Single‐step solution polymerization of poly(alkylene terephthalate)s: synthesis parameters and polymer characterization

Abstract

Poly(alkylene terephthalate)s represent one of the most frequently used polymer classes worldwide. Well‐known examples include poly(ethylene terephthalate) (n = 2) and poly(butylene terephthalate) (n = 4). The conventional synthesis method for these polymers is based on melt polycondensation, a two‐stage process performed under harsh conditions that includes the synthesis of an intermediate prepolymer and the presence of a catalyst, which may induce toxicity issues. The present work reports on a straightforward single‐step solution polycondensation method performed under mild conditions and in the absence of a catalyst. A homologous series of poly(alkylene terephthalate)s (n = 5 − 10) of molar masses up to 20 000 g mol−1 and dispersity <2.4 was synthesized and characterized thoroughly. Great attention was given to the thermal properties assessment by using state‐of‐the‐art techniques and a highly sensitive prototype technique called rapid heat − cool DSC. Similar to melt‐synthesized polyesters, a particular odd − even trend of the thermal properties versus the number of methylene groups within the monomer unit was revealed. To the best of our knowledge, this is the first report covering a single‐step solution‐based polycondensation performed in the absence of a catalyst that results in highly reproducible polyesters possessing unaltered thermal properties compared to polyesters synthesized through industrially applied conventional routes. © 2017 Society of Chemical Industry

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

“…Based on our experiments, this optimal comonomer ratio is 0.985 for PAT ( n = 10) , which resulted in a polymer with M n and M w of 187,000 g/mol (DP = 616) and 298,000 g/mol, respectively (as measured by GPC). This value is among the highest values described in the literature, irrespective of the synthesis method. ,,,,,,, As anticipated, the molar mass decreases as we deviate from the optimal value, either by increasing or decreasing the comonomer ratio. These data further confirm our expectations that the molar mass can easily be controlled by varying the comonomer ratio.…”

“…Furthermore, at equimolarity, the obtained polymer molar masses are even competitive to those of some polymers prepared via ROP reported in the literature. 2,9,26,28,44,53,61 Finally, by varying the comonomer ratio, we have obtained polymers with various molar masses, thereby gaining control over this very important polymer property. While this control has been claimed by various authors in the literature, none could achieve this in a similarly broad molar mass range and with such straightforward methods.…”

Structure–property relationship of poly(cyclohexane 1,4‐dimethylene terephthalate) modified with high trans‐1,4‐cyclohexanedimethanol and 2,6‐naphthalene dicarboxylicacid

“…Magnified image of the specific region of TGA thermograms clearly indicates that trans‐CHDM isomers improve the thermal stability of synthesized PC#TN copolyesters. Our results are compatible with previous reports …”

Substituent Effects on Thermal and Mechanical Properties of Resorcinol‐Based Semiaromatic Polyesters

“…A similar trend was observed in poly(alkylene terephthalate)s, and the polymers with diols containing even numbers of methylene groups exhibited higher T g than the corresponding polymers with odd counterparts. [ 39 ] Therefore, T g of the polyesters with resorcinol could be affected by an odd‐even effect. In the polyesters containing monomethylated resorcinol, the polymers with Ad or Pi unit respectively exhibited close T g (P(2MR‐Ad) versus P(5Mr‐Ad).…”

“…[ 38,42 ] The relationship between T m of the polyesters was similar to that between their T g (P(R‐Ad) > P(R‐Gl) > P(R‐Pi), P(2MR‐Pi) > P(R‐Pi)), and T m of the polyesters containing resorcinol could be affected by an odd‐even effect. [ 39,43 ]…”