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首页> 外文期刊>Macromolecular chemistry and physics >Preparation of scratch- and abrasion-resistant polymeric nanocomposites by monomer grafting onto nanoparticles, 4 - Application of MALDI-TOF mass spectrometry to the characterization of surface modified nanoparticles
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Preparation of scratch- and abrasion-resistant polymeric nanocomposites by monomer grafting onto nanoparticles, 4 - Application of MALDI-TOF mass spectrometry to the characterization of surface modified nanoparticles

机译：通过将单体接枝到纳米颗粒上来制备耐刮擦和耐磨的聚合物纳米复合材料，4-MALDI-TOF质谱在表征表面改性纳米颗粒方面的应用

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摘要

To obtain transparent, scratch- and abrasion-resistant coating materials a high content of nanosized silica and alumina filler was embedded in radiation-curable acrylate formulations by acid catalyzed silylation using trialkoxysilanes. Si-29 magic angle spinning (MAS) NMR spectroscopy and matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF MS) were used to elucidate the structure of the surface-grafted methacryloxypropyl-, vinyl-, and n-propyltrimethoxysilane. Si-29 MAS NMR measurements revealed a predominance of T-2 and T-3 structures of silicon atoms, i.e., silane oligomers have been formed by an extensive loss of water. For methacryloxypropyltrimethoxysilane, the proportion of the highly condensed T3 silicon atoms was estimated to be 75%. In accordance with these NMR findings, MALDI-TOF MS showed highly condensed oligomeric siloxanes of more than 20 monomeric silane units. The degree of silane condensation is higher on alumina than on silica, irrespective to the addition of maleic acid as catalyst. Moreover, completely condensed silsesquioxanes, e.g., octamers, decamers, and dodecamers, were detected. Based on the observed MS pattern, a ladder-like arrangement of two linked siloxane chains forming connected eight-membered rings is proposed, which is similar for all of the condensed organosilanes under study. The grafted polysiloxanes lead to an organophilation of inorganic nanofillers and improve their dispersibility in acrylate suspensions. [References: 20]
机译：为了获得透明，耐刮擦和耐磨的涂料，使用三烷氧基硅烷通过酸催化的甲硅烷基化将高含量的纳米级二氧化硅和氧化铝填料嵌入到可辐射固化的丙烯酸酯配方中。使用Si-29幻角旋转（MAS）NMR光谱和基质辅助激光解吸/电离飞行时间质谱（MALDI-TOF MS）来阐明表面接枝的甲基丙烯酰氧基丙基，乙烯基和甲基丙烯酸的结构。正丙基三甲氧基硅烷。 Si-29 MAS NMR测量表明，硅原子的T-2和T-3结构占主导地位，即由于水分大量流失而形成了硅烷低聚物。对于甲基丙烯酰氧基丙基三甲氧基硅烷，高缩合的T 3硅原子的比例估计为75％。根据这些NMR结果，MALDI-TOF MS显示了具有20多个单体硅烷单元的高度缩合的低聚硅氧烷。不论添加马来酸作为催化剂，在氧化铝上的硅烷缩合度都比在二氧化硅上的高。此外，检测到完全缩合的倍半硅氧烷，例如八聚物，十聚物和十二聚物。基于观察到的MS模式，提出了形成连接的八元环的两条连接的硅氧烷链的梯状排列，这对于所有正在研究的缩合有机硅烷都是相似的。接枝的聚硅氧烷可导致无机纳米填料的亲有机化并改善其在丙烯酸酯悬浮液中的分散性。 [参考：20]

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