Synthesis of poly(naphthalenecarboxamide)s with low polydispersity by chain-growth condensation polymerization
Synthesis of poly(naphthalenecarboxamide)s with low polydispersity by chain-growth condensation polymerization
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链增长缩聚法合成低多分散性聚萘甲酰胺
DOI：
10.1002/pola.24737
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发表时间：
2011
期刊：
影响因子：
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通讯作者：
Tsutomu Yokozawa
中科院分区：
文献类型：
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作者：
Koichiro Mikami;Hiroaki Daikuhara;Jyunya Kasama;Akihiro Yokoyama;Tsutomu Yokozawa
研究了6-(N-取代氨基)-2-萘酸酯(1)的缩聚反应，作为链增长缩聚反应(CGCP)的延伸。以对甲基苯甲酸苯酯(2)为引发剂，1，1，1，3，3，3，3-六甲基二硅氮化锂(LiHMDS)为碱，在−温度10℃下聚合了6-(3，7-二甲基氨基)-2-萘甲酸甲酯(1b)。当投料比[1a]0/[2]0为10或20时，可制得相对分子质量一定、多分散性低的聚萘甲酰胺，并可得到少量的环状三聚体。但在[1a]0/[2]0=34的条件下，聚合过程中有聚合物析出。为了提高聚合物的溶解性，合成了含有三甘醇(TEG)单甲醚侧链而不是3，7-二甲基己基侧链的单体1。甲酯单体的聚合不能很好地进行，只得到低聚物和未反应的1c，而苯酯单体的聚合得到了定义明确的聚(萘甲酰胺)和少量的环状低聚物[1D]0/[2]0=10和29。在高投料比([1D]0/[2]0=32.6)下聚合时，伴随着自缩聚反应，得到的聚酰胺的相对分子质量低于计算值。这种不希望的自我缩合是由于酰胺阴离子的给电子共振效应使亲电酯部分失活不足所致。©2011 Wiley期刊公司J Polym Sci Part A：Polym Chem，2011
Condensation polymerization of 6‐(N‐substituted‐amino)‐2‐naphthoic acid esters (1) was investigated as an extension of chain‐growth condensation polymerization (CGCP). Methyl 6‐(3,7‐dimethyloctylamino)‐2‐naphthoate (1b) was polymerized at −10 °C in the presence of phenyl 4‐methylbenzoate (2) as an initiator and lithium 1,1,1,3,3,3‐hexamethyldisilazide (LiHMDS) as a base. When the feed ratio [1a]0/[2]0was 10 or 20, poly(naphthalenecarboxamide) with defined molecular weight and low polydispersity was obtained, together with a small amount of cyclic trimer. However, polymer was precipitated during polymerization under similar conditions in [1a]0/[2]0= 34. To increase the solubility of the polymer, monomers1cand1dwith a tri(ethylene glycol) (TEG) monomethyl ether side chain instead of the 3,7‐dimethyloctyl side chain were synthesized. Polymerization of the methyl ester monomer1cdid not proceed well, affording only oligomer and unreacted1c, whereas polymerization of the phenyl ester monomer1dafforded well‐defined poly(naphthalenecarboxamide) together with small amounts of cyclic oligomers in [1d]0/[2]0= 10 and 29. The polymerization at high feed ratio ([1d]0/[2]0= 32.6) was accompanied with self‐condensation to give polyamide with a lower molecular weight than the calculated value. Such undesirable self‐condensation would result from insufficient deactivation of the electrophilic ester moiety by the electron‐donating resonance effect of the amide anion. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011