| In this work,two ionic liquid copolymers containing PEG segments and imidazoletype structures were synthesized and prepared,and introduced into PLA / PVDF blends.The effects of ionic liquid copolymers of two structures on the aggregate structure,phase morphology,phase interface,and dielectric behavior of PLA / PVDF blends were studied.Ionic liquid copolymer was introduced into the PLA/PCL/Gra composites,which has a significant effect on the structure and properties of blends.The surface modification effects of ionic liquid copolymers on Gra and the effects of the modification on the dispersion properties of Gra in composites,and the effects of ionic liquid copolymers and Gra on the aggregate structure and properties of composites were studied.In addition,ionic liquid copolymers were introduced into the PLA/PCL/MWCNTs composites,and the migration of MWCNTs from the PLA phase to the PCL phase was controlled by dynamics,so that MWCNTs could be selectively distributed at the continuous interface of the immiscible PLA/PCL mixture to achieve the preparation of high-performance electromagnetic shielding materials.The changes of aggregate structure,phase morphology and properties of the composites were studied after the introduction of ionic liquid copolymers.The main contents as follows:1)Two ionic liquid copolymers containing PEG segment and imidazole structure were synthesized: P[MPEGMA-MV] and P [MPEGMA-IL].The effect of two types of ionic liquid copolymers on the aggregation state structure,phase morphology and dielectric properties of PLA/PVDF blends was studied by DSC,SEM and LCR meter.It was found that P[MPEGMA-IL] had a more significant regulation effect on the aggregation structure and phase morphology of PLA and PVDF.P[MPEGMA-IL] promotes the orderly arrangement of the matrix molecular chains,and the crystallization performance of PLA and PVDF was improved.Due to the presence of ionic elements in P[MPEGMA-IL],it had the function of emulsifier.P[MPEGMA-IL] improved the interface force between PLA and PVDF to promote the dispersion of PVDF as a compatibilizer and interfacial emulsifier.With the increase of P [MPEGMA-IL] content,the number of space carriers increases,the interface polarization and orientation polarization increase,and the dielectric properties of the blends increased significantly.2)P[MPEGMA-IL] had a significant control on the structure and performance of the blends.It was found that the dispersion of PCL was improved,the crystallization ability of PLA was enhanced,and the dielectric properties improvement was improved significantly when P[MPEGMA-IL] was introduced into the PLA/PCL blends.After the introduction of Gra in blends,the high content of Gra hindered the movement of the PCL segment,which reduced the arrangement and aggregation of the PCL segment,and regulated the aggregation state structure and phase morphology of the two phases of PLA and PCL.In addition,due to the formation of ?-? interaction between P[MPEGMA-IL] and Gra,the effective dispersion of Gra is promoted,and the dielectric permittivity of the composites was increased by nearly 25 times.The electrical performance was significantly improved.3)P[MPEGMA-IL] was introduced into the PLA / PCL / MWCNTs composites,and the MWCNTs were migrated from the PLA phase to its PCL phase through kinetic control.And MWCNTs could be selectively distributed at the continuous interface of the immiscible PLA/PCL.Due to the plasticizing effect and biocompatibility of the PEG segment in P [MPEGMA-IL],the flexibility,dispersion and compatibility of the matrix macromolecules are changed,and the interaction between imidazole groups and carbon tubes was used to promote the effective dispersion of carbon tubes,and improves the crystallization performance of PLA and PCL.The carbon tubes form more conductive network structures in the composites and improve the conductivity of the composites.The electromagnetic shielding efficiency reached up to 48 d B in the PLA / PCL / MWCNTs / P [MPEGMA-IL] composites. |
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