A study on the anticorrosion performance of the epoxy-polyamide nanocomposites containing ZnO nanoparticles

Epoxy nanocomposites were prepared using different loadings (2, 3.5, 5 and 6.5 wt%) of ZnO nanoparticles. Nanocomposites were applied on steel substrates. Samples were immersed in 3.5 wt% NaCl solution for 1344 h. Corrosion resistance of the coatings was studied by an electrochemical impedance spectroscopy (EIS). The effects of addition of nanoparticles on the mechanical properties of the epoxy coating were studied by a dynamic mechanical thermal analysis (DMTA). Curing behavior of the coatings containing nanoparticles was studied by a differential scanning calorimeter (DSC). Atomic force microscope (AFM) was utilized to investigate the surface topography and surface morphology of the coatings. Coating resistance against hydrolytic degradation was studied by FTIR (Fourier Transform Infrared).Results showed that addition of low loadings of nanoparticles can increase T_g of the composite. Decrease in T_g and cross-linking density of the coating were observed at high loadings of nanoparticles. It was found that nanoparticles can influence the curing behavior of the epoxy coating. Nanoparticles improved the corrosion resistance of the epoxy coating. Increase in coating resistance against hydrolytic degradation was obtained using nanoparticles.     

Solubility enhancement of steviol glycosides and characterization of their inclusion complexes with gamma-cyclodextrin

Steviol glycosidesrebaudioside (reb) A, C and D have low aqueous solubilities. To improve their aqueous solubilities, inclusion complex of steviol glycosides, reb A, C and D and gamma cyclodextrin were prepared by freeze drying method and further characterized by means of differential scanning calorimetry, Fourier transform infrared spectroscopy and Raman spectroscopy. The effect of gamma cyclodextrin on chemical shifts of the steviol glycosides was also studied in proton NMR experiments as well as in solid state (13)C CP/MAS NMR experiments. These results indicated that the steviol glycosides were clearly in inclusion complex formation with the gamma cyclodextrin which also results in solubility enhancement of these steviol glycosides. Phase solubility studies showed that amounts of soluble reb A, C and D increased with increasing amounts of gamma cyclodextrin indicating formation of 1:1 stoichiometric and higher order inclusion complexes.     

Synthesis and characterization of mesoporous TiO2 nanostructured films prepared by a modified sol-gel method for application in dye solar cells

Anatase TiO₂ colloidal dispersions were obtained by hydrothermal synthesis at 200 °C from titanium isopropoxide gels modified with acetic acid in the presence of a non-ionic surfactant. Absolute ethanol, anhydrous terpineol and ethyl cellulose were added to this anatase dispersion resulting in a 23 wt% TiO₂ paste. Mesoporous films for application as working electrodes in dye-sensitized solar cells were prepared by the screen-printing method, yielding reproducible films with thicknesses about 10 μm and desired porosity levels in a single printing operation. An average energy conversion efficiency of 5.2%, and a fill factor of 0.66 were achieved with anatase particle sizes ranging between 15 and 20 nm. The reproducibility of the results was confirmed by electrochemical impedance spectroscopy analysis.     

Structural studies of poly(butyl acrylate) - poly(ethylene oxide) miktoarm star polymers

Structural behavior of miktoarm star polymers comprising poly(butyl acrylate) (PBA) and poly(ethylene oxide) (PEO) arms was studied by means of Differential Scanning Calorimetry (DSC), Wide Angle X-Ray Scattering (WAXS), Polarized Optical Microscopy (POM) and Fourier Transform Infrared Spectroscopy (FTIR) methods. The aim of this study was to correlate changes in the composition of the arms of the PBA/PEO miktoarm star polymers with their structures. As a consequence of increasing PBA content, the decrease in crystallinity of the studied PBA/PEO heteroarm star copolymers was observed. Regardless of the copolymer composition, fraction of oxyethylene units in the crystalline PEO phase was similar in all investigated systems. The POM images showed spherulitic morphology of the materials having low PBA content, while an increase in PBA arms fraction leads to the formation of less ordered structures. The analysis of FTIR vibrational spectrum indicates helical conformation of PEO chains in the crystalline phase. Isothermal crystallization studies carried out using the FTIR technique suggest the existence of isolated domains in the nanoscopic scale of investigated materials.     

热氧处理聚丙烯粉料DSC结晶参数研究

给出了一种采用DSC结晶参数评估聚丙烯回收料降解程度的方法。实验结果表明,随着热氧处理时间的增加,结晶峰温（Tpc）、外推结晶起始温度（Teic）、结晶起始温度（Tic）和结晶热焓（ΔHc）都逐渐下降,且呈现出较好的规律性。可以利用这种规律对聚丙烯回收料的降解程度做定量评估。     

聚异丁烯磷酸酯的合成及性能研究

以高活性聚异丁烯（PIB）和苯酚为原料（C6H5OH）,三氟化硼乙醚为催化剂合成了聚异丁烯苯酚,然后加入P2O5对其进行酯化反应合成聚异丁烯磷酸酯。通过红外光谱（FT-IR）分别对合成的聚异丁烯苯酚和聚异丁烯磷酸酯进行了分析,结果表明产物为预期产物。通过差示扫描热分析（DSC）,表明聚异丁烯苯酚与高活性聚异丁烯相比具有较高的热稳定性。通过产物与大庆原油进行降凝效果的测定,证实聚异丁烯磷酸酯在大庆原油中的加入量为0.6%时降凝效果最好,降幅为9℃。     

SP179抗冲共聚聚丙烯性能评价

运用差示扫描量热仪(DSC)、动态热机械分析仪(DMA)、红外光谱(IR)和凝胶渗透色谱(GPC)等对SPi79抗冲共聚聚丙烯的相关性能参数进行了表征研究,评价了4个样品的乙烯含量、平均分子质量及其分布和热性能.实验证明,随着乙烯含量的增加,乙丙橡胶相增加,重均分子质量增大,样品的冲击强度升高,但弯曲模量下降,刚性降低...     

聚丙烯管材料鉴别方法的研究

通过红外光谱、差热分析(DSC)以及宏观物理机械性能等分析方法,分析了吉林石化公司乙烯厂生产的三种不同类型的聚丙烯产品;同时介绍了不同类型管材料的特点及应用范围.     

Differential scanning calorimetry analysis of an enhanced LiNi0.8Co0.2O2 cathode with single wall carbon nanotube conductive additives

The replacement of traditional conductive carbon additives with single wall carbon nanotubes (SWCNTs) in lithium metal oxide cathode composites has been shown to enhance thermal stability as well as power capability and electrode energy density. The dispersion of 1 wt% high purity laser-produced SWCNTs in a LiNi_0.8Co_0.2O₂ electrode created an improved percolation network over an equivalent composite electrode using 4 wt% Super C65 carbon black; evidenced by additive connectivity in SEM images and an order of magnitude increase in electrode electrical conductivity. The cathode with 1 wt% SWCNT additives showed comparable active material capacity (185–188 mAh g⁻¹), at a low rate, and Coulombic efficiency to the cathode composite with 4 wt% Super C65. At increased cycling rates, the cathode with SWCNT additives had higher capacity retention with more than three times the capacity at 10C (16.4 mA cm⁻²). The thermal stability of the electrodes was evaluated by differential scanning calorimetry after charging to 4.3 V and float charging for 12 h. A 40% reduction of the cathode exothermic energy released was measured when using 1 wt% SWCNTs as the additive. Thus, the results demonstrate that replacing traditional conductive carbon additives with a lower weight loading of SWCNTs is a simple way to improve the thermal transport, safety, power, and energy characteristics of cathode composites for lithium ion batteries.     

Electrodeposition of eutectic Sn96.5Ag3.5 films from iodide–pyrophosphate solution

Electrodeposition of SnAg alloy films and the effect of additives like PEG-600 and hydrazine hydrochloride on the same were studied in KI–K₄P₂O₇ solutions. PEG-600 was found to adsorb on the electrode surface, resulting in strong reduction inhibition of tin pyrophosphate complex ions, but it does not affect the reduction of silver iodide complex. It was found that hydrazine hydrochloride acted as a reducing agent for Sn⁴⁺ species and greatly improved surface morphology and roughness of the films by preventing the formation of Sn dendrites during electrodeposition. Eutectic Sn_96.5Ag_3.5 was obtained from a plating solution that contained both PEG-600 and hydrazine hydrochloride as additives, at the deposition current density of 40 mA cm⁻². Stress measurements of the SnAg films showed that it was tensile. X-ray analysis of the deposit showed the presence of β-Sn and ?-Ag₃Sn phases in the eutectic SnAg film. The DSC profile of SnAg film gave the melting point as 222 °C.