Characterization of polyester composites reinforced with Hibiscus canescens stem fiber and filled with Carica papaya leaf powder

Hibiscus canescens stem fiber-reinforced polyester composites and composites filled with Carica papaya leaf powder (CCLP) were developed and experimentally studied and their mechanical and thermal properties were investigated. A constant 10-layer woven fiber configuration was adopted in making the composite laminates by hand lay-up process and the filler loading of the CCLP was changed from 2 wt%, 4 wt%, 6 wt%, 8 wt%, to 10 wt%. The structural and thermal properties of the pristine CCLP have been studied by SEM, EDX, DSC, TGA, DTG, XRD and AFM methods. Thermal analysis results showed moisture removal started around 100°C and thermal degradation started at higher temperatures, which meant good thermal stability characteristics of the filler material. The mechanical properties such as tensile strength, flexural strength, impact energy and Knoop hardness have been tested as per the standard methods. The experimental results showed that the use of a CLCP has a significant effect on the composite properties up to the 8 wt% of the filler. The composite with 8 wt% CCLP had the highest tensile strength (∼165 MPa), flexural strength (∼185 MPa), impact strength (∼24 J), and hardness (∼70 HK). At this level, it was noticed that there was a slight reduction in properties as a result of possible filler agglomeration and non-uniform dispersion. This improved performance was thought to be due to better adhesion between the fiber, filler and polyester.This improved performance was thought to be due to better adhesion between the fiber, filler and polyester. The study proves that CCLP is an effective sustainable bio-filler to enhance mechanical properties of natural fiber-reinforced polyester composites.