Synthesis of H-shaped carbon-dioxide-derived poly(propylene carbonate) for topology-based reduction of the glass transition temperature
Synthesis of H-shaped carbon-dioxide-derived poly(propylene carbonate) for topology-based reduction of the glass transition temperature
复制标题
DOI：
10.1039/c3py01319g
复制
发表时间：
2014-02
影响因子：
4.6
通讯作者：
Asato Yoshida;S. Honda;H. Goto;H. Sugimoto
中科院分区：
文献类型：
--
作者：
Asato Yoshida;S. Honda;H. Goto;H. Sugimoto
以四官能团聚碳酸亚丙酯(PPC)为原料合成了H型聚碳酸亚丙酯(PPC)。首先，在钴-卟啉络合物催化下，通过二氧化碳(CO_2)和环氧丙烷(PO)交替共聚反应合成了线型α，ω-二羟基聚碳酸酯(1)。然后用1，3，5-苯三甲酰基三氯化物进行链端官能化，得到了两个链端都带有二元酸的四官能团线型PPC(2)。以2为大分子链转移剂，通过CO2与PO进一步交替共聚，合成了H型PPC(3)。此外，DSC测定3的热性能表明，3的玻璃化转变温度(Tg=21℃)明显低于线型PPC(Tg=30℃)。然后将H型拓扑的这一属性(Tg降低)应用于一种新的自组装系统。因此，合成了链两端带有两个胸腺嘧啶基团的PPC(4)和主链中心带有2，6-二氨基吡啶基团的PPC(5)，并以1：2的比例简单地混合自组装。有趣的是，自组装产物(4和5)的Tg与3相当，表明通过互补的氢键作用形成了H型拓扑。
H-shaped poly(propylene carbonate) (PPC) was synthesized from a tetrafunctional linear PPC. First, a linear α,ω-dihydroxy PPC (1) was synthesized via the alternating copolymerization of carbon dioxide (CO2) and propylene oxide (PO) catalysed by a cobalt porphyrin complex and DMAP system. A subsequent chain-end functionalization with 1,3,5-benzenetricarbonyl trichloride afforded a tetrafunctional linear PPC (2) with dicarboxylic acid groups at both chain ends. H-shaped PPC (3) was synthesized from 2, as the macromolecular chain-transfer agent, by further alternating copolymerization of CO2 and PO. Moreover, the thermal properties of 3, as determined by DSC, indicated that the glass transition temperature (Tg) of 3 (Tg = 21 °C) is significantly lower than that of linear PPC (Tg = 30 °C). This attribute of the H-shaped topology (lowering of Tg) was then applied to a new self-assembly system. Thus, a PPC with two thymine groups at both chain ends (4) and a PPC with a 2,6-diaminopyridine group at the centre of the main chain (5) were synthesized and self-assembled simply by mixing at a 1:2 ratio. Interestingly, the Tg of the self-assembled product (from 4 and 5) was comparable to that of 3, indicating the formation of an H-shaped topology through complementary hydrogen-bonding interactions.