The low temperature properties of polydimethylsiloxane(PDMSN) containing hexaphenylcyclotrisilazane(P3N) and the commerical PDMS were comparable according to their DSC data.The glass transition temperature of PDMSN was -120℃.After heating for 24 hours at 350℃ in a sealed N2 system

the weight loss of PDMSN was 4～10 times lower as that of the commericial PDMS

and decreased with increasing its nitrogen content

thus

its least weight loss was 1.1%.The 29Si-NMR spectra

IR spectra and the relationship between the molecular weight (by GPC) and limiting viscosity number of PDMSN

which was synthesized through the polymerization of cyclosiloxane with trilithium salt (P3NLi) of hexaphenylcyclotrisilazane as an initiator

demonstrated that PDMSN was a star polymer.Also

N

N

N-trimethylhexaphenylcyclotrisilazante

which was prepared quantitatively through the reaction of P3NLiand MeI in the polar solvent

was characterized by the elemental analysis

1H-NMR and 29Si-NMR spectra

IR spectra

The star polymer nature of PDMSNwas also proved indirectly by the characterization of N

N

N-trimethylhexaphenylcyclotrisilazane.