The Effect of Trifluoroacetic Acid on Molecular Weight Determination of Polyesters: An in Situ NMR Investigation

Tu, Yanyan; Wan, Xueting; Huan, Jie; Zhu, Xiang; Li, Xiaohong; Tu, Yingfeng

doi:10.1007/s10118-021-2605-0

Cited by 13 publications

(7 citation statements)

References 36 publications

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“…The esterification of the terminal hydroxyl group by trifluoroacetic anhydride (TFA) is carried out to confirm that the epoxide acts as the first cleaved ring in initiation and thus is located inside the backbone. 40 After TFA treatment, the signals of epoxides (H c , H b1 , and H b2 ) keep the same as before, while that of methylene proton (H a ) at chain end shifts from 3.69 to 4.36 ppm (Figure 3). Additionally, SEC results of the copolymers demonstrate unimodal distributions (Figure S4), indicating identical living species and reactivity in the polymerization.…”

Section: ■ Introductionmentioning

confidence: 56%

“…The protons attributed to the PO group in the corresponding polymer are observed at 5.13 ppm (H c ), 1.26, and 1.16 ppm (methyl group, H b1 and H b2 ) (Figure ) in 1 H NMR. The esterification of the terminal hydroxyl group by trifluoroacetic anhydride (TFA) is carried out to confirm that the epoxide acts as the first cleaved ring in initiation and thus is located inside the backbone . After TFA treatment, the signals of epoxides (H c , H b1 , and H b2 ) keep the same as before, while that of methylene proton (H a ) at chain end shifts from 3.69 to 4.36 ppm (Figure ).…”

Section: Resultsmentioning

confidence: 88%

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Iron(III) Triflate as a Green Catalyst for Janus Polymerization to Prepare Block Polyesters

Zhang,

Bai,

Ling

2023

Macromolecules

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Iron-based compounds are promising but challenging catalysts for the ring-opening polymerization of cyclic esters and ethers due to their nontoxicity, inexpensiveness, and adequate supply. Herein, iron(III) triflate [Fe(OTf)3], a commercially available catalyst, is successfully applied to catalyze the copolymerization of ε-caprolactone (CL) with tetrahydrofuran (THF) which is confirmed to be Janus polymerization, where cationic ring-opening polymerization (CROP) and anionic ring-opening polymerization (AROP) propagate at the two ends, respectively, in one single growing chain. CROP of THF with CL produces an amorphous P(THF-co-CL) block, while AROP of CL generates a semicrystalline homo-PCL one. As a result, P(THF-co-CL)-b-PCL block polymers are obtained in one step. It is the first time post-transition metal catalysts have activated Janus polymerization instead of rare earth ones, facilitating the potential application of the products as biomaterials.

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Section: ■ Introductionmentioning

confidence: 56%

Section: Resultsmentioning

confidence: 88%

Iron(III) Triflate as a Green Catalyst for Janus Polymerization to Prepare Block Polyesters

Zhang,

Bai,

Ling

2023

Macromolecules

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“…With the determination of chain-ends, the molecular weights of PBAT copolyesters could be calculated by quantitative 1 H NMR spectra. 53,54 The M n values estimated by 1 H NMR for PBAT-2/1, PBAT-1/1 and PBAT-1/2 are 34, 27 and 21 kg mol −1 (Table 1), respectively, which are much higher than the theoretical values obtained for ROP, confirming the PROP mechanism.…”

Section: Papermentioning

confidence: 70%

Chemical recycling of poly(butylene terephthalate) into value-added biodegradable poly(butylene adipate-co-terephthalate)

Yan,

Huang,

Huan

et al. 2024

Polym. Chem.

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“…In this regard, some studies reported the occurrence of esterification between the TFA and OH groups of PET under mild conditions. 35,36 PET is a hydrophobic polymer produced via the condensation of aromatic terephthalic acid units. Accordingly, a water wettability analysis confirmed the hydrophobic nature of the PET fibers (see Figure S2 in the Supporting Information).…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…This demonstrates that chemical modification occurred on the PET structure. In this regard, some studies reported the occurrence of esterification between the TFA and OH groups of PET under mild conditions. , …”

Section: Resultsmentioning

confidence: 99%

Valorization of Polyethylene Terephthalate (PET) Plastic Wastes as Nanofibrous Membranes for Oil Removal: Sustainable Solution for Plastic Waste and Oil Pollution

Topuz

Oldal

Székely

2022

Ind. Eng. Chem. Res.

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The accumulation of plastic wastes has become a global environmental issue, because of their ever-growing production, slow degradation, and potential environmental hazards. Consequently, reducing their presence in the environment by upcycling has sparked tremendous research interest. Herein, we report the valorization of poly(ethylene terephthalate) (PET) plastic wastes to produce nanofibrous adsorptive membranes for their applications in oil removal. In this study, plastic wastes derived from PET bottles were dissolved in trifluoroacetic acid (TFA) or a TFA/ dichloromethane (DCM) binary solvent system and then electrospun into nanofibrous recycled PET (rPET) membranes. The nanofiber morphology was tuned by adjusting the polymer concentration. The nanofibers produced via electrospinning from TFA solutions were more uniform than those produced using TFA/DCM. The influence of acid-mediated recycling on the PET structure was explored via thermogravimetric and X-ray photoelectron spectroscopy analyses. A dynamic mechanical analysis showed that the membranes exhibited high flexibility with effective Young's moduli. The sorption capacities of the nanofibrous PET membranes for crude oil, diesel, gasoline, and pump oil were 22.9 ± 2, 19.6 ± 1.8, 11.1 ± 1, and 19.3 ± 1.6 g g −1 , respectively. The membrane could be recycled by squeezing and reused five times for oil removal while maintaining an sorption capacity of >75%. After the sorption tests, an apparent increase in the fiber diameter was observed due to the oil uptake into the fiber matrix. The present study provides a sustainable solution to plastic and oil pollution management, minimizing the production of new carbonbased materials and lowering carbon emissions. This work aligns with the United Nations' Sustainable Development Goals, specifically, Goal #12 on responsible consumption and production and #14 on life below water.

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The Effect of Trifluoroacetic Acid on Molecular Weight Determination of Polyesters: An in Situ NMR Investigation

Cited by 13 publications

References 36 publications

Iron(III) Triflate as a Green Catalyst for Janus Polymerization to Prepare Block Polyesters

Iron(III) Triflate as a Green Catalyst for Janus Polymerization to Prepare Block Polyesters

Chemical recycling of poly(butylene terephthalate) into value-added biodegradable poly(butylene adipate-co-terephthalate)

Valorization of Polyethylene Terephthalate (PET) Plastic Wastes as Nanofibrous Membranes for Oil Removal: Sustainable Solution for Plastic Waste and Oil Pollution

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