International Journal of Chemistry

International Journal of Chemistry | Vol. 1, No. 11, November 2010 | pp. 177–184

DOI: 10.46882/2010/IJC/000022

Article Type: Original Research Paper

Title: Synthesis and Evaluation of Physicochemical Properties of Novel Polyurethane Elastomers Derived from Castor Oil

Names of Authors: F. E. Okieimen¹, J. U. Radhakrishnan¹*

Authors’ Affiliations:
¹Department of Chemistry, University of Benin, Benin City, Nigeria.

Abstract: The production of polyols from non-edible plant lipids offers a sustainable platform for replacing petroleum feedstocks in the polymer manufacturing sector. This research examines the structural design and material optimization of novel polyurethane elastomers synthesized via a green pathway using crude castor oil (Ricinus communis). The hydroxyl-rich triglyceride structure of castor oil was directly reacted with toluene diisocyanate (TDI) at varying isocyanate-to-hydroxyl (NCO/OH) molar ratios ranging from 1.0 to 1.6 in the presence of dibutyltin dilaurate as a catalyst. Structural network crosslinking was confirmed via Fourier-transform infrared (FT-IR) spectroscopy by noting the complete disappearance of the characteristic isocyanate peak at 2270 cm⁻¹ and the appearance of intense urethane linkage bands (N-H at 3300 cm⁻¹, C=O at 1710 cm⁻¹). Tensile strength evaluations showed that elastomer sheets prepared with an NCO/OH ratio of 1.4 achieved a maximum tensile strength of 24.5 MPa and an elongation at break of 185%. Thermogravimetric analysis (TGA) demonstrated high thermal stability, with initial decomposition commencing above 285°C. Water absorption and chemical resistance tests in 10% HCl and 10% NaOH solutions revealed strong hydrolytic stability due to the hydrophobic nature of long-chain fatty acid segments, establishing these bio-rubbers as protective industrial coatings.

Keywords: Polyurethane; Castor oil; Bio-based polymers; Crosslinking density; Tensile strength; Thermogravimetric analysis

Manuscript Timeline: Received: August 11, 2010; Revised: September 20, 2010; Accepted: October 12, 2010; Published: November 10, 2010.

Citation: Okieimen, F. E., & Radhakrishnan, J. U. (2010). Synthesis and Evaluation of Physicochemical Properties of Novel Polyurethane Elastomers Derived from Castor Oil. International Journal of Chemistry, 1(11), 177–184.

International Journal of Chemistry | Vol. 1, No. 12, December 2010 | pp. 185–193

DOI: 10.46882/2010/IJC/000023

Article Type: Original Research Paper

Title: Spatial Analysis and Chemical Characterization of Particulate Matter (PM2.5 and PM10) in an Industrial Area of Lagos

Names of Authors: O. S. Alani¹, J. I. Onwuteaka², T. A. Ajayi¹*

Authors’ Affiliations:
¹Department of Chemistry, University of Lagos, Surulere, Nigeria.
²Department of Chemical Sciences, Yaba College of Technology, Yaba, Nigeria.

Abstract: Atmospheric particulate pollution in highly crowded industrial cities presents severe respiratory health hazards, requiring continuous air matrix characterization. This study assesses the atmospheric concentrations and trace metal profiles of fine (PM2.5) and coarse (PM10) particulate matter across five commercial nodes within the Ikeja industrial zone of Lagos. Air sampling was executed concurrently over a six-month period using high-volume air samplers configured with quartz fiber filters. The quantitative elemental distribution was resolved using Energy-Dispersive X-ray Fluorescence (EDXRF) spectrometry. Average PM2.5 concentrations ranged from 45.8 to 92.4 μg/m³, while PM10 spans reached 112.5 to 245.6 μg/m³, consistently exceeding the air safety guidelines set by the World Health Organization. Chemical characterization revealed elevated footprints of lead (Pb), zinc (Zn), iron (Fe), and copper (Cu) in both particle fractions. Enrichment factor (EF) calculations showed high values for Pb (EF > 45) and Zn (EF > 60), indicating significant industrial contributions rather than natural crustal weathering paths. Principal Component Analysis (PCA) identified fossil fuel combustion, metallurgical smelting effluents, and vehicular tire wear as the primary emission sources, highlighting a strong need for stringent stack monitoring protocols in urban centers.

Keywords: Air pollution; Particulate matter; Trace metals; X-ray fluorescence; Enrichment factors; Principal component analysis

Manuscript Timeline: Received: September 02, 2010; Revised: October 18, 2010; Accepted: November 05, 2010; Published: December 03, 2010.

Citation: Alani, O. S., Onwuteaka, J. I., & Ajayi, T. A. (2010). Spatial Analysis and Chemical Characterization of Particulate Matter (PM2.5 and PM10) in an Industrial Area of Lagos. International Journal of Chemistry, 1(12), 185–193.