EFFECTS OF NaOH MODIFICATION ON THE MECHANICAL PROPERTIES OF BAOBAB POD FIBER REINFORCED LDPE COMPOSITES

Abstract

In order to improve properties of natural fibers as reinforcement, different treatment methods have being adopted by researchers. However, the use of sodium hydroxide (NaOH) for the treatment of baobab pod fiber as reinforcement in low density polyethylene is sparsely reported. Therefore, this study, investigated the effect of 2 wt%, 4 wt% 6 wt%, 8 wt% and 10 wt%  concentration of NaOH on baobab pod fibers as reinforcement for low density polyethylene (LDPE). Two roll mill machine and hydraulic press at a pressure of 10 kN and temperature of 120^oC aided the production of the composite. FT-IR was used to analyze the functional groups of the treated and un-treated fibers. The result showed the disappearance of the peak 1550 cm^-1 corresponding to lignin after modification. Further, the composites were characterized for the following tensile strength (TS), modulus of elasticity (MOE), elongation at break, impact strength and water absorption. Preliminary studies on the effect of loading of the unmodified baobab fiber in the LDPE matrix showed desirable properties at 10 wt%, where fiber content was in the range of 5 wt% to 30 wt% at interval of 5 wt%. The composite produced from the 8 wt% NaOH modified fiber had the highest tensile strength, MOE, elongation at break. At this modification level, the tensile strength, MOE and elongation at break were about 75.48%, 92.18% and 28% respectively higher than the composite produced from unmodified fiber. Composite produced with 10 wt% NaOH modified fiber exhibited least water absorption of 1.80%, which was 50% lower than unmodified. These showed that the modification of the fiber improved the composite properties. These properties compared favorably with some reported properties for natural fiber reinforced polymer composites.

http://dx.doi.org/10.4314/njt.v36i1.12