Crosslinking thermosets with hyperbranched polymers confers them superior comprehensive performance.However,it still remains a further understanding of polymer crosslinking from the molecular chains to the role of agg...Crosslinking thermosets with hyperbranched polymers confers them superior comprehensive performance.However,it still remains a further understanding of polymer crosslinking from the molecular chains to the role of aggregates.In this study,three hyperbranched polysiloxane structures(HBPSi-R)are synthesized as model macromolecules,each featuring distinct terminal groups(R denotes amino,epoxy,and vinyl groups)while similar molecular backbone(Si-O-C).These structures were subsequently copolymerized with epoxy monomers to construct interpenetrating HBPSi-R/epoxy/anhydride co-polymer systems.The spatial molecular configuration and flexible Si-O-C branches of HBPSi-R endow them with remarkable reinforcement and toughening effects.Notably,an optimum impact strength of 28.9 kJ mol^(−1) is achieved with a mere 3%loading of HBPSi-V,nearly three times that of the native epoxy(12.9 kJ mol^(−1)).By contrasting the terminal effects,the aggregation states and crosslinking modes were proposed,thus clarifying the supramolecular-dominant aggregation mechanism and covalent-dominant dispersion mechanism,which influences the resulting material properties.This work underscores the significance of aggregate science in comprehending polymer crosslinking and provides theoretical insights for tailoring material properties at a refined molecular level in the field of polymer science.展开更多
基金National Natural Science Foundation of China,Grant/Award Number:22175143Key Research and Development Project of Shaanxi,Grant/Award Number:2022GY-353+1 种基金Science Center for Gas Turbine Project,Grant/Award Number:P2022-DB-V-001-001Fundamental Research Funds for the Central Universities,Grant/Award Number:D5000230086。
文摘Crosslinking thermosets with hyperbranched polymers confers them superior comprehensive performance.However,it still remains a further understanding of polymer crosslinking from the molecular chains to the role of aggregates.In this study,three hyperbranched polysiloxane structures(HBPSi-R)are synthesized as model macromolecules,each featuring distinct terminal groups(R denotes amino,epoxy,and vinyl groups)while similar molecular backbone(Si-O-C).These structures were subsequently copolymerized with epoxy monomers to construct interpenetrating HBPSi-R/epoxy/anhydride co-polymer systems.The spatial molecular configuration and flexible Si-O-C branches of HBPSi-R endow them with remarkable reinforcement and toughening effects.Notably,an optimum impact strength of 28.9 kJ mol^(−1) is achieved with a mere 3%loading of HBPSi-V,nearly three times that of the native epoxy(12.9 kJ mol^(−1)).By contrasting the terminal effects,the aggregation states and crosslinking modes were proposed,thus clarifying the supramolecular-dominant aggregation mechanism and covalent-dominant dispersion mechanism,which influences the resulting material properties.This work underscores the significance of aggregate science in comprehending polymer crosslinking and provides theoretical insights for tailoring material properties at a refined molecular level in the field of polymer science.
