Construction And Dielectric Properties Of POSS-based Porous Materials

Polyhedral oligomeric silsesquioxane(POSS), a kind of containing nanometer hollow structure of organic-inorganic hybrid molecules, has a low dielectric constant and dielectric loss. In addition, POSS has the advantages of good dimensional stability, nanometer enhancement effect and thermal stability. Especially the structure of good plasticity with nanoscale hole contributes to the performance of POSS organic-inorganic hybrid. Introduce octavinyl-polyhedral oligomeric silsesquioxane(OV-POSS) into base material by physical blending and chemical crosslinking to abtian the material with porous structure. Research the relation of dielectric properties with the porous structure.Using Heck reaction to modify OV-POSS with benzocyclobutene to form BCB-POSS. BCB-POSS derived could be obtained by crosslinking of BCB-POSS. 1H NMR shows that the BCB-POSS is synthesized successfully, and the substituted rate of POSS is about 50%. Structural analysis and performance test results show that BCB-POSS can achieve a crosslinked polymer by [2+4] cycloaddition; T5% reach up to 477?, it shows excellent thermal stability. The surface of BCB-POSS crosslinked resin film is bright and clean, which can be applied for microelectronics.Introducing OV-POSS into polystyrene(PS) by physical blending. Optical microscope, SEM and XRD proves that POSS crystal in the PS matrix. DSC and dielectric properties test indicate that the size of POSS crystal have a huge impact on the thermal properties, dielectric constant and dielectric loss of materials. At 80?, the dielectric constant of the film which the PS matrix with 6 wt% POSS can be reduced to 2.29. The introduction to POSS influences polymer chain segment motion of the matrix and interface between POSS crystal and matrix, leads to a decline in dielectric constant.Synthesis of block copolymer PEO-b-PS, and introduces OV-POSS into PEO-b-PS by physical blending. By changing substrate, the method of annealing, and the annealing time to control the micro-phase separation of PEO-b-PS block polymer. POSS observed distribution of the matrix by the AFM, Optical microscopy and DSC.