RAFT polymerization of hydrophobic acrylamide derivatives
RAFT polymerization of hydrophobic acrylamide derivatives
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DOI：
10.1016/j.polymer.2004.11.092
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发表时间：
2005-01
期刊：
影响因子：
4.6
通讯作者：
B. Lambert;M. Charreyre;C. Chaix;C. Pichot
中科院分区：
文献类型：
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作者：
B. Lambert;M. Charreyre;C. Chaix;C. Pichot
分别以偶氮二异丁腈（AIBN）和二硫代苯甲酸叔丁酯（tBDB）为引发剂和可逆链转移剂（CTA），采用可逆加成-断裂链转移（RAFT）法合成了N-叔丁基丙烯酰胺（TBAm）、N-十八烷基丙烯酰胺（ODAm）和N-二苯基甲基丙烯酰胺（DPMAm）。在动力学和分子量（MW）控制方面对均聚进行了比较，并根据单体结构和几个实验参数（如[CTA]/[AIBN]比率和[MIBN]/[CTA]比率）的影响对结果进行了讨论。TBAm和ODAm单体在宽的转化率范围内（直到70%）表现出良好控制的聚合（对于数均分子量（Mn）直到30，000 gmol-1，多分散性指数（PDI）低于1.3），而DPMAm转化率保持低于20%，部分是由于空间位阻。采用体积排阻色谱/在线光散射检测器（SEC/LSD）、1H NMR、13 C NMR和基质辅助激光解吸电离飞行时间质谱（MALDI-TOF MS）四种独立的分析技术测定了几种聚TBAm样品的分子量，结果一致，接近理论值。此外，MALDI-TOF MS分析表明存在寄生链，导致RAFT中间自由基上的不可逆终止。
Several hydrophobic acrylamide derivatives: the N-tert-butylacrylamide (TBAm), the N-octadecylacrylamide (ODAm) and the N-diphenylmethylacrylamide (DPMAm) have been polymerized by reversible addition–fragmentation chain transfer (RAFT) process in the presence of azobis(isobutyronitrile) (AIBN) and tert-butyl dithiobenzoate (tBDB) as initiator and reversible chain transfer agent (CTA), respectively. Homopolymerizations were compared as regards to kinetics and molecular weight (MW) control, and the results were discussed according to the monomer structure and to the influence of several experimental parameters, such as the [CTA]/[AIBN] ratio and the [Monomer]/[CTA] ratio. TBAm and ODAm monomers exhibited a well controlled polymerization (polydispersity index (PDI) below 1.3 for number average molecular weight (Mn) until 30,000gmol−1) over a wide range of conversion (until 70%), whereas DPMAm conversion remained below 20% partly due to steric hindrance. The molecular weights of several poly(TBAm) samples determined by four independent analytical techniques, size exclusion chromatography/on-line light scattering detector (SEC/LSD),1H NMR,13C NMR and matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS), were in agreement, close to the theoretical ones. Moreover, the MALDI-TOF MS analyses suggested the presence of parasite chains resulting from irreversible termination onto RAFT intermediate radicals.