茚基钠/四氢呋喃体系引发丙烯腈聚合的研究

以茚基钠为引发剂,对丙烯腈在四氢呋喃中的聚合反应进行了研究,考察了引发剂用量、单体与溶剂配比、反应时间及反应温度对丙烯腈聚合的影响,并用粘度法对聚合产物的粘均分子量进行了表征.结果发现茚基钠/四氢呋喃体系对丙烯腈聚合反应具有一定的引发活性,且随着引发剂用量增加聚合反应转化率增大,聚合产物的粘均分子量下降;当单体用量一定时,溶剂的量越多,聚合反应的转化率越低,而聚合产物的粘均分子量却越大;反应时间在1 h之内,延长反应时间,转化率和粘均分子量都增大;反应温度对聚合反应转化率影响不大,但对聚合产物粘均分子量有明显影响.     

环戊二烯钠／甲苯体系引发丙烯腈聚合反应研究

文章以环戊二烯钠为引发剂,对丙烯腈在甲苯中的聚合反应进行了研究,考察了引发剂用量、单体浓度、反应时间及反应温度对丙烯腈聚合的影响,并且用粘度法对聚合产物的粘均分子量进行了表征。发现环戊二烯钠／甲苯体系对丙烯腈聚合反应具有较高的引发活性。随着引发剂用量增加,聚合反应转化率增大,聚合产物的分子量下降;延长反应时间,转化率和分子量都增大;发现在0℃和引发剂与单体摩尔比为1／200时,聚合反应的转化率及聚合物产物粘均分子量均较高。     

α,α’-邻苯二甲基桥联茚基钐胺化物（C9H6CH2C6H4CH2C9H6）SmNPh2催化甲基丙烯酸甲酯聚合

文章以α,α’-邻苯二甲基桥联茚基钐胺化物(C9H6CH2C6H4CH2C9H6)Sm NPh2为催化剂,对甲基丙烯酸甲酯聚合反应进行了研究,考察了催化剂用量、反应时间及反应温度对甲基丙烯酸甲酯聚合的影响,并且用粘度法对聚合产物的粘均分子量进行了表征。发现α,α’-邻苯二甲基桥联茚基钐胺化物(C9H6CH2C6H4CH2C9H6)Sm NPh2对甲基丙烯酸甲酯聚合反应具有较高的催化活性。温度降低,聚合反应转化率增加,聚合产物粘均分子量升高;催化剂用量增加,聚合反应转化率增大,聚合产物的粘均分子量下降;延长反应时间,转化率和分子量都增大。     

(C9H6CH2C6H4CH2C9H6)Sm催化MMA聚合的研究

文章以α,α’-邻苯二甲基桥联茚基钐胺化物(C9H6CH2C6H4CH2C9H6)Sm为催化剂,对甲基丙烯酸甲酯聚合反应进行了研究,考察了催化剂用量、反应时间及反应温度对甲基丙烯酸甲酯聚合的影响,并且用粘度法对聚合产物的粘均分子量进行了表征。发现α,α’-邻苯二甲基桥联茚基钐胺化物(C9H6CH2C6H4CH2C9H6)Sm对甲基丙烯酸甲酯聚合反应具有较高的催化活性。温度降低,聚合反应转化率增加,聚合产物粘均分子量升高;催化剂用量增加,聚合反应转化率增大,聚合产物的粘均分子量下降;延长反应时间,转化率和分子量都增大。     

α，α’-邻苯二甲基桥联环戊二烯基二价钐配合物催化丙烯腈聚合

文章以α,α＇-邻苯二甲基桥联环戊二烯基二价钐配合物为催化剂,对丙烯腈聚合反应进行了研究。考察了催化剂用量、反应时间及反应温度对丙烯腈聚合的影响,并且用粘度法对聚合产物的粘均分子量进行了表征。发现．α,α＇-邻苯二甲基桥联环戊二烯基二价钐配合物对丙烯腈聚合反应具有较高的催化活性。随着催化剂用量增加聚合反应转化率增大,聚合产物的粘均分子量下降;延长反应时间,转化率和分子量都增大。通过^13C-NMR对所得聚合物的立构规整性进行了表征,所得聚丙烯腈为无规立构聚合物。     

羟基偶氮酯引发剂合成双端羟基聚苯乙烯

以偶氮二异丁腈 ,乙二醇为原料合成双 ( 2 -羟乙基 ) 2 ,2′ -偶氮二异丁酸酯。将其作为引发剂 ,合成了遥爪型羟端基聚苯乙烯 ,其分子量为 3 .0× 10 3～ 6 .5× 10 3。讨论了单体浓度、引发剂浓度、聚合反应温度及反应时间对聚合转化率和产物分子量的影响。结果表明 ,聚合转化率和产物分子量随着单体浓度的增加而增加 ;而引发剂浓度增加 ,则聚合转化率明显提高 ,分子量却随之下降 ;温度升高 ,聚合转化率增加 ,产物分子量下降 ;而反应时间主要影响聚合转化率 ,对分子量影响不大。     

超声波辅助引发MAA/AN自由基共聚合研究

考察了超声波辅助甲基丙烯酸(MAA)和丙烯腈(AN)共聚合时,单体配比、引发剂浓度、超声波频率以及超声场温度对体系转化率的影响。结果表明,超声波能够辅助MAA/AN进行本体聚合,加快聚合反应速率。超声波辐照下,本体聚合的转化率随反应温度的升高而增大,引发剂用量为0.2%时,反应的转化率最大。外加能量的超声波利于加快聚合反应速率,在频率为24 kHz的超声波辐照下,对提高共聚反应转化率的作用最大。     

三亚甲基桥联双茚基钐二苯胺化物催化己内酯聚合

研究了三亚甲基桥联双茚基钐二苯胺化物( C9H6CH2CH2CH2C9H6) SmNPh2作为单组分催化剂催化ε-己内脂开环聚合反应,考察了催化剂用量、聚合反应时间和聚合反应温度对ε-己内酯聚合反应的影响.结果表明,配合物对己内酯聚合有较高的催化活性;温度升高,聚合反应的转化率增加,但产物粘均分子量降低.通过粘度法对聚...     

反相乳液聚合合成聚丙烯酰胺

以甲苯为介质,Span80/Span20为乳化剂,叔丁基过氧化氢/亚硫酸氢钠氧化还原体系为引发剂,采用反相乳液聚合制备了分子量高达9.4×106的聚丙烯酰胺乳液。研究了乳化剂种类及用量、引发剂种类及用量、油水比、单体浓度,反应温度对共聚物相对分子量、聚合转化率以及聚合反应速率的影响。其最佳聚合配方及工艺条件为:油水体积比为1.4,单体浓度30%,引发剂用量0.003%,乳化剂用量12%,聚合温度30℃。     

丙烯酰胺在聚乙二醇水溶液中可逆加成-断裂链转移聚合

结合双水相聚合和可逆加成-断裂链转移(RAFT)聚合,提出在聚乙二醇(PEG)水溶液中进行丙烯酰胺(AM)的RAFT双水相聚合,考察反应条件对聚合反应速率和产物分子量及分布的影响。结果表明:高引发剂浓度、单体浓度和聚合温度可以提高初始聚合速率和最终转化率,PEG和RAFT试剂浓度的增加会导致聚合速率减慢和最终转化率降低;峰值聚合速率随引发剂浓度、单体浓度和聚合温度的增加而增大,同时峰值聚合速率对应的时间提前;RAFT试剂浓度增加会推迟峰值聚合速率对应的时间,但可制得分子量分布较窄的产物;PEG浓度的增加会导致产物的分子量分布变宽。     

碳纤维原丝用聚丙烯腈的聚合反应条件

采用水相沉淀聚合法,以过硫酸铵为引发剂,制备了丙烯腈-丙烯酸甲酯-甲叉丁二酸三元共聚物,研究了聚合温度、单体浓度、引发剂浓度对聚丙烯腈共聚物相对分子质量和单体转化率的影响。结果表明:当反应温度为58℃,反应时间为2.5 h,单体质量分数为25%,引发剂质量分数为1.5%时,聚合物的黏均分子质量达3.8×105,单体转化率为79%。     

High‐molecular‐weight polyacrylonitrile by atom transfer radical polymerization

A single‐pot atom transfer radical polymerization was used for the first time to successfully synthesize polyacrylonitrile with a molecular weight higher than 80,000 and a narrow polydispersity as low as 1.18. This was achieved with CuBr/isophthalic acid as the catalyst, 2‐bromopropionitrile as the initiator, and N,N‐dimethylformamide as the solvent. The effects of the solvent on the polymerization of acrylonitrile were also investigated. The induction period was shorter in N,N‐dimethylformamide than in propylene carbonate and toluene, and the rate of the polymerization in N,N‐dimethylformamide was fastest. The molecular weight of polyacrylonitrile agreed reasonably well with the theoretical molecular weight in N,N‐dimethylformamide. When chlorine was used in either the initiator or the catalyst, the rate of polymerization showed a trend of decreasing, and the molecular weight deviated from the theoretical predication significantly. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3372–3376, 2006     

Reverse atom‐transfer radical polymerization of acrylonitrile catalyzed by FeCl3/iminodiacetic acid

FeCl₃ coordinated by iminodiacetic acid (IMA) was Changed used for the first time as the catalyst in azobisisobutyronitrile‐initiated reverse atom‐transfer radical polymerization (ATRP) of acrylonitrile (AN). An FeCl₃ to IMA ratio of 1:2 not only gave the best control of molecular weight and its distribution but also provided a rather rapid reaction rate. The effects of solvents on the polymerization of AN were also investigated. The rate of the polymerization in N,N‐dimethylformamide (DMF) was faster than in propylene carbonate or toluene. The molecular weight of polyacrylonitrile agreed reasonably well with the theoretical molecular weight in DMF. The rate of polymerization increased with increasing polymerization temperature and the apparent activation energy was calculated to be 54.8 kJ mol⁻¹. The reverse ATRP of AN did not show obvious living characteristics with CuCl₂ instead of FeCl₃. Copyright © 2005 Society of Chemical Industry     

低分子量AN/AA共聚物的制备

以过硫酸钾—亚硫酸氢钠的氧化还原体系为引发剂,采用水相沉淀聚合法制备了AN/AA共聚物,用不同链转移剂控制共聚物的分子量。研究了反应时间、引发剂含量、链转移剂含量对聚合物转化率以及聚合物分子量的影响。结果表明,选用N,N-二乙基羟胺为链转移剂,其用量为5%,反应时间为2 h时,共聚物分子量最小,控制在15000左右。     

聚合条件对P（AN-co—IA）分子质量分布影响的研究

采用凝胶色谱（GPC）法测定了丙烯腈与衣康酸共聚物P（AN—co—IA）的重均分子质量和数均分子质量,并通过已知聚丙烯腈的重均分子质量数据和数均分子质量数据对所测的分子质量进行校正,进一步计算得到共聚物的多分散系数。同时研究了引发剂用量、单体浓度、聚合温度、聚合时间对P（AN—co—IA）分子质量分布的影响。研究结果表明,P（AN-co-IA）分子质量分布随引发剂用量的增大、聚合单体浓度的增加而变宽,与聚合反应温度、聚合反应时间无明显的变化趋势。     

Compatibilization of acrylic polymer–silk fibroin blend fibers. I. Graft copolymerzation of acrylonitrile onto silk fibroin

To synthesize effective compatibilizers for the compatibilization of acrylic polymer–silk fibroin blend fibers, the homogeneous graft copolymerization of acrylonitrile onto silk fibroin, initiated by potassium persulfate–sodium bisulfite redox system in 60 wt % ZnCl₂ aqueous solution was investigated. The percentage graft, percentage efficiency, and molecular weight of the grafted polyacrylonitrile increase with the increase of the concentration of initiator, the concentration of acrylonitrile, and the temperature to optimum values, respectively, and then decrease. With the increase of reaction time, the percentage graft and percentage efficiency increase, whereas the molecular weight of the grafted polyacrylonitrile decreases. The influence of the reactionconditions on the molecular architecture of the graft copolymers is also discussed. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 69: 1089–1097, 1998     

Atom transfer radical polymerization of acrylonitrile

Iron(II) chloride coordinated by succinic acid was first used as the catalyst in 2‐chloropropionitrile‐initiated atom transfer radical polymerization (ATRP) of acrylonitrile. N,N‐dimethylformamide was used as a solvent to improve the solubility of the ligand. An iron(II) chloride to succinic acid ratio of 0.5 not only gives the best control of molecular weight and its distribution but also provides rather rapid reaction rate. Effects of solvent on polymerization of acrylonitrile were also investigated. The induction period is shorter in N,N‐dimethylformamide than in propylene carbonate and toluene and the rate of the polymerization in N,N‐dimethylformamide is fastest. The molecular weight of polyacrylonitrile agrees reasonably well with the theoretical molecular weight of N,N‐dimethylformamide. The rate of polymerization increases and the induction period becomes shorter with increasing polymerization temperature, and the apparent activation energy was calculated to be 56.5 kJ mol^?1. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 1050–1054, 2006     

Reverse atom transfer radical polymerization of acrylonitrile

FeCl₃ coordinated by succinic acid was used as the catalyst for the first time in azobisisobutyronitrile‐initiated reverse atom transfer radical polymerization of acrylonitrile (AN). N,N‐dimethylformamide (DMF) was used as a solvent to improve the solubility of the ligand. A FeCl₃ to succinic acid ratio of 0.5 not only gives the best control of molecular weight and its distribution but also provides rather rapid reaction rate. Effects of different solvents on polymerization of AN were also investigated. The rate of the polymerization in DMF is faster than that in propylene carbonate and toluene. The molecular weight of polyacrylonitrile agrees reasonably well with the theoretical molecular weight in DMF. The rate of polymerization increases with increasing the polymerization temperature, and the apparent activation energy was calculated to be 64.8 kJ mol^?1. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 32–36, 2006