The Building Of Metal Coordination Crosslinking High Performance Polymers And The Study Of Their Performance

High-performance polymers have attracted great interest of many research groups and have been widely used in many areas,such as aerospace,machinery,electronics,etc.,due to their excellent heat resistance,good chemical stability,and outstanding mechanical performance.Despite their widespread commercial use and practical utility,there has been little recent success in the synthesis and design of new rigid linear polymers with better combination properties and good processing properties.It is well known that chemical crosslinking has been proved to be an effective manner to enhance the thermal stability and mechanical strength of polymers.Despite considerable effort,the availability of these chemical crosslinking polymers is limited to a certain extent for a variety of reasons,including poor solubility in common organic solvents,difficult to be remolded once cured,thermally decompose upon heating to high temperatures,apt to leave contaminants in the environment,etc.In this thesis,of particular interest to us is the use of metal-ligand interaction in facilely building supramolecular crosslinked high performance polymers with higher thermal stability,mechanical strength and chemical stability that can respond to variant external stimuli,endowing the resulting polymers with a recyclable behavior.Hence,a type of Cu???-coordination crosslinked poly?benzimidazolyl pyridine?s were firstly prepared successfully via the Cu²⁺coordination interactions with the ligand of 2,6-bis?2-benzimidazolyl?pyridine.These physical crosslinked materials possessed outstanding thermal stability?T_d>500? ,T_g>250 ??and good mechanical property,the tensile strength up to 107 MPa.What's more,owing to the reversibility of coordination bonding interaction,the recycling of the physical crosslinked high-performance polymers were realized in the presence of PPi,and the samples that have been subjected to multiple recycling treatments still had nearly the same stress-strain behaviors as the original sample.Indole is ubiquitous in biological and biochemical structures,and has attracted extensive interest in the construction of pharmaceuticals,fragrances,agrochemicals,dyes and materials in the past decades due to its unique electrical,chemical,and optical properties.The reactive sites in indole group could be used to construct indole-based polymers for the applications in electronics,electrocatalysis,anode materials,anticorrosion coatings and biological areas.Herein,we have successfully synthesized a kind of linear polymer N-polyindoles with the bipyridine motifs as ligands,and then several metal coordination polymers M-N-polyindoles?M-N-PINs?with good comprehensive performance were obtained followed by coordinating with Cu²⁺,Zn²⁺,Fe²⁺,Co²⁺,respectively.The recycle of these crosslinked high-performance polymers also could be achieved in the presence of PPi.Taking Cu²⁺ as an example,we verified the power function relations between the fluorescence intensity and thermal or mechanical properties of polymers with various metal contents.Meanwhile,the nondestructively detecting for tensile strength?RM?and glass transition temperature?T_g?of high performance polymers was achieved.Moreover.in this research.Zn???-coordination crosslinked poly?benzimidazolyl pyridine sulfone?s(PSUEMpys-Zn²⁺),as a novel class of recyclable high performance polymer films,have also been successfully prepared.These physical crosslinked materials also possessed outstanding thermal stability and good mechanical property.The recycling of the obtained crosslinked high-performance polymers were also realized in the presence of PPi.We could also established the linear function relations between the transmittance and thermal or mechanical properties of polymers with various metal contents,which suggested that the visually detecting for tensile strength?RM?and glass transition temperature?T_g?of high performance polymers was further achieved.