1. Department of Chemistry, School of Physical and Mineral Sciences; University of Limpopo (Turfloop); Private Bag X1106, Polokwane Sovenga 0727 South Africa
2. CSIR Materials Science and Manufacturing, Polymers and Composites; Nonwovens and Composites Research Group; P.O. Box 1124, 4 Gomery Avenue Summerstrand Port Elizabeth 6000 South Africa
3. Department of Polymer Science and Engineering; Inha University; Incheon 402-751 Korea
4. DST/CSIR, National Centre for Nano-Structured Materials; Council for Scientific and Industrial Research; P.O. Box 395 Pretoria 0001 South Africa