全氟甲基乙烯基醚和其它含氟单体乳液共聚合的竞聚率测定

分别通过气相色谱法测定了全氟甲基乙烯基醚 (PMVE)与偏氟乙烯 (VDF)以及PMVE与四氟乙烯(TFE)二元乳液共聚反应中的气相单体组成和共聚物组成 ,然后用非线性回归法 (RREVM )计算得TFE PMVE及VDF PMVE乳液共聚合反应的表观竞聚率分别为γTFE =3 89和γPMVE =0 0 5以及γVDF =1 0 6和γPMVE =0 11.结合已经测定的TFE VDF二元乳液共聚的表观竞聚率 ,计算了由VDF TFE PMVE三元乳液共聚合反应合成的共聚物组成 ,后者与由1 9F NMR实测的共聚物组成吻合

MONOMER REACTIVITY RATIO MEASUREMENT OF PERFLUOROMETHYL VINYL ETHER WITH SOME VINYL MONOMERS CONTAINING FLUORINE IN EMULSION COPOLYMERIZATION

The monomer reactivity ratios of emulsion copolymerization for some fluorine containing gaseous monomers,i.e.perfluoromethyl vinyl ether (PMVE) with TFE and PMVE with vinylidene fluoride (VDF) were measured and studied.At relatively low pressure,the copolymer composition equation could be kept in the same way as Mayo-Lewis equation after replacing the monomer concentration with gaseous mole fraction,and the monomer reactivity ratios with apparent monomer reactivity ratios.The initial and the end monomer mole fractions existing in the copolymerization systems were determined with gas chromatography (GC) and the copolymer compositions were calculated from the GC experimental data.The apparent monomer reactivity ratios estimated from reactivity ratio error-in variables model (RREVM) were γTFE=3.89,γPMVE=0.05 and γVDF=1.06,γPMVE=0.11 for these two copolymerization systems respectively.The composition of ternary copolymer composed of TFE/VDF/PMVE made from emulsion copolymerization was calculated according to the ternary copolymer composition equation with these apparent monomer reactivity ratios measured.It was found that the composition of such a ternary copolymer was in good agreement with that measured by means of 19F-NMR.