Polypropylene composites of snail shell powder were prepared at filler contents, 0 to 40 wt%. The particle sizes of the snail shell powder investigated were 0.150, 0.30, and 0.42 µm. Talc, of particle size, 0.150 µm was used as the reference filler. The polypropylene composites were prepared in an injection moulding machine and the resulting composites were extruded as sheets. Some mechanical and end-use properties of the prepared composites were determined. Results showed that the snail shell powder improved the tensile modulus, flexural strength, and impact strength of polypropylene and these properties increased with increases in the filler content and decreases in the filler particle size. The elongation at break of the composites was however observed to decrease with increases in the filler content, and particle size. The elongation at break of talc filled polypropylene was zero, an indication of the brittle nature of polypropylene composites of talc. The hardness, water sorption (24-hr) and specific gravity of the composites were found to increase with increases in the filler content, and decreases in the filler particle size. The level of water absorbed by snail shell powder composites of polypropylene is considerably higher than that of talc filled polypropylene. The flame retardant properties of the prepared composites were however found to decrease with increases in the filler content, and particle size. Generally, snail shell powder was found to show greater property improvement over talc in the prepared composites

The mechanical and end-use properties of egg shell and fish bone powder filled polypropylene have been determined at filler contents, 0 to 40 wt. %, and particle sizes, 0.150, 0.30, and 0.420 µm. Talc, of particle size, 0.150 µm was used as the reference filler. The incorporation of egg shell and fish bone powder into polypropylene resulted in improvement in the tensile strength, tensile modulus, flexural, and impact strength of the composites, and these properties increased with increase in filler contents, and decrease in filler particle sizes. The elongation at break of the composites was observed to decrease with increase in filler contents, and particle sizes. The hardness, specific gravity, and water absorption (24 h) of the prepared composites were found to increase with increase in filler contents, and decease in filler particle size. Talc filled polypropylene was observed to absorb less water than fish bone or egg shell powder filled polypropylene. The amount of water absorbed by these composites was observed to be independent of filler content or particle size but on the nature of the filler used. The fillers under investigation efficiently reduced the rate of burning of polypropylene at high filler contents, and particle sizes. Generally, egg shell, and fish bone powder fillers have shown greater property improvement over talc in the prepared composites. Egg shell, and fish bone powder fillers could be viable alternatives to the conventional mineral fillers for the plastic industry, and for applications where the high water absorption of the fillers is not a critical factor of interest.

Native starch extracted from sweet potato tubers was modified via extrusion. The native starch and modified starch were characterized by Fourier transform infrared (FTIR) spectroscopy, which revealed slight modifications in peak position and intensities on starch modification. The modified starch was evaluated as a corrosion inhibitor of galvanized steel in 1 M HCl solution by gravimetric and potentiodynamic polarization measurement techniques. Results obtained from gravimetric measurement reveals that the modified starch inhibition efficacy was dependent on time, concentration and temperature, increasing with increase in concentration and decreasing with increase in time of immersion and temperature of the system. Maximum inhibition efficiency of 64.26% was obtained at a concentration of 0.7 g/L PMS. Also, result from polarization technique indicated that the modified starch belonged to a mixed-type inhibitor. Adsorption of the inhibitor on the galvanized steel surface was found to obey the Langmuir adsorption isotherm.

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This study investigates the morphological and physical/end-use properties of corn cob powder-filled recycled polypropylene composites. The composites were prepared by incorporating corn cob powder of particle sizes 150 µm, 300 µm and 425 µm respectively at filler loadings of 5 to 25 wt%. The properties were determined according to standard test procedures. Results showed that the incorporation of corn cob powder as filler resulted to enhancement of water absorption and solvent sorption, which were found to increase with both increase in filler loading and increase in filler particle size, probably due to the hydrophilic nature of corn cob powder. It was also discovered that solvent sorption was most pronounced with benzene, followed by toluene and lastly xylene, in accordance with the relative proximity of their solubility parameters to that of polypropylene. Flame propagation rate was also found to improve by the incorporation of corn cob powder due to its high content of cellulose, a combustible organic matter. However, specific gravities of the composites were found to be lower than for the unfilled polypropylene, an implication that the composites produced are lighter in weight than the unfilled. Specific gravity increased with increase in filler loading but decreased with increase in particle size. The Morphological studies showed increase in the number of spherulites with increase in filler loading and increase in the size of the spherulites with increase in particle size. Further observation showed that the particle sizes and pores sizes detected increased with increase in filler particle size probably due to poor interaction and distribution of coarse particles. It is hoped that this present study will to help place the usefulness of corn cob as filler in the development of thermoplastic composites in future and develop its niche in the scientific record.