Preparation and characterization of mulch film from biodegradable polymer with natural fillers

Abstract

This research has been interested in developing and producing the agriculture product as mulch film from biodegradable polymer incorporated with natural fillers. To investigate the effect of natural fillers on the physical properties, mechanical properties, degradability, and field test. The biodegradable polymers were used in this work including poly(lactic acid); PLA and polybutylene succinate; PBS. The natural fillers were used early immature ginger (EG), mature ginger (MG), and lemongrass leaf (LE) with approximately 45 μm of particle size. All the natural fillers are Thai herbal and easier to found in the country. First section, the natural fillers were compounded with PLA and then the good natural filler was chosen for improving the properties of bio-composite film. The addition of natural filler affects the mechanical of biocomposite film was reduced due to the continuous phase was reduced by natural fillers. Especially, the addition of ginger powder causing generated more agglomerate in the polymer matrix. The physical properties were found the addition of natural filler can be improved the colorlessness of PLA that help to reduce the UV-light transmit through out the biocomposite film. The addition of LE powder can absorb the highest UV-light that shows the UV-light can transmit around 1-2%. This section can be summarized, the use of LE powder is good natural filler for improving the light barrier. However, the selection of only PLA as a polymer matrix probably unsuitable due to PLA has hard and brittle. This research has been interested to used PBS for improve the flexibility of polymer matrix. The addition of PBS into the PLA matrix was developed the flexibility and strength of the PLA, which increasing the tensile strength and %elongation of the biopolymer film. LE powder was used for natural filler to prevent UV-light transmittance. Because the requirement of mulch film must be loss of UV-light transmittance for manage the weed generation. The addition of LE powder can be reduced the UV-light transmittance that absorbs the UV-light high to 90%. The biocomposite film was carried on the field under environment for 2 months, which used the real condition for agriculture crop. To investigate the performance of LE powder on the mechanical and physical properties (color parameter and %UV transmittance). The color of biocomposite film was changed to pale color with greater field time which believes that cause from the reaction of compounds in the LE powder changes. While in after 2 months, the biocomposite film also absorbs the UV-light at a high level (~90%). The changing of color is hardly affecting the UV-light transmittance. The mechanical properties of biocomposite film after 2 months were decreased trend but less different value when compared with start value. The reduction of mechanical properties probably the chain scission from water, microbial, and sunlight. The addition of LE powder into biocomposite film has the excellent advantage that prevent weed growth, reduce toxic because all material has non-toxic chemical and biodegradable. Especially, the use of natural fillers as herbal and plants in-country can help to increase the value of these plant and steam revenue to farmers, and the community.

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