Characterization on mixed-crystal structure of poly(butylene terephthalate/succinate/adipate) biodegradable copolymer fibers

Solid-State NMR Study of Poly(3-Hydroxybutyrate) and Ecoflex reser Blends

“…These results are consistent with those published in literature [13][14][15][16][17][18]. As the repetition time used by spectrum acquisition is long enough for relaxation of carbonyl and methylene groups [14], the fractions of adipic, butanediol and terephthalic units in Ecoflex ® can be determined by means of intensities of the individual peaks as well as by means of the deconvolution of the spectrum. Calcu- [19].…”

“…Both mentioned peaks are obviously composed of two overlapping peaks. In the case of Ecoflex ® these peaks correspond to the methylene carbons in butanediol and adipic units which may be built in crystalline or amorphous region of Ecoflex ® [13][14][15][16][17]. In the case of PHB the methyl signal at 21 ppm is composed of a narrower signal at higher ppm of CH 3 groups in the crystalline regions with the trans conforma-tion of the backbone and a broader one at lower ppm corresponding to methyl groups in amorphous region with the trans/gauche dominant conformation of the backbone [1,4,7].…”

“…Solid-state NMR study of PBAT employed 13 C CP MAS techniques [13][14][15][16][17]. The existence of two components of the spin-lattice relaxation times T 1 (C) for butylene-terephthalate units revealed incorporation of these units in both, amorphous and crystalline regions of polymer.…”

“…The existence of two components of the spin-lattice relaxation times T 1 (C) for butylene-terephthalate units revealed incorporation of these units in both, amorphous and crystalline regions of polymer. However, there is no uniform opinion on the presence of butylene-adipate units in crystalline regions of PBAT [14][15][16][17]. Relatively short relaxation times T 1 (C) ascribed to butylene-adipate units in crystalline regions of PBAT implied their high mobility or possibly incorporation of these units into an interface between crystalline and amorphous regions of PBAT [15].…”

A Review of the Recent Advances in Cyclic Butylene Terephthalate Technology and its Composites

“…figure 14). The α-crystal with gauche-trans-gauche conformation of the butylene moiety is the stable form under standard conditions, whereas the β form with all-trans conformation develops only under stretching of unoriented crystals 10,[56][57][58][59] or during crystallization at pressures above 2000 bar 60 . This α to β crystal transition is completely reversible when the stress is removed.…”