Biobased products from aromatic Curcuma longa L. leaves

Abstract

Maximizing the use of natural resources and consequently minimizing the use of non-biodegradable synthetic polymers are major efforts towards promoting circular economy and achieving sustainable development goals. Turmeric is a major commercial crop and is mainly grown for the root or rhizome. However, about 30–40 tons of turmeric leaves are generated per acre and are generally disposed as waste and are burnt or buried. Turmeric leaves are inevitably generated and are renewable, sustainable, biodegradable and low cost sources for developing bioproducts. In addition, turmeric leaves also have inherent fragrance and other unique properties that can be utilized to develop biodegradable and disposable bioproducts. In this research, turmeric leaves were used as a reinforcement for polypropylene (PP) to fabricate bio-based composites by compression molding. Composites with up to 90 % turmeric leaves were developed, and the morphology, mechanical properties, flame-resistance, sound absorption, water absorption, and thermal properties were studied. Further, the biocomposites were fabricated into disposable fan blades. The tensile and flexural properties of the composites containing 60 % powdered turmeric leaf were comparatively higher than those of other ratios. Addition of a compatibilizer (maleated polypropylene) enhanced the tensile strength to 8.5 MPa and flexural strength to 14.5 MPa. The composite had sound absorption coefficient up to ∼0.36, thermal conductivity in the range of 0.402–0.317 W/mK, and flame resistance rating of V1 and LOI of 24, acceptable for most applications. Biobased products such as fan blade could be fabricated and the composites could be used for various high value applications. Valorization of turmeric leaves will assist in making turmeric more economical and affordable for food and non-food applications.