NÂNG CAO ĐỘ BỀN NHIỆT CỦA POLYLACTIDE BẰNG PHƯƠNG PHÁP BIẾN TÍNH VỚI ACID CINNAMIC

Tóm tắt

PolyL-lactide (PLLA) and polyD-lactide (PDLA) were synthesized via a ring-opening polymerization of
L-lactide and D-lactide using L-lactic acid and D-lactic acid as initiators and tin (II) ethyl hexanoate
(SnOct2) as a catalyst. Cinnamic acid (CA) was successfully conjugated into end hydroxyl group of
PLLA and PDLA. The chemical structures of CA-PLLA and CA-PDLA were confirmed by FT-IR and
1H-NMR analysis. The crystanilities and solubilities of polymers were maintained after the terminal
conjugation of CA. The thermal properties were significantly improved, especially the 10% weight-loss
temperature showed the increase of over 50 oC as compared to that of corresponding original polymer.
In addition, CA-PLLA or CA-PDLA revealed 99.2 or 98.8 wt% weight remaining although the original
PLLA or PDLA showed 17 or 22 wt% pyrolysis at 200 oC after 120 minutes of isothermal heating,
respectively. At 240 oC of isothermal degradation, PLLA and PDLA were completely pyrolyzed after 13
minutes of isothermal heating, while CA-PLLA and CA-PDLA showed about 90 wt% weight remaining.
The terminal conjugation of CA showed effective method for thermal improvement of PLLA and PDLA