Poly l-lactide-layered double hydroxide nanocomposites via in situ polymerization of l-lactide

TY - JOUR

T1 - Poly l-lactide-layered double hydroxide nanocomposites via in situ polymerization of l-lactide

AU - Katiyar, Vimal

AU - Gerds, Nathalie Christiane

AU - Bender Koch, Christian

AU - Risbo, Jens

AU - Hansen, Hans Chr. Bruun

AU - Plackett, David

PY - 2010/12

Y1 - 2010/12

N2 - The use of clay nanofillers offers a potential route to improved barrier properties in polylactide films. Magnesium-aluminium layered double hydroxides (LDHs) are interesting in this respect and we therefore explored synthesis of PLA-LDH nanocomposites by ring-opening polymerization. This method is attractive because it should ensure good dispersion of LDH in the polymer. The effect of adding either LDH carbonate (LDH-CO3) or laurate-modified LDH (LDH-C12) was investigated. X-ray diffraction, scanning electron microscopy, and transmission electron microscopy revealed that exfoliated nanocomposites were obtained when using LDH-C12 but that LDH-CO 3 gave a partly phase-separated morphology. Thermogravimetric analysis showed that PLA-LDH combinations exhibited higher degradation onset temperatures and differential scanning calorimetry confirmed that LDHs can act as nucleating agents. However, PLA molecular weight was significantly reduced when in-situ polymerization was conducted in the presence of the LDHs and we suggest that chain termination via LDH surface hydroxyl groups and/or metal-catalyzed degradation could be responsible.

AB - The use of clay nanofillers offers a potential route to improved barrier properties in polylactide films. Magnesium-aluminium layered double hydroxides (LDHs) are interesting in this respect and we therefore explored synthesis of PLA-LDH nanocomposites by ring-opening polymerization. This method is attractive because it should ensure good dispersion of LDH in the polymer. The effect of adding either LDH carbonate (LDH-CO3) or laurate-modified LDH (LDH-C12) was investigated. X-ray diffraction, scanning electron microscopy, and transmission electron microscopy revealed that exfoliated nanocomposites were obtained when using LDH-C12 but that LDH-CO 3 gave a partly phase-separated morphology. Thermogravimetric analysis showed that PLA-LDH combinations exhibited higher degradation onset temperatures and differential scanning calorimetry confirmed that LDHs can act as nucleating agents. However, PLA molecular weight was significantly reduced when in-situ polymerization was conducted in the presence of the LDHs and we suggest that chain termination via LDH surface hydroxyl groups and/or metal-catalyzed degradation could be responsible.

U2 - 10.1016/j.polymdegradstab.2010.07.031

DO - 10.1016/j.polymdegradstab.2010.07.031

M3 - Journal article

SN - 0141-3910

VL - 95

SP - 2563

EP - 2573

JO - Polymer Degradation and Stability

JF - Polymer Degradation and Stability

IS - 12

ER -