羟甲基木质素磺酸钠/膨胀石墨/次磷酸铝阻燃聚氨酯泡沫的研究

本研究利用木质素磺酸钠对聚氨酯泡沫进行改性,提高其阻燃性能。首先,对木质素磺酸钠进行羟甲基化反应,得到羟甲基木质素磺酸钠（HSL）,再将HSL部分替代聚醚多元醇,与聚合4,4'-二苯基甲烷二异氰酸酯（MDI）混合,制备羟甲基木质素磺酸钠改性聚氨酯泡沫,再添加膨胀石墨（EG）和次磷酸铝（AHP）进一步提高聚氨酯泡沫的阻燃性。制备出样品后分别进行极限氧指数（LOI）、热重分析（TGA）和扫描电子显微镜（SEM）测试。通过极限氧指数测试分析聚氨酯泡沫样品阻燃性能表明：当羟甲基木质素磺酸钠替代量为60%（以HSL质量占HSL和聚醚多元醇总质量的百分比计）时,所得聚氨酯泡沫材料的LOI指数达到21.6%,最大热降解速率降低了1.53 %/min,残炭量提高了15.04个百分点,泡沫试样中泡沫孔隙数量和面积减少。继续添加混合阻燃剂（膨胀石墨和次磷酸铝质量比为3:1）时,所得聚氨酯泡沫材料的LOI指数能达到26.3%,最大热降解速率降低了1.52 %/min,残炭量提高了23.52个百分点,泡沫试样的泡沫孔隙数量和面积进一步减少。因此,本实验制备出一种具有优异阻燃性能的聚氨酯泡沫,其在建筑领域、交通领域、食品保温领域有广阔的应用前景。     

衣康酸/2-丙烯酰胺-2-甲基丙磺酸/次磷酸钠共聚物的合成与阻垢性能

以衣康酸为单体,2-丙烯酰胺-2-甲基丙磺酸及次磷酸钠为原料,水为溶剂,异丙醇为链转移剂,过硫酸铵和偶氮化合物为引发剂,合成了新型的共聚物阻垢剂.研究确定了共聚物合成的最佳条件:引发剂用量为12％,链转移剂用量为10％,聚合反应温度为90℃,聚合反应时间为4h时.将合成共聚物与市售的阻垢剂进行阻垢性能的对比试验,结果表明合成共聚物的阻垢效果优于市售的阻垢剂,阻垢率高达90％以上.     

Carbon-supported Pd nanocatalyst modified by non-metal phosphorus for the oxygen reduction reaction

A carbon-supported palladium catalyst modified by non-metal phosphorus (PdP/C) has been developed as an oxygen reduction catalyst for direct methanol fuel cells. The PdP/C catalyst was prepared by the sodium hypophosphite reduction method. The as-prepared Pd nanoparticles have a narrow size distribution with an average diameter of 2 nm. Energy dispersive X-ray analysis (EDX), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD) results indicate that P enters into the crystal lattice of Pd and forms an alloy. The PdP/C catalyst has an oxygen reduction reaction (ORR) activity comparable to the commercial Pt/C catalyst and a higher activity than the Pd/C catalyst synthesized by the conventional NaBH₄ reduction method. Its high catalytic activity can be attributed to its small size, lower relative crystallinity, and the formation of PdP alloy.     

Effect of hypophosphite on electrodeposition of graphite@copper powders

The effect of sodium hypophosphite (NaH₂PO₂) on the electrodeposition of copper coated graphite powders (graphite@Cu) was investigated in this paper. The cathodic polarization curves were determined by potentiodynamic scanning method in the electrolyte containing various concentrations of NaH₂PO₂. Hypophosphite could reduce the overpotential of copper deposited on the graphite particles surface and accelerate electroless copper nuclei generated by the reduction reaction. The applied potential promoted the formation of copper nuclei on the surface of graphite powders. Uniform graphite@Cu powders were fabricated by optimizing the NaH₂PO₂ concentration in the range of 10–15 g dm⁻³. The residue of NaH₂PO₂ could be depleted to less than 0.25 g dm⁻³ by decomposition on the anode and chemical reduction in the bath during electrodeposition. The effect of hypophosphite on the electrodeposition of graphite@Cu is also discussed.     

共聚物MA-TA-AA-AM-SH的反相乳液合成及其阻垢分散性能研究

以环己烷为分散介质,油∶水为1∶1.5,Span80-Tween80为乳化剂,过氧化氢为引发剂,以马来酸酐(MA)、牛磺酸(TA)、丙烯酸(AA)、丙烯酰胺(AM)和次亚磷酸钠(SH)为单体反相乳液合成共聚物(MA-TA-AA-AM-SH)阻垢剂。通过静态阻垢实验表明:综合经济因素,阻垢剂投加量达到10 mg/L对CaCO3、Ca3(PO4)2和CaSO4的阻垢效果较佳,分别为82.3%,95.9%和78%;在高温条件下对碳酸钙和磷酸钙分别有56.6%,68.9%较佳阻垢率;高pH、高硬度恶劣条件下对碳酸钙仍分别有40.8%,57.9%的较好阻垢率;投加量达到8 mg/L时对氧化铁的分散性能最佳,透光率为56.7%。并利用IR对其结构进行表征。该阻垢剂是一种较好耐苛刻条件的多功能阻垢分散性剂。     

次磷酸钠在CA整理体系中的催化作用

研究分析次磷酸钠在柠檬酸整理体系中的催化作用。柠檬酸在焙烘过程中形成酯键的数量与织物的防皱性能之间有密切的关系，柠檬酸脱水生成不饱和产物与织物的泛黄之间也有显著的相关性。次磷酸钠既能催化纤维的酯化交联，提高织物的纺皱性能，又能促使不饱和产物的生成，在柠檬酸防皱整理体系中具有双重的作用。     

次磷酸钙生产工艺与展望

对次磷酸钙的应用拓展、生产工艺和发展趋势进行了研究。着重介绍了5种制取次磷酸钙的方法,包括：黄磷与石灰乳反应法、中和法、氯化钙与次磷酸钠转化法、硝酸钙与次磷酸钠反应法、液相催化法。并对每种工艺的原料、原理、优缺点及推广应用情况进行了详细的剖析,以期对促进次磷酸钙产业的发展提供参考。     

以次磷酸钠为还原剂的化学镀铜

研究了以次磷酸钠为还原剂、硫酸镍为再活化剂的化学镀铜工艺和镀层结构,指出工艺的基本特性。结果表明,在含有次磷酸钠和硫酸镍的镀液中,化学镀铜过程可以持续进行并呈现自催化特性;只有在合适的镀液pH范围内才可获得铜镀层;铜镀层为面心立方结构,没有明显的晶面择优取向现象,镀层结构的晶面间距d和晶胞参数a与标准Cu粉末的相比均较大,说明铜镀层仍存在应力和缺陷。     

Improvement the Conductivity and Flame Retardant Properties of Carboxylated Single-Walled Carbon Nanotube/Cotton Fabrics Using Citric Acid and Sodium Hypophosphite

Improvement of existing properties and creation of new material properties are the most important reasons for increasing industrial uses of cotton fabrics. In this research work, carboxylated single-walled carbon nanotubes (CSWCNT) were stabilized by different methods on a cotton fabric surface, using citric acid (CA) as a cross-linking agent and sodium hypophosphite (SHP) as a catalyst. A scanning electron microscope, electrical resistivity equipment, reflective spectrophotometer has been applied to investigate the influence of carboxylated single-walled carbon nanotube on the performance of the cotton fabrics. Also the flammability of cotton fabric modified by CSWCNT, CA, and SHP was evaluated by measuring the percentage of char yield. The test results were compared and discussed.     

Preparation and characterization of aluminum hypophosphite/reduced graphene oxide hybrid material as a flame retardant additive for PBT

Aluminum hypophosphite/reduced graphene oxide (AHP/RGO) hybrid flame retardant with high thermal stability was successfully prepared by a one‐step method consisting of the simultaneous reduction of graphene oxide and the deposition of AHP on graphene. The as‐prepared sample was characterized by X‐ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, Raman spectroscopy, and X‐ray photoelectron spectroscopy. The obtained sample was used as a flame retardant for polybutylene terephthalate, and the flame retardancy of the composites was investigated by a limiting oxygen index test, a UL‐94 test, and cone calorimetry. The results showed that AHP/RGO exhibited improved flame retardancy when compared with bare AHP. The addition of AHP/RGO to polybutylene terephthalate led to a significant reduction in the heat release rate and resulted in excellent anti‐dripping properties for the composites. Copyright © 2016 John Wiley & Sons, Ltd.