In Situ Synthesis of Ferrites in Cellulosics
In Situ Synthesis of Ferrites in Cellulosics
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DOI：
10.1021/cm00038a025
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发表时间：
1994-02
影响因子：
8.6
通讯作者：
L. Raymond;J. Revol;D. Ryan;R. Marchessault
中科院分区：
文献类型：
--
作者：
L. Raymond;J. Revol;D. Ryan;R. Marchessault
采用原位合成铁氧体的方法制备了超顺磁性纤维素纤维。在以下四种基材上进行五个循环的反应：羧甲基纤维素钠叠浆（Na-CMC）、藻酸钙纤维、连续长丝人造丝轮胎帘线和磺化热机械木浆（TMP）。振动样品磁力测定法表明，磺化TMP表现出最高的饱和磁化强度（在五个反应循环后约25 J/T/kg样品）。横截面的TEM显微照片表明，最大浓度的铁氧体（尺寸为~ 100）排列在纤维的外表面。显微照片还显示尺寸小于20 A的铁氧体，分散在纤维细胞壁上。电子衍射分析表明，氧化物的主要成分为-γ-Fe_（20）_3（针状）和Fe_（30）_4（片状）。原位反应后，磺化TMP的室温穆斯堡尔谱表明，第一次和第二次循环样品中存在小的超顺磁性铁氧体。由于纸浆纤维表面和内腔内形成了更大的铁氧体颗粒，在第三个循环样品中观察到了铁磁成分，并且在第四个和第五个循环样品中占主导地位。
Superparamagnetic cellulosic fibers were prepared by synthesizing ferrites by an in situ method. Five cycles of the reaction were performed on the following four substrates: sodium carboxymethylcellulose lap pulp (Na-CMC), calcium alginate fibers, continuous filament rayon tire cord, and sulfonated thermomechanical wood pulp (TMP). Vibrating sample magnetometry showed that the sulfonated TMP exhibited the highest saturation magnetization (~ 25 J/T/kg of sample after five cycles of reaction). TEM micrographs of sections of sulfonated TMP fibers showed that the largest concentrationof ferrites (^—100 A in size) were arranged at the external fiber surfaces. The micrographs also showed ferrites of less than 20 A in size, dispersed across the fiber cell wall. Electron diffraction indicated that the major components of the oxides were-y-Fe203 (needles) and Fe304 (disks). Room-temperature Mossbauer spectra of the sulfonated TMP, afterthe in situ reaction, indicated the presence of small superparamagnetic ferritesfor the first and second cycle samples. A ferrimagnetic component was observed for the third cycle sample and predominatedin the fourth and fifth cycle samples as a result of larger ferrite grains being formed both on the surface and inside the lumen of the pulp fibers.