Structure–Property–Processing Relations of Short-Chain Branched Poly(butylene terephthalate) (PBT) with Biobased Comonomers

Mielke C, Kuhnigk J, Pospiech D, Komber H, Boldt R, Lederer A, El Fray M, Standau T, Ruckdaeschel H, Altstaedt V, Voit B (2022)

Publication Type: Journal article

Publication year: 2022

Journal

Macromolecular Materials and Engineering Wiley-VCH Verlag

Book Volume: 307

Article Number: 2200208

Journal Issue: 9

DOI: 10.1002/mame.202200208

Abstract

Poly(butylene terephthalate) (PBT) is difficult to foam due to its unfavorable rheological behavior (low melt strength, no strain hardening). In particular, a high expansion and a homogeneous cell morphology are difficult to achieve. This can be altered successfully by addition of multifunctional chain extenders. Chain extenders cause nondefined and rarely understood changes in the polymer architecture usually described as branching. In this contribution, the synthesis of two series of PBT copolyesters with defined short-chain branched units is presented. Dilinoleic derivatives with linear C9 and C7 alkyl side chains are employed to reflect short-chain branches and are incorporated into PBT in various molar ratios. Characterization by NMR spectroscopy and size exclusion chromatography demonstrates the random chain structure and high molar masses of the terpolyesters. Incorporation of dilinoleic derivatives results in the reduction of PBT crystallinity, decreased glass transition temperatures, and altered rheological behavior, in particular of extensional rheology characterized by strain hardening. The comparison to control copolyesters without branches proves that strain hardening is caused by the branches. A higher concentration of branches induces stronger strain hardening, resulting in successful foaming. It is demonstrated that the new terpolyesters have properties comparable with PBT treated with chain extenders.

Involved external institutions

Leibniz-Institut für Polymerforschung Dresden e. V. DE Germany (DE) Universität Bayreuth DE Germany (DE) West Pomeranian University of Technology Szczecin / Zachodniopomorski Uniwersytet Technologiczny w Szczecinie (ZUT) PL Poland (PL)

How to cite

APA:

Mielke, C., Kuhnigk, J., Pospiech, D., Komber, H., Boldt, R., Lederer, A.,... Voit, B. (2022). Structure–Property–Processing Relations of Short-Chain Branched Poly(butylene terephthalate) (PBT) with Biobased Comonomers. Macromolecular Materials and Engineering, 307(9). https://doi.org/10.1002/mame.202200208

MLA:

Mielke, Christian, et al. "Structure–Property–Processing Relations of Short-Chain Branched Poly(butylene terephthalate) (PBT) with Biobased Comonomers." Macromolecular Materials and Engineering 307.9 (2022).

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