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991.
Polymer blends of poly(propylene) (PP) and polyacetal (polyoxymethylene, POM) with ethylene vinyl alcohol (EVOH) copolymers were investigated by differential scanning calorimetry (DSC), rheological, tensile, and impact measurements, Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). The PP–POM–EVOH blends were extruded with a co‐rotating twin‐screw extruder. The ethylene group in the EVOH is partially miscible with PP, whereas the hydroxyl group in the EVOH can form hydrogen bonding with POM. The EVOH tends to reside along the interface, acting as a surfactant to reduce the interfacial tension and to increase the interfacial adhesion between the blends. Results from SEM and mechanical tests indicate that a small quantity of the EVOH copolymer or a smaller vinyl alcohol content in the EVOH copolymer results in a better compatibilized blend in terms of finer phase domains and better mechanical properties. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1471–1477, 2003 相似文献
992.
季戊四醇合成技术进展与市场分析 总被引:2,自引:0,他引:2
介绍了季戊四醇国内外生产现状,市场需求及发展趋势,重点介绍季戊四醇分离技术进展,分析我国国外先进水平存在的差距,并提出一些发展建议。 相似文献
993.
994.
995.
从481—2B型废催化剂中回收钼工艺述评 总被引:2,自引:0,他引:2
钼酸铵是一种主要的化工原料,本文对从工业生产的废催化剂中回收钼的工艺进行了比较系统的概括,对各种工艺进行了比较,并给出了最佳的工艺条件。 相似文献
996.
A 6-bit 2 GS/s ADC was implemented using a 65 nm digital CMOS technology.The design is based on a single-channel flash ADC architecture,and utilizes interpolating and averaging techniques.A two-stage CML-CMOS high-speed hybrid comparator is designed for optimal speed and power performance.The total power consumption of the converter is 52 mW and the area is 0.24 mm2.The ADC achieves 42.5 dB SFDR and5.2 bit ENOB at input frequency of 123 MHz,and at Nyquist frequency 37.67 dB SFDR and 4.9 bit ENOB. 相似文献
997.
互联网技术的不断发展对信息系统的安全提出了更高的要求,需要对系统提供更多方面的防护机制,而系统进程则是其中防范的一个方面。本文在Windows内核驱动程序理解的基础上,对系统进程监控技术进行了深入研究,采用事件触发的机制和技术,实现了对系统进程实时可靠的监控。 相似文献
998.
999.
The miscibility, crystallization behavior, tensile properties, and environmental biodegradability of poly(β‐hydroxybutyrate) (PHB)/cellulose acetate butyrate (CAB) blends were studied with differential scanning calorimetry, scanning electron microscopy, wide‐angle X‐ray diffraction, and polarizing optical microscopy. The results indicated that PHB and CAB were miscible in the melt state. With an increase in the CAB content, the degree of crystallinity and melting temperature of the PHB phase decreased, and this broadened the narrow processability window of PHB. As the elongation at break increased from 2.2 to 7.3%, the toughness and ductility of PHB improved. From the degradation test, it could be concluded that degradation occurred gradually from the surface to the inside and that the degradation rate could be adjusted by the addition of the CAB content. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2116–2122, 2003 相似文献
1000.
At room temperature atom transfer radical polymerization (ATRP) of N-vinylpyrrolidone (NVP) was carried out using 5,5,7,12,12,14-hexamethyl-1,4,8,11-tetra-azacyclo-tetradecane (Me6Cyclam) as ligand in 1,4-dioxane/isopropanol mixture. Methyl 2-chloropropionate (MCP) and copper(I) chloride were used as initiator and catalyst, respectively. The polymerization of NVP via ATRP could be mediated by the addition of CuCl2. The resultant poly(N-vinylpyrrolidone) (PNVP) has high conversion of up to 65% in 3 h, a controlled molecular weight close to the theoretical values and narrow molecular weight distribution between 1.2 and 1.3. The living nature of the ATRP for NVP was confirmed by the experiments of PNVP chain extension. With PNVP-Cl as macroinitiator and N-methacryloyl-N′-(α-naphthyl)thiourea (MANTU) as a hydrophobic monomer, novel fluorescent amphiphilic copolymers poly(N-vinylpyrrolidone)-b-poly(N-methacryloyl-N′-(α-naphthyl)thiourea) (PNVP-b-PMANTU) were synthesized by ATRP. PNVP-b-PMANTU copolymers were characterized by 1H NMR, GPC-MALLS and fluorescence measurements. The results revealed that PNVP-b-PMANTU presented a blocky architecture. 相似文献