Ethylene glycol-soluble Ti/Mg-citrate complex catalyst for synthesis of high intrinsic viscosity poly(ethylene terephthalate)

Lin, Qisong; Gao, Feng; Wang, Yongjun; Lü, Wangyang

doi:10.1016/j.polymer.2022.124741

Cited by 11 publications

(13 citation statements)

References 48 publications

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“…In industry, the workhorse catalysts are often antimony-based (e.g., antimony trioxide), which are hazardous. , Other catalysts have also been investigated and used, such as tin-, zinc-, calcium-, aluminum-, zirconium-, magnesium-, and especially titanium-based catalysts, as well as several organocatalytic systems. Nonetheless, all of them exhibit one or more disadvantages, such as toxicity, discoloration, high cost, low availability, susceptibility to hydrolysis, and/or decreased thermo-oxidative stability of the polymers. ,,,,,,,− Finally, the catalyst system also influences the crystallization rate, making it more difficult to reproducibly study the crystallization behavior of these polymers …”

Section: Introductionmentioning

confidence: 99%

“…While the latter has been achieved to some extent with certain end groups (e.g., sodiosulfonate and dodecyl end groups), the options remain limited . Furthermore, molar masses obtained via melt polycondensation are typically around 20,000 g/mol and hardly ever exceed 50,000 g/mol. − ,,,− Nonetheless, high molar masses are desired or even required for some purposes, including electrospinning and aerospace applications (>30,000 and >120,000 g/mol, respectively). ,− While increasing the molar mass after the initial melt polycondensation is possible by performing a solid-state polymerization, this only increases the molar mass to a limited extent and adds another time-consuming processing step (a maximum molar mass of 120,000 g/mol is reached only after 40 h), while other drawbacks accompanying the melt polycondensation method remain relevant. ,,− …”

Section: Introductionmentioning

confidence: 99%

“…The resulting dimer is then polymerized in a second step called melt polycondensation. To this end, high temperatures (i.e., 250–280 °C) and a vacuum are applied to remove byproducts (e.g., diol), thereby shifting the equilibrium of the reaction toward polymerization, which is accelerated through the use of a catalyst. − …”

Section: Introductionmentioning

confidence: 99%

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Catalyst-Free Single-Step Solution Polycondensation of Polyesters: Toward High Molar Masses and Control over the Molar Mass Range

et al. 2023

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Poly(alkylene terephthalate)s are frequently used polymers serving a plethora of applications, including packaging, textiles, and biomedical applications. However, their current synthesis procedures have some limitations, such as harsh reaction conditions and requirement of a catalyst. Furthermore, there is no control over the molar mass and only polymers with limited molar masses can be obtained. New optimized synthesis methods are therefore desired. To this end, we further improved our previously reported catalyst-free single-step solution polycondensation. By varying the comonomer ratio of both monomers, we gained control over the molar mass range and obtained polymers with number-average molar masses up to 187 kg/mol. Furthermore, by using a small excess of diol, we obtained polymers with alcohol end groups, allowing further functionalization. Finally, the melt recrystallization behavior for all investigated polymers was demonstrated using modulated differential scanning calorimetry. In conclusion, the synthesis method described in this paper circumvents the disadvantages of the current synthesis procedures.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Catalyst-Free Single-Step Solution Polycondensation of Polyesters: Toward High Molar Masses and Control over the Molar Mass Range

et al. 2023

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“…The chemical structure of the catalysts was determined by FT-IR and XPS. ,, Figure shows the infrared spectra of the ligand and different bimetallic coordination catalysts. The characteristic absorption peaks of the ligand were the stretching vibration peak of the hydroxyl group (ν −OH) in the carboxyl group (−COOH) at 3497 cm –1 , the strong carbonyl (ν CO) stretching vibration peak at 1720–1730 cm –1 , and the flexural vibration peak of the hydroxyl group (δ −OH) at 850–950 cm –1 , which was due to the presence of three carboxyl groups and one hydroxyl group in citric acid.…”

Section: Resultsmentioning

confidence: 99%

Comparison of Eco-friendly Ti–M Bimetallic Coordination Catalysts and Commercial Monometallic Sb- or Ti-Based Catalysts for the Synthesis of Poly(ethylene-co-isosorbide terephthalate)

et al. 2023

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Sustainable development greatly benefits from the effective synthesis of bio-based copolymers that are environmentally friendly. To enhance the polymerization reactivity for the production of poly(ethylene-co-isosorbide terephthalate) (PEIT), five highly active Ti−M (M = Mg, Zn, Al, Fe, and Cu) bimetallic coordination catalysts were designed. The catalytic activity of Ti−M bimetallic coordination catalysts and single Sb-or Ti-based catalysts was compared, and the effects of catalysts with a different type of coordination metal (Mg, Zn, Al, Fe, and Cu) on the thermodynamic and crystallization properties of copolyesters were explored. In polymerization, it was found that Ti−M bimetallic catalysts with 5 ppm (Ti) had higher catalytic activity than traditional antimonybased catalysts or Ti-based catalysts with 200 ppm (Sb) or 5 ppm (Ti). The Ti− Al coordination catalyst showed the best-improved reaction rate of isosorbide among the five transition metals used. Utilizing Ti−M bimetallic catalysts, a highquality PEIT was successfully synthesized with the highest number-average molecular weight of 2.82 × 10 4 g/mol and the narrowest molecular weight distribution index of 1.43. The glass-transition temperature of PEIT reached 88.3 °C, allowing the copolyesters to be used in applications requiring a higher T g , like hot filling. The crystallization kinetics of copolyesters prepared by some Ti−M catalysts was faster than that of copolyesters prepared by conventional titanium catalysts.

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“…We used UV spectrophotometry to measure the TiO 2 amount. This method has been reported in many previous literature works. , The raw TiO 2 powders that were used in this measurement were the same as those used for fabricating the TiO 2 /PET fibers.…”

Section: Methodsmentioning

confidence: 99%

Size Dispersion of the Filler Particles and Its Consequences on the Light-Extinction Properties of TiO₂/PET Nanocomposite Fibers

et al. 2023

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Titanium dioxide (TiO2) nanoparticles have been extensively used to modify the optical properties of various types of materials. In particular, they have been intensively loaded onto polymer fibers to quench the light reflection. In situ polymerization and online addition are two common strategies for fabricating TiO2-loaded polymer nanocomposite fibers. The former does not require separate preparation of masterbatches as the latter does and therefore has its advantages in terms of decreasing the fabrication steps and economic costs. Moreover, it has been found that in situ-polymerized TiO2-loaded polymer nanocomposite fibers (e.g., TiO2/poly(ethylene terephthalate) fibers) usually have enhanced light-extinction properties over those prepared by the online addition process. Intuitively, there should be a difference in the filler particle dispersion for the two fabrication processes. This hypothesis has not yet been tackled due to the technical difficulty in acquiring the three-dimensional (3D) filler morphology inside the fiber matrix. In this paper, we report a study using the powerful focused ion beam-scanning electron microscopy (FIB-SEM) with a resolution of 20 nm to directly acquire the 3D microstructure of TiO2/poly(ethylene terephthalate) nanocomposite (TiO2/PET) fibers. This microscopy technique allows us to characterize the particle size statistics and the dispersion inside TiO2/PET fibers. We have found that the particle size of TiO2 inside the fiber matrix can be well modeled by Weibull statistics. Surprisingly, we find that TiO2 nanoparticles form more significant agglomeration in the in situ-polymerized TiO2/PET fibers. This observation is contrary to our common understanding of the two fabrication processes. Namely, slightly altering the particle dispersion with increased TiO2 filler size helps improve the light-extinction properties. The slightly increased filler size may have altered the Mie scattering between the nanoparticles and the incident visible light, leading to enhanced light-extinction properties of in situ-polymerized TiO2/PET nanocomposite fibers.

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Ethylene glycol-soluble Ti/Mg-citrate complex catalyst for synthesis of high intrinsic viscosity poly(ethylene terephthalate)

Cited by 11 publications

References 48 publications

Catalyst-Free Single-Step Solution Polycondensation of Polyesters: Toward High Molar Masses and Control over the Molar Mass Range

Catalyst-Free Single-Step Solution Polycondensation of Polyesters: Toward High Molar Masses and Control over the Molar Mass Range

Comparison of Eco-friendly Ti–M Bimetallic Coordination Catalysts and Commercial Monometallic Sb- or Ti-Based Catalysts for the Synthesis of Poly(ethylene-co-isosorbide terephthalate)

Size Dispersion of the Filler Particles and Its Consequences on the Light-Extinction Properties of TiO₂/PET Nanocomposite Fibers

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Ethylene glycol-soluble Ti/Mg-citrate complex catalyst for synthesis of high intrinsic viscosity poly(ethylene terephthalate)

Cited by 11 publications

References 48 publications

Catalyst-Free Single-Step Solution Polycondensation of Polyesters: Toward High Molar Masses and Control over the Molar Mass Range

Catalyst-Free Single-Step Solution Polycondensation of Polyesters: Toward High Molar Masses and Control over the Molar Mass Range

Comparison of Eco-friendly Ti–M Bimetallic Coordination Catalysts and Commercial Monometallic Sb- or Ti-Based Catalysts for the Synthesis of Poly(ethylene-co-isosorbide terephthalate)

Size Dispersion of the Filler Particles and Its Consequences on the Light-Extinction Properties of TiO2/PET Nanocomposite Fibers

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Size Dispersion of the Filler Particles and Its Consequences on the Light-Extinction Properties of TiO₂/PET Nanocomposite Fibers