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A two-step heat treatment was utilized as a means to improve the mechanical properties of a high-density polyethylene structure which was fabricated using the three-dimensional printing technique. It was found that the relationship between structure and properties was strongly influenced by heat treatment conditions including treatment times (15-60 min) and treatment temperatures (140-180 • C) of both primary and secondary steps. The use of primary heating at 180 • C for 15 min and secondary heating at 160 • C for 60 min resulted in the highest tensile modulus and strength, 0.7 GPa and 14.8 MPa, respectively. The changes in both shrinkage and tensile properties were governed by the level of residual porosity and quality of polyethylene interface in samples which were both influenced by the degree of thermally induced densification and binder degradation. Empirical correlations between porosity and shrinkage or tensile properties were found to be power functions.

The objective of this research is to produce the low-cost activated carbon from Jatropha curcas L. by chemical activation using zinc chloride ZnCl2. The effects of the impregnation ratio on the surface and chemical properties of activated carbon were investigated. The impregnation ratio was selected at the range of 1:1–10:1 for investigation. The optimum conditions resulted in an activated carbon with a carbon content of 80% wt, while the specific surface area evaluated using nitrogen adsorption isotherm corresponds to 600 m2/g.