Biodegradable PVA/glycerol-plasticized thermoplastic starch (TPS) and its intumescent flame retardant composites are prepared. Microencapsulated ammonium polyphosphate (MCAPP) was used not only to utilize the charring capacity of the polyhydric compounds but also to restrain the reaction between APP and starch during processing. The flame retardancy and thermal stability of TPS and TPS/MCAPP were characterized by LOI, UL 94, TG, and microscale combustion calorimeter (MCC). TPS/MCAPP composites with only 2 wt % MCAPP can pass V-0 in UL 94 test. However, neat TPS cannot pass any rating. The presence of MCAPP can reduce the total heat release of TPS sharply in MCC test. The thermal degradation and gas products of TPS and TPS/MCAPP were monitored by TG-FTIR and dynamic FTIR. XPS and SEM measurements were utilized to investigate the chemical structure, as well as the surface morphology of the residual char.

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A bimorph composed of ferrimagnetic cobalt ferrite (CoFeO, CFO) and flexible muscovite was fabricated via van der Waals epitaxy. The combination of X-ray diffraction and transmission electron microscopy was conducted to reveal the heteroepitaxy of the CFO/muscovite system. The robust magnetic behaviors against mechanical bending were characterized by hysteresis measurements and magnetic force microscopy, which maintain a saturation magnetization (M) of ∼120-150 emu/cm under different bending states. The large magnetostrictive response of the CFO film was then determined by digital holographic microscopy, where the difference of magnetostrction coefficient (Δλ) is -104 ppm. The superior performance of this bimorph is attributed to the nature of weak interaction between film and substrate. Such a flexible CFO/muscovite bimorph provides a new platform to develop next-generation flexible magnetic devices.