Influence of Fillers on Sizing Efficiency and Hydrolysis of Alkyl Ketene Dimer

The influence of various fillers on sizing efficiency, adsorption and hydrolysis of alkyl ketene dimer (AKD) has been investigated. Results indicated that the precipitated calcium carbonate (PCC) improved AKD retention, both bound and unbound. The sizing efficiency was reduced as PCC contents increased, which might be attributed to the decrease in the relative AKD dosage to fibres and AKD hydrolysis promoted by PCC. Less amount of AKD was adsorbed on PCC, compared with calcined clay and TiO₂ fillers under the same conditions. Hydrolysis studies indicated that PCC had a more detrimental effect on AKD hydrolysis than clay and TiO₂.     

Desulfurization of commercial fuels by π-complexation: Monolayer CuCl/γ-Al2O3

Monolayer CuCl/γ-Al₂O₃ sorbent was studied for desulfurization of a commercial jet fuel (364.3 ppmw S) and a commercial diesel (140 ppmw S). The sorbent was prepared by means of spontaneous monolayer dispersion methods. Deep desulfurization (sulfur levels of <1 ppmw) was accomplished with this sorbent using a fixed-bed adsorber. The CuCl/γ-Al₂O₃ sorbent was capable of removing 6.4 and 11.2 mg of sulfur per gram for jet fuel at breakthrough (at <1 ppmw S) and saturation, respectively. The same sorbent was capable of removing 0.94 and 1.8 mg of sulfur per gram for BP diesel at breakthrough and saturation, respectively. The difference in sulfur capacities for jet fuel and diesel was apparently caused by the difference in concentrations of strongly binding compounds, such as nitrogen heterocycles, heavy (polynuclear) aromatics and fuel additives. In comparison with CuCl/γ-Al₂O₃, Cu(I)Y zeolite has higher sulfur capacities but is less stable and can be easily oxidized to Cu(II)Y by fuel additives (such as oxygenates) and moisture and consequently loses π-complexation ability. However, all these cuprous π-complexation sorbents selectively adsorb thiophenic compounds over aromatics and olefins (as predicted by the high separation factors), which resulted in the observed desulfurization capability. A feasibility study is shown for efficient regeneration of CuCl/γ-Al₂O₃ using ultrasound at ambient temperature. Possible problems associated with desulfurization using π-complexation sorbents for commercial fuels are discussed.     

远红外日用陶瓷釉的研究

通过在普通日用陶瓷釉中掺入远红外陶瓷粉,研究了远红外陶瓷粉对釉面质量(白度、光泽度、显微硬度)及远红外陶瓷釉辐射率的影响,探讨了不同分散剂对远红外陶瓷粉在基釉中的分散情况及其对陶瓷釉显微结构的影响。制备出了符合国家日用瓷质量标准、且具有高的远红外辐射性能的远红外日用陶瓷釉。     

Effect of the use of mineral filler on the properties of concrete

Engineers of the concrete technology are increasingly concerned with the material passing through a sieve of the size under 0.149 mm. Materials called very fine aggregate or mineral filler may affect the performance of concrete in an either positive or a negative way. Discussions on aggregate containing very fine material are vitally important. Washing the aggregate residue has been the sole way to solve this matter to date. This is mainly based on the debatable opinion that materials of this kind are regarded as clay material. The goal of the study was to determine how the content of mineral filler might affect properties of concrete. Two types of aggregates with different amounts of cement and mineral filler were used. Basically, mineral filler replaced sand. The effect of applying different amounts of mineral filler on concrete was then determined. The addition of 7-10% of mineral filler to fine aggregate (0-2 mm) was found to considerably improve the properties of concrete.     

填料对反-1,4-聚异戊二烯性能的影响

研究了填料对反－1，4－聚异戊二烯（TPI）硫化胶和混炼胶的物理机械性能和结晶性能的影响。结果表明，在TPI中加入填料后，其硫化胶的300％定伸应力随填料用量的增加而增加，拉伸强度则在填料用量为20份时达到最大值；加入填料同时能降低TPI混炼胶的结晶度，填料用量增加，TPI混炼胶的结晶下降；且填料增强效果越好，结晶度下降越大。     

Investigation of allyl‐capped carbosilane dendrimers used as crosslinker for silicone rubber

High‐temperature vulcanized silicone rubber was prepared by using allyl‐capped carbosilane dendrimers, in which the core molecules were Si(CH₂CH?CH₂)₄ and Ph₂Si(CH₂CH?CH₂)₂ as crosslinker and nanoscale reinforcing filler, respectively. Allyl‐capped carbosilane dendrimers improved the mechanical properties of silicone rubber. The optimum tensile strength and tear strength were 9.6 MPa and 31.0 kN/m, respectively, when using SiG_n(allyl)m as the crosslinker and 10.1 MPa and 32.0 kN/m, respectively, when using Ph₂SiG_n(allyl)m as the crosslinker. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1772–1775, 2006     

聚偏氟乙烯/聚丙烯酸酯复合乳液的合成与性能

在含氟表面活性剂存在下，将聚偏氟乙烯超声分散于甲基丙烯酸甲酯和丙烯酸丁酯的混合单体中进行乳液聚合，制备了聚偏氟乙烯／聚丙烯酸酯复合乳液。采用动态光散射DLS、透射电镜TEM和红外光谱FT—IR对乳液组成及乳胶粒子的形态进行了表征，并对聚合物胶膜的性能进行了测试分析。结果表明：聚偏氟乙烯的加入，使复合乳液膜的拉伸强度显著增大，吸水率减小。     

In situ visualization of drop deformation,erosion, and breakup in high viscosity ratio polymeric systems under high shearing stress conditions

In this paper, deformation and breakup under simple shear of single molten polymer drops in a polymer matrix were investigated. Flow visualization was carried out in a Couette‐Flow apparatus under relatively high shear rates and temperatures up to 230°C. Drop/Matrix combinations were composed of polystyrene drops of 0.5–0.6 mm in diameter in polyethylene matrix, and ethylene–propylene copolymer drops of approximately the same size in polypropylene matrix. The deformation and breakup processes were studied under steady state and time‐dependent shearing conditions. Either for steady state or time‐dependant shearing conditions, drop elasticity generated at relatively high shear rates helped the drops to align perpendicular to the flow direction, i.e., parallel to vorticity axis. Also, the most striking non‐Newtonian effects for the high viscosity ratio systems were the surface erosion and the drop splitting mechanisms. The particles eroded off the main droplet surface were very fine, in the range of 10–50 μm, and led to a significant reduction in main drop size before its final breakup. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 2582–2591, 2006     

CacO3在PP和PP/mPE共混物基体中的作用比较

研究CaCO3填料在取丙烯（PP）和茂金属聚乙烯（mPE)弹性体增韧PP共混物（PP／mPE)2种基体中的不同作用。结果表明：在PP基体中，填料显著提高其刚性，而在共混物基体中，由于弹性体的存在，填料的增强作用减弱；弹性体能够改善填料粒子和基体的界面粘合，增大弹性体分散相的尺寸，使PP/mPE共混物的拉伸断裂韧性提高。低温下（－30℃）的Charpy缺口冲击实验表明：少量的CaCO3即可导致PP/mPE体系冲击强度的迅速下降。     

Optimising the dewatering behaviour of clay tailings through interfacial chemistry, orthokinetic flocculation and controlled shear

The effect of shear on dewatering behaviour and particle interactions of Na-exchanged smectite and kaolinite clay dispersions has been investigated at pH 7.5, using hydrolysable Ca(II) and Mn(II) ions as coagulants and high molecular weight anionic and non-ionic polyacrylamide (PAM A and PAM N, respectively) and polyethylene oxide (PEO) flocculants. Metal ion addition enhanced the flocculation performance by dramatically reducing the magnitude of the particle zeta potential and, in the case of smectite pulp, suppressing osmotic swelling. Under optimum orthokinetic flocculation conditions of controlled agitation rate and duration, PAM A and PEO-based flocs settled faster than those of PAM N whilst kaolinite pulps produced higher sedimentation rates than smectite pulps. The settling rates are nearly an order of magnitude greater than those observed under standard flocculant-pulp mixing/flocculation methods of inversion and plunging. The difference in the flocculant behaviour is attributed to the more expanded conformation of PAM A and PEO polymer chains in contrast to PAM N, whilst the lower yield stresses, reflecting inter-particle bridging and floc network structure strength that are conducive to faster clarification, were displayed by kaolinite pulps. Following shear, similar consolidation enhancement of ≈ 5-7 wt.% solid for both pulps was achieved at an optimum agitation range of 100-200 rpm. This was accompanied by decreased yield stress in the case of PAM A-based pulps, indicating non-reversible disruption of polymer mediated particle and floc network structure. In contrast, the yield stresses of PAM N and PEO flocculated dispersions indicated similar and stronger particle interactions, respectively, upon consolidation following shear. The findings show clear links between effect of shear, interfacial chemistry and polymer structure on pulp particle interactions and dewaterability.