PAA/PAM共聚新型功能高分子材料对土壤结构性状的影响

研究了用60Coγ辐照方法制备的PAA/PAM共聚新型功能高分子材料(新材料)对土壤结构性状的影响。试验结果表明,新材料显著改善供试土壤的物理性状,尤其对盐碱土作用显著,是一种很有前途的土壤结构改良剂。     

Recapitulation of In Situ Endochondral Ossification Using an Injectable Hypoxia-Mimetic Hydrogel

Due to the limited ability for perfusion, traditional intramembranous ossification (IMO) often fails to recapitulate the natural regeneration process of most long bones and craniofacial bones. Alternatively, endochondral ossification (ECO) strategy has emerged and has been evidenced to circumvent the drawbacks in the routine application of IMO. Here, an injectable, poly(glycerol sebacate)-co-poly (ethylene glycol)/polyacrylic acid (PEGS/PAA) hydrogels are successfully developed to induce a hypoxia-mimicking environment and subsequently recapitulate ECO via in situ iron chelation. With the incorporation of PAA, these hydrogels present remarkable viscoelasticity and high efficacy of iron ion-chelating after injection, giving rise to the activation of HIF-1α signaling pathway and suppression of inflammatory responses, and thereby improving chondrogenic differentiation in the early stage and facilitating vascularization in the later stage, which consequently trigger typical ECO. More importantly, through sustained and stable expression of HIF-1α regulated by PEGS/PAA hydrogels throughout the regeneration, a harmonious chondrogenic/osteogenic balance can be struck and thereby accelerating the progress of ECO compared to the PEGS. The findings provide an efficient strategy to achieve in situ ECO via biomaterial-based iron ion-chelating and ensuing hypoxia-mimicking, representing a novel and promising concept for future application in bone regeneration.     

TiO2纳米管对十二烷基苯磺酸钠的光催化降解

以多孔阳极氧化铝为模板制备 Ti O2 纳米管。研究锐钛矿型 Ti O2 纳米管对降解低浓度的十二烷基苯磺酸钠的光催化作用。实验表明 ,与 Ti O2 膜相比 ,Ti O2 纳米管对十二烷基苯磺酸钠的降解具有更好的光催化效果     

吸附途径对α-Al2O3-H2O-PAA悬浮液流变性影响

采用两阶段吸附法(两个pH不同的阶段)研究了不同吸附途径制备的浆料的稳定性．结果表明，pH值为6．5的浆料，经过pH值高于粉体等电点阶段的吸附，浆料的稳定性显著提高，第一吸附阶段的pH值对浆料的稳定性有很大的影响，其pH从8．0提高到10．0，浆料的粘度降低，稳定性提高，但当pH值增加到11．0时，浆料的稳定性则下降，增加第一阶段的吸附时间，有利于改善PAA在粒子表面的分布状态和提高浆料的稳定性。     

聚丙烯酸铵对纳米SiO2悬浮液性能的影响

研究了聚丙烯酸铵(NH4PAA)对纳米SiO2粉体表面电动特性及其悬浮液稳定性的影响。结果表明。NH4PAA在SiO2表面吸附．提高了颗粒间的排斥势能，改善了悬浮液的稳定性。在pH为8、NH4PAA的加入量为0．9％时，纳米SiO2颗粒表面吸附达到饱和。     

碳布增强聚芳基乙炔新防热材料

本文了新型高碳聚芳基乙炔树脂的成碳率及其碳布增强防热材料成型工艺,对复合材料的性能进行了表征。     

聚丙烯酸钠/尿素多孔材料的制备与吸湿性能

首次以丙烯酸(AA)和尿素(U)为原料,N,N′-亚甲基双丙烯酰胺(MBAA)为交联剂,亚硫酸氢钠-过硫酸铵为引发剂,采用水溶液聚合法制备聚丙烯酸钠/尿素多孔材料(PAA/U)。研究了中和度、尿素含量等聚合条件对其吸湿性能的影响。由正交实验确定了最佳反应条件,其吸湿率最高达0.975 g/g。应用SigmaStat3.5进行多元线性回归分析得到各因素与吸湿率的数学关联式。红外光谱(FT-IR)和热重(TGA)分析表明,添加尿素后,形成了新的吸湿基团异氰酸根。扫描电镜(SEM)观察到PAA/U表面出现孔洞,增加了有效吸湿比表面积,其吸湿性能明显提高。     

Suspension and solution thermal spray coatings

The emerging methods of coating deposition by suspension and solution thermal spraying are described. The liquid suspensions of fine powders and liquid precursors are injected into flames and/or jets generated in the torches. The formulation and stability of suspensions as well as the methods of fine powders synthesis are briefly described. Typical solutions, being often the liquid organo-metallics are also briefly described. An important problem of injection of liquids into jets and flames is then presented. Two principal modes of injection, used at present, are outlined, i.e.: (i) atomization; and, (ii) injection of a continuous jet. Subsequently, the phenomena occurring in flames and plasma jets are discussed and the major differences to these occurring during conventional spraying are stressed up. The build up of coatings starting from the impact of fine particles on the substrate is described and typical microstructures of suspension and solution sprayed coatings are shown. Some properties of the sprayed coatings, including mechanical, electrical, chemical, and thermophysical ones are collected and presented. Finally, the emerging applications of coatings are shown and the possible future applications are discussed.     

强碱性固体凝胶电解质电性能研究

采用自由基溶液聚合方法,将KOH嵌入由聚丙烯酸/聚丙烯酰胺(PAA/PAAM)构成的固体凝胶中,制成具有较高机械强度的强碱性固体凝胶电解质。研究发现,固体凝胶电解质电导率接近KOH水溶液电导率,在KOH质量分数为20%时其电导率达最大值0.28 S/cm;电导率随温度的变化遵循Arrhenius原理。     

磁性壳聚糖-聚丙烯酸载药微球的释放性能研究

对合成的壳聚糖-聚丙烯酸及磁性壳聚糖-聚丙烯酸微球用扫描电镜进行形貌观察,并测定了磁性壳聚糖-聚丙烯酸微球的热稳定性.以牛血清白蛋白(BSA)为模拟蛋白药物,研究了载有BSA的磁性壳聚糖-聚丙烯酸微球的释放性能.结果表明,壳聚糖-聚丙烯酸共聚物外形呈片层状;而磁性壳聚糖-聚丙烯酸微球为致密微球,粒径约在100～400nm之间,具有较好的分散性,磁性壳聚糖-聚丙烯酸微球在温度区间(0～135℃)内具有良好的热稳定性.载有BSA的磁性微球在模拟肠液中刚开始时有一个突释过程,之后缓慢释放,在6h左右达到了平衡,最终释放率可达到80.5%;而在模拟胃液中几乎没有释放,平衡释放率只有5.8%.