Suitable block mold formulations for copper alloy casting have been developed and the formulations used were 25% plaster of paris (POP), 75% silica sand and 31-37% water. Silica sand with a grain size of 106-212 µm was added into dilute suspension of POP and the mixing process was continued until a thick slurry (mixture) was obtained. It has been found that the mixing time of molding materials was highly depended on the type of plaster and optimum slurry viscosity around the diameter of 7.7 – 9.6 cm (slump test) was essential to ensure that the wax pattern could be fully invested. In the dewaxing process, the mold was subjected to the temperature of 170oC for 3 hours and burnout process was effectively achieved by heating the molds at 750oC for 5 hours. The pouring process was successfully carried out without any leakage and it was found that all molds can be easily broken under a force of a hammer.The developed mold also able to produce fully formed of casting without any major defects such as misrun, fin or flash and rat tail, which can be associated with inadequate mold temperature, mold cracks and the separation of mold’s material respectively.

Shape memory polyurethane (SMPU) has received tremendous interest because of its low cost, low density, as well as easy processing. However, its inferior mechanical properties com-pared to shape memory alloys have constrained its application in a broad range of engineering areas. Nanofillers are commonly added to polymers to overcome the problem associated with low mechanical characteristics. This study aims to examine the effect of various loadings of multi- walled carbon nanotubes (MWCNT) on the thermal stability, soft segment crystallinity, tensile and shape memory behaviour of palm oil polyol based SMPU nanocomposites. The SMPU nanocom- posites were synthesised using a two-step polymerisation process. Microphase-separated SMPU nanocomposites obtained as the differential scanning calorimetric analysis showed two melting transitions, which belonged to the soft and hard phase domains. Furthermore, it was found that MWCNT had acted as a nucleating agent, which promoted the crystallisation process of SMPU nanocomposites. The thermal stability and tensile properties of SMPU/MWCNT nanocomposites were enhanced significantly as the MWCNT was added to the SMPU matrix. A considerable enhancement in the shape fixity (SF) value was revealed for PU-30 and PU-40 samples with the addition of MWCNT. The shape recovery (SR) time of SMPU was faster for samples reinforced with MWCNT, whereas SF increased while SR decreased upon increasing the shape memory cycle.

Hybrid Polyurethane (PU) biofoam based on cellulose nanocrystal (CNC) and nanoclay is synthesised via in-situ technique in polymerization process. In a production of hybrid PU biofoam, isocyanate reacted with palm oil-based polyol with the presence of catalyst and the addition of fillers which are CNC and nanoclay. The weight percent of CNC is 0.10%, 0.15%, 0.20%, 0.25% and 0.3% and nanoclay is 2%, 4%, 6%, 8%, and 10% was added in the production of hybrid PU biofoam. This hybridization of Pu foam with CNC and Nanoclay reduced the reaction time for foam formed. Morphological study using Optical Microscope shows a smaller cell size as well as spherical close and polyhedral shape in the hybrid biofoam. A reduction cell size in formation of hybrid biofoam caused a reduction density and increases its performance. Morphological analysis was showed a cell size reduces and increases in number density of cells at higher content of CNC and nanoclay that attributed to the nucleation effect during the foaming process.