Determination of the equilibrium enthalpy of melting of two-phase semi-crystalline polymers by fast scanning calorimetry

Fosse, Clément; Bourdet, Aurélie; Ernault, Estève; Esposito, Antonella; Delpouve, Nicolas; Delbreilh, Laurent; Thiyagarajan, Shanmugam; Knoop, Rutger J. I.; Dargent, Éric

doi:10.1016/j.tca.2019.03.035

Cited by 27 publications

(18 citation statements)

References 96 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In short, Δ h m,100 ‐values for α ‐crystals scatter between around 90 and 200 J g −1 while for the disordered α ’‐crystal polymorph values between 57 and 107 J g −1 are reported. [ 10–21 ]…”

Section: Introductionmentioning

confidence: 99%

“…In short, Δh m,100 -values for 𝛼-crystals scatter between around 90 and 200 J g −1 while for the disordered www.mrc-journal.de 𝛼'-crystal polymorph values between 57 and 107 J g −1 are reported. [10][11][12][13][14][15][16][17][18][19][20][21] In order to contribute to the further evaluation of the bulk enthalpy of melting of 𝛼-crystals of PLLA, in this work fast scanning chip calorimetry (FSC) was employed, for analysis of the correlation between the measured enthalpy of melting of a set of samples of different crystallinity on one side and the corresponding change of the heat capacity at a temperature higher than the glass transition temperature (T g ) of ≈60 °C [22,23] and lower than the onset temperature of the melting process on the other side. Since the heat capacity of a polymer at temperatures higher than T g depends on the solid fraction, [24] extrapolation of this relationship toward the heat capacity of solid PLLA yields the bulk enthalpy of melting.…”

Section: Introductionmentioning

confidence: 99%

“…A similar approach, using the heat-capacity step at T g instead the heat capacity at a slightly higher temperature, has been applied in the past. [15,20,21] It relies on the assumption of a two-phase structure, that is, the presence of a liquid amorphous phase and of solid crystals between T g and the final melting temperature only. However, the presence of a two-phase structure in semicrystalline PLLA is debated and formation of a rigid amorphous fraction (RAF) [25,26] related to the crystallization process is frequently suggested.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Bulk Enthalpy of Melting of Poly (l‐lactic acid) (PLLA) Determined by Fast Scanning Chip Calorimetry

Jariyavidyanont

et al. 2022

Macromol. Rapid Commun.

View full text Add to dashboard Cite

The bulk enthalpy of melting of 𝜶-crystals of poly (L-lactic acid) (PLLA) is evaluated by fast scanning calorimetry (FSC), by correlating the melting enthalpy of samples of different crystallinity with the corresponding heat capacity at 90 °C, that is at a temperature higher than the glass transition temperature of the bulk amorphous phase and lower than the melting temperature. Extrapolation of this relationship for crystals formed at 140 °C towards the heat capacity of fully solid PLLA yields a value of 104.5±6 J g −1 when melting occurs at 180-200 °C. The analysis relies on a two-phase structure, that is, absence of a vitrified rigid amorphous fraction (RAF) at the temperature of analysis the solid fraction (90 °C). Formation and vitrification of an RAF are suppressed by avoiding continuation of primary crystallization and secondary crystallization during cooling the system from the crystallization temperature of 140 °C to 90 °C, making use of the high cooling capacity of FSC. Small-angle X-ray scattering (SAXS) confirmed thickening of initially grown lamellae which only is possible if these lamellae are not surrounded by a glassy RAF. Linear crystallinity values obtained by SAXS and calorimetrically determined enthalpy-based crystallinities agree close to each other.

show abstract

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Bulk Enthalpy of Melting of Poly (l‐lactic acid) (PLLA) Determined by Fast Scanning Chip Calorimetry

Jariyavidyanont

et al. 2022

Macromol. Rapid Commun.

View full text Add to dashboard Cite

show abstract

“…The position of the two carboxyl substituents in 2,4-FDCA makes this isomer less symmetric than 2,5-FDCA, which explains the lower ability of 2,4-PEF to crystallize compared to 2,5-PEF. 51 …”

Section: Introductionmentioning

confidence: 99%

Poly(butylene 2,4-furanoate), an Added Member to the Class of Smart Furan-Based Polyesters for Sustainable Packaging: Structural Isomerism as a Key to Tune the Final Properties

Bianchi

Soccio

Siracusa

et al. 2021

ACS Sustainable Chem. Eng.

Self Cite

View full text Add to dashboard Cite

High-molecular-weight poly(butylene 2,4-furanoate) (2,4-PBF), an isomer of well-known poly(butylene 2,5-furanoate) (2,5-PBF), was synthesized through an eco-friendly solvent-free polycondensation process and processed in the form of an amorphous film by compression molding. Molecular characterization was carried out by NMR spectroscopy and GPC analysis, confirming the chemical structure and high polymerization degree. Thermal analyses evidenced a reduction of both glass-to-rubber transition and melting temperatures, as well as a detriment of crystallization capability, for 2,4-PBF with respect to 2,5-PBF. Nevertheless, it was possible to induce crystal phase formation by annealing treatment. Wide-angle X-ray scattering revealed that the crystal lattices developed in the two isomers are distinct from each other. The different isomerism affects also the thermal stability, being 2,4-PBF more thermally inert than 2,5-PBF. Functional properties, such as wettability, mechanical response, and gas barrier capability, were tested on both amorphous and semicrystalline 2,4-PBF films and compared with those of 2,5-PBF. Reduced hydrophilicity was determined for 2,4-isomer, in line with its lower average dipole moment, suggesting better chemical resistance to hydrolysis. Stress–strain tests have evidenced the higher flexibility and toughness of 2,4-PBF with respect to those of 2,5-PBF and the possibility of improving its mechanical resistance by annealing. Finally, the different isomerism deeply affects the gas barrier performance, being the O 2 - and CO 2 -transmission rates of 2,4-PBF 50 and 110 times lower, respectively, than those of 2,5-PBF. The gas barrier properties turned out to be outstanding under a dry atmosphere as well as in humid conditions, suggesting the presence of interchain hydrogen bonds. The gas blocking capability decreases after annealing because of the presence of disclination associated with the formation of crystals.

show abstract

“…The DSC scans were recorded while heating from 30 to 275 °C at a heating rate of 10 °C min −1 and then cooled to 30 °C. The crystallinity index was calculated according to the following equation [ 36 ]: Crystallinity index = (∆H m /W∆H m0 ) × 100 where ∆H m (Jg −1 ) is the heat of fusion of the PET sample, ∆H m0 is the heat of fusion for completely crystalline PET (140 Jg −1 ) [ 37 ], and W(g) is the weight fraction of residual PET in the samples.…”

Section: Methodsmentioning

confidence: 99%

Progressing Ultragreen, Energy-Efficient Biobased Depolymerization of Poly(ethylene terephthalate) via Microwave-Assisted Green Deep Eutectic Solvent and Enzymatic Treatment

Attallah

Azeem²,

Nikolaivits

et al. 2021

Polymers

View full text Add to dashboard Cite

Effective interfacing of energy-efficient and biobased technologies presents an all-green route to achieving continuous circular production, utilization, and reproduction of plastics. Here, we show combined ultragreen chemical and biocatalytic depolymerization of polyethylene terephthalate (PET) using deep eutectic solvent (DES)-based low-energy microwave (MW) treatment followed by enzymatic hydrolysis. DESs are emerging as attractive sustainable catalysts due to their low toxicity, biodegradability, and unique biological compatibility. A green DES with triplet composition of choline chloride, glycerol, and urea was selected for PET depolymerization under MW irradiation without the use of additional depolymerization agents. Treatment conditions were studied using Box-Behnken design (BBD) with respect to MW irradiation time, MW power, and volume of DES. Under the optimized conditions of 20 mL DES volume, 260 W MW power, and 3 min MW time, a significant increase in the carbonyl index and PET percentage weight loss was observed. The combined MW-assisted DES depolymerization and enzymatic hydrolysis of the treated PET residue using LCC variant ICCG resulted in a total monomer conversion of ≈16% (w/w) in the form of terephthalic acid, mono-(2-hydroxyethyl) terephthalate, and bis-(2-hydroxyethyl) terephthalate. Such high monomer conversion in comparison to enzymatically hydrolyzed virgin PET (1.56% (w/w)) could be attributed to the recognized depolymerization effect of the selected DES MW treatment process. Hence, MW-assisted DES technology proved itself as an efficient process for boosting the biodepolymerization of PET in an ultrafast and eco-friendly manner.

show abstract

Determination of the equilibrium enthalpy of melting of two-phase semi-crystalline polymers by fast scanning calorimetry

Cited by 27 publications

References 96 publications

Bulk Enthalpy of Melting of Poly (l‐lactic acid) (PLLA) Determined by Fast Scanning Chip Calorimetry

Bulk Enthalpy of Melting of Poly (l‐lactic acid) (PLLA) Determined by Fast Scanning Chip Calorimetry

Poly(butylene 2,4-furanoate), an Added Member to the Class of Smart Furan-Based Polyesters for Sustainable Packaging: Structural Isomerism as a Key to Tune the Final Properties

Progressing Ultragreen, Energy-Efficient Biobased Depolymerization of Poly(ethylene terephthalate) via Microwave-Assisted Green Deep Eutectic Solvent and Enzymatic Treatment

Contact Info

Product

Resources

About