The effect of hydrolysis derivatives of hexachlorocyclotriphosphazene (HCCP) on its thermal vacuum polymerization was investigated.FTIR and 31P-NMR spectra were used to analyze the impurities in HCCP.The impurity removing effectiveness of different purification methods and the influence of residual impurities on thermal vacuum ring-open polymerization reaction of HCCP were studied.Poly(bistrifloroethoxy)phosphazene (PTFEP) was synthesized according Allock’s method by using HCCP which was purified with different methods.FTIR

31P-NMR

WAXR

DSC and GPC were used to analyze the characteristic properties of PTFEP.The results showed that HCCP with chloroattached rings could be hydrolyzed by water vapor in the atmosphere and generated impurities such as Trimer-1

Gem-2

Dimmer-3

et al.Recrystallization can remove Gem-2

Dimmer-3 and some Trimer-1.There were still some Trimer-1 remaining in HCCP purified only by recrystallization.Sublimation can remove trimer-1 well.In the process of thermal vacuum ringopen polymerization of unpurified HCCP (250℃

10 Pa)

with unpurified monomers

which contained impurities of Trimer-1

Gem-2 and Dimmer-3

the soluble polydichlorophosphazene (PDCP) could be got only when the polymerization time was within range of 8 h and the monomer conversion was 6.8%. When the polymerization time exceeded 10 h crosslinking polymer appeared.When HCCP purified by twice recrystallization or by one recrystallization plus one sublimation was used as polymerization monomer

the conversion of the former were 21.4% (64 h) and 32.6% (78 h)

that of the latter were 60.0% (64 h) and 70.6% (78 h)

and no crosslinking polymer appeared.For the polymer PTFEP made from HCCP purified by recrystallization or by recrystallization plus sublimation

its crystalline state

crystallinity

glass temperature

crystalline state conversion temperature and the melting temperature also changed.The FTIR spectra showed that there were phosphinyl (1621 cm-1) and imino (2971 cm-1) groups existed in PTFEP systhesized with HCCP purified only by recrystallization.It was considered that the hydroxy groups in Gem-2 and Dimmer-3 resulted in crosslinking of PDCP and unsoluble polymerization.The inpurity of Trimer-1 reduced the polymerization rate

brought in the phosphinyl and imino groups in the polymer and then influences its characteristic properties.It’s the reason that the yield of soluble polydichlorophosphazen produced from HCCP purified just by recrystallization was smaller than that from HCCP purified by recrystallization and sublimation.FTIR or 31P-NMR analysis were advised to validate the purified effect of HCCP and assure the polymerization.