The phosphaphenanthrene-containing 1-pentyne monomer (M-34) was synthesized through the successive esterification of 2-(6-oxide-6H-dibenz1

2oxaphos-phorin-6-yl)-dihydroxyphenylene (ODOPB) with 4-(4-pentynoxy)benzoyl and 4-butyloxybenzoyl

respectively.Due to the introduction of 9

10-dihydro-9-oxa-10-phosphaphenanthrene 10-oxide (DOPO) group

the catalytic ability of Rh-based catalysts ([Rh(nbd)Cl]2 and Rh(nbd)B(C6H5)4) is decreased and the yields of polymer are relatively low.The polymerization of model monomer (M-0) in the absence of phosphaphenanthrene side-group was

however

carried out in high yield at the same condition.The microstructure of the poly(1-pentyne) derivants was characterized by means of 1H-NMR.The experimental results indicate that the main-chains of poly(1-pentyne) derivants with high trans-content configuration are produced due to the strong - stacking and polar interactions between phosphaphenanthrene-containing pendent groups.Thus

the interaction between adjacent pendent groups is further strengthened.The molecular weights and distribution of P-34 and its model polymer P-0 were measured by GPC; Their thermal properties were evaluated by TGA and DSC.Comparing with P-0 in the absence of phosphaphenanthrene side-group

TGA analysis reveals the excellent thermal stability of P-34

losing 1% of weights during heating to 270℃ and retaining 50% of weights after pyrolyzis at 550℃.And the char yield of P-34 is over 50 wt% at 550℃.The DSC results indicate that Tg of P-34 is lower than that of P-0 because DOPO increases the volume of side-groups in P-34.