engleski

Biodegradable blends of low polyethylene and thermoplastic starch

The petroleum-based polymers are highly durable and resistant to almost all forms of degradation, and cause serious economic and environmental problems related to the increasing volume of the plastic waste. In order to minimize the environmental problems caused by plastic wastes, with emphasis on accelerate the biodegradability of polymeric materials the idea is replacing some or all of the synthetic polymers with natural polymers in many applications. Polymer blends, immiscible or miscible, are of recent interest for developing new materials with properties suitable for packaging industry, specifically for short term packaging and disposable applications. The development of environmental friendly polymers from renewable resources has been recognized as an important alternative to synthetic polymer based packaging materials. The aim of this study was preparation of LDPE/TPS biodegradable blends from thermoplastic starch (TPS) (40 wt. % of starch + glycerol) and low density polyethylene (LDPE). Maleic anhydride grafted- styreneethylene/ butylene-styrene (SEBS-g-MA) block copolymer was introduced into the LDPE/TPS blends as compatibilizers for phase compatibility improvement. The effects of the compatibilizer on morphological, mechanical, thermal and barrier properties of the LDPE/TPS biodegradable blends were investigated. Thermal behaviour of the LDPE/TPS blends without and with compatibilizer were characterised using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The results confirmed that the incorporation of (SEBS-g-MA) block copolymer enhanced the thermal stability of the LDPE/TPS biodegradable blends. The improvement of thermal stability was caused by the enhanced interfacial adhesion between LDPE and TPS with the addition of the compatibilizer. In addition, a morphology study confirmed that SEBS-g-MA contributed to the better interfacial adhesion of LDPE/TPS blends, leading to better mechanical, thermal and barrier properties of resultant biodegradable blends.

low density polyethylene ; thermoplastic starch ; maleic anhydride grafted-styrene-ethylene/butylene-styrene block copolymer ; biodegradable

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