Synthesis of Well-Defined Thermoresponsive Polyphosphoester Macroinitiators Using Organocatalysts

Iwasaki, Yasuhiko; Yamaguchi, Etsuko

doi:10.1021/ma100242s

Cited by 127 publications

(125 citation statements)

References 25 publications

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“…In order to avoid metal contamination without any special purification steps, the organocatalytic approach has emerged as a powerful metal-free polymerization process in recent years. 7 Considerable effort has been directed toward the evaluation of various types of both organic acids/bases for the ROP of cyclic esters, 7-37 cyclic carbonates, [38][39][40][41][42][43] epoxides, [44][45][46][47] lactams, 48 cyclic (carbo)siloxanes, 49 cyclic phosphates, [50][51][52][53][54] etc. Regarding the ROP of cyclic esters, organic Brønsted acids, e.g., methane sulfonic acid (MSA) and triflimide, were found to be suited for the polymerization of lactones, [8][9][10][11][12][13][14][15][16][17][18][19] whereas organic bases, e.g., 1,8-diazadicyclo [5.4.0]undec-7-ene (DBU) and 4-dimethylaminopyridine (DMAP), were effective for the ROP of the lactide (LA).…”

Section: Introductionmentioning

confidence: 99%

Organophosphate-catalyzed bulk ring-opening polymerization as an environmentally benign route leading to block copolyesters, end-functionalized polyesters, and polyester-based polyurethane

et al. 2015

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Abstract. The ring-opening polymerizations (ROPs) of ε-caprolactone (ε-CL), -varelolactone, 1,5-dioxepan-2-one, trimethylene carbonate, and L-lactide were performed in the bulk using an organophosphate, such as diphenyl phosphate, bis(4-nitrophenyl)phosphate, and di(2,6-xylyl)phosphate, as the catalyst. The ROPs proceeded in a well-controlled manner even in the bulk condition to afford well-defined aliphatic polyesters, polyester-ether, and polycarbonate with relatively low dispersities. Notably, the amount of the loaded catalyst was successfully reduced when compared to the conventional organophosphate-catalyzed ROP in solution. A kinetic study revealed the controlled/living nature of the present bulk ROP system, which allowed us to produce the block copolymers composed of polyesters, polyester-ether, and polycarbonate in one-pot. Syntheses of the end-functionalized poly(ε-caprolactone)s (PCLs) and poly(trimethylene carbonate) were successfully demonstrated using alcohol initiators possessing highly reactive functional groups. Furthermore, the α,ω-dihydroxy telechelic PCL-diol as well as the three-and four-armed star-shaped PCL-polyols were also easily obtained by using the polyols as an initiator. Finally, the one-pot synthesis of polyurethane via the ROP of ε-CL and subsequent urethane forming reaction was demonstrated by taking advantage of the dual catalytic abilities of the organophosphate for both the ROP and polyurethane synthesis.

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Section: Introductionmentioning

confidence: 99%

Organophosphate-catalyzed bulk ring-opening polymerization as an environmentally benign route leading to block copolyesters, end-functionalized polyesters, and polyester-based polyurethane

et al. 2015

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“…In previous literature, we reported that polyphosphoesters show thermoresponsivity in aqueous media. 21,23 Supporting Information, Figure S2, shows the repeated temperature dependence of the swelling degree of PIPP 78 -b-PLLA 77 . The temperature-dependent swelling was reversible with temperature regardless of the number of repetitions.…”

Section: ■ Experimental Sectionmentioning

confidence: 99%

Low-Temperature Processable Block Copolymers That Preserve the Function of Blended Proteins

et al. 2016

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Low-temperature processable polymers have attracted increasing interest as ecological materials because of their reduced energy consumption during processing and suitability for making composites with heat-sensitive biomolecules at ambient temperature. In the current study, low-temperature processable biodegradable block copolymers were synthesized by ring-opening polymerization of l-lactide (LLA) using polyphosphoester as a macroinitiator. The polymer films could be processed under a hydraulic pressure of 35 MPa. The block copolymer films swelled in water because the polyphosphoester block was partially hydrated. Interestingly, the swelling ratio of the films changed with temperature. The pressure-induced order-to-disorder transition of the block copolymers was characterized by small-angle X-ray scattering; a crystallinity reduction in the block copolymers was observed after application of pressure. The crystallinity of the block copolymers was recovered after removing the applied pressure. The Young's modulus of the block copolymer films increased as the LLA unit content increased. Moreover, the modulus did not change after multiple processing cycles and the recyclability of the block copolymers was also confirmed. Finally, polymer films with embedded proteinase K as a model protein were prepared. The activity of catalase loaded into the polymer films was evaluated after processing at different temperatures. The activity of catalase was preserved when the polymer films were processed at room temperature but was significantly reduced after high-temperature processing. The suitability of low-temperature processable biodegradable polymers for making biofunctional composites without reducing protein activity was clarified. These materials will be useful for biomedical and therapeutic applications.

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“…Moreover, organocatalysts, already extensively used in polymerization of cyclic esters (such as lactides) [45], have successfully been applied for the first time in the polymerization of cyclic esters of phosphoric acid, using both 1,8-diazabicyclo [5.4.0]undec-7-ene (DBU) and 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) [46].…”

Section: Synthesis Of Poly(alkylene Phosphates) Without Direct Reactimentioning

confidence: 99%

Reactions of H3PO4 forming polymers. Apparently simple reactions leading to sophisticated structures and applications

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et al. 2015

Progress in Polymer Science

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Synthesis of Well-Defined Thermoresponsive Polyphosphoester Macroinitiators Using Organocatalysts

Cited by 127 publications

References 25 publications

Organophosphate-catalyzed bulk ring-opening polymerization as an environmentally benign route leading to block copolyesters, end-functionalized polyesters, and polyester-based polyurethane

Organophosphate-catalyzed bulk ring-opening polymerization as an environmentally benign route leading to block copolyesters, end-functionalized polyesters, and polyester-based polyurethane

Low-Temperature Processable Block Copolymers That Preserve the Function of Blended Proteins

Reactions of H3PO4 forming polymers. Apparently simple reactions leading to sophisticated structures and applications

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