Methacrylate/acrylate ABA triblock copolymers by atom transfer radical polymerization; their properties and application as a mediator for organically dispersible gold nanoparticles
Methacrylate/acrylate ABA triblock copolymers by atom transfer radical polymerization; their properties and application as a mediator for organically dispersible gold nanoparticles
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DOI：
10.1016/j.polymer.2009.04.071
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发表时间：
2009-07
期刊：
影响因子：
4.6
通讯作者：
H. Datta;A. Bhowmick;N. Singha
中科院分区：
文献类型：
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作者：
H. Datta;A. Bhowmick;N. Singha
本文报道了用原子转移自由基聚合(ATRP)法制备了一系列规整的聚(甲基丙烯酸甲酯)-b-聚丙烯酸己酯-b-聚甲基丙烯酸甲酯(PMMA-b-PHA-b-PMMA)三嵌段共聚物。对其形态、动态力学性能和拉伸性能进行了深入的研究。所有上述三嵌段共聚物均观察到相分离现象，其中PMMA外层嵌段的相对分子质量为10,000-80,000，而PHA内层嵌段的相对分子质量为20,000-40,000。动态力学测量基本上揭示了两个玻璃化转变和中间平坦的橡胶平台。拉伸研究表明，随着PMMA含量的增加，拉伸强度增加，断裂伸长率下降，这是大多数热塑性弹性体(TPE)的情况。最终，所制备的嵌段共聚物(PMMA含量为50-80%)为制备金纳米粒子聚集体提供了一种有效的稳定剂，其形状和大小可以通过调节嵌段共聚物的组成来调节。通过UV-Vis分析、透射电子显微镜、能量色散X射线光谱、动态光散射和傅里叶变换红外光谱证实了纳米粒子聚集体的形成及其与基聚合物可能的非共价相互作用。
This investigation reports the preparation of a series of well-defined Poly(methyl methacrylate)-b-poly(hexyl acrylate)-b-poly (methyl methacrylate) (PMMA-b-PHA-b-PMMA) triblock copolymers by Atom Transfer Radical Polymerization (ATRP). Their morphology, dynamic mechanical and tensile properties are thoroughly investigated. Phase separation is observed for all the above-mentioned triblock copolymers, which contain PMMA outer blocks in the molecular weight (Mn) range of 10,000–80,000 and PHA inner blocks with Mnin the range 20,000–40,000. The dynamic mechanical measurements essentially reveal two glass transitions and an intermediate flat rubbery plateau in between. Tensile studies indicate that as the PMMA content increases, there is an increase in tensile strength and decrease in elongation at break, which is the case for most of the thermoplastic elastomers (TPE). Eventually, the as prepared block copolymers (with PMMA content 50–80%) offer to be an effective stabilizer for preparing gold nanoparticle aggregates, the shape and size of which can be modulated by tuning the block copolymer composition. The formation of nanoparticle aggregates and their possible non-covalent interaction with the base polymer has been substantiated by UV–vis analysis, transmission electron microscopy, energy-dispersive X-ray spectroscopy, dynamic light scattering and Fourier transform infrared spectroscopy.