【作者】 周弟；

【导师】 朱秀林；

【作者基本信息】 苏州大学 ， 高分子化学与物理， 2004， 硕士

【摘要】 本文合成了2—腈基—2—丙基—1—二硫代萘甲酸酯（2-cyanoprop-2-yldithionaphthalate，α-CPDN）和2—腈基—2—丙基—2—二硫代萘甲酸酯（2-cyanoprop-2-yl-2-dithionaphthalate，β-CPDN），并将它们应用于苯乙烯类和甲基丙烯酸类单体的可逆加成断裂链转移聚合（reversible addition fragmentation chain transfer polymerization，RAFT polymerization），主要研究了以下体系：（1） 以α-CPDN为RAFT试剂的甲基丙烯酸环氧丙酯（glycidyl methacrylate，GMA）可逆加成断裂链转移聚合 （2） 以α-CPDN为RAFT试剂的甲基丙烯酸异丁酯（iso-butyl methacrylate，i-BMA）可逆加成断裂链转移聚合 （3） 以β-CPDN为RAFT试剂的苯乙烯（styrene，St）可逆加成断裂链转移聚合。 通过对体系1的研究发现：使用α-CPDN为RAFT试剂可以在本体或者溶液中制备结构有效控制的PGMA。单体浓度半对数（ln（[M]₀／[M]））和聚合时间的关系在本体和溶液聚合中都呈现为一级线性关系，通过凝胶色谱（gel permeation chromatographic，GPC）测定的聚合物分子量（M_n）与通过理论计算(M_n，th)得到的值十分接近。同时聚合物分子量与转化率也保持良好的线性关系，聚合物分子量分布（M_w／M_n）始终维持在较低值。GMA在本体中的RAFT聚合速率要明显大于在溶液中的聚合速率。通过成功的扩链反应证实绝大部分得到的聚合物末端都含有RAFT试剂结构片断。说明聚合是通过RAFT聚合机理进行的。聚合物的核磁图谱（¹H-NMR）测定表明在得到的聚合物中保持含有环氧基团。 通过对体系2的研究发现：偶氮二异丁腈（2，2’-azobisisobutyronitrile，AIBN）引发，α-CPDN作为RAFT试剂的i-BMARAFT本体聚合结果呈现活性可控特征：聚合物分子量可控、分子量分布窄、一级线性动力学。并由核磁共振（¹H-NMR）谱图和扩链反应验证了RAFT聚合机理。RAFT试剂的浓度和聚合诱以二硫代蔡甲酸醋为链转移试的可逆加成断裂链转移聚合中文摘要导期存在一定关系，即浓度大，诱导期长。当[A]BN」武cPDNI。之比小于卜1时聚合具有较好的可控性。 通过对体系3的研究发现:p一CPDN为RAF，试剂St的AIBN引发和热引发RAFT本体聚合，聚合动力学并未表现为一级线性关系，但这一结果并未明显影响所得聚合物分子量及其分布，所得聚合物分子量随单体转化率升高而线性增大，并且与理论值吻合，分子量分布维持在较低值（一般M研M。<l .3），证明仍为一“活性”/可控聚合。AIBN引发时「p一CPDN」武AIBN]。值为2至3时聚合的可控性较好，热引发时聚合温度采用100℃聚合过程的控制性最佳。 以上结果表明，一定条件下，以蔡基为Z基团的RAFT试剂进行单体RAFT聚合，聚合结果表现为“活性，’/可控自由基聚合特征:聚合物分子量可控，分子量分布窄，与理论计算值较为接近，核磁共振验证链端具有活性端基，并且可以进行扩链反应，符合RAFT聚合机理。说明二硫代条甲酸酷是可逆加成断裂链转移聚合的优良RAFT试剂，即链转移剂（chain transfel agent，CTA）。更多还原

【Abstract】 2-cyanoprop-2-yI-dithionaphthalate (a-CPDN) and 2-cyanoprop-2-yl-2-dithionaphthalate (P-CPDN) were synthesized and used as chain transfer agents for reversible addition-fragmentation chain transfer (RAFT) polymerizations. In addition, the following systems were also successfully carried out: (1) RAFT polymerizations of glycidyl methacrylate (GMA) using a-CPDN as RA FT agent in the presence of 2, 2’-azobisisobutyronitrile (AIBN). (2) RAFT bulk polymerization of iso-butyl methacrylate (i-BMA) using a-CPDN as RAFT agent in the presence of AIBN. (3) RAFT polymerizations of styrene (St) in bulk using P-CPDN as RAFT agent and with or without AIBN as initiator.It was found that RAFT polymerizations of GMA both in bulk and in solvent using a-CPDN as RAFT agent in the presence of AIBN could be proceeded in a controlled way, and the polymerization rate was first order with respect to monomer concentration, and molecular weight increased linearly with monomet conversion up to 96.7% at 60 C, 98.9% at 80 C in bulk and 64.3% at 60 C in benzene solution. The polymerization rate of GMA in bulk was obvious faster than that in benzene solution. The molecular weights (Mn) obtained from gel permeation chromatographic (GPC) closed to the theoretical values (Mn,th) and the Mw/Mn of polymer were relatively low up to high conversion in all cases. It was confirmed by chain extension reaction that AIBN initiated polymerizations of GMA using a-CPDN as RAFT agent were well controlled and were consistent with RAFT mechanism. The epoxy group remained intact in the polymers after the RAFT polymerization of GMA as indicated by the 1H-NMR spectrum.The RAFT bulk polymerization of i-BMA using a-CPDN as RAFT agent in the presence of AIBN showed that i-BMA could polymerize in a controlled way, i.e., the polymerization rate was first order with respect to monomer concentration, molecular weight increased linearly with monomer conversion, and Mw/Mn were relatively low(Mw/Mn < 1.2). The structure of the polymer was characterized by ’H-NMR. Chain extension experiment of resulted polymer was successfully carried out. The influences of [i-BMA]0/[ a-CPDN]0/[AIBN]o molar ratio and reaction temperature were investigated.The RAFT polymerizations of styrene in bulk using -CPDN as RAFT agent and with or without AIBN initiated showed that styrene could be polymerized in a controlled way. The polymer molecular weights increased linearly with monomer conversions and were closed to the theoretical values. At the same time the Mw/Mn of polymer remained in the relatively low values (lower than 1.3). The suitable malor ratio between [P-CPDN]0 and [AIBN]o was confirmed to be 2 to 3 when using AIBN initiating the polymerizations. The controllability of polymerization was best at 100C when thermal initiated thepolymerizations.In conclusion, the reversible addition fragmentation chain transfer polymerization using dithionaphthalate as RAFT agent showed controlled free radical characters: well controlled molecular weight, narrow polydispersity and linear relationship between molecular weight and monomer conversion. The dithionaphthalates are effective RAFT agents.更多还原