STUDY ON ACTIVE FILLER ADDITION TO POLYCARBOSILANE/DIVINYLBENZENE

摘要

In the paper, active filler additions (Ti,Cr,TiB_2) to polycarbosilane( PCS) /divinylbenzene( DVB) were studied. Reactions involved during the pyrolysis process were traced by combined TG-DTA,XPS,XBD,dilatometer,and density measurements. The sample with Ti powder shows a strong exothermal peak at 650 °C in DTA curve, indicating TiN fonas. This is confirmed by both weigh tgain in TG and characteristic patterns of TIN in XRD.As treatment temperature increases, apparent "ceramic yield" and density exceed 100%, 4. 3g/cm~3,respectively,and more complex species (Tie ,Ti_5SX_3, SiO_2) appear accompanied by decrease in free carbon content. Linear shrinkage decreases significantly from 32%(fillerfree) to 20%.Similar results are obtained in Cr and TiB_2 additions.Nq distinct exothermal or endothermal peaks appear in Cr and TiB_2 addition. Linear shrinkages are 14% and 10.5% for Cr and TiB_2, respectively. XRD patterns show at 1200 °C increment, there appear new phases of Cr_3C_2 ,Cr_7C_3,Cr_xSi,CrN,Cr2N in Cr addition,and TiC,TiN in TiB_2 addition.