Ultrafast ring-opening copolymerization of lactide with glycolide toward random poly(lactic-<i>co</i>-glycolic acid) copolymers by an organophosphazene base and urea binary catalysts

Shen, Yong; Dong, Li; Kou, Xinhui; Wang, Rui; Liu, Fusheng; Li, Zhibo

doi:10.1039/d1py01653a

Cited by 11 publications

(4 citation statements)

References 44 publications

(76 reference statements)

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“…An increase in feed rate resulted in longer glycolate sequences, reflecting glycolide's higher reactivity compared to lactide, as supported by the literature. 49,50 The average sequence lengths of lactide (L̅ L ) and glycolate (L̅ G ) were determined using eq 2 36 Table 2 illustrates that slower monomer feed rates resulted in shorter lactide and glycolate sequence lengths. For CP1, L̅ L was 7.92 and L̅ G was 3.99, while for CP3, these lengths were 8.31 and 4.72, respectively.…”

Section: Characterizations Of Plga−peg-plga Triblockmentioning

confidence: 99%

Modulating the Thermoresponsive Characteristics of PLGA–PEG-PLGA Hydrogels via Manipulation of PLGA Monomer Sequences

Jo,

Roh,

Shim

et al. 2024

Biomacromolecules

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Hydrogels are promising materials for biomedical applications, particularly in drug delivery and tissue engineering. This study highlights thermoresponsive hydrogels, specifically poly(lactic-co-glycolic acid) (PLGA)−poly(ethylene glycol) (PEG)-PLGA triblock copolymers, and introduces a feed rate-controlled polymerization (FRCP) method. By utilizing an organic catalyst and regulating the monomer feed rate, the sequence distribution of PLGA within the triblock copolymer is controlled. Various analyses, including 13 C NMR and rheological measurements, were conducted to investigate the impact of sequence distribution. Results show that altering sequence distribution significantly influences the sol−gel transition, hydrophobicity−hydrophilicity balance, and drug release profile. Increased sequence uniformity lowers the glass transition temperature, raises the sol−gel transition temperature due to enhanced hydrophilicity, and promotes a more uniform drug (curcumin) distribution within the PLGA domain, resulting in a slower release rate. This study emphasizes the importance of PLGA sequence distribution in biomedical applications and the potential of FRCP to tailor thermoresponsive hydrogels for biomedical advancements.

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Section: Characterizations Of Plga−peg-plga Triblockmentioning

confidence: 99%

Modulating the Thermoresponsive Characteristics of PLGA–PEG-PLGA Hydrogels via Manipulation of PLGA Monomer Sequences

Jo,

Roh,

Shim

et al. 2024

Biomacromolecules

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“…自 2016 年 Chen 等 [27] 开创性报道的 γ-丁内酯的开环聚合, 证明了其生成的聚酯可全部解聚回单体以来, 聚酯作为可闭环回收的高分子材料被寄予厚望. 交酯作为脂肪族聚酯合成中的一类非常重要的单体, 已被广泛地图 20 经典的含硫环状单体 Figure 20 Typical sulfur-containing cyclic monomers 化学学报综述研究 [153][154][155] , 但仍存在单体的成环能力与聚合活性相互矛盾的瓶颈问题. 例如用于合成聚乳酸的丙交酯单体, 具有较大的环张力, 因此丙交酯单体开环聚合的活性较高, 但丙交酯单体的规模化合成并不容易(直接环化的收率不到 50%).…”

Section: 闭环回收的含硫高分子unclassified

Recent Advances in Monomer Design for Recyclable Polymers

Cai¹,

Liu²,

Tao³

et al. 2022

Acta Chimica Sinica

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The development of modern society highly depends on polymer materials. However, progressive usage and accumulation of polymer products caused the waste of resources and severe environmental issues. To address the abovementioned problem, the development of chemical recycling polymers that could transform the polymers back to monomers and repolymerize to produce polymer materials without value loss is an attractive and important strategy. In recent years, significant advances in the design of "ideal monomers" have enabled the regulation of "polymerization−depolymerization" equilibrium and achieved the closed-loop recycling under mild conditions. This review will focus on the closed-loop recycling of polyesters, polycarbonates, sulfur-containing polymers, and poly(cyclic olefin)s, illustrate the challenges of this field, and provide a perspective on the future development direction.

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“…The reactivity ratios of mixed monomers can be finely tuned by various stimuli, such as solvent, additives, and the chemical catalyst, − enabling the composition sequence along the chain to change from random to block copolymerization. Pioneering advancements in monomer sequence selectivity have been demonstrated in processes, including ring-opening copolymerization (ROCOP). − In the pursuit of advancing the eco-friendly nature, a multitude of organocatalytic systems have been explored for polymerization. − With significant accomplishments using organocatalysts, the synthesis of sequence-controlled (multi)block copolyesters has been achieved in one pot via ROCOP of epoxides, cyclic anhydrides, − and cyclic esters or O -carboxyanhydride (OCA) and epoxide mixtures. , However, when dealing with similar monomer mixtures, the lack of kinetic differentiation is preferred to generate random copolymerization of these mixed monomers. , To date, well-defined block copolyesters have been predominantly obtained through sequential monomer addition or utilizing a difunctional initiator. , The task of organocatalyzing similar monomer mixtures to access block sequences in a one-pot fashion remains a significant challenge.…”

Section: Introductionmentioning

confidence: 99%

Sequence-Controlled Copolymerization of Salicylic O-Carboxyanhydrides by Organocatalysts

Liang,

Yang

2024

Macromolecules

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The composition sequence of a copolymer is intricately linked to its physical and mechanical properties. However, achieving chemical selectivity for copolymerization monomers and controlling the sequence structure of copolymers remain a challenge. This study delves into a strategy that involves tuning the organocatalyst transition from hydrogen bonding interaction to ionic pair to realize copolymerization sequence control in one-pot reactions. Ring-opening copolymerization (ROCOP) of salicylic acid O-carboxyanhydride (SAOCA) and its analogous monomers, including 5-methylsalicylic acid Ocarboxyanhydride (5-MeSAOCA) and 4-fluor-salicylic acid Ocarboxyanhydride (4-FSAOCA), is successfully conducted in tetrahydrofuran (THF) at ambient conditions, resulting in narrow chain distributions (Đ < 1.25). This accomplishment is made possible by utilizing a catalytic combination of 1,8-diazabicyclo [5.4.0]undec-7-ene (DBU) and thioureas (TUs) with varying pK a values. The acidity of TU influences its interaction with DBU to generate the transition states of hydrogenbonding or ionic pair, while the quantity of TU affects the steric hindrance around the anion; both are crucial factors in regulating the sequence distribution of PSA-series copolymers ranging from random to block architecture.

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Ultrafast ring-opening copolymerization of lactide with glycolide toward random poly(lactic-co-glycolic acid) copolymers by an organophosphazene base and urea binary catalysts

Abstract: The preparation of poly(lactic-co-glycolic acid) (PLGA) copolymers with controllable random microstructures remains as a challenge due to the much higher reactivity of glycolide (GA) compared to lactide (LA). In this...

Cited by 11 publications

References 44 publications

Modulating the Thermoresponsive Characteristics of PLGA–PEG-PLGA Hydrogels via Manipulation of PLGA Monomer Sequences

Modulating the Thermoresponsive Characteristics of PLGA–PEG-PLGA Hydrogels via Manipulation of PLGA Monomer Sequences

Recent Advances in Monomer Design for Recyclable Polymers

Sequence-Controlled Copolymerization of Salicylic O-Carboxyanhydrides by Organocatalysts

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