苯甲醛及其衍生物对铈离子存在下丙烯酰胺聚合的影响

<正> 虽然Santappa等早已报道Ce~(4+)(高氯酸铈)/甲醛体系能引发丙烯腈(AN)、甲基丙烯酸甲酯(MMA)的聚合,但对醛的活性以及参与引发单体聚合的自由基都未有详细报道,近来孙燕慧等发现脂肪醛能显著促进Ce~(4+)(硝酸铈铵CAN)引发丙烯酰胺(AAM)的聚合,而且醛的活性远大于相应的醇。至于芳香醛对于Ce~(4+)引发烯类单体的聚合的影响也未见详细报道。本文扼要报道苯甲醛(BA)及其衍生物对-硝基苯甲醛(PNBA)、间-硝基苯甲醛(MNBA)、间-溴苯甲醛(MBBA)、对-氯苯甲醛(PCBA)对Ce~(4+)(CAN)存在下丙烯酰胺聚合的影响,测定了其聚合速率,以UV吸收光谱、ESR波谱测定

THE EFFECTS OF BENZALDEHYDES ON THE POLYMERIZATION OF ACRYLAMIDE IN THE PRESENCE OF CERIC ION

The effects of benzaldehyde (BA), p-nitrobenzaldehyde(PNBA),m-nitrobenzaldehyde (MNBA), m-bromobenzaldehyde(MBBA),and p-chlorobenzaldehyde(PCBA) on the polymerization of acrylamide (AAM) in the presence of eerie ion (Ce4+) have been studied: Vinyl monomers such as AAM, acrylonitrile(AN) could polymerize using cerie ion (ceric ammonium nitrate ) as an initiator. In the presence of cerie ion the rate of polymerization Rp of AAM could be enhanced by adding an aliphatic aldehyde to the polymerization system. Adding benzaldehyde , however, could not increase the Rp of AAM initiated by cerie ion. The Rp of AAM initiated by eerie ion/BA system is always lower than that of cerie ion alone. The values of overall activation energy of polymerization Ea were determined and the Ea values for ceric ion/ MBBA and ceric ion/BA were evaluated to be 41. 6 KJ/mol and 36. 8KJ/mol respectively. The reaction of BA and eerie ion was investigated by UV spectra and the free radical intermediate was detected by ESR spectrum. The end group of polymer formed was detected by IR spectrum analysis method and it revealed the presence of aliphatic aldehyde moiety in the polymer obtained with ceric ion/aldehyde system.