Polymer Chemistry最新文献_第10页

Ethylene and alkyl acrylate copolymers made-to-order using dynamic cation switching polymerization and evidence for improved polymer degradability with low polar group density 动态阳离子开关聚合制备乙烯和丙烯酸烷基酯共聚物及低极性基团密度下聚合物可降解性改善的证据

IF 3.9 2区化学 Q2 POLYMER SCIENCE

Polymer Chemistry

Pub Date : 2025-10-09 DOI: 10.1039/d5py00819k

Tuhin Ganguly , Lorenzo C. Ruiz De Castilla , Rumela Adhikary , Loi H. Do

The industrial synthesis of functional polyolefins relies on free radical polymerization, which requires high temperature and pressure and offers poor microstructure control. Herein, we report a cation-switching strategy to access ethylene and alkyl acrylate copolymers with made-to-order molecular weight, molecular weight distribution, and polar monomer density, tunable within a catalyst-dependent range. This precision was achieved by exploiting the cation exchange dynamics between M⁺ and M′⁺ (where M⁺, M′⁺ = Li⁺, Na⁺, K⁺, or Cs⁺, and M ≠ M′) with our nickel phenoxyphosphine-polyethylene glycol catalyst. Under non-switching conditions, copolymerization of ethylene and methyl acrylate (MA) using our nickel catalyst in the presence of M⁺ and M′⁺ salts afforded ethylene-MA copolymers (EMA) with adjustable molecular weight distributions based on the ratio of M⁺ : M′⁺ employed. Under dynamic cation switching conditions, this catalyst system yielded monomodal EMA with molecular weight and MA incorporation that can be varied independently. Studies of the EMA revealed that while they retain the thermal and mechanical properties of polyethylene having the same molecular weight, increasing the MA per chain by as few as 1–3 units leads to measurable increase in their wettability and susceptibility toward oxidative cleavage. This work adds to a growing body of evidence suggesting that ethylene-based materials can be designed for improved degradability without compromising their performance.

功能聚烯烃的工业合成依赖于自由基聚合，这需要高温高压，并且微观结构控制不好。在此，我们报告了一种阳离子开关策略来获得乙烯和丙烯酸烷基酯共聚物，其分子量、分子量分布和极性单体密度在催化剂依赖范围内可调。这种精度是通过利用我们的镍苯氧膦-聚乙二醇催化剂在M+和M ' +（其中M+， M ' + = Li+, Na+， K+或Cs+， M≠M '）之间的阳离子交换动力学实现的。在非开关条件下，使用镍催化剂在M+和M ' +盐的存在下，乙烯和丙烯酸甲酯（MA）共聚得到了基于M+:M ' +比例可调节分子量分布的乙烯-丙烯酸甲酯共聚物（EMA）。在动态阳离子开关条件下，该催化剂体系产生了分子量和MA掺入量可以独立变化的单模态EMA。EMA的研究表明，虽然它们保留了相同分子量的聚乙烯的热性能和机械性能，但每条链增加1-3个单位的MA会导致它们的润湿性和对氧化裂解的敏感性显著增加。这项工作增加了越来越多的证据，表明乙烯基材料可以在不影响其性能的情况下设计成更好的可降解性。

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引用次数: 0

Dual wavelength photopolymerization of amphiphilic block copolymers via a chalcone-2959-based initiator 以查尔酮-2959为引发剂的两亲嵌段共聚物双波长光聚合

IF 3.9 2区化学 Q2 POLYMER SCIENCE

Polymer Chemistry

Pub Date : 2025-10-09 DOI: 10.1039/d5py00674k

Jingfang Li , Luran Chun , Zhouju Zhong , Zihan Zhang , Jun Nie

The synthesis of high-purity amphiphilic block copolymers (BCPs) via photopolymerization remains challenging due to homopolymer impurities and oligomer byproducts generated by conventional photoinitiators, in which a single initiator fragment is unfavorable for generating two or more free radicals. To address this, we report the rational design of a novel unimolecular dual-color photoinitiator, IAB-2959, synthesized by bridging Irgacure 2959 to an indole-chalcone chromophore. Under sequential blue (425 nm) and UV (275 nm) irradiation, this initiator leverages distinct mechanisms: hydrogen abstraction polymerizes the first monomer, while α-cleavage of the resultant α-hydroxy ketone initiates polymerization of the second monomer, yielding well-defined A–B BCPs. Although minor oligomers were produced during the initiation stage, they were readily removed during the second-stage purification by leveraging solubility differences. Comprehensive characterization including DFT calculations, UV-Vis spectra, ESR and photolysis tests confirms the initiation mechanism. Using the initiator IAB-2959, PMMA_m-b-PHEA_n and PHEA_m-b-PMMA_n diblock copolymers were successfully synthesized with high purity and low dispersity (Đ < 1.75) and verified by GPC analysis and ¹H NMR spectroscopy. This work pioneers a dedicated photoinitiator strategy, enabling precise and efficient BCP synthesis with minimal impurities.

由于传统的光引发剂会产生均聚物杂质和低聚物副产物，单个引发剂片段不利于生成两个或多个自由基，因此通过光聚合合成高纯度两亲性嵌段共聚物（bcp）仍然具有挑战性。为了解决这一问题，我们报道了一种新的单分子双色光引发剂ab -2959的合理设计，该引发剂是由Irgacure 2959桥接到吲哚-查尔酮发色团合成的。在连续蓝光（425nm）和紫外线（275nm）照射下，该引发剂利用不同的机制：氢萃取聚合第一个单体，而α-羟基酮的α-裂解引发第二个单体的聚合，生成定义明确的A-B bcp。虽然在起始时间产生少量低聚物，但在第二阶段纯化时，它们很容易通过利用溶解度差异来去除。包括DFT计算、UV-Vis光谱、ESR和光解实验在内的综合表征证实了引发机理。采用引发剂ab -2959，成功合成了高纯度、低分散性的PMMAm-b-PHEAn和PHEAm-b-PMMAn二嵌段共聚物（Đ< 1.75），并通过GPC分析和¹H NMR谱进行了验证。这项工作开创了一种专用的光引发剂策略，能够以最少的杂质精确，高效地合成BCP。

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引用次数: 0

Enhanced suppression of chain transfer in ethylene (co)polymerization via synergistic axial substituent effects in pyridine-imine Ni(ii) and Pd(ii) catalysts 吡啶-亚胺型Ni（II）和Pd（II）催化剂轴取代基协同效应对乙烯（Co）聚合链转移的抑制作用

IF 3.9 2区化学 Q2 POLYMER SCIENCE

Polymer Chemistry

Pub Date : 2025-10-09 DOI: 10.1039/d5py00857c

Huijun Fan , Mengya Ma , Shengyu Dai

Controlling chain-transfer reactions represents a fundamental challenge in pyridine-imine nickel and palladium catalyzed ethylene (co)polymerization. We present a breakthrough dual-axial-substituent strategy that synergistically suppresses chain transfer, enabling efficient production of high-molecular-weight polyethylenes and polar functionalized copolymers. A family of well-defined nickel and palladium complexes featuring both 8-benzhydryl and 2-diarylmethyl naphthylpyridine-iminate ligands were synthesized and thoroughly characterized. The nickel catalysts, activated by diethylaluminum chloride, showed high activities (∼10⁶ g mol⁻¹ h⁻¹) while producing branched polyethylene with high molecular weights (M_n up to 246.4 kg mol⁻¹) – an order of magnitude higher than single-substituent control systems. Remarkably, analogous palladium catalysts generated hyperbranched polyethylenes with M_n up to 43.8 kg mol⁻¹. These systems further achieved outstanding methyl acrylate incorporation (up to 13 mol%) in copolymerizations while maintaining practical molecular weights (4.1–8.4 kg mol⁻¹). Mechanistic studies reveal that cooperative shielding of both axial sites by the dual substituents prevents displacement of active intermediates, while the flexible 8-benzhydrylnaphthyl moiety enhances activity 5–7-fold compared to rigid analogues by facilitating ethylene coordination. This work establishes new design principles for chain-transfer suppression in late-transition-metal polymerization catalysis.

控制链转移反应是吡啶-亚胺镍和钯催化乙烯（co）聚合的基本挑战。我们提出了一种突破性的双轴取代基策略，协同抑制链转移，使高分子量聚乙烯和极性功能化共聚物的高效生产成为可能。合成了一类具有8-苄基和2二芳基甲基萘基吡啶亚胺配体的镍钯配合物，并对其进行了表征。由二乙基氯化铝活化的镍催化剂表现出中等的活性（~10 5 g mol⁻¹h⁻），同时产生高分子量的支链聚乙烯（Mn高达246.4 kg/mol）——比单取代基控制系统高一个数量级。值得注意的是，类似的钯催化剂生成的超支化聚乙烯的M高达43.8 kg/mol。这些系统在共聚过程中进一步实现了出色的丙烯酸甲酯掺入（高达13 mol%），同时保持实际分子量（4.1-8.4 kg/mol）。机理研究表明，双取代基对两个轴位的协同屏蔽阻止了活性中间体的位移，而柔性的8benzhyylnaphthyl片段通过促进乙烯配位，使活性比刚性类似物提高了5-7倍。本工作建立了抑制后过渡金属聚合催化链转移的新设计原则。

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引用次数: 0

The effect of 1,2-dipiperidinoethane derivatives on the composition and hydride sequence distribution in the LAP of styrene and isoprene 1,2-二吡啶乙烷衍生物对苯乙烯和异戊二烯在LAP中的组成和氢化物序列分布的影响

IF 3.9 2区化学 Q2 POLYMER SCIENCE

Polymer Chemistry

Pub Date : 2025-10-09 DOI: 10.1039/d5py00352k

Yang Yang , Qiqi Dai , Yao Long , Yujie Wang , Zhifang Chen , Yi Yang , Le Zhou , Yi Xiao , Xinyu Han , Jiexun Zhang , Shihan Ding , Kun Liu , Lijun Li

Precise control of monomer sequences is of significant importance for the functional modification of polyolefins. For styrene/isoprene (ST/IP) random/alternating copolymers with a constant composition, F_ST = 0.5, variations in the content of isomeric 1,3-diene units in alternating sequences (ST-alt-1,4-IP, ST-alt-3,4-IP and ST-alt-1,2-IP) significantly influence the properties of polyolefins. In this paper, a sterically hindered active center was constructed using 1,2-dipiperidinoethane (DPE)-derived polar additives and n-butyllithium. The regulatory effects of these novel structure regulators on copolymer composition distributions and isomeric unit sequence distributions were systematically characterized by ¹H NMR spectroscopy, and the microstructure information was further verified by FTIR and DSC analyses. GPC analysis confirmed the living and controllable nature of the copolymerization. Finally, the thermal performance differences of random copolymers with various hybrid sequence distributions were systematically investigated by DSC. These research results advance the understanding of sequence regulation polymerization mechanisms and provide a novel strategy for the controlled preparation of liquid rubber.

单体序列的精确控制对聚烯烃的功能改性具有重要意义。对于固定组分FST=0.5的苯乙烯/异戊二烯（ST/IP）无规/交替共聚物，交替序列（ST-alt-1,4-IP、ST-alt-3,4-IP和ST-alt-1,2-IP）中1,3-二烯异构单元的含量变化显著影响聚烯烃的性能。本文采用1,2-二哌替啶乙烷（DPE）极性添加剂和正丁基锂构筑了位阻活性中心。通过1H NMR谱分析系统表征了这些新型结构调节剂对共聚物组成分布和异构单元序列分布的调节作用，并通过FTIR、DSC分析进一步验证了其微观结构信息。GPC分析证实了共聚反应的活性和可控性。最后，通过DSC系统地研究了不同杂化序列分布的无规共聚物的热性能差异。这些研究结果促进了对序列调控聚合机理的认识，为液体橡胶的可控制备提供了新的策略。

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引用次数: 0

Bimetallic aluminum complexes bearing β-pyridyl-enamino ligands: synthesis, characterization and their applications in the ring-opening polymerization of ε-caprolactone 含β-吡啶氨基配体的双金属铝配合物：合成、表征及其在ε-己内酯开环聚合中的应用

IF 3.9 2区化学 Q2 POLYMER SCIENCE

Polymer Chemistry

Pub Date : 2025-10-09 DOI: 10.1039/d5py00481k

Peng Wang , Ziyao Su , Zeqian Yang , Jianhua Cheng , Hengquan Yang , Israel M. Kibeye , Xia Chen

A series of bridged β-pyridyl-enamino dinuclear aluminum complexes were prepared in high yields, where complexes , , , and were characterized by single-crystal X-ray diffraction. The distance between two Al centers in was in the range of 3.7–5.8 Å, which is far shorter than that in and (about 8.0 Å). All of these aluminum complexes were used as initiators for the ring-opening polymerization of ε-caprolactone in the presence of benzyl alcohol. Complexes exhibited higher catalytic activity compared to complexes under the same conditions, indicating that the distance between the Al atoms affects the catalytic activity. Complexes and with Al–Me groups exhibited higher catalytic activity than complexes and with Al–Et groups. This is likely due to the larger steric hindrance or the electron-donating group, which weakens the Lewis acidity of aluminum and results in a reduced reaction rate between the complexes and benzyl alcohol. Herein, two factors affect the polymerization activity in the ROP of ε-caprolactone: one is the distance between the two Al centers in bimetallic systems and the other is the alkyl groups on the Al atoms. The MALDI-TOF mass spectra of the polymers revealed that the ring-opening polymerization of ε-caprolactone catalyzed by these catalysts yields linear polycaprolactones with controlled molecular weights, narrow distributions and end-group fidelity.

高收率制备了一系列桥接β-吡啶基-对氨基双核铝配合物1 - 6，其中配合物1、2、3、5和6用单晶x射线衍射进行了表征。1-3两个Al中心之间的距离在3.7 ~ 5.8 Å之间，远小于5和6的距离（约8.0 Å）。这些铝配合物均作为引发剂在苯甲醇存在下进行了ε-己内酯开环聚合反应。在相同的条件下，配合物1 ~ 3的催化活性高于配合物4 ~ 6，说明Al原子之间的距离对催化活性有影响。含有Al-Me基团的配合物3和5比含有Al-Et基团的配合物4和6具有更高的催化活性。这可能是由于较大的位阻或给电子基团削弱了铝的路易斯酸，从而降低了配合物与苯甲醇之间的反应速率。其中，影响ε-己内酯ROP聚合活性的因素有两个：一是双金属体系中两个Al中心之间的距离；另一个是Al原子上的烷基。聚合物的MALDI-TOF质谱分析表明，在这些催化剂的催化下，ε-己内酯的开环聚合得到了分子量可控、分布窄、端基保真度高的线性聚己内酯。

{"title":"Bimetallic aluminum complexes bearing β-pyridyl-enamino ligands: synthesis, characterization and their applications in the ring-opening polymerization of ε-caprolactone","authors":"Peng Wang , Ziyao Su , Zeqian Yang , Jianhua Cheng , Hengquan Yang , Israel M. Kibeye , Xia Chen","doi":"10.1039/d5py00481k","DOIUrl":"10.1039/d5py00481k","url":null,"abstract":"<div><div>A series of bridged β-pyridyl-enamino dinuclear aluminum complexes were prepared in high yields, where complexes , , , and were characterized by single-crystal X-ray diffraction. The distance between two Al centers in was in the range of 3.7–5.8 Å, which is far shorter than that in and (about 8.0 Å). All of these aluminum complexes were used as initiators for the ring-opening polymerization of ε-caprolactone in the presence of benzyl alcohol. Complexes exhibited higher catalytic activity compared to complexes under the same conditions, indicating that the distance between the Al atoms affects the catalytic activity. Complexes and with Al–Me groups exhibited higher catalytic activity than complexes and with Al–Et groups. This is likely due to the larger steric hindrance or the electron-donating group, which weakens the Lewis acidity of aluminum and results in a reduced reaction rate between the complexes and benzyl alcohol. Herein, two factors affect the polymerization activity in the ROP of ε-caprolactone: one is the distance between the two Al centers in bimetallic systems and the other is the alkyl groups on the Al atoms. The MALDI-TOF mass spectra of the polymers revealed that the ring-opening polymerization of ε-caprolactone catalyzed by these catalysts yields linear polycaprolactones with controlled molecular weights, narrow distributions and end-group fidelity.</div></div>","PeriodicalId":100,"journal":{"name":"Polymer Chemistry","volume":"16 43","pages":"Pages 4745-4754"},"PeriodicalIF":3.9,"publicationDate":"2025-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145247324","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Ambient and metal-free C(sp2)–C(sp3) cross-coupling polymerization of dichalcones and activated methylenes to prepare clusteroluminescent polyarylacrylonitriles 环境和无金属C(sp2)-C（sp3）交叉偶联聚合制备团簇发光聚芳基丙烯腈

IF 3.9 2区化学 Q2 POLYMER SCIENCE

Polymer Chemistry

Pub Date : 2025-10-09 DOI: 10.1039/d5py00624d

Tianbai Xiong , Liguo Xu , Yongfu Qiu , Lingxi Yang , Jia Wang , Xin Wang

Carbon–carbon (C–C) bond cross-coupling is an important tool for constructing functional polymers, yet it typically relies on expensive transition metal catalysts and inert atmospheres. In this study, we designed a class of chalcone derivatives and established their metal-free C(sp²)–C(sp³) cross-coupling polymerization and activated methylenes via C(sp³)–H Michael addition under ambient conditions. 16 polyarylacrylonitriles (PAANs) with diverse structures and high molecular weights (M_w up to 60 200) were obtained in high yields (up to 96.6%). Remarkably, PAANs without conventional luminophores exhibited enhanced fluorescence compared to their monomeric counterparts, demonstrating distinct polymerization-induced emission (PIE) and clusterization-triggered emission (CTE) phenomena. The study of photophysical properties and theoretical calculations prove that the emission mechanism of PAANs is attributed to the through-space conjugation (TSC) between heteroatoms (N and O) and separated benzene rings in the polymer structure. In addition, the fluorescent PAANs selectively detect Fe³⁺ with a low detection limit of 4.55 × 10⁻⁵ M.

碳-碳（C-C）键交叉偶联是构建功能聚合物的重要工具，但它通常依赖于昂贵的过渡金属催化剂和惰性气氛。在本研究中，我们设计了一类查尔酮衍生物，并建立了它们的无金属C(sp2) -C （sp3）交叉偶联聚合，并在环境条件下通过C(sp3) -H Michael加成活化亚甲基。以高收率（96.6%）得到了16种结构多样、分子量高（Mw达60200）的聚芳基丙烯腈（PAANs）。值得注意的是，与单体相比，没有常规发光phone的PAANs表现出增强的荧光，表现出不同的聚合诱导发射（PIE）和聚簇触发发射（CTE）现象。光物理性质的研究和理论计算证明了PAANs的发射机理是由聚合物结构中杂原子（N和O）和分离苯环的通过空间共轭作用（TSC）引起的。此外，荧光PAANs选择性检测Fe3+，检测限低，为4.55 × 10−5 M。

{"title":"Ambient and metal-free C(sp2)–C(sp3) cross-coupling polymerization of dichalcones and activated methylenes to prepare clusteroluminescent polyarylacrylonitriles","authors":"Tianbai Xiong , Liguo Xu , Yongfu Qiu , Lingxi Yang , Jia Wang , Xin Wang","doi":"10.1039/d5py00624d","DOIUrl":"10.1039/d5py00624d","url":null,"abstract":"<div><div>Carbon–carbon (C–C) bond cross-coupling is an important tool for constructing functional polymers, yet it typically relies on expensive transition metal catalysts and inert atmospheres. In this study, we designed a class of chalcone derivatives and established their metal-free C(sp<sup>2</sup>)–C(sp<sup>3</sup>) cross-coupling polymerization and activated methylenes <em>via</em> C(sp<sup>3</sup>)–H Michael addition under ambient conditions. 16 polyarylacrylonitriles (PAANs) with diverse structures and high molecular weights (<em>M</em><sub>w</sub> up to 60 200) were obtained in high yields (up to 96.6%). Remarkably, PAANs without conventional luminophores exhibited enhanced fluorescence compared to their monomeric counterparts, demonstrating distinct polymerization-induced emission (PIE) and clusterization-triggered emission (CTE) phenomena. The study of photophysical properties and theoretical calculations prove that the emission mechanism of PAANs is attributed to the through-space conjugation (TSC) between heteroatoms (N and O) and separated benzene rings in the polymer structure. In addition, the fluorescent PAANs selectively detect Fe<sup>3+</sup> with a low detection limit of 4.55 × 10<sup>−5</sup> M.</div></div>","PeriodicalId":100,"journal":{"name":"Polymer Chemistry","volume":"16 43","pages":"Pages 4709-4717"},"PeriodicalIF":3.9,"publicationDate":"2025-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145241391","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Emulsion polymerisation stabilised by block-random copolymers: ultra-small particles at low stabiliser levels 由嵌段无规共聚物稳定的乳液聚合：低稳定剂水平下的超小颗粒

IF 3.9 2区化学 Q2 POLYMER SCIENCE

Polymer Chemistry

Pub Date : 2025-10-09 DOI: 10.1039/d5py00884k

Arthur Werner , Connor A. Sanders , Sandra E. Smeltzer , Michael F. Cunningham

Poly(methyl methacrylate)-b-poly(methyl methacrylate-r-acrylic acid) block-random copolymers were used as stabilisers in the semi-batch emulsion polymerisation of methyl methacrylate (MMA). By adjusting the pH, nano-latexes with particle sizes ∼30–200 nm were obtained using a surprisingly low stabiliser content (∼0.01 wt% based on monomer).

采用聚甲基丙烯酸甲酯-b-聚甲基丙烯酸-r-丙烯酸嵌段无规共聚物作为稳定剂，进行了甲基丙烯酸甲酯（MMA）半间歇乳液聚合。通过调节pH值，在稳定剂含量极低（以单体为基础为0.01 wt%）的情况下，获得了粒径为30-200 nm的纳米乳液。

引用次数: 0

Synthesis of tetramethylguanidine-based photobase generators: light-guided dynamics in thioester networks 四甲基胍基光碱发生器的合成：硫酯网络中的光导动力学

IF 3.9 2区化学 Q2 POLYMER SCIENCE

Polymer Chemistry

Pub Date : 2025-10-08 DOI: 10.1039/d5py00779h

Pia-Maria Egger , Hannah Sivetz , Simon Renner , Roman Korotkov , Christoph Schmidleitner , Marco Sigl , Inge Mühlbacher , Gregor Trimmel , Sandra Schlögl , Elisabeth Rossegger

Covalent adaptable networks are crosslinked structures with bonds that undergo reversible exchange reactions when exposed to an external stimulus, enabling a reorganization of their topology. The incorporation of photolatent catalysts allows precise tuning of viscoelastic properties and on-demand activation. Herein, the local control of dynamic bond exchange reactions in thiol–ene resins, bearing thioester linkages and free thiol groups, was investigated, by synthetizing numerous tetramethylguanidine (TMG) based photobase generators with varying UV-Vis absorption profiles to improve the orthogonality between curing reaction and photobase activation. UV-induced activation of the photolatent base yields a strong guanidine base, which is able to efficiently catalyze thiol–thioester exchange reactions. Rheological studies, combined with pH measurements upon UV activation of the bases, identified the most promising photolatent base 1,1,3,3-tetramethylguanidine 2-(naphthalen-2-yl)-2-oxoacetate (). In addition to light, also temperature can be used to activate that further increases its applicability. The influence of the developed photobases on the material properties and the curing kinetics were investigated using FTIR- spectroscopy, TGA and DSC measurements. Utilizing the network containing , the spatially controlled activation of the thiol–thioester exchange mechanism in selected areas was demonstrated at temperatures between 40–70 °C through local imprinting experiments, photochemical drawing and thermally induced healing.

共价适应性网络是一种交联结构，当受到外部刺激时，其化学键会发生可逆的交换反应，从而使其拓扑结构得以重组。光致催化剂的结合允许精确调整粘弹性特性和按需激活。本文通过合成具有不同紫外-可见吸收谱的四甲基胍（TMG）基光碱生成剂，研究了含硫酯键和游离巯基的巯基树脂中动态键交换反应的局部控制，以提高固化反应和光碱活化之间的正交性。紫外线诱导的光电位激活产生强胍碱，它能够有效地催化硫-硫酯交换反应。通过流变学研究，结合紫外光活化后的pH值测定，确定了最有前途的光敏碱1,1,3,3-四甲基胍2-（萘-2-基）-2-氧乙酸酯（TMG-NOA）。除了光，温度也可以用来激活TMG-NOA，这进一步增加了它的适用性。利用FTIR、TGA和DSC测试研究了显影光碱对材料性能和固化动力学的影响。利用含有TMG-NOA的网络，通过局部印迹实验、光化学拉伸和热诱导愈合，在40 - 70°C的温度范围内，在选定区域展示了硫醇-硫酯交换机制的空间控制激活。

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引用次数: 0

Photocontrolled cationic polymerization of fluorinated vinyl ethers 氟化乙烯醚的光控阳离子聚合

IF 3.9 2区化学 Q2 POLYMER SCIENCE

Polymer Chemistry

Pub Date : 2025-10-08 DOI: 10.1039/d5py00648a

Jianxu Chen , Xun Zhang , Zan Yang , Yu Jiang , Saihu Liao

Fluorinated polymers have been widely used in many fields, by virtue of their unique properties and excellent performances. The application of photopolymerization methods has further expanded the accessibility and application scope of fluorinated polymers. Herein, we report the development of a photocontrolled cationic polymerization of fluorinated vinyl ethers, which is enabled by employing a bisphosphonium-type photoredox catalyst. This method features metal-free conditions, low-energy visible light regulation, good livingness, and excellent temporal control over chain growth, which allow for the synthesis of fluorinated polymers with controlled molecular weight, variable fluorine content, and high chain-end group fidelity under mild conditions. Further synthesis of fluorinated di- and tri-block copolymers with tunable properties via this photopolymerization method is also demonstrated.

氟化聚合物以其独特的性质和优异的性能被广泛应用于许多领域。光聚合方法的应用，进一步扩大了氟化聚合物的可及性和应用范围。在此，我们报告了氟化乙烯醚的光控阳离子聚合的发展，这是通过采用双磷型光氧化还原催化剂实现的。该方法具有无金属条件、低能量可见光调节、良好的活性和对链生长的良好时间控制等特点，可以在温和的条件下合成分子量可控、氟含量可变、链端基保真度高的氟化聚合物。还证明了用这种光聚合方法进一步合成具有可调性能的氟化二嵌段和三嵌段共聚物。

引用次数: 0

Turning down the heat: catalyst-free, low-temperature chemical degradation of thermoplastic polyurethanes 降低热量：无催化剂，低温化学降解热塑性聚氨酯。

IF 3.9 2区化学 Q2 POLYMER SCIENCE

Polymer Chemistry

Pub Date : 2025-10-08 DOI: 10.1039/d5py00881f

Adrià Roig , Hao Wang , Filip E. Du Prez

Thermoplastic polyurethanes (TPUs) constitute one of the most industrially relevant polymers because of their versatile and tunable properties, which makes them very interesting for a wide range of applications. However, their chemical degradability and recyclability is only achievable through hydrolysis or glycolysis of the urethane moieties, which typically occurs when using catalysts and elevated temperatures, thus resulting in a poorly cost- and energy-efficient process. Herein, we report a novel strategy where variable amounts of chemically degradable β-amino ester (BAE) moieties are incorporated into the main backbone of the thermoplastic urethanes. The amino group in the β-position of the ester was thought to act as an internal, covalently bonded catalyst that not only enables the preparation of materials without the use of external and potentially leachable toxic catalysts, but also the chemical degradation of the resulting TPUs under relatively mild conditions and shorter times via a straightforward transesterification process. The addition of different amounts of BAE groups has been investigated for both aliphatic and aromatic polyurethane thermoplastic backbones. Their chemical, structural and thermal properties have been investigated in-depth, and kinetic studies have been additionally performed with low molar mass model compounds to find the optimal conditions for their chemical degradation. The final aim of this bottom-up molecular design was not only to enable a catalyst-free polyurethane synthesis but also to open new avenues for developing TPUs with an enhanced, cost-effective and energy-efficient degradation process.

热塑性聚氨酯（tpu）是工业上最相关的聚合物之一，因为它们具有多用途和可调的特性，这使得它们具有广泛的应用前景。然而，它们的化学可降解性和可回收性只能通过聚氨酯部分的水解或糖酵解来实现，这通常发生在使用催化剂和高温时，因此导致成本低且节能的过程。在此，我们报告了一种新的策略，其中可变量的化学可降解β-氨基酯（BAE）部分被纳入热塑性聚氨酯的主骨架。酯β位的氨基被认为是内部共价键催化剂，不仅可以在不使用外部和潜在可浸出的有毒催化剂的情况下制备材料，而且还可以在相对温和的条件下通过直接的酯交换过程在较短的时间内进行化学降解。研究了脂肪族和芳香族聚氨酯热塑性骨架中添加不同数量的BAE基团。我们深入研究了它们的化学、结构和热性能，并对低摩尔质量模型化合物进行了动力学研究，以找到它们化学降解的最佳条件。这种自下而上的分子设计的最终目的不仅是实现无催化剂聚氨酯的合成，而且还为开发具有增强、成本效益和节能降解过程的tpu开辟了新的途径。

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引用次数: 0