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

Abstract

The kinetics of the ring-opening polymerization (ROP) of ε-caprolactone (ε-CL) initiated by soluble aluminum tri-sec-butoxide (Al(OsecBu) 3 ) 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 a were determined from Kissinger (63 ± 2 kJ mol −1 ), Friedman (31.0 -63.0 kJ mol −1 ), and Starink (64.0 -71.0 kJ mol −1 ) methods. From isothermal DSC, the dα/dt and the apparent rate constant (k app ) increased with increasing polymerization temperatures. The ROP of ε-CL initiated by Al(OsecBu) 3 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 withM n of 2.4 × 10 4 was obtained using a molar ratio of monomer to Al-O active center ([M]/[Al-O]) of 400 at 150ºC for 24 h. Al(OsecBu) 3 is one of the promising initiator due to its solubility, low transesterification reaction, and high efficiency in ε-CL polymerization. C 2015 Wiley Periodicals, Inc. Int J Chem Kinet 47: [734][735][736][737][738][739][740][741][742][743] 2015

Thermomechanical Characterization of an Unsaturated Polyester Vitrimer Synthesized Using a Titanium Transesterification Catalyst

“…A few works in the state of the art have already reported the kinetics of various metal alkoxides , on the transesterification of poly-lactide-acid (PLA), poly-caprolactone (PCL), or poly- l -lactide (PLL). The application of active centers like Al­(III), Ti­(IV), Sn­(II), and Sn­(IV) for the synthesis of the polymer matrix with biodegradable properties has been successfully described in several papers. − The catalytic performance of titanium (IV) butoxide was reported in the experimental work of Punyodom et al, who investigated the effect of three different metal-based catalysts on the processing of PLA. The results confirmed the reduction of PLA’s molecular weights throughout the fragmentation of the polymeric chain derived from the catalyzed intramolecular exchange.…”