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Studies on the optimal conditions for synthesizing poly(butylene succinate‐co‐terephthalate) copolyesters with targeted properties
Author(s) -
Tsai PingHsun,
Wang ChingHuang,
Kan LouSing,
Chen C. Will
Publication year - 2012
Publication title -
asia‐pacific journal of chemical engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.348
H-Index - 35
eISSN - 1932-2143
pISSN - 1932-2135
DOI - 10.1002/apj.645
Subject(s) - condensation polymer , intrinsic viscosity , materials science , succinic acid , molar ratio , polyethylene terephthalate , polymer chemistry , melting point , molar mass , nuclear chemistry , monomer , polymer , viscosity , biodegradation , organic chemistry , chemistry , composite material , catalysis
ABSTRACT The aliphatic‐aromatic copolyesters are becoming more important due to their desirable mechanical properties and biodegradability. In this study, a series of Poly(butylene succinate‐co‐terephthalate) (PBST) of various monomer compositions were synthesized from succinic acid (SA), dimethyl terephthalate (DMT), and 1,4‐butanediol (BDO) in the presence of tetrabutyl titanate (Ti(Obu) 4 ). The experiment was divided into three parts. The first part is a 2 3 factorial design with permutations of three factors, namely, temperature, molar ratio of BDO/DMT, and molar ratio of SA/DMT in polycondensation. Our statistical analysis showed that the temperature has a more significant effect on the intrinsic viscosity ([η]) of PBST than the other two factors. The number‐average molecular weight (M n ) of the PBST was determined from the intrinsic viscosity by using the Berkowitz model of M n = 1.521 × 10 5 [η] 1.5 . The second part of the experiment is a time course investigation of polycondensation under various temperatures, molar ratios of BDO/(DMT + SA), and concentrations of Ti(Obu) 4 . Our results showed the best polycondensation occurred at 1.5 hr with [η] reaching 0.49 dL/g when the temperature was held at 250 °C, BDO/(SA + DMT) = 1.2 mol/mol with SA/(SA + DMT) = 50 mol%, and 0.97 mmol of Ti(Obu) 4 per mol of SA + DMT. The third part of the experiment involves searching for the best molar ratio of SA/(SA + DMT) in obtaining desirable polymer properties and biodegradability. The results showed that the highest melting point of PBST can be as high as 177 °C at SA/(SA + DMT) = 30 mol%. The maximum tensile strength of 25.6 MPa is obtained at SA/(SA + DMT) = 30 mol%. The maximum elongation at break of 269.3% and the maximum Young's modulus of 754.8 MPa are reached at SA/(SA + DMT) = 60 mol% and at SA/(SA + DMT) = 30 mol%, respectively. The fastest lipase‐decomposition rate of PBST reached 100 % at day six for samples with molar ratio SA/(SA + DMT) = 80 mol%. © 2011 Curtin University of Technology and John Wiley & Sons, Ltd.