摘要
研究了以甲醇为溶剂,偶氮二异丁腈(AIBN)为引发剂的醋酸乙烯酯聚合过程,采用多检测凝胶渗透分析仪和黏度测定的研究方法,比较醇解前后聚醋酸乙烯酯(PVAc)和聚乙烯醇(PVA)聚合度的变化和差异研究过程参数如溶剂和引发剂分批加入以及反应时间对PVAc支链化程度的影响。结果表明,在溶剂总质量分数为20%、引发剂总质量分数为0.000 63%情况下分批加入溶剂,在合适的反应时间内可控制PVAc支链化程度,缩小PVAc和PVA聚合度的差异并获得相对较高PVA聚合度。分批加入引发剂使PVAc支链化程度增加,醇解后PVA聚合度与PVAc相比有所下降。无论是一次性加入溶剂或分批加入溶剂,过长的反应时间都使PVAc的支链化程度增加,当反应到7 h后,醇解后的PVA聚合度相比PVAc下降可达31.6%。
With methanol as solvent and azobisisbutyronitrile（AIBN） as initiator,the vinyl acetate polymerization process was studied.Gel permeation chromatography（GPC） and viscosity testing method were used to determine polyvinyl acetate（PVAc） and polyvinyl alcohol（PVA） polymerization degree respectively,and by comparing the difference of polymerization degree between PVAc and PVA before and after alcoholysis,the influence of process parameters such as two-step adding way for solvent and initiator and reaction time on PVAc chain branching were studied.The results show that the chain branching can be controlled,and the gap between PVAc and PVA polymerization degree can be reduced by adding solvent in two steps under the condition of total mass fraction of solvent 20% and total mass fraction of initiator 0.000 63%,and can obtain higher polymerization degree of PVA within certain reaction time.The chain branching is increased by adding initiator in two steps and the gap between PVAc and PVA polymerization degree is enlarged.The chain branching is increased when the total reaction time is more than 7 h in both one-step or two-step solvent adding way,and the PVA polymerization degree is reduced to more than 31.6% compared with PVAc after alcoholysis.
出处
《化学工程》
CAS
CSCD
北大核心
2011年第11期66-69,78,共5页
Chemical Engineering(China)
