THE EFFECT OF CHAIN BRANCHING ON THE CRYSTALLINITY BEHAVIOR OF POLYLACTIDE WITH THE PRESENCE OF DISSOLVED CO_2

摘要

This paper investigates the effect of chain extender on the crystallinity behavior of Polylactide with/without the presence of dissolved CO_2 by a high-pressure differential scanning calorimeter (HPDSC). It is shown that without CO_2, the crystallinity increases by decreasing the branched structure due to better chain regularity. With the presence of low-pressure (15bar) CO_2, the crystallinity of PLAs significantly increased due to CO_2's great plasticization effect. However, with the increase of pressure (from 15bar to 45bar), crystallinity dramatically decreases, even though more CO_2 is dissolved. However, as the pressure increases from 45bar to 60bar, the crystallinity of all PLAs dramatically increases.