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Rosin side chain type catalyst-free vitrimers with high cross-link density,mechanical strength,and thermal stability

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Frontiers of Chemical Science and Engineering 2023年第9期17卷 1267-1279页

作者： Yunpeng Shen Weishan Tang Jinyang Li Zhijun Ke Lirong Liao Peng Yang Yuntao Lu Xiaoping Rao College of Chemical Engineering Huaqiao UniversityXiamen361021China Academy of Advanced Carbon Conversion Technology Huaqiao UniversityXiamen361021China

The emergence of vitrimer,a new class of polymer materials can address the problem of recyclability,reprocess ability and recyclability of thermosetting ***,a natural product,is an ideal raw material for the preparation of polymers in a more sustainable ***,due to the huge steric hindrance caused by the hydrogenated phenanthrene ring structure,the cross-link density of materials is frequently *** this study,hydrogenated rosin was adopted for preparing hydrogenated rosin side-chain type diacids,which were reacted with mixed epoxy to obtain rosin side-chain type *** was completely characterized by differential scanning calorimetry test,thermogravimetric analysis,shape memory test and self-healing *** prepared vitrimers exhibited good self-healing properties,excellent heat resistance(T_(d)=352℃)as well as high mechanical properties(tensile strength of 46.75 MPa).The tricyclic diterpene structure of rosin was introduced into the side chain in order to avoid the reduction of cross-link density resulting from the huge steric hindrance of the rigid tricyclic hydrophenylene *** can undergo dynamic transesterification reaction without external catalysts due to the autocatalytic effect of tertiary amines from ***,our work expanded the application field of rosin,increased the added value of rosin,and provided a novel method for preparing rosin-based vitrimers with ideal properties.

关键词： vitrimers rosin catalyst-free high mechanical properties dynamic transesterification reaction

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Catalyst Control of Interfacial Welding Mechanical Properties of vitrimers

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Chinese Journal of Polymer Science 2022年第6期40卷 611-617页

作者： Zong-Tang Lv Hong-Kun Yang Dong Wang State Key Laboratory of Organic-Inorganic Composites Beijing University of Chemical TechnologyBeijing 100029China

Interfacial welding of thermosetting polymers has been a challenge,but vitrimers with dynamic covalent networks open numerous opportunities for welding and adhesion of these *** this work,we performed interfacial welding between epoxy-based vitrimers and an epoxy vitrimer and a thermoplastic polyurethane(TPU).Catalyst-controlled interfacial mechanical properties for both the vitrimer/vitrimer and vitrimer/TPU are observed,that is,the more efficient the catalyst for the transesterification reactions,the larger the interfacial fracture energy is,and the better the welding strength will *** interfacial mechanical properties are also found to be independent of the original mechanical properties of the *** for a vitrimer with poor mechanical properties,both the welded vitrimer/vitrimer and vitrimer/TPU exhibit larger interfacial fracture energy than the one with better mechanical properties as long as the former uses more efficient catalyst.

关键词： vitrimers Interfacial welding Epoxy Catalyst Thermoplastic polyurethane

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Recycling strategies for vitrimers

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International Journal of Smart and Nano Materials 2022年第3期13卷 367-390页

作者： Haochuan Zhang Jingjing Cui Guang Hu Biao Zhang Frontiers Science Center for Flexible Electronics(FSCFE) Ningbo Institute of Northwestern Polytechnical UniversityNorthwestern Polytechnical UniversityXi’anShaanxiChina Queen Mary University of London Engineering School Northwestern Polytechnical University(NPU)Xi’anP.R.China

Vitrimer is a new type of material that combine the advantages of thermoplastic and thermoset *** rapid dynamic exchange reactions at high temperature allow the topology of cross-linked networks to change and rearrange while keeping material structures and properties *** concept of vitrimer has emerged to provide a viable strategy for the recycling of highperformance polymer materials,and lots of research works have been carried out for the development of various types of *** addition,the recycling strategies for vitrimers are particularly important to determine the performance and potential applications of the recovered ***,it is an innovative and valu-able perspective to discuss vitrimer materials according to their different recycling *** this review,we start with a brief overview of vitrimers,and then,focus on recycling strategies for ***,we highlight the advantages and disadvan-tages of the two different recycling strategies:physical and chemi-cal recycling methods,and then explore the feasibility of upcycling vitrimers using 3D printing ***,the impact of recy-cling strategies on vitrimer materials and the prospects for max-imizing the use of vitrimer materials are discussed.

关键词： vitrimers chemical recycling physical recycling 3D printing

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Covalently Crosslinked Networks from Telechelic Polycyclooctene with Reinforced Properties

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Chinese Journal of Chemistry 2023年第16期41卷 2002-2009页

作者： Shengquan Zheng Yue Liu Guifu Si Min Chen CAS Key laboratory of Soft Matter Chermistry Department of Polymer Science and EngineeringUniversity of Science and Technology of ChinaHefeiAnhui 230026China Institutes of Physicol Science and Informotion Technology Anhui UniversityHefeiAnhui 230601China

Comprehensive Summary Introducing covalently crosslinked network to telechelic polymers can enable the formation of advanced polymeric materials with enhanced material *** this contribution,well-defined telechelic polymers bearing acetoacetate groups were synthesized via Ru-catalyzed ring-opening metathesis polymerization of cyclooctene in the presence of chain transfer *** the unique feature of muti-site reactive acetoacetate end groups,several crosslinked networks were constructed using different crosslinkers under mild *** the Michael addition reaction system,the introduction of di/trifunctional aliphatic acrylate as crosslinkers significantly enhanced the mechanical properties of the generated crosslinked network(tensile strength up to 27 MPa,elongation at break up to 500%).On the other hand,vitrimers with dynamic covalent crosslinked networks were accessed via transamination of vinylogous urethane reaction using telechelic polymers and tris(2-aminoethyl)amine.

关键词： Telechelic polycyclooctene Crosslinking Networks vitrimers Reinforced properties Recyclable polymers

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Production and closed-loop recycling of biomass-based malleable materials

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Science China Materials 2020年第10期63卷 2071-2078页

作者： Zhiping Su Yiming Hu Xiye Yang Rong Long Yinghua Jin Xiaohui Wang Wei Zhang State Key Laboratory of Pulp and Paper Engineering South China University of TechnologyGuangzhou 510641China Department of Chemistry University of ColoradoBoulderCO 80309USA

The search of biomass-based substitutes for fossil-based plastics has become a pressing task due to the severe long-term threats of plastic wastes to the ***,the development in this area is strongly impeded by the high cost of biomass separation and the poor processability of unseparated ***,we demonstrate,for the first time,an efficient and scalable method to generate greener plastics by directly integrating unseparated biomass waste(i.e.,wood powder)with crosslinked covalent adaptable *** a simple compression molding process,the wood biomass and polymer particles can be fused together to form a continuous material,which is endowed with repairability,reprocessibility,and closed-loop full *** method demonstrated in this work paves the way for largescale industrial production of environmentally friendly biomass-based plastics.

关键词： wood biomass plastic polyimine recyclable vitrimers

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纳米颗粒交联环氧化天然橡胶复合材料：可交换界面的构筑及性能研究

纳米颗粒交联环氧化天然橡胶复合材料：可交换界面的构筑及性能研...

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作者：邱敏华南理工大学

学位级别：硕士

纳米填充橡胶复合材料因其良好的力学性能而被广泛应用。通常来说,纳米填充橡胶复合材料一般采用硫磺或过氧化物等作为交联剂,所形成的不可逆交联网络无法实现材料的重塑与再加工,造成极大的资源浪费和环境污染,制约着橡胶复合材料的发... 详细信息

纳米填充橡胶复合材料因其良好的力学性能而被广泛应用。通常来说,纳米填充橡胶复合材料一般采用硫磺或过氧化物等作为交联剂,所形成的不可逆交联网络无法实现材料的重塑与再加工,造成极大的资源浪费和环境污染,制约着橡胶复合材料的发展与应用。针对上述问题,本论文提出在橡胶与纳米颗粒之间构筑可交换界面,进而制备力学性能优异且具有可再加工性能的纳米填充橡胶复合材料。主要内容如下:(1)通过重氮化反应对炭黑表面进行羧基接枝改性,将改性炭黑(g-CB)作为环氧化天然橡胶(ENR)交联剂,制备ENR/g-CB复合材料。结果表明,复合材料体系中,g-CB同时充当交联剂和补强剂的作用,其表面接枝的羧基可与ENR基体的环氧基团形成β-羟基酯界面,赋予橡胶复合材料优异的力学性能。在常温下,复合材料的交联网络拓扑结构被冻结,因而具有良好的回弹性。而在高温作用下,复合材料中界面β-羟基酯可通过交换反应实现交联网络的拓扑重排和应力的完全松弛,赋予材料良好的可锻性和再加工性能。其中,添加20 phr g-CB的再加工试样,其拉伸强度和断裂伸长率恢复率分别高达83%和100%。(2)通过重氮化反应对多壁碳纳米管(MWCNTs)进行表面改性,得到羧基接枝的g-MWCNTs。随后将其与ENR复合,g-MWCNTs表面羧基与ENR环氧基团反应形成界面β-羟基酯交联键,制备ENR/g-MWCNTs复合材料。研究表明,β-羟基酯可交换界面的构筑改善了g-MWCNTs在ENR中的分散性,进而提高了复合材料的力学性能,其中,添加20 phr g-MWCNTs的EC20试样100%定伸模量达到11.4 MPa,相比较未改性对比样ECB20(100%定伸模量仅为7.1 MPa),提高了50%。此外,利用界面β-羟基酯键的可交换特性,复合材料的交联网络拓扑结构在高温下可实现重排,因而具有可塑性和再加工能力。其中,添加20 phr g-MWCNTs的再加工EC20试样100%定伸模量、拉伸强度和断裂伸长率恢复率分别高达94%、74%和67%,明显优于未改性对比样ECB20(100%定伸模量、拉伸强度和断裂伸长率恢复率分别仅为60%、36%和56%),说明β-羟基酯可交换界面的构筑可有效改善复合材料的再加工性能。值得注意的是,由于再加工过程中,复合材料界面交联网络的重排能进一步促进g-MWCNTs的解缠和分散。因此,经多次再加工的复合材料样品的力学性能回复率提高。

关键词： vitrimers 橡胶界面可交换键炭黑多壁碳纳米管

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从弹性体到塑性体的可加工环氧网络聚合物

从弹性体到塑性体的可加工环氧网络聚合物

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中国化学会2017全国高分子学术论文报告会

作者：陈嘉慧曽建兵西南大学化学化工学院

近年来,对关于vitrimers的研究大都以弹性体材料为研究对象,这大大限制了其在一些重要领域的发展。因此,我们将带刚性六元环的1,4-环己烷二甲酸（CHDA）引入到癸二酸交联的环氧网络中,调控环氧网络的结构,从而调控其性能,以制备从弹性... 详细信息

近年来,对关于vitrimers的研究大都以弹性体材料为研究对象,这大大限制了其在一些重要领域的发展。因此,我们将带刚性六元环的1,4-环己烷二甲酸（CHDA）引入到癸二酸交联的环氧网络中,调控环氧网络的结构,从而调控其性能,以制备从弹性体到塑性体可加工环氧网络聚合物。刚性链段CHDA提高了癸二酸交联环氧树脂网络的硬度,使其玻璃化转变温度随CHDA含量增加而升高,其力学性能如拉伸强度、杨氏模量与断裂伸长率均随CHDA含量变化而变化,获得了从弹性体到高韧性塑料以及刚性材料的一系列可加工环氧网络。CHDA的含量同时影响着vitrimers的应力松弛行为,提高CHDA的含量会降低其骨架的流动性从而使松弛现象变得缓慢。反复压板成型的样品的凝胶分数和机械性能测定可以体现vitrimers良好的可回收性。本研究实现了vitrimers从弹性体到刚性结构的转变,有利于环氧树脂的进一步研究和可持续发展。

关键词： vitrimers 机械性能应力松弛可回收性

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