改性核壳增韧母料的制备及应用

以马来酸酐接枝物为改性剂制得增韧母料，考察了这种母料对均聚聚丙烯的增韧效果以及增韧体系的微观结构，探讨了这种增韧体系的增韧机理。结果表明：这种增韧母料具有典型的核壳结构，与传统增韧母料相比，能够以更小的尺寸均匀分散在聚丙烯树脂中，既能获得较高的韧性，又保持了良好的刚性，使增韧母料的用量显著减少。     

自交联型纸张—铝箔复合膜粘合剂的研究

以醋酸乙烯酯和丙烯酸丁酯为主要原料，引入自交联型单体羟甲基丙烯酸胺合成了纸张——铝箔复合膜粘合剂。探索了单体组成、自交联单体用量、缓冲剂用量和种类、核壳聚合等对粘合剂性能的影响以及该粘合剂的粘合性能。     

Analysis of the constant molar flow semi-batch vessel in contact with permeable core-shell composites

An exact analytical solution was derived for the concentration of solute or the temperature of the fluid in a constant molar flow semi-batch well-stirred vessel in contact with permeable core-shell composites. The linear equilibria at both the fluid-particle interface and the core-shell interface are assumed and the extraparticle film resistance is included. Several particular solutions can be readily degenerated from the solution derived in this work. By taking the contact affinity at the core-shell interface to zero, the solution in case of impermeable core-shell composites can be degenerated. By taking both the contact affinity at the core-shell interface and the ratio of mass or thermal effective diffusivities in the core and the shell to unity or by taking the size of the core to zero, the solution in case of homogeneous particles can be degenerated. The solution for the batch vessel is also degenerated by the differentiation of the solution for the constant molar flow semi-batch vessel with respect to time.     

VAC/BA/AN/AA四元共聚乳液研制

研制VAC／BA／AN／AA四元共聚乳液，讨论乳液的稳定性、耐水性、耐寒性、粘接强度和抗蠕变性。     

Comparison of methanol and ethylene glycol oxidation by alloy and Core-Shell platinum based catalysts

Two Core-Shell, Ru_Core-Pt_Shell and IrNi_Core-PtRu_Shell, XC72-supported catalyst were synthesized in a two-step deposition process with NaBH₄ as reducing agent. The structure and composition of the Core-Shell catalysts were determined by EDS, XPS and XRD. Electrochemical characterization was performed with the use of cyclic voltammetry. Methanol and ethylene glycol oxidation activities of the Core-Shell catalysts (in terms of surface and mass activities) were studied at 80 °C and compared to those of a commercial Pt-Ru alloy catalyst. The surface activity of the alloy based catalyst, in the case of methanol oxidation, was found to be superior as a result of optimized surface Pt:Ru composition. However, the mass activity of the PtRu/IrNi/XC72 was higher than that of the alloy based catalyst by ∼50%. Regarding ethylene glycol oxidation, while the surface activity of the alloy based catalyst was slightly higher than that of the Pt/Ru/XC72 catalyst, the latter showed ∼66% higher activities in terms of A g⁻¹ of Pt. These results show the potential of Core-Shell catalysts for reducing the cost of catalysts for DMFC and DEGFC.     

游离链段在环氧官能化ABS增韧PBT中的作用研究

采用种子乳液聚合方法,在聚丁二烯(PB)表面接枝苯乙烯(St)、丙烯腈(AN)和甲基丙烯酸环氧丙酯(GMA),合成了具有反应活性的ABS-g-GMA核-壳改性剂;通过超速离心方法将改性剂中的苯乙烯-丙烯腈-甲基丙烯酸环氧丙酯共聚物(SAN-co-GMA)游离链段分离出来,得到了ABS-g-GMA'核-壳改性剂;最后将分...     

Fabrication of Al2O3@BaFe12O19 core-shell powder by a modified heterogeneous precipitation method

Core-shell structural composites are promising to quench the desire for low-cost, lightweight and multifunctional magnetic materials, but the fabrication of highly pure shell nanoparticles with a desired morphology on a heterogeneous nuclear is still a big challenge. This study gives a successful illustration by in-situ synthesizing BaFe₁₂O₁₉ nanoparticles as a shell on Al₂O₃ core powders using BaCl₂ and FeCl₃ as precursors, instead of commonly used Ba(NO₃)₂ and Fe(NO₃)₃, by a modified heterogeneous precipitation process followed by calcination for crystallization. After calcination of the precipitants from the raw precursor mixture of BaCl₂:FeCl₃ for 1:10 at 800?°C, and for 1:8.5 at 900?°C, respectively, pure BaFe₁₂O₁₉ formed on pristine Al₂O₃, mostly with a hexagonal plane, about 100–200?nm in basal diameter and 20–100?nm in thickness. The highest saturation magnetization and coercivity of the coated Al₂O₃ @?BaFe₁₂O₁₉ powders was 23.3?emu/g and 5149?Oe, quite higher than that of the direct-mixed Al₂O₃-BaFe₁₂O₁₉ composite powder, and BaFe₁₂O₁₉-containing composites reported in literature, which could be attributed to the hexagonal shape of BaFe₁₂O₁₉ and uniform shell dispersion on Al₂O₃ core. The formation mechanism for the Al₂O₃@BaFe₁₂O₁₉ powders was discussed in detail.     

Mesoporous silica nanoparticle core-shell matrix (MSN CSM) engineered by green approach for pH triggered release of anticancer drugs

The present work exhibits an alternative route to design a nano-carrier using simple electrostatic interactions of biopolymeric layers on Mesoporous Silica Nanoparticle surface using Layer by Layer (LbL) technique. The doxorubicin (DOX) loaded MSN nano-carrier is coated with positively charged chitosan followed by a coating of negatively charged sodium carboxymethyl cellulose (Na-CMC) to form a DOX-loaded MSN Core-Shell Matrix (DOX-MSN CSM). The prepared MSN nano-carrier exhibits a high encapsulation efficiency of DOX (～93 %) due to its porous nature (～832 m²/gm) and negative surface charge (-21.5 mV). It exhibits a controlled release of DOX (～21 %) at physiological pH (7.4 pH) and improved drug release (～67 %) at cancer cells pH (5.4 pH) after 48 h. Further, the in-vitro cell line study using MDA-MB 231 cells reconfirms the slower and controlled release of DOX from the engineered DOX-MSN CSM. The confocal microscopy result shows that the DOX is internalized via endocytosis into the nucleus of the cells. The cell viability assay confirms more cells viable (～76 %) for DOX-MSN CSM than free DOX (～49 %) at the end of 24 h. The present study shows an alternate route to the conventional complex multi-step processes such as coupling reactions or chemical crosslinkers involving solvents. The proposed MSN core–shell matrix can be a potential nano-carrier for cancer drug delivery.     

核壳型聚丙烯酸酯乳液的耐水性能研究

采用种子乳液二阶段聚合法,制备了经丙烯酸(AA)/丙烯酰胺(AM)交联、具有核壳结构的甲基丙烯酸甲酯(MMA)/丙烯酸丁酯(BA)/丙烯腈(AN)复合乳液,研究了核壳软硬单体比、AN及壳层中交联单体AM含量对乳胶膜吸水率的影响。结果表明:乳胶膜吸水率主要受壳层软硬单体比例的影响,软硬单体比值越小,乳胶膜的吸水率越低;丙烯酸/丙烯酰胺复合交联剂对乳胶膜吸水率的影响不明显;功能单体丙烯腈可明显降低乳胶膜的吸水率,乳胶膜吸水率随丙烯腈含量的增加而逐渐降低,最低达到9.40%。     

聚苯乙烯和聚丙烯酸丁酯无皂核壳乳液聚合反应的研究

聚苯乙烯 (PS)和聚丙烯酸丁酯 (PBA)复合乳液是无皂乳液聚合反应生成的 ,采用丙烯酸丁酯加到聚苯乙烯种子微粒中反应得到的。PS/PBA复合微粒的结构通过红外光谱图明显的吸收峰特征而得到证实。纯PS微粒和低BA含量的PS/PBA微粒几乎是球形和规则的 ,而随着BA单体含量的增加 ,PS/PBA复合微粒的粒子尺寸变大和呈现类似高尔夫球形状。同时 ,本文进一步研究了PS/PBA复合微粒的表面形态学