Reaction kinetics and simulations of ring-opening polymerization for the synthesis of polybutylene terephthalate

Abstract

Cyclic polybutylene terephthalate (PBT) was polymerized with 2-ethylhexanoic acid tin(II) salt activated by 1-dodecanol in order to study the reaction mechanisms dominant in ring-opening polymerization (ROP) for polyester synthesis. Initiator-to-monomer content and temperatures were varied from 0.05% to 0.5% and 190 o C to 250 o C, respectively. The living-like character of ROP was confirmed by the characteristic effect of initiator content on cyclic oligomer conversion, along with the linear dependence of the number-average molecular weight upon conversion. The molecular weight distribution is mainly a function of the interplay between chain transfer and transesterification reactions. Since the PBT macrocycles appear in different sizes from 2 to 7 repeat units, each carbonyl group theoretically contributes to ring reactivity, where in this system both size-dependent and size-independent approaches to simulate propagation deliver appreciable results. The corresponding rate constants have been determined and, in contrast to other polymer systems, the proximity of these values to those of chain transfer and transesterification is significant.

Catalyst-Free Single-Step Solution Polycondensation of Polyesters: Toward High Molar Masses and Control over the Molar Mass Range

“…Finally, we have obtained low polydispersity (D) values of 1.5 ± 0.1, which are similar to the typical values reported in the literature (i.e., around 2). 40,42,45,53,55 The data obtained through 1 H NMR spectroscopy show the same trends as those calculated from GPC, but the absolute values are slightly different. While the DP as determined via 1 H NMR spectroscopy is higher than the DP obtained from GPC for PAT (n = 8) and PAT (n = 9) at ratio 1.00, they are remarkably similar for PAT (n = 10−12) .…”

“…The above-mentioned disadvantages of the melt polycondensation method have led to the development of a ring-opening polymerization (ROP) approach as a new synthetic strategy to produce PATs. This method starts from cyclic oligomers instead of the two standard monomers and can involve shorter reaction times and milder reaction conditions, thereby limiting thermal degradation and the formation of side products. ,,,− Furthermore, polymers with high molar masses (i.e., >50,000 g/mol) can be obtained via ROP …”

A Cascade Polymerization Method for the Property Modification of Poly(butylene terephthalate) by the Incorporation of Isosorbide

“…Polymerization of cyclic oligo­(butylene terephthalate)­s (COBTs) has been proved to be an alternative path for the synthesis of PBT. − Application of this method for the synthesis of copolyesters has been reported recently, where COBTs were copolymerized with other aliphatic lactones, yet it is not applicable for the improvement of PBT’s T g . , Recently, we have developed an in situ cascade polycondensation-coupling ring-opening polymerization (PROP) method for the facile synthesis of polyesters and poly­(ether ester) multiblock copolymers, − utilizing polyether diols as initiator and cyclic oligoesters as monomer. At certain temperatures, ring-opening polymerization (ROP) occurs first to produce α,ω-dihydroxyl polyesters (triblock copolymers), which further cascade undergoes CP to yield high molecular weight polyesters (multiblock copolymers).…”

3D-MID Technology for Surface Modification of Polymer-Based Composites: A Comprehensive Review

“…It is used primarily on account of its good dimensional stability, temperature resistance and electrical properties. PBT exhibits high resistance to many solvents, but it is not inherently flame retardant [ 110 , 111 , 112 , 113 , 114 , 115 , 116 , 117 , 118 , 119 ].…”