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首页> 外文期刊>Journal of Polymer Science, Part A. Polymer Chemistry >Synthesis, Characterization and Cleavage of Linear Polymers Attached to Silica Nanoparticles Formed Using Thiol-Acrylate Conjugate Addition Reactions
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Synthesis, Characterization and Cleavage of Linear Polymers Attached to Silica Nanoparticles Formed Using Thiol-Acrylate Conjugate Addition Reactions

机译:硫醇-丙烯酸酯共轭加成反应形成的附着于二氧化硅纳米颗粒上的线型聚合物的合成,表征和裂解

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摘要

This study investigates the formation of linear polymer grafts using thiol-acrylate conjugate addition reactions on nanoparticle surfaces. Silica nanoparticles were first modified with an amine functionality, followed by the attachment of a photocleavable acrylate. Dithiol-diacrylate films were attached to the particles through the surface acrylate groups at various stoichiometric ratios of thiol to acrylate by conducting amine-catalyzed conjugate addition polymerizations. The particles were then exposed to LTV light to release the grafted polymer by photocleavage. The cleaved, grafted polymers were analyzed using infrared spectroscopy and gel permeation chromatography and compared to polymers formed in the bulk, which remained unattached to the particles. The measured number and weight average molecular weights were similar for both polymer types within experimental error and increased from 2000 to 5000 g/mol and 4000 to 10,000 g/mol, respectively, as the ratio of limiting to excess functionality increased from 0.8 to 1. Both number and weight average molecular weights followed the trend of step growth polymers with the highest molecular weight achieved for stoichiometric monomeric mixtures. Surface coverage of the nanoparticles was estimated using the molecular weight and thermogravimetric data and was found to be uniform (similar to 0.15 chains/mn(2)) irrespective of the stoichiometry of the reacting monomers. (c) 2008 Wiley Periodicals, Inc.
机译:这项研究调查了在纳米粒子表面上使用硫醇-丙烯酸酯共轭加成反应形成线性聚合物接枝的方法。首先用胺官能团修饰二氧化硅纳米颗粒,然后附着可光裂解的丙烯酸酯。通过进行胺催化的共轭加成聚合反应,二硫醇二丙烯酸酯薄膜通过表面丙烯酸酯基团以硫醇对丙烯酸酯的各种化学计量比附着在颗粒上。然后将颗粒暴露于LTV光下以通过光裂解释放接枝的聚合物。使用红外光谱和凝胶渗透色谱法分析裂解的接枝聚合物,并将其与本体中形成的聚合物进行比较,该本体未附着在颗粒上。在实验误差范围内,两种聚合物的实测数均分子量和重均分子量均相似,并且由于极限官能团与过量官能团的比例从0.8增至1,因此分别从2000增至5000 g / mol和4000增至10,000 g / mol。数均分子量和重均分子量均遵循逐步增长的趋势,对于化学计量的单体混合物,该聚合物具有最高的分子量。纳米粒子的表面覆盖率是使用分子量和热重数据估算的,并且发现是均匀的(类似于0.15链/ mn(2)),而与反应单体的化学计量无关。 (c)2008年Wiley Periodicals,Inc.

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