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Bioinspired All‐Polyester Diblock Copolymers Made from Poly(pentadecalactone) and Poly(3‐hydroxycinnamate): Synthesis and Polymer Film Properties
Author(s) -
Saar Julia S.,
Shi Yue,
Lienkamp Karen
Publication year - 2020
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/macp.202000045
Subject(s) - copolymer , polymer chemistry , materials science , polyester , glass transition , fluoropolymer , polymer , molar mass , composite material
A bioinspired diblock copolymer is synthesized from pentadecalactone and 3‐hydroxy cinnamic acid. Poly(pentadecalactone) (PPDL) with a molar mass of up to 43 000 g mol −1 is obtained by ring‐opening polymerization initiated by propargyl alcohol. Poly(3‐hydroxycinnamate) (P3HCA) is obtained by polycondensation and end‐functionalized with 3‐azido propanol. The two functionalized homopolymers are connected via 1,3‐dipolar Huisgen addition to yield the block copolymer PPDL‐triazole‐P3HCA. The structure of the block copolymer is confirmed by proton NMR, FTIR spectroscopy and GPC. By analyzing the morphology of polymer films made from the homopolymers, from a 1:1 homopolymer blend, and from the PPDL‐triazole‐P3HCA block copolymer, clearly distinct micro‐ and nanostructures are revealed. Quantitative nanomechanical measurements reveal that the block copolymer PPDL‐triazole‐P3HCA has a DMT modulus of 22.3 ± 2.7 MPa, which is lower than that of the PPDL homopolymer (801 ± 42 MPa), yet significantly higher than that of the P3HCA homopolymer (1.77 ± 0.63 MPa). Thermal analytics show that the melting point of PPDL‐triazole‐P3HCA is similar to PPDL (89–90 °C), while it has a glass transition temperature similar to P3HCA (123–124 °C). Thus, the semicrystalline, potentially degradable all‐polyester block copolymer PPDL‐triazole‐P3HCA combines the thermal properties of either homopolymer, and has an intermediate elastic modulus.