Groundwater samples from boreholes and open-hand-dug wells of six communities in the Isoko North Local Government Area of Nigeria were analyzed in respect to physicochemical factors, biological factors, and the metals Na, K, Mg, Ca, Ba, Pb, Cd, Zn, Cu, and Fe for eight consecutive months to give mean values for the wet (July to October 2010) and the dry seasons (November 2010 to February 2011) for each location. The physicochemical parameters complied with World Health Organization (WHO) guidelines, except for the pH being lower and the concentrations of Pb, Cd, and Ba, being higher than the permissible limits of WHO. Total coliform counts indicated bacterial contaminations, especially in one location. The presence of Pb in the drinking water of all communities seemed to be associated with oil exploration and processing activities.

ABSTRACT:The cure characteristics and physicomechanical properties of natural rubber (standard Nigerian rubber) vulcanizates filled with the fiber of bowstring hemp (Sansevieria liberica) and carbon black were investigated. The results showed that the scorch and cure times decreased, whereas the maximum torques increased, with increasing filler loadings for both bowstring hemp fiber and carbon black filled vulcanizates. The tensile strength of both bowstring hemp fiber and carbon black filled vulcanizates increased to a maximum at a 40 phr filler concentration before decreasing. The elongation at break and rebound resilience decreased, whereas the modulus, specific gravity, abrasion resistance, and hardness increased, with increasing filler contents. The carbon black/natural rubber vulcanizates had higher tensile strength, which was about 1.5 times that of bowstring hemp fiber/natural rubber vulcanizates. This superiority in the tensile strength was probably due to the higher moisture content and larger particle size of the bowstring hemp fiber. However, the bowstring hemp fiber/natural rubber vulcanizates showed superior hardness.

This work focused on the development of a reinforcing filler from renewable natural plant resources as part of the ongoing search for environmental friendly fillers that will substitute synthetic reinforcing fillers such as carbon black and silica in rubber manufacturing. The cure characteristics, physico-mechanical and equilibrium swelling properties of natural rubber, Standard Nigerian Rubber (SNR 10) vulcanizates separately filled with commercial grade carbon black (CB), N330 and pulverized natural plant material, Velvet tamarind (VT), seed shell were investigated. The results of the analyses showed that the scorch and cure times decreased while the maximum torques increased with increasing filler loading for both filled-SNR 10 vulcanizates. The tensile strengths of both VT-filled and CB (N330) filled-SNR 10 vulcanizates increased to 30 phr and 40 phr respectively and decreased with increasing filler loading. The modulus at 100% strain, specific gravity, abrasion resistance and hardness increased while elongation at break, equilibrium swelling and rebound resilience decreased with increasing filler loading for both filled-SNR 10 vulcanizates. The results showed that Velvet tamarind seed shell manifested a reinforcing effect on the SNR 10 compounds but lower than that of CB (N330) filler.

ABSTRACT:The cure characteristics and the physico-mechanical properties of natural rubber, standard Nigerian rubber, SNR10 filled with cherry seed shell (CSS) and standard carbon black CB (N330) were determined. The results showed that the scorch, cure times and the maximum torque gradually increased with increasing filler content for CSS-filled natural rubber, but in the case of CB-filled natural rubber, the scorch and the cure times decreased while the maximum torque increased with increasing filler content. The tensile strength of both CSS and CB-filled vulcanizates increased to a maximum at 40 phr filler content before declining. The moduli (M100 and M300), specific gravity (S.G), hardness and abrasion resistance increased while the elongation at break and Dunlop resilience decreased with increasing filler content for both vulcanizates. The locally sourced CSS filler, had a lower reinforcement properties compared to the CB (N330) filler, probably due to its higher moisture content and larger particle size. @JASEM Raw dry rubber is seldom, if ever used in its original state for any engineering application. Rubber manufacture involves the addition to rubber many ancillary materials called additives. This is to allow the rubber compounds to be satisfactorily processed and when vulcanized improve the application properties of the rubber articles. Additives in rubber include; vulcanizing agents, accelerators, activators/retarders, antidegradents, fillers, plasticizers and other ancillary ingredients. One of the most important additives and second largest following the base polymer in rubber compounding is the filler. Fillers improve processability, physicomechanical properties such as tensile properties, hardness, flex fatigue, tear and abrasion resistances, and may cheapen the final product. They achieve performance enhancement by forming strong chemical bonds with the rubber, that is, strong fillerelastomer interactions. The fillers used in rubber compounding can be classified into reinforcing and non-reinforcing types. A reinforcing filler is one which increases the tensile strength, hardness and abrasion resistance of the rubber article. The finer the particle size the more reinforcing a filler is. Examples of reinforcing filler include; carbon black and silica. Non-reinforcing fillers cause reduction in strength properties but may increase hardness and modulus of the rubber product. They are usually applied as diluents or extenders to generally reduce cost, examples include the whitings (CaCO 3 ) and china clay (Blow et al, 1982;Bello, 2001;Whelan et al, 1979).Carbon black is presently the most commonly used filler in the rubber industry, but it's petroleum derived and expensive commercially. Locally available materials such as limestones, eggshells, corn cobs, groundnut shells, rubber seed shells, rice husk, cocoa pod husk and Cherry (Chrysophyllum albidum) are amongst the underutilized renewable resources in our society today which can be used directly or converted by simple processes to valuable materials...

Locally sourced red earth (RE) was air-dried, pulverized, and screened with a sieve of mesh size 75 nm. It was characterized in terms of its moisture content, loss on ignition, silica content, iodine adsorption number, oil absorption, pH, and metal oxide compositions. Natural rubber, standard Nigerian rubber used for this work was first characterized in terms of its dirt, ash and nitrogen contents, volatile matter, plasticity retention index, and Mooney viscosity. The RE was applied as filler wholly and in blends with standard carbon black, CB (N330) filler in the natural rubber compounding using efficient vulcanization system. The cure and the physicomechanical properties of the compounds and vulcanizates were, respectively, measured as function of filler loading. The results were compared with those of the standard carbon black (N330)-filled natural rubber. It was found, that the RE-filled natural rubber showed substantial reinforcement of the rubber, though inferior to carbon black (N330) filled vulcanizates, the tensile strength of the carbon black-filled vulcanizates is about one half times that of the RE-filled vulcanizates. The tensile properties of the RE-filled vulcanizates improved markedly by blending the RE-filler with the carbon black (N330).