International Polymer Processing, Vol.22, No.5, 502-511, 2007
Preparation and properties of metallocene-catalyzed PE/starch nanocomposites: Role of nanocompatibilizer
The properties of metallocene catalyzed polyethylene (mPE)/ starch blends and nanocomposites containing mPE-g-maleic anhydride (mPE-g-MA) compatibilizer reinforced with 1 phr commercial organoclay (20A) at various amounts of pristine starch are discussed. The results from X-ray diffraction (XRD) and transmission electron microscope (TEM) experiments revealed that nanocomposites were achieved in all cases. No observable diffraction peaks in the low angle region were detected. Clay was preferentially located within the mPE and starch interface and the mPE matrix. The crystallization temperatures of nanocomposites increased with the addition of clay acting as a nucleating agent. However, the melting temperatures and the glass transition temperatures remained largely unchanged. Clay incorporation provided a heat barrier that profoundly increased the blend thermal stability. A maximum increase in tensile strength and Young's modulus was obtained, up to 60 % and 105 %, respectively, using nanoclay reinforced compatibilizer (termed nanocompatibilizer) in comparison with neat compatibilizer for pristine starch filled cases. Slightly lower water absorption capability was observed for nanocompatibilizer reinforced cases through the sheet-like structure of clay compared with neat compatibilizer cases.