Conjugated microporous polymer nanoparticle hollow spheres loaded with DOPO and chitosan with excellent thermal insulation and flame retardant properties

The development of new materials with heat-insulating and flame-retardant properties is particularly important in the development of various fields such as construction, electric power, transportation, and aerospace. In this study, two kinds of conjugated microporous polymer (CMPs) nanospheres with hollow structures (H CMPs) were prepared by Sonogashira-Hagihara cross-coupling reaction using 1,3,5-triethynylbenzene and 1,4-diethynylbenzene as the monomers and SiO 2 nanospheres as the hard templates, respectively. Then 9,10-dihydro-9-oxa-10-phospha-phenanthrene-10-oxide (DOPO) and chitosan (CTS) were loaded on the surface of H CMPs using a layer-by-layer assembly method to obtain the composite flame retardant H CMPs@CTS@DOPO. H CMP1@CTS@DOPO, H CMP2@CTS@DOPO and ammonium polyphosphate (APP) were introduced into the flammable epoxy resin (EP) in different ratios to obtain EP1, EP2, EP3, EP4 and EP5, which were compared with pure EP to evaluate their thermal insulation and flame retardant properties. The thermal conductivity of EP2, EP3 was measured to be 0.0359 W m -1 K -1 and 0.0170 W m -1 K -1 , respectively, which has excellent thermal insulation performance. The peak heat release rate (pHRR) of EP4, EP5 was reduced by 57.3 % and 64.8 %, and the peak CO 2 production (CO 2 P) was reduced by 72.7 % and 77.3 %, respectively, compared with that of pure EP, as measured by conical calorimetry (CC), which has an excellent flame retardant effect. Therefore, H CMPs@CTS@DOPO, as a new class of heat-insulating and flame-retardant materials, has great potential for application in the fields of construction, electronics and transportation.