增韧剂及成核剂对PP–R复合材料性能的影响

采用注射成型法制备无规共聚聚丙烯(PP–R)复合材料,结合差示扫描量热仪、扫描电子显微镜、X射线衍射仪及偏光显微镜等技术,分析了乙烯–辛烯共聚物+高密度聚乙烯增韧剂及WBGⅡ型β成核剂对PP–R复合材料力学性能和结晶行为的影响。结果表明,增韧剂与成核剂对复合材料的综合性能有明显的影响,β成核剂和增韧剂同时加入到PP–R材料中,协效提高了复合材料的冲击强度,为78.7 k J/m~2,与纯PP–R材料比较提高了175%,而对拉伸及弯曲强度影响较小。同时,加入增韧剂及成核剂均能诱导α晶向β晶转变,晶粒细化,进而改善其冲击韧性。     

Effect of the thermal treatment on the phase composition of the surface of coatings based on Si–B–ZrB<Subscript>2</Subscript> and modified with ZrO<Subscript>2</Subscript> fibers

Coatings on graphite that are stable to oxidation and based on the silicon–boron–zirconium boride composite containing from 5 to 50% of fibrous zirconium dioxide as a modifying dopant have been produced by the suspension–annealing method. A nonporous layer is formed at the zirconium dioxide content ranging from 5 to 15%, while a porous layer is formed at its 50% content. A glass-forming melt, as well as zirconium dioxide and silicate, is formed during thermal treatment as a result of the chemical reactions with the oxygen in air. The zirconium silicate content increases, along with the modifier’s concentration and temperature.     

膜法生产饮用水过程中纳滤膜生物污染的研究

研究了在地表水生产饮用水过程中纳滤膜上微生物的污染情况,以分子生物学方法研究其纳滤膜在不同过滤时间的主要污染生物种类。通过对膜的水通量、进出水的水质变化等条件进行膜污染的研究,其结果表明纳滤膜对水中生物去除效率很高;通过对提取不同时期污膜上微生物DNA进行PCR-DGGE指纹图谱聚类分析发现,在污染的纳滤膜上,变形菌纲、杆菌属的细菌则成为了优势细菌。研究为减轻膜生物污染的研究提供了理论基础。     

Application of Poly(acetic Acid)–Based Graft Copolymer as a Compatibilizer for Poly(L-lactic Acid)/Poly(butylenesuccinate) Blend System

Poly(L-lactic acid) (PLLA) was blended with poly(butylenesuccinate) (PBS) using a single-screw extruder to modify the poor characteristics of these polymers. Furthermore, when both polymers were blended, the graft copolymer that was synthesized by partially saponified poly(vinyl alcohol) (PSPVA) and ?-caprolactone (?-CL) was used as a novel compatibilizer. The structure of the synthesized compatibilizer was determined by ¹H or ¹³C NMR. From this result, the ring-opening polymerization of the ?-CL occurred at the hydroxyl group of PSPVA. The structures of the PLLA/PBS solvent-cast blended films could be observed via an optical microscope. From the optical microscopic observation, the structures of the solvent-cast blended films with the synthesized compatibilizer were more homogeneous than those of the solvent-cast blended films without the compatibilizer. The mechanical properties of the PLLA/PBS extruded blended films were determined by a tensile test. The result showed the tensile strength of the blended films with the synthesized compatibilizer was greater than that of the blended films without the compatibilizer.     

Effect of the thermal treatment mode on the composition and structure of ZrB2-SiC system composites

The composite materials and coatings for graphite based on a ZrB₂-SiC system were obtained by the formation of a glass-forming melt in air. The effect of the heating mode on the structure and properties of the materials synthesized was shown. The coatings can be used for protecting graphite from oxidation for several hours at temperatures up to 1400°C.     

Design and production of Hg0 calibrator,Hg2+ calibrator,and Hg2+ to Hg0 converter for a continuous Hg emission monitor

Hg calibration and conversion systems, which are integral parts of a continuous emission monitor for were designed, produced, and tested. First, both Hg⁰ and Hg²⁺ calibrators showed less than 10% difference between measured and theoretical values. Next, a Hg²⁺ to Hg⁰ thermal converter with a scrubber and heated gas lines showed a conversion efficiency higher than 95%. Finally, the laboratory-prepared Hg converter was tested at a full-scale medical waste incinerator. The Ontario Hydro Method was used for measurement and speciation of Hg. The results showed that the laboratory-prepared Hg converter was highly effective with highest conversion efficiency close to 94%.     

Production of bioethanol from waste money bills – A new cellulosic material for biofuels

Waste money bills that are no longer legal tender are non-recyclable and are usually destroyed. In this study, we used this cellulose-rich material for bioethanol fermentation for the first time. Glucose production was enhanced by using diluted H₂SO₄ during pretreatment. Different incubation periods were tested for saccharification and subsequent bioethanol fermentation. The highest yield of glucose (41.90 mg/ml) was shown to increase with 27.20% and 25.90% respectively by increasing the reaction period by 30 min and by increasing the acid concentration by 0.5%. Bioethanol production was enhanced by adding 0.4 mM benzoic acid under anoxic condition. In accordance with three different conditions, the highest amount of bioethanol (22.01 mg/ml) was obtained and bioethanol fermentation was increased by 59.38%, 110.02% and 64.13% respectively with 30 min of reaction periods, 0.5% of acid concentrations and under anoxic condition with benzoic acid. This procedure for the production of bioethanol from a waste material would reduce waste money bill management costs and make a profit from ethanol.     

Pyrazine-interior-embodied MOF-74 for selective CO2 adsorption

A series of pyrazine-interior-embodied metal–organic framework-74 composites (py-MOF-74) were successfully synthesized by a post-synthetic vapor modification method. Here, pyrazine molecules occupy the cavity to block the wide pores of MOF-74, which accentuates the difference in adsorption of a pair of gases on MOFs and consequently reinforces the adsorption selectivity. Different from the “physical confinement” of occupants, the pyrazine molecule with dual “para-nitrogen” atoms donates one N atom to bond with the open metal ion of MOF-74 for stability and the other N atom for potential CO₂ trapping. Typically, py-MOF-74c with the highest pyrazine insertion ratio displays selectivity greatly superior to that of MOF-74 in equimolar CO₂/CH₄ (598 vs. 35) and in simulated CO₂/N₂ flue gas (471 vs. 49). Py-MOF-74 entities are long-lived adsorbents, and their CO₂ capacity can be maintained even after storage for 1 year in air. Py-MOF-74 also showed a sharp molecular sieve property in fixed-bed cycle adsorption tests, which implies its great potential in real applications.     

热处理对AlFeCrCoNiMo高熵合金微观组织与硬度的影响

利用真空电弧熔炼法制备了AlFeCrCoNiMo高熵合金。用X射线衍射(XRD)、扫描电镜(SEM)、硬度仪,研究了退火对高熵合金的微观组织及硬度的影响。结果表明:铸态以及退火后的合金是树枝晶结构,枝晶间是由Cr_9Mo_(21)Ni_(20)和NiCoCr金属间化合物组成的共晶结构;随着退火温度的升高,FCC相逐渐减少,并会析出新的金属间化合物;合金的微观应力表现出先增大后减少的变化趋势;合金的硬度随着退火温度的升高先升高再降低,合金的应力与硬度的变化趋势一致,当退火温度达到800℃时,合金的硬度达到最大。     

Synthesis and photophysical properties of host materials with high triplet energy based on dibenzofuran and triphenylamine functionalities

A host material with high triplet energy based on dibenzofuran and triphenylamine interconnected through diphenylmethylene linkage was synthesized and photophysical properties of the host material were investigated. A high triplet energy of 2.90 eV was obtained due to complete separation of an electron donating triphenylamine and accepting dibenzofuran by diphenylmethylene linkage. It was found out that intermolecular charge transfer dominated the light emission of the host material.