Synthesis and properties of a novel epoxidised natural rubber-g-cassava starch polymer and its use as an impact strengthening agent

The polarity of epoxidised natural rubber (ENR) was improved by grafting it with cassava starch (CSt). A graft copolymer between ENR and CSt (ENR-g-CSt) was synthesised from CSt solution and ENR latex by using K₂S₂O₈ as an initiator. The highest percentage efficiency of grafting was obtained with 10 parts per hundred (phr) CSt. The swelling ratio of the ENR-g-CSt particles also decreased as a function of the CSt in the sample due to the polarity of the incorporated CSt. After synthesis, it was used as an impact strengthening agent for a polymer blend. Chemically modified NR polymers can form the basis of many value-added NR products that are environmentally friendly and cost effective for use as biopolymers in the future.     

Formulation and characterization of compatibilized poly(lactic acid)‐based blends and their nanocomposites with silver‐loaded kaolinite

Biodegradable polymer nanocomposites have been developed in this study as materials for use in the packaging of moisture‐sensitive products. Poly(lactic acid) (PLA) was the main component of the nanocomposites with poly(butylene adipate‐co‐terephthalate) (PBAT) as flexibility enhancer. Tetrabutyl titanate was also added as a compatibilizer to enhance the interfacial affinity between PLA and PBAT by inducing the formation of some PLA/PBAT via transesterification during the melt blending process, thereby improving the mechanical properties of the blends. Silver‐loaded kaolinite synthesized via chemical reduction was also incorporated into the compatibilized blends for further property improvement. Herein, we report a novel biodegradable quaternary nanocomposite system with intercalated‐exfoliated clay dispersion that was uniquely achieved by increasing the interlamellar space between kaolinite layers through silver nanoparticle insertion. The resultant nanocomposites containing as little as 4 phr modified clay reduced the elongation at break from 213.0 ± 5.85% to 53.8 ± 1.81%, enhanced thermal stability (initial decomposition temperature increased from 378 °C to 399 °C) and exhibited a water vapor permeability reduction of 41.85%. On the basis of these properties, the developed nanocomposites are considered to be promising candidates for use in bio‐packaging applications to replace non‐biodegradable and petro‐based plastics. © 2014 Society of Chemical Industry