DSC Kinetics Analysis for the Synthesis of Three-Arms Poly(ε-caprolactone) Using Aluminum Tri-sec-Butoxide as Initiator

• Main Authors: Wanich Limwanich, Winita Punyodom, Nawee Kungwan, Puttinan Meepowpan
• Format: Journal
• Published: 2018
• Subjects: Agricultural and Biological Sciences
• Online Access: https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=84942429573&origin=inward; http://cmuir.cmu.ac.th/jspui/handle/6653943832/44091
• Institution: Chiang Mai University

© 2015 Wiley Periodicals, Inc. The kinetics of the ring-opening polymerization (ROP) of ε-caprolactone (ε-CL) initiated by soluble aluminum tri-sec-butoxide (Al(OsecBu) < inf > 3 < /inf > ) has been investigated by the differential scanning calorimetry (DSC). The DSC polymerizations were carried out under nonisothermal and isothermal conditions to obtain three-arms poly(ε-caprolactone) (PCL). From nonisothermal DSC, the polymerization rate (dα/dt) increased with increasing heating rates. The values of E < inf > a < /inf > were determined from Kissinger (63±2 kJ mol < sup > -1 < /sup > ), Friedman (31.0 - 63.0 kJ mol < sup > -1 < /sup > ), and Starink (64.0 - 71.0 kJ mol < sup > -1 < /sup > ) methods. From isothermal DSC, the dα/dt and the apparent rate constant (k < inf > app < /inf > ) increased with increasing polymerization temperatures. The ROP of ε-CL initiated by Al(OsecBu) < inf > 3 < /inf > occurred via the coordination insertion mechanism. The number average molecular weight (M¯n) and percent yield of the synthesized PCL was enhanced by increasing polymerization temperature. The synthesized PCL with M¯n of 2.4 × 10 < sup > 4 < /sup > was obtained using a molar ratio of monomer to Al-O active center ([M]/[Al-O] ) of 400 at 150°C for 24 h. Al(OsecBu) < inf > 3 < /inf > is one of the promising initiator due to its solubility, low transesterification reaction, and high efficiency in ε-CL polymerization.