Preparation And Properties Of Bio-based Isomannitol Vitrimer

The vitrimer is a new kind of polymer material,which has the performance of thermosetting materials under the use conditions.Triggering the exchange reaction of dynamic covalent bond under certain stimulation conditions can endow the material with the reprocessing performance.The emergence of vitrimer effectively solves the problem of traditional polymer materials being difficult to recycle.In addition,most polymer materials are synthesized from non renewable fossil resources,and using natural renewable biomass resources as raw materials to synthesize sustainable polymer materials is another effective way to reduce the consumption of fossil resources.Therefore,the preparation of high-performance bio-based vitrimer not only solves the problems of traditional polymer materials being difficult to recover and reducing environmental burden,but also promotes the development of natural bio based chemicals.In this paper,a series of bio-based vitrimer were prepared by a green and efficient preparation process.By adjusting the proportion of glycols and the type of dynamic covalent bond,the performance of bio-based vitrimer was adjusted,and its comprehensive performance was analyzed.The specific research results are as follows:(1)Biobased glass polymer based on transesterification(IMT-COO)was synthesized by using isomannitol(IMT)as raw material,pentaerythritol as crosslinking agent and dibutyltin lauric acid as catalyst.The structure was characterized by FT-IR and XPS.At the same time,gel fraction,TGA,DSC,DMA,stress relaxation,mechanics,XRD and SEM were used to analyze the comprehensive performance of IMT-COO.The results indicate that IMT-COO has good solvent resistance,thermal stability,and mechanical properties.At the same time,the dynamic exchange of ester bonds in IMT-COO at high temperatures causes a rearrangement of the polymer network topology,enabling IMT-COO to have self-healing functions.In addition,IMT-COO can still be restored to their original state.After SEM observation of the surface morphology of the repaired material,there was no significant change in the surface morphology after repair.(2)2,2’-dithiodiethanol(DTBO)was synthesized from thiodiethanol(ME)as raw material.The structures of DTBO was characterized by FT-IR.Secondly,the synthesized DTBO was introduced into the main chain of the bio based polymer,and pentaerythritol was used as a crosslinking agent to prepare a bio-based IMT-COO-S containing both dynamic ester bonds and dynamic disulfide bonds.The structures of polymer were characterized by FT-IR.Gel fraction,TGA,DSC,DMA,stress relaxation,mechanics,XRD and SEM were used to analyze the comprehensive performance of IMT-COO-S.The results indicate that the solvent resistance,thermal stability,and mechanical properties of IMT-COO-S have been improved.After shearing and hot pressing,the IMT-COO-S glass polymer material can still be restored to its original state,and the Young’s modulus of the repaired material is around 90%of the original material.Finally,carbon fiber reinforced composite materials were synthesized using IMT-COO-S as the matrix,significantly improving the mechanical properties of the materials.The composite materials were recycled,and compared with the original fibers and recycled fibers,there was no damage to the fiber surface.