Mechanism of Dendritic Crystals in Poly(butylene adipate) Blended with Amorphous Polymers

摘要

Effects of various amorphous polymers at specific contents in blends of poly(butylene adipate) (PBA) on crystal growth and morphology were analyzed using polarized-light microscopy (PLM), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and wide angle X-ray diffraction (WAXD). PBA was blended with various loading of an amorphous polymer, such as polyhydroxy ether of bisphenol-A (phenoxy), poly(styrene-co-acrylonitrile) (SAN), poly(vinyl phenol) (PVPh), or poly(ether imide) (PEI), respectively. Of these four, the PB A/phenoxy blend was used as a model system for investigation in greater details. Upon crystallization at T_c = 33℃, unusual morphologies of hexagon crystals at early stages and feather-like dendritic lamellar bundles at final stage of crystallization were observed in all blends of PBA/amorphous polymer, including PBA/phenoxy, specifically at 5～10 wt% loading of the amorphous polymers, where the growth rates of blends of PBA/amorphous polymer were found to be minimum in comparison to those for other compositions or T_c's.