ABSTRACT
This research studied the effect of filler dimensions on some major properties of pineapple leaf fibre-reinforced polypropylene composites. In this study, composites of PALF/PP were produced, the PALF were extracted from pineapple leaves. This was achieved by adopting the mechanical scrapping method. The surface of the extracted PALF were modified with 6% NaOH, 14% C3H6O3, 6% HNO3 and 3% ZnCl. The surface modified PALF as well as the control (untreated/unmodified) gave FTIR spectrum indicated that the modified PALF chemical structures were not significantly altered. Microbial load analysis were carried out to ascertain and determine the shelf life for the PALF, aspergillus was identified as the microorganism that predominantly affected the PALF after a 12 months observation period. Molds were fabricated using mild steel plates by adopted the modern methods of producing molds, with the aid of a computer numerically controlled machine (CNCm) called the vertical milling center (VMC). TAPPI methods were used to ascertain the composition of the PALF, specifically the percentage composition of lignin, hemicellulose and cellulose in the PALF. Elemental composition of the PALF were equally analyzed, the data were subsequently compared and analyzed with the data collected from analyzing same samples using a more accurate and state of the art equipment called the SEM-EDX. The PALF went through particle size reduction stages, broadly classified into the macro (2-6 mm), micro (70 - 300 μm) and nano (20 - 500 nm). The method adopted in the conversion of the PALF into micro and nano fibrils is termed chemo-mechanical method. The PALF micro fibrils were characterized using JOEL JSM 750F SEM, the micographs of the modified PALF showed morphologies of PALF that could easily produce composites with enhanced properties. Similarly, the PALF nanofibrils were characterized using JEOL JEM 2100 High resolution (HR-TEM), the micrographs of the modified nanofibrils displayed a spider web-like structure with nano scale diameter cellulose fibrils or branches of similar fibril bundle hooked up to produced larger aggregates of nano cellulose. The PALF/PP composites exhibits improved mechanical, physical and thermal and properties at the macro cellulose, micro and nano fibrils dimensions of PALF respectively. These enhanced behaviours are seen even in the unmodified PALF/PP composites, where the TS at the optimal performance with ratio of 30/70 of PALF/PP, there is an increase by 27.88 % of TS for the micro PALF/PP composite and an amazing 70.65 % increase at the nano fibrils PALF/PP composites level. However, the behaviour of the modified PALF are higher than the unmodified PALF/PP composites when compared. The results show that the reinforced HNO3 modified PALF/PP composites have higher performance index than the reinforced C3H6O3 modified PALF/PP composites which gives better performance index that the reinforced NaOH modified PALF/PP composites which performs higher than the reinforced ZnCl modified PALF/PP composites, which gave higher performance index than the unmodified reinforce PALF/PP composites.