demonstrate great promise in plastic welding.