Preparation Of Conjugated Microporous Polymer Nano-hollow Spherical Matrix Composites And Their Thermal And Flame Retardant Performance

In recent years,the rapid development of the world economy has led to the continuous depletion of global energy,which has a significant impact on human sustainable development.Among them,building energy consumption accounts for a relatively large proportion.Developing high-performance thermal materials is an effective means of achieving building energy efficiency,but common polymer based thermal materials are limited in their practical applications due to their flammability.Therefore,developing materials with excellent thermal and flame retardant properties is of great practical significance for building energy conservation.Conjugated microporous polymers（CMPs）is a kind of typical porous organic polymers.The rich rigid aromatic units in their structures and special skeleton connections endow CMPs with excellent physical-chemical stability and high porosity,which provides a theoretical possibility for the construction of thermal insulation materials.In addition,CMPs not only forms rich carbon layers during high-temperature carbonization,but also maintains the integrity of microstructure and pore structure,making it an ideal candidate for flame retardant materials.More importantly,the synthesis of CMPs has flexibility.Different morphologies of CMPs can be prepared by changing the monomer structure,synthesis conditions,and other factors,especially those with cavity structures.The cavity structure further improves the thermal insulation performance of the material and provides effective space for the loading of flame retardants.Based on this,this paper designed and synthesized CMPs composite materials with hollow spherical structures through block monomer polymerization,and systematically studied the thermal insulation and flame retardant properties of the composite materials.The main research content of this paper is as follows:（1）Two"core-shell"structures（CMPs@SiO₂）were prepared using SiO₂nanoparticles as hard templates,1,3,5-triacetylbenzene as alkynyl monomer,3-amino-2,6-dibromopyridine and 2,4,6-tribromoaniline as brominated monomers respectively by Sonogashira-Hagihara cross coupling reaction.CMPs was etched into hollow spherical structures（CMP1-HNS and CMP2-HNS）by acid solution.CMPs based composite flame retardants（CMP1-HNS-BSb and CMP2-HNS-BSb）were obtained by physical impregnation of bisphenol A-bis（diphenylphosphate）（BDP）and antimony pentoxide（Sb₂O₅）.Research has found that impregnated CMPs-HNS not only have excellent thermal insulation performance,but also can effectively improve the flame retardancy of epoxy resin（EP）matrix.The results show that the thermal conductivity of CMP1-HNS-BSb and CMP2-HNS-BSb is 0.052 W m^-1 K^-1 and 0.049 W m^-1 K^-1,respectively.The peak heat release coefficient（p HRR）of CMP1-HNS-BSb and CMP2-HNS-BSb is 73.05 W g^-1 and 76.5 W g^-1,respectively.The p HRR value of EP with 0.5%CMP2-HNS-BSb added is 643.80 k W m^-2,which is 14.87%lower than pure EP under the same conditions,significantly improving the flame retardancy of EP.（2）Two kinds of hollow CMPs hollow microspheres（HCMP1-NHS and HCMP2-NHS）were prepared by Sonogashira-Hagihara cross coupling reaction with SiO₂nanospheres as hard templates and 1,3,5-triacetylbenzene and 1,4-diacetylbenzene as monomers respectively.CMPs based composite flame retardants modified were prepared by"Click"reaction using HCMPs-NHS and diphenyl azide phosphate（DPPA）as monomers,respectively（HCMP1-NHS-FR and HCMP2-NHS-FR）.Research has found that composite flame retardants treated through chemical reactions exhibit excellent thermal insulation and flame retardancy.The thermal conductivity of HCMP1-NHS-FR and HCMP2-NHS-FR are 0.049 W m^-1 K^-1 and 0.050 W m^-1 K^-1,respectively.The p HRR of 94.834 W g^-1and 70.799 W g^-1,respectively.To further investigate the advantages and disadvantages of its flame retardancy,HCMPs-NHS-FR was introduced into the EP matrix to prepare EP-1 and EP-2.The cone calorimetry（CC）test results showed that the p HRR of EP-1 and EP-2 was 496.38 k W m^-2 and 596.96k W m^-2,respectively.Compared with pure EP under the same conditions,their values decreased by 30.4%and 16.3%,respectively.