• Macosko, Christopher W.
• Xu, Yuewen
• Topolkaraev, Vasily
• Loi, Jesse
• Saba, Stacey A.
• Mceneany, Ryan J.
• Tower, Ted
• Delgado, Paula
• Todd, Alexander D.

Abstract

<p>Semi-crystalline polylactide (PLA)/polyolefin multi-component blends were used as precursors for the generation of a new class of micro-cellular polymers. Either a polypropylene-based elastomer (PBE) or polypropylene (PP) homopolymer were utilized as dispersed phases at the 10 wt% level. An epoxy-functionalized terpolymer (PEGMMA) was introduced (1 wt%) as a reactive compatibilizer to reduce the dispersed phase droplet size and provide sufficient adhesion between the matrix and dispersed phase. In addition, a polyalkylene glycol liquid (PAG) was added to the blend (4 wt%) to serve as a PLA plasticizer and interfacial modifier. The multicomponent blends exhibited significant increases in strain at break as compared to neat PLA and were subjected to a range of uniaxial strains (10–90%) at room temperature. These cold drawn materials exhibited nearly constant cross-sectional area and fine micro-cellular structures, as revealed by scanning electron microscopy. Distinct different voiding mechanisms observed for the PBE- and PP-containing blends were ascribed to the differences in the dispersed phase elastic moduli and deformability. The material density of cold drawn blends was reduced by up to 34% when compared to the precursor blends without a noticeable change in cross-sectional area. The novel low-density microcellular PLA blends demonstrated outstanding mechanical properties such as high strength, high modulus, substantial ductility, and a 14-fold increase in impact resistance as compared to PLA homopolymer.</p>

Topics

• density
• phase
• scanning electron microscopy
• reactive
• strength
• interfacial
• ductility
• homopolymer
• elastomer