Linear Viscoelasticity of ABA-type Vitrimer Based on Dioxaborolane Metathesis  

作　　者：Shi-Long Wu Huan-Huan Yang Quan Chen 

机构地区：[1]State Key Laboratory of Polymer Physics and Chemistry,Changchun Institute of Applied Chemistry,Chinese Academy of Science,Changchun,130022,China [2]University of Science and Technology of China,Hefei,230026,China

出　　处：《Chinese Journal of Polymer Science》2024年第10期1495-1504,I0010,共11页高分子科学（英文版）

基　　金：financially supported by the National Natural Science Foundation of China(Nos.22173095 and 52103021)。

摘　　要：In this study,we synthesized a series of ABA-type vitrimers by crosslinking the short A moieties of precursors with a bifunctional crosslinker and evaporating the small molecular byproduct.The vitrimer samples thus prepared exhibit linear viscoelasticity dependent on the length of A moiety as well as the content of the crosslinks.When the average number of A monomers per end moiety m=1.1,the crosslinker can only extend the chain but not crosslink the chain.When m becomes 2.8 or higher,introducing a crosslinker first leads to the gelation,whereas excess in crosslinker molecules leads opening of the crosslinking sites and accordingly reentry into the sol regime.Surprisingly,a further increase in the length of the A moieties increases the relaxation time much weaker than the exponential increase seen for the physically crosslinked ABAtype ionomers.We attribute this difference to the distinct relaxation mechanisms:the relaxation of the vitrimer samples is based on relatively independent exchange reactions,which contrasts with the ABA-type ionomers that relax through the collective hopping of connected ionic groups from one ion aggregate to another.

关 键 词：Polymer rheology Linear viscoelasticity ABA-type vitrimer Relaxation mechanism Kinetics and thermodynamics 

分 类 号：TQ317[化学工程—高聚物工业]