助剂对聚烯烃发泡母粒性能的影响

将不同含量助剂添加到聚烯烃发泡母粒中,通过对样品进行力学性能测试,表明当分散剂聚乙烯蜡用量为5份、成核剂TiO_2用量为7.5份、填充剂改性碳酸钙用量为7.5份时,聚烯烃发泡材料的力学性能最好,材料内部泡孔大小均一,且分布均匀。     

氮化硅针晶的分离研

结合氮化硅浆料的悬浮性能,提出了液相分离针晶的新方法。测出了粉体的zeta电位。探讨了pH值和分散剂的含量对浆料的悬浮性能的影响,并对浆料做了沉降分析。结果表明,当DarvanC的含量为0.15wt%,pH值为10时,浆料的性能满足分离要求。SEM显示,分离后,针晶中已经基本没有球状颗粒。     

褐铁矿反浮选脱硅新工艺试验研究

试验针对广东某褐铁矿矿石共生关系简单的特点,采用强化矿浆分散阳离子反浮选脱硅新工艺,即采用碳酸钠用量为1250g／t和水玻璃用量为600g／t实现矿浆的强化分散。在磨矿细度为80％-0．074mm、十二胺用量200g／t、浮选时间18min的条件下,选别该褐铁矿石获得铁精矿铁品位为59．25％、全铁回收率为83．42％的较好指标。     

Effect of binder addition on optimum additive amount of dispersant for aqueous BaTiO3 slurry

In ceramic wet-shaping processes, the effects of the addition of binder is seldom taken into account when determining the optimum amount of dispersant to be used. Hence, in this study, the effect of the addition of PVA, which is commonly used as a binder, on the particle dispersion state of aqueous BaTiO₃ slurry was investigated. Dispersant adsorption, rheological characteristics evaluation, and sedimentation tests were conducted on slurries with and without PVA addition. The slurry with 2 mg･g⁻¹ PCA but no PVA was well dispersed; however, the addition of PVA caused significant aggregation. Although slurries containing more than 4 mg･g⁻¹ PCA plus PVA were more aggregated than those without PVA, the amount of aggregation was less than that with 2 mg･g⁻¹ PCA. The aggregation mechanism was the interaction between PCA as a dispersant and PVA, with the degree of aggregation depending on the amount of non-adsorbed PCA.     

Influence of a few important parameters on the rheological behaviour of silicon carbide nanoparticles dispersed aqueous suspension

In this study, investigations have been carried out on the effect of a few important parameters such as molecular weight and concentration of dispersant (polyethyleneimine) as well as that of pH on the rheological behaviour of aqueous suspension comprising silicon carbide (SiC) nanoparticles. In addition to this, the effect of particle size and addition of finer SiC particles on the rheological behaviour of SiC suspension have been examined. It is observed that viscosity of suspension increases with the increase in molecular weight of dispersant and decreases as the concentration of dispersant increases. Further, it is noticed that viscosity of the suspension progressively increases below the pH ≈?7.6 and above the pH ≈?9.3, indicating that minimum viscosity i.e. maximum stabilization of suspension is obtained within the pH range of ≈ 7.6–9.3. It has been observed that variation of SiC particle size from submicrometer to nanometer range and addition of nanometric SiC powder in SiC suspension containing coarser particles increase the viscosity significantly.     

分散剂对碳纤维水泥砂浆力学性能及压敏性的影响研究

研究了分散剂的种类(HPMC、MC、HEC)和掺量(0、0.2%、0.4%)对碳纤维水泥砂浆(CFRM)力学性能和压敏性的影响。结果表明:当分散剂掺量为0.2%时,掺HPMC和MC的CFRM试件抗压、抗折强度均高于基准组,其中,HPMC对力学性能的提升效果最好;各组试件的电阻变化率均随着应力的增大而减小,其中,HPMC掺量为0.2%的试件灵敏度最高。综合考虑,采用0.2%的HPMC时,CFRM的力学性能和压敏性达到最佳。     

粒度对一水硬铝石和高岭石浮选分离的影响

研究了不同粒度一水硬铝石和高岭石的浮选行为,结果表明:油酸钠作捕收剂时,随着粒度的变细,一水硬铝石的上浮率变小,十二胺作捕收剂时,情况相反;高岭石的上浮率变化规律与一水硬铝石相反。人工混和矿试验表明:采用油酸钠和十二胺正、反浮选分离一水硬铝石和高岭石要尽量放粗两者的入选粒度,才能达到较好的分选效果。     

并流沉淀法制备纳米氧化锌

着重阐述了并流沉淀法制备纳米氧化锌的优点及方法,结合实验结果讨论了料液浓度、并流速度、底液组成、分散剂种类、加入量及加入方式、前驱体干燥条件、前驱体煅烧条件等对纳米氧化锌制备的影响。用XRD、TG和TEM对产品纳米氧化锌的形貌和粒度进行表征,结果表明实验制得纳米氧化锌呈球形、粒度分布均匀且范围窄,平均粒径为40nm。     

Improvement of current withstand capacity of high gradient ZnO varistors

The effects of the dispersant and the inorganic high resistance coating on the microstructure and the electrical properties of the ZnO varistors, especially on the current withstand capacity, were studied. The results showed that under the premise of adequate slurry dispersion, when the dispersant content was the minimum, the porosity of the varistor was the minimum, and the current withstand capacity was up to 24 A/cm² in 2 ms square waveform impulse test. By coating a high resistance layer with high proportion of spinel forming elements, the content of spinel near the side of the varistor ceramic was increased, thus increasing the resistivity and alleviating the current impact near the edge. The current withstand capacity of 2 ms square waveform impulse was upgraded to 32 A/cm².     

Dispersion of calcite by poly(sodium acrylate) prepared by reversible addition-fragmentation chain transfer (RAFT) polymerization

Calcite is dispersed into nanoparticles with the use of polysodium acrylate, PAANa. The molecular weight distribution of PAANa greatly influences the characteristics of the dispersion. Near-monodisperse PAANa adsorbs irreversibly and totally onto the CaCO₃ surface, but for polydisperse PAANa, a mass segregation occurs, where only chains with a selected molecular weight are adsorbed. With polydisperse samples, small spherical CaCO₃ particles are generated in addition to calcite crystals. This bimodal dispersion is less viscous than the dispersion containing only calcite crystals.