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111.
This research studied the initiator efficiency for producing polymeric particles of poly(styrene-co-methylmethacrylate) copolymers by a Shirasu porous glass membrane (SPG) emulsification technique followed by suspensioncopolymerization. BPO, ADVN, and AIBN were used as initiators and we found that BPO is the most suitable initiator.Copolymers for various feed ratios of styrene/methyl methacrylate were thus synthesized by benzoyl peroxide, and theircopolymer particle size, molecular weight distribution and particle size distribution were characterized. Then n-BMA or 2-EHMA was added as the third monomer to decrease the terpolymer glass transition temperature. This article describes thepreparation technique, recipes and polymerization conditions for producing both copolymer and terpolymer panicles, particlesize changes, the corresponding particle morphologies and glass transition temperatures. 相似文献
112.
113.
采用水热合成技术,制备了ZrO2胶体,用旋涂法镀制了单层ZrO2介质膜以及添加了有机粘合剂PVP的复合ZrO2-PVP薄膜。采用X射线衍射(XRD)、椭偏仪、红外分光光度计(FTIR)、原子力显微镜(AFM)等仪器对干凝胶及薄膜进行了性能测试和表征,并用输出波长为1.064 μm、脉宽为10 ns的电光调Q激光系统产生的强激光测试其激光损伤阈值。测得ZrO2和ZrO2-PVP薄膜在300 ℃热处理60 min后的激光损伤阈值分别为24.5 J/cm2和37.8 J/cm2。研究表明:添加有机粘合剂后的复合薄膜具有平整的表面结构;有机粘合剂的添加有助于提高薄膜的折射率和激光损伤阈值,其中,ZrO2-PVP 复合薄膜的折射率可高达1.75,激光损伤阈值达到37.8 J/cm2,比ZrO2单层膜的激光损伤阈值提高50%。 相似文献
114.
以木薯淀粉为主要原料,自行研制的有机膨润土为改性剂,经过熔融和溶液插层等工艺制备木薯淀粉/膨润土复合粘结剂。采用FTIR和XRD手段表征及力学性能测试。结果表明,PVA插层改性后的有机膨润土的层间距大于有机膨润土的层间距大于Na基膨润土的层间距,膨润土的层间距越大,越有利于淀粉与膨润土的插层反应,得到的复合粘结剂的干强度也越高。该复合粘结剂具有粘结强度高、 抗吸潮性好,且成本低、 工艺简单和环境友好。 相似文献
115.
J. VilasauC. Solans M.J. GómezJ. Dabrio R. Mújika-GaraiJ. Esquena 《Colloids and surfaces. A, Physicochemical and engineering aspects》2011,392(1):38-44
Paraffin emulsions are important in technological applications such as coating in the food packaging industry or to provide waterproof properties to particleboard panels. Small particle size (about 1.0 μm) and low polydispersity are required to form stable paraffin emulsions for these applications. In this context, the main objective of the present work is to study the influence of the surfactant system and the emulsification process on the properties of paraffin emulsions. A high pressure homogenizer was used to prepare the emulsions and its characterization was made by means of optical microscopy, laser diffraction and electrophoretic mobility measurements. Emulsions were prepared as a function of the ionic/nonionic surfactant ratio, the total surfactant concentration and the homogenization pressure. A simple theoretical model to predict the minimum particle size was used, assuming that surfactant is either at the oil-water interface or as monomer in the external phase. Experimental and theoretical data are on good agreement and the formation of stable emulsions is explained according to such model. This result could be of prime importance in order to formulate new paraffin emulsions. 相似文献
116.
X. Liu 《Journal of Dispersion Science and Technology》2016,37(9):1252-1258
In this work, the water-repellent capacity of the paraffin emulsion?covered soy flour (SF) substrate has been studied. Effect of paraffin emulsion content on the structure and properties of the resulting films were studied using laser particle size distribution analyzer, water absorption test, x-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and tensile testing. Study on the emulsion particle size and stability revealed that the particle size distribution and stability were strongly dependent on the pH of the system. And the optimum pH was 9.9. The incorporation of paraffin emulsion produced at pH 9.9 could markedly enhance the water resistance of films. However, the improvement was realized at the expense of decreased thermal stability and tensile strength of SF?paraffin emulsion films. The addition of paraffin emulsion could destroy the crystalline domains of soy protein and change the protein secondary structure. 相似文献
117.
When sectioning a 3D porous scaffold made of a soft elastomeric material embedded in paraffin medium, it is not easy to obtain a section because of the different mechanical properties of the paraffin and tissue/scaffold. We describe a new embedding material for histological analysis of various biomaterials that is composed of paraffin and ethylene vinyl acetate (EVA) resin (0, 3, 7, and 13 wt.%). 3D porous poly(l-lactide--caprolactone) (PLCL) and chitosan scaffolds were fabricated to test the sectioning efficiency of the paraffin/EVA embedding material. The new embedding material was characterized by rheological analysis and solvent solubility testing in xylene and n-hexane. The hydrophilicity of the new material was assessed by contact angle measurement and its surface roughness was measured using AFM analysis. The staining efficiency of sections embedded in a paraffin/EVA mixture was determined by eosin staining of the chitosan scaffold and chitosan/collagen hybrid scaffold using a fluorescently labeled collagen. Section roughness decreased with increasing EVA content. The softening temperature of the paraffin/EVA mixture was similar to that of paraffin (50–60 °C by rheometer). The paraffin/EVA mixture dissolved completely in xylene after 30 min at 50 °C, and after 30 min in n-hexane at 60 °C. Therefore, the new embedding medium can be used for histological analysis of various biomaterials and natural tissues. 相似文献
118.
In order to better understand the role of binder content, molecular dynamics (MD) simulations were performed to study the interfacial interactions, sensitivity and mechanical properties of 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane/2,4,6-trinitrotoluene (CL-20/TNT) based polymer-bonded explosives (PBXs) with fluorine rubber F2311. The binding energy between CL-20/TNT co-crystal (1 0 0) surface and F2311, pair correlation function, the maximum bond length of the N–NO2 trigger bond, and the mechanical properties of the PBXs were reported. From the calculated binding energy, it was found that binding energy increases with increasing F2311 content. Additionally, according to the results of pair correlation function, it turns out that H–O hydrogen bonds and H–F hydrogen bonds exist between F2311 molecules and the molecules in CL-20/TNT. The length of trigger bond in CL-20/TNT were adopted as theoretical criterion of sensitivity. The maximum bond length of the N–NO2 trigger bond decreased very significantly when the F2311 content increased from 0 to 9.2%. This indicated increasing F2311 content can reduce sensitivity and improve thermal stability. However, the maximum bond length of the N–NO2 trigger bond remained essentially unchanged when the F2311 content was further increased. Additionally, the calculated mechanical data indicated that with the increase in F2311 content, the rigidity of CL-20/TNT based PBXs was decrease, the toughness was improved. 相似文献
119.
《Analytical letters》2012,45(15):2625-2633
Abstract A procedure is presented for the determination of donor identity or commonality of origin among paraffinembedded tissues and slides. Samples are de-paraffinized with xylene and ethanol and subjected to ChelexR extraction. The Polymarker forensic DNA typing kit is utilized for identity testing. Following multiplex amplification, PCR product is verified on an agarose gel and then the samples are geiotyped using reverse dot-blot hybridization. When this procedure was applied to paraffin-embedded samples involved in a legal action, all samples were successfully genotyped. The advantages of using this procedure are discussed. 相似文献
120.
Dr. Xuefeng Wang Yejing Li Zhaoruxin Guan Prof. Zhaoxiang Wang Liquan Chen 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(17):6465-6468
Low storage capacity and poor cycling stability are the main drawbacks of the electrode materials for sodium‐ion (Na‐ion) batteries, due to the large radius of the Na ion. Here we show that micro‐structured molybdenum disulfide (MoS2) can exhibit high storage capacity and excellent cycling and rate performances as an anode material for Na‐ion batteries by controlling its intercalation depth and optimizing the binder. The former method is to preserve the layered structure of MoS2, whereas the latter maintains the integrity of the electrode during cycling. A reversible capacity of 90 mAh g?1 is obtained on a potential plateau feature when less than 0.5 Na per formula unit is intercalated into micro‐MoS2. The fully discharged electrode with sodium alginate (NaAlg) binder delivers a high reversible capacity of 420 mAh g?1. Both cells show excellent cycling performance. These findings indicate that metal chalcogenides, for example, MoS2, can be promising Na‐storage materials if their operation potential range and the binder can be appropriately optimized. 相似文献