Copolyesters. I. Sequence distribution of poly(butylene terephthalate‐co‐adipate) copolyesters determined by 400 MHz NMR

The positional effect of sulfonate groups on poly(butylene succinate) (PBS) microstructure was investigated. In this regard, unsaturated poly(butylene fumarate) (PBF) and poly(butylene succinate‐ran‐fumarate) copolymers, synthesized via esterification/polycondensation reactions, were modified through post‐polymerization modification. The progress of the PBF sulfonation reaction was analyzed via 1H NMR, dynamic light scattering and field emission SEM. The microstructure and thermal behavior of the functional polyesters were studied through DSC, TGA, elemental analysis and 1H NMR. Based on the results, the sulfonation reaction of unsaturated polymer chains, which are not experiencing a phase separation, is instantaneous, but sulfonation of the chains that have formed colloidal particles is a time‐consuming process. Surprisingly, the outcomes of 1H NMR analysis revealed a kind of heterogeneity along the fully sulfonated PBS backbone, similar to what is usually observed for copolymers. This is due to the ability of sulfonate groups to locate in different sites and create various block types. Due to the attraction between sulfonate groups, they tend to attach to the chain such that they provide the greatest number of second type blocks (containing two sulfonate groups). The randomness of sulfonated polymers after the sulfonation reaction was increased compared to that of the corresponding unsaturated copolymers. Increasing the content of sulfonate groups also led to a significant decrease in the thermal resistance (ca 120 °C) and crystallinity, along with a dramatic increase in ash content and Tg (up to 156 °C). © 2018 Society of Chemical Industry

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“…Then, the average sequence lengths of butylene succinate ( L nBS ) and butylene fumarate ( L nBF ) were determined using the expressions

L_{nBS} = \frac{2 P_{BS}}{A_{e'}}

L_{nBF} = \frac{2 P_{BF}}{A_{e'}}

…”

Section: Resultsmentioning

confidence: 99%

“…Thereafter, Eqn (5) was applied to determine the randomness of the polymer chains:

R = \frac{1}{L_{normalnBS}} + \frac{1}{L_{normalnBF}}

…”

Section: Resultsmentioning

confidence: 99%

Sulfonated poly(butylene succinate) as a pseudo‐random copolymer: effect of sulfonate groups on microstructure and thermal behavior

Kaykha

Rafizadeh

2018

Polymer International

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“…The calculation of b has been carried out taking into consideration the resonance peaks of the carbon atoms of the succinic subunit (c and d), so that it can be expressed [14]: where P S‐DG and P DG‐S are the probability of finding a S unit next to a DG unit and the probability of finding DG unit next to a S unit, respectively.…”

Section: Resultsmentioning

confidence: 99%

Synthesis and characterization of novel poly(butylene succinate)‐based copolyesters designed as potential candidates for soft tissue engineering

Gigli

Lotti

Gazzano

et al. 2012

Polymer Engineering & Sci

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Poly(butylene succinate/diglycolate) copolymers by reactive blending were subjected to molecular and solidstate characterization to study the effects of transesterification reactions. 13 C-nuclear magnetic resonance analysis evidenced the formation of block copolymers. Thermal measurements showed that all the samples were semicrystalline, with a soft amorphous phase and a rigid crystal phase. Wide-angle x-ray diffraction measurements indicated that the copolymers are characterized by cocrystallization. The mechanical properties were found related to crystallinity degree. The random copolymer, characterized by the lowest crystallinity degree, exhibits the lowest elastic modulus and the highest deformation at break. Therefore, solid-state properties of poly(butylene succinate/diglycolate) copolymers can be tailored by acting on the molecular architecture.

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“…In particular, using the 13 C analysis of the two homopolymers, the peak at 133.30 has been ascribed to the PET homopolymer sequence, the peak at 133.35 to the PBHEBST homopolymer sequence, while the two peaks at 133.38 and 133.27 to the mixed sequences. The degree of randomness has been calculated using a method previously reported in the literature25 using peak deconvolution before integration, as the signals were very close. The degree of randomness obtained for the polymer with 30% of BHEBS units was 0.92 and therefore, analogously to what observed for PBT‐ co ‐BHEBST copolymers,23 the structure of the copolymers can be considered random.…”

Section: Resultsmentioning

confidence: 99%

Poly(ethylene terephthalate), modified with bisphenol S units, with increased glass transition temperature

Lotti¹,

Colonna²,

Fiorini³

et al. 2012

J of Applied Polymer Sci

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Novel copolyesters have been prepared by melt mixing poly(ethylene terephthalate) (PET) with an ethoxylated bisphenol S, with the aim to prepare new polyesters with increased Tg, to be used in a wider range of temperatures with respect to neat PET. No side reactions occur during the synthesis of the samples, as proved by NMR analysis. The insertion of the bisphenol S (sulfonyldiphenol) groups does not significantly alter the thermal stability of PET. The thermal analysis showed that Tm and crystallization rate of the copolymers decreased with incasing co‐unit content. The Tg of the copolyesters can be increased by bisphenol S insertion, up to 40°C higher with respect to neat PET, that allows the use of amorphous PET in a wider range of applications. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

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Copolyesters. I. Sequence distribution of poly(butylene terephthalate‐co‐adipate) copolyesters determined by 400 MHz NMR

Cited by 42 publications

References 10 publications

Sulfonated poly(butylene succinate) as a pseudo‐random copolymer: effect of sulfonate groups on microstructure and thermal behavior

Sulfonated poly(butylene succinate) as a pseudo‐random copolymer: effect of sulfonate groups on microstructure and thermal behavior

Synthesis and characterization of novel poly(butylene succinate)‐based copolyesters designed as potential candidates for soft tissue engineering

Poly(ethylene terephthalate), modified with bisphenol S units, with increased glass transition temperature

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