反式-1,4-聚异戊二烯的后处理及质量稳定化

研究了反式-1,4-聚异戊二烯(TPI)的后处理及老化对其相对分子质量及结构与性能的影响。结果表明,TPI极易老化,其相对分子质量随老化时间的延长而迅速降低,熔点及结晶度也逐渐降低。用空气、水、乙醇终止的聚合产物的相对分子质量及老化行为相近,防老剂264的加入极大地延缓了TPI的老化降解。TPI较理想而廉价的后处理方式为用定量水终止聚合,同时加入质量分数1%的防老剂264进行处理,可以保证TPI贮存过程中的稳定性。

Catalytic synthesis of perfluorolyethers

Perfluorolyether is characterized by highly chemical inertness, oxidative stability, anticorrosion as well as radiation resistance. It can be used as lubricant especially in harsh environmental conditions. In this work, hexafluoropylene oxide was catalytically polymerized at low temperature using the methods of anionic polymerization, and perfluorolyethers were obtained with number-average degree of polymerization more than 15. CsF and RbF were used as catalysts and their catalytic activities were investigated. Experimental results show that perfluorolyethers with number-average molar masses up to 3 000 g/mol could be obtained using the two kinds of catalysts, respectively. As compared to CsF, the number-average degree of polymerization is higher and the relative molecular mass distribution interval is narrower when RbF is used as catalyst. The effect of factors such as impurities＇ content, reaction temperature and reaction time on the number-average degree of polymerization was also investigated. It is found that low impurities＇ content and low temperature are beneficial to the generation of high number-average degree of perfluorolyethers. The optimization reaction time is 24 h, and fiarther increase of reaction time does not significantly affect the average relative molecular mass. The product was characterized by IR, 19F NMR and GC-MS, and the catalytic mechanism was analyzed finally.

From Steady 4D Quantization of Valence Electrons to Material Space Paradigm

Potential electric and gravitational fields do not change steady quantized states of electrons in chemical bonds, microscopic clusters of charges and macroscopic superconducting rings. There are no theoretical grounds to create Squid-type instruments to measure electric and gravitational fields with quantum accuracy basing on the Bohr-Sommerfeld quantization of charged particles. Squid-verified spatial flatness for superfluid electrons corresponds to the material space paradigm for reality.

Preliminary Studies on Composition, Quality and Oxidative Stability of Commercial Avocado Oil Produced in Chile

Avocado oil is a relatively new oil in the market and is highly appreciated by the consumers because of its fine aroma, pleasant taste and health benefits. A study on the characterization of commercial avocado oils produced in Chile was conducted in order to discuss their quality parameters. The study was applied to two marketed avocado oils. The main analytical parameters evaluated to the oils were： fatty acid composition, total chlorophylls, total carotenoids, tocopherols, acid value, peroxide value, total phenolic compounds, polar compounds, oil stability, UV absorption and 3.5-stigmastadiene content. The fatty acid compositions of the studied oils were according with oil composition of pulp pure of avocado fruit. The analysis of tocopherols by high performance liquid chromatography （HPLC） revealed significant differences between the avocado oils studied. Total phenolic compounds, oil stability, UV Absorption characteristics, peroxide value, acid value, tocopherols content, total chlorophylls, total carotenoids and polar compounds were also significantly different between the commercial studied oils. All the above results show a different quality between both commercial avocado oils, showing that the sample C has worse values for the parameters of quality as those required by legislation in many countries. Also, 3.5-stigmastadiene content shows high concentration for one of the commercial avocado oil evaluated which demonstrates the presence of refined oil or that the oil has been submitted to high temperatures. On the other hand it is remarkable that despite the fact that there are many differences in quality parameters, both oils are labeled and marketed as extra virgin quality oils, demonstrating the need to regulate the classification of appreciated oils by the consumers.

Bounds on Higgs and top quark masses from vacuum stability(degeneracy) with gravitational contributions

Based on the two-loop RGE of standard model gauge, top-Yukawa as well as scalar quartic couplings with full one-loop gravitational contributions in harmonic gauge, we study the constraints on the Higgs and top quark mass from the requirement that the other degenerate vacua at the Planck-dominated region exists. Our numerical calculations show that nature will not develop the other degenerate vacua at the Planck-dominated region with current Higgs and top quark masses. On the other hand, requiring the existence of the other degenerate vacua at the Planck-dominated region will constrain the Higgs and top mass to lie at approximately 130 and 174 Ge V, respectively.