Biobased poly(lactides)/poly(methyl methacrylate) blends: A perfect association for durable and smart applications?

Abstract

Biobased poly(L-lactide) (PLLA) undoubtedly represents an interesting alternative to petro-based polymers, but still remains excluded from most of high-value and durable applications. The introduction of poly(methyl methacrylate) (PMMA) in poly(lactides)-based materials is thereby exposed to develop miscible polymer blends with new functionalities and superior thermomechanical properties. The miscibility between PLLA and PMMA was first evaluated and only miscible blends were recovered using melt-processes. Interestingly, these miscible binary blends are marked by a high transparency with tunable, enhanced and promising thermomechanical and barrier performances. PMMA was also found to be miscible with stereocomplexable poly(lactides) and, surprisingly, the amount of PLA stereocomplexes formed during high-speed cooling is significantly enhanced by PMMA. Consequently, highly-crystalline ternary PLLA/PDLA /PMMA blends can be easily produced with impressive and complex thermomechanical behavior. Shape-memory properties of miscible PLLA / PMMA blends were also investigated and triple-shape memory effects were demonstrated. Under appropriate stretching conditions, multiple shapes could be stored and recover. The symmetric formulation was found to be particularly suitable for advanced triple-shape memory applications.