Multiphase Polylactide Blends: Toward a Sustainable and Green Environment guides the reader through fundamentals, science, preparation, and key areas of innovation in polylactide (PLA) blends. Bio-based polymers, and notably PLA, have not only gained increasing interest as a more sustainable alternative but also bring challenges in terms of mechanical, rheological, thermal and physical properties, processability, shapability, and foamability. The use of blends looks to address these, with the development of new types of economically viable and environmentally friendly systems. This is a valuable book for academic researchers, scientists, and graduate students across bio-based polymers, polymer science, chemistry, and materials science, as well as engineers, R&D professionals, and all those in industry with interest in PLA-based blends, biopolymers, and sustainable materials and products. More specifically, the first three chapters of this book overview the fundamentals of thermoplastic polymers, polymer blends, and structure and properties of PLA. These chapters could technically be used as a valuable textbook on the noted topics. The rest of the chapters inclusively study the fundamentals, investigations, and achievements in PLA-based blends with various types of polymers. These include miscible blends of poly L-lactide and poly D-lactide, binary immiscible/miscible blends of PLA with other thermoplastics and elastomers, PLA-based ternary blends and blend nanocomposites, as well as PLA-based blend foams. Overall, this book provides a thorough and critical overview of the state of the art in PLA-based blends, including significant past and recent advances, with the aim of supporting and shaping further research and industrial application of these materials for the development of a green and sustainable future.