Effects of Methyl Branching on the Properties and Performance of Furandioate-Adipate Copolyesters of Bio-Based Secondary Diols

TY - JOUR

T1 - Effects of Methyl Branching on the Properties and Performance of Furandioate-Adipate Copolyesters of Bio-Based Secondary Diols

AU - Little, Alastair

AU - Pellis, Alessandro

AU - Comerford, James William

AU - Naranjo-Valles, Edwin

AU - Hafezi, Nema

AU - Mascal, Mark

AU - Farmer, Thomas James

N1 - © 2020 American Chemical Society

PY - 2020/9/28

Y1 - 2020/9/28

N2 - Furandioate-adipate copolyesters are an emerging class of bio-based biodegradable polymers with great potential to replace fossil-derived terephthalic acid-based copolyesters such as poly(butylene adipate-co-terephthalate) (PBAT). Furandioate-adipate polyesters have almost exclusively been prepared with conventional primary (1°) alcohol diols, while secondary (2°) alcohol diol monomers have largely been overlooked until now, despite preliminary observations that using methyl-branched diols increases the Tg of the resultant polyesters. Little is known of what impact the use of 2° alcohol diols has on other properties such as material strength, hydrophobicity, and rate of enzymatic hydrolysis—all key parameters for performance and end-of-life. To ascertain the effects of using 2° diols on the properties of furandioate-adipate copolyesters, a series of polymers from diethyl adipate (DEA) and 2,5-furandicarboxylic acid diethyl ester (FDEE) using different 1° and 2° alcohol diols was prepared. Longer transesterification times and greater excesses of diol (diol/diester molar ratio of 2:1) were found to be necessary to achieve Mws > 20 kDa using 2° alcohol diols. All copolyesters from 2° diols were entirely amorphous and exhibited higher Tgs than their linear equivalents from 1° diols. Compared to linear poly(1,4-butyleneadipate-co-1,4-butylenefurandioate), methyl-branched, poly(2,5-hexamethyleneadipate-co-2,5-hexamethylenefurandioate) (0:7:0.3 furandioate/adipate ratio) displayed both higher modulus (67.8 vs 19.1 MPa) and higher extension at break (89.7 vs 44.5 mm). All other methyl-branched copolyesters displayed lower modulus but retained higher extension at break compared with their linear analogues. Enzymatic hydrolysis studies using Humicola insolens cutinase revealed that copolyesters from 2° alcohol diols have significantly decreased rates of biodegradation than their linear equivalents synthesized using 1° alcohol diols, allowing for fine-tuning of polymer stability. Hydrophobicity, as revealed by water contact angles, was also found to generally increase through the introduction of methyl branching, demonstrating potential for these materials in coatings applications.

AB - Furandioate-adipate copolyesters are an emerging class of bio-based biodegradable polymers with great potential to replace fossil-derived terephthalic acid-based copolyesters such as poly(butylene adipate-co-terephthalate) (PBAT). Furandioate-adipate polyesters have almost exclusively been prepared with conventional primary (1°) alcohol diols, while secondary (2°) alcohol diol monomers have largely been overlooked until now, despite preliminary observations that using methyl-branched diols increases the Tg of the resultant polyesters. Little is known of what impact the use of 2° alcohol diols has on other properties such as material strength, hydrophobicity, and rate of enzymatic hydrolysis—all key parameters for performance and end-of-life. To ascertain the effects of using 2° diols on the properties of furandioate-adipate copolyesters, a series of polymers from diethyl adipate (DEA) and 2,5-furandicarboxylic acid diethyl ester (FDEE) using different 1° and 2° alcohol diols was prepared. Longer transesterification times and greater excesses of diol (diol/diester molar ratio of 2:1) were found to be necessary to achieve Mws > 20 kDa using 2° alcohol diols. All copolyesters from 2° diols were entirely amorphous and exhibited higher Tgs than their linear equivalents from 1° diols. Compared to linear poly(1,4-butyleneadipate-co-1,4-butylenefurandioate), methyl-branched, poly(2,5-hexamethyleneadipate-co-2,5-hexamethylenefurandioate) (0:7:0.3 furandioate/adipate ratio) displayed both higher modulus (67.8 vs 19.1 MPa) and higher extension at break (89.7 vs 44.5 mm). All other methyl-branched copolyesters displayed lower modulus but retained higher extension at break compared with their linear analogues. Enzymatic hydrolysis studies using Humicola insolens cutinase revealed that copolyesters from 2° alcohol diols have significantly decreased rates of biodegradation than their linear equivalents synthesized using 1° alcohol diols, allowing for fine-tuning of polymer stability. Hydrophobicity, as revealed by water contact angles, was also found to generally increase through the introduction of methyl branching, demonstrating potential for these materials in coatings applications.

KW - Bio-based polymers

KW - 5-(chloromethyl)furfural

KW - adipic acid

KW - secondary alcohol diols

KW - 2,5-furandicarboxylic acid

U2 - 10.1021/acssuschemeng.0c04513

DO - 10.1021/acssuschemeng.0c04513

M3 - Article

SN - 2168-0485

VL - 8

SP - 14471

EP - 14483

JO - ACS Sustainable Chemistry & Engineering

JF - ACS Sustainable Chemistry & Engineering

IS - 38

ER -