Miscibility, crystallization and mechanical properties of poly[(3‐hydroxybutyrate)‐co‐(4‐hydroxyvalerate)]/poly(propylene carbonate)/poly(vinyl acetate) ternary blends

Abstract A ternary blend of poly[(3‐hydroxybutyrate)‐ co ‐(4‐hydroxyvalerate)] (P34HB), poly(propylene carbonate) (PPC) and poly(vinyl acetate) (PVAc) was initially melt‐blended in an effort to obtain an excellent balance of mechanical performance. The effect of PVAc content on the miscibility, phase morphology, thermal behavior, isothermal melt crystallization and mechanical properties of P34HB/PPC/PVAc ternary blends was systematically investigated. Dynamic mechanical analysis indicated that P34HB and PPC were immiscible, and PVAc exhibited immiscibility with PPC. PVAc was selectively dispersed in the P34HB matrix and phase morphology was refined by reducing the interfacial tension. Moreover, the PVAc component suppressed the cold crystallization and reduced the isothermal melt crystallization rate of P34HB in the ternary blends. Unexpectedly, marked increases of 32.7% and 3025% were achieved in the tensile modulus and elongation of the ternary blend containing 20 wt% PVAc compared to neat P34HB. Meanwhile, the strength did not deteriorate. The unusual combination of high ductility, strength and modulus is of great potential for expanding the practical application of sustainable and biological polymers. © 2021 Society of Industrial Chemistry.