Characterization And Properties Of Thermoplastic Tapioca Starch Based High Density Polyethylene / Natural Rubber Blends
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Date
2013-06
Authors
b Wahab, Mohamad Kahar
Journal Title
Journal ISSN
Volume Title
Publisher
Universiti Sains Malaysia
Abstract
Effects of thermoplastic tapioca starch (TPS) on the properties of HDPE/NR (70/30) blends were investigated. Tapioca starch was chosen to incorporate into HDPE/NR blends due to its abundance and biodegradability properties. However certain drawbacks, such as poor compatibility with the hydrophobic polymer matrix, tendency not to disperse during processing and affinity for moisture are factors which lower the potential of TPS based blends. TPS loadings were varied from 0 wt% to 30 wt% and incorporated into HDPE/NR blends using HAAKE rheomix 600 internal mixer. The melt blending was carried out at temperature of 150 ⁰C with the rotor speed of 50 rpm for 12 minutes. Mechanical properties of blends were evaluated as a function of TPS loadings and the influence of blend’s modification. The tensile strength showed a sharp drop on addition of TPS particle into the blends system due to the inability of TPS to support the stress transfer between phases. Few series of blend’s modification have been done in order to improve the mechanical properties of the blends. TPS was treated with citric acid in order to improve the plasticization and fluidity of TPS in HDPE/NR blends. TPS can be partly depolymerised to produce low viscosity product when processed with citric acid. It is also found that TPS with low molecular weight (Mw) is easy to disperse in the thermoplastic elastomer (TPE) blend and improve wettability at the inter phase of TPS-HDPE/NR as shown by scanning electron microscope (SEM).
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Keywords
Thermoplastic Tapioca Starch , Polyethylene / Natural Rubber Blends