Zingibain-Pectin-LDPE as a biodegradable composite material

A. M. P. B Samarasekara, J. D. C. M. Jayakody, A. G. S. Madurasangani


Polymers have become common materials of our everyday lives due to their superior properties. However, polymer applications also contribute to the growing amounts of solid waste generated, as polymer products are often used only once before disposal. The disposal problem is not simply technical, but it also has social and economic aspects. Biodegradable polymers are materials with the ability to function for a temporary period and subsequently degrade to save the environment. Nowadays, fruit waste which are highly perishable and seasonal, is a problem to the processing industries and pollution monitoring agencies. Suitable methods have to be adopted to utilize them for the conversion into value-added products. The objective of this research was to produce biodegradable composite material with the help of Low Density Polyethylene (LDPE), pectin and natural enzymes. Pectin was extracted from the passion fruit waste (passion fruit rind) using hot acid extraction method. The biodegradability imparted by pectin can be further improved by introducing chemical enzymes. Enzymes are complex molecules and biological catalysts have the ability to increase rate of chemical reaction. Zingibain was used as a natural enzyme to enhance the biodegradability of the LDPE – pectin polymer blends. Zingibain was extracted from the ginger roots by using dry powder method with a yield of 20 wt%. The extracted pectin and zingibain were analyzed and characterized using Fourier Transform Infrared Spectroscopy (FTIR).  All characteristic peaks related to pectin and zingibain were available in the extracted FTIR spectra. Laboratory scale internal mixture was used to prepare the LDPE – Pectin – Zingibain polymer mixture by using 3 wt% pectin and varying 1 wt% to 5 wt% Zingibain. Biodegradable polymer composite was prepared by using a hydraulic press. Time dependent weight loss, water absorption and tensile properties were measured to evaluate the degree of degradability. Pure LDPE samples retained high level of tensile strength and constant weight for the entire soil burial test period. On the other hand, LDPE- pectin  - zingibain blend showed a significant decrease in the tensile strength and elongation. Soil burial test results showed that biodegradability of the LDPE – Pectin composite further accelerated by adding zingibain. This composite material can be used for different applications to control the environmental pollution.


Zingibain, Pectin, LDPE, Biodegradable


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Proceedings of International Polymer Science and Technology Symposium, University of Sri Jayewardenepura, Sri Lanka