To solve problems of stiffness of EVOH in film preparation, new formulations are investigated. First, dipentaerythritol (DPE) is blended with EVOH: it acts as plasticizer, decreases the EVOH crystallization temperature and allows the preparation of articles featuring enhanced flexibility and stretchability. However, beyond a certain loading (above 10 wt %) DPE can crystallize and segregate during cooling, causing further problems in EVOH processability due to material embrittlement. Then, a small amount of montmorillonite (MMT) is mixed in the EVOH/DPE system: it results that for specific compositions MMT inhibits the DPE crystallization. At the same time, DPE, thanks to its high polarity and affinity with both clay and polymeric matrix, improves the intercalation of the nanoclays, promoting the penetration of the polymer chains within the layers of the clay. The synergistic effects of DPE and MMT in EVOH matrix is confirmed by DSC, WAXD, SAXS and TEM analyses.
Vannini, M., Marchese, P., Celli, A., Marega, C., Marigo, A., Lorenzetti, C. (2015). Synergistic effect of dipentaerythritol and montmorillonite in EVOH-based nanocomposites. JOURNAL OF APPLIED POLYMER SCIENCE, 132(28), 1-9 [10.1002/app.42265].
Synergistic effect of dipentaerythritol and montmorillonite in EVOH-based nanocomposites
VANNINI, MICAELA;MARCHESE, PAOLA;CELLI, ANNAMARIA;
2015
Abstract
To solve problems of stiffness of EVOH in film preparation, new formulations are investigated. First, dipentaerythritol (DPE) is blended with EVOH: it acts as plasticizer, decreases the EVOH crystallization temperature and allows the preparation of articles featuring enhanced flexibility and stretchability. However, beyond a certain loading (above 10 wt %) DPE can crystallize and segregate during cooling, causing further problems in EVOH processability due to material embrittlement. Then, a small amount of montmorillonite (MMT) is mixed in the EVOH/DPE system: it results that for specific compositions MMT inhibits the DPE crystallization. At the same time, DPE, thanks to its high polarity and affinity with both clay and polymeric matrix, improves the intercalation of the nanoclays, promoting the penetration of the polymer chains within the layers of the clay. The synergistic effects of DPE and MMT in EVOH matrix is confirmed by DSC, WAXD, SAXS and TEM analyses.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
