丙烯腈-丁二烯-异戊二烯三元共聚物的合成

Synthesis of arcylonitrile-butadiene-isoprene terpolymer

采用乳液聚合法于5℃合成了丙烯腈-丁二烯-异戊二烯三元共聚物(NBIR)。考察了单体配比、引发剂、乳化剂及相对分子质量调节剂用量对乳液聚合反应速率的影响,并通过傅里叶变换红外光谱、核磁共振氢谱与核磁共振碳谱对NBIR的组成及微观结构进行了表征。结果表明,随着乳化剂、引发剂用量的增加,聚合反应速率均增大;单体配比、相对分子质量调节剂对聚合反应速率无明显影响。固定总单体用量为100份、丙烯腈用量为33份,当丁二烯/异戊二烯(质量比)为50.0/17.0、33.5/33.5、17.0/50.0时,所得NBIR的结合丙烯腈质量分数均为33.3%左右,结合异戊二烯质量分数从19.7%增加到51.6%,其结合量均大于单体投料量;而结合丁二烯质量分数从47.2%下降到15.1%,其结合量均小于单体投料量。改变单体配比对NBIR聚丁二烯链段的1,2-结构含量和聚异戊二烯链段的3,4-结构含量均无明显影响。

Acrylonitrile - butadiene -isoprene terpolymer （NBIR） was synthesized by emulsion polymerization method at 5 ~C. The effects of monomer ratio, amount of initiator, emulsi- fier and regulator of relative molecular mass on the polymeriza- tion rate were investigated. The microstructure and composition of terpolymers were characterized by Fourier transform-infrared spectroscopy, ^1H-nuclear magnetic resonance and ^13C-nuclear magnetic resonance. The results showed that the polymerization rate increased with increasing the amount of emulsifier or initia- tor, but the monomer ratio and the amount of regulator had a lit- tle effect. When the total amount of monomer was 100 phr, acry- louitrile 33 phr, the mass ratios of butadiene to isoprene were 50. 0/17.0, 33.5/33. 5, 17.0/50. 0 respectively, the mass frac- tions of bound acrylonitrile in NBIR were about 33.3% , the mass fraction of bound isoprene of NBIR increased from 19. 7% to 51.6% , and both of them were more than their feeding level respectively; the mass fraction of bound butadiene in terpolymer decreased from 47. 2% to 15.1% ,less than its feeding level. The change of monomer ratio had no obvious effect on 1,2-unit content of polybutadiene and 3,4-unit content of polyisoprene.