Effect of Carboxylated Carbon Nanotubes on the Structure and Properties of PLA / PVDF / ADR Blends

ABSTRACT Poly(lactide) (PLA)/polyvinylidene difluoride (PVDF)/chain extender containing epoxy functional groups (ADR)/carboxylate multiwall carbon nanotubes (MWCNTs‐COOH) composites were prepared by combining solution blending and melt blending techniques. The dispersion state of MWCNTs‐COOH in the composites was controlled by the in situ reaction between carboxyl groups in MWCNTs‐COOH and epoxy groups in ADR, and the effects of MWCNTs‐COOH on the structure and properties of the blends were systematically studied. The torque data demonstrated that the introduction of MWCNTs‐COOH could enhance the melt strength of the blends. DSC data showed that the MWCNTs‐COOH could act as a nucleating agent to improve the crystallization ability of PLA. DMA data and rheological behavior revealed that MWCNTs‐COOH could reinforce the interaction between PLA and PVDF interface. The mechanical data indicated that the introduction of the MWCNTs‐COOH enhanced the tensile strength of the composites, but significantly reduced the elongation at break. With the increase of MWCNTs‐COOH content, the heat deflection temperature (HDT) of the material was obviously increased, and the dielectric constant of the composites showed an upward trend.