硅灰石填充尼龙-6复合体系的非等温结晶行为及动力学研究

用差示扫描量热法(DSC)考察了硅灰石填充尼龙-6复合体系的非等温结晶行为,并用Avrami以及Mo法研究了其非等温结晶动力学。结果表明,随着降温速率的增加,复合体系的结晶峰变宽并向低温方向移动,结晶速率增加。通过对比,Mo法能很好地描述硅灰石填充尼龙-6复合体系的非等温过程。     

Studies on Impact Toughening and Thermal Properties of Nylon-6/LDPE-g-MAH Blends

Polyamide (PA)-6 is an engineering thermoplastic. It finds its application in electrical, mechanical, and automotive parts due to its very high processing and excellent barrier properties to oils. Unfortunately, Nylon-6 (Ny6) is relatively high priced, has poor impact strength, particularly when notched, and poor dimensional stability as well as poor barrier properties to moisture, which limits its applicability. On the other hand, due to low cost, low coefficient of friction, lightweight, high strength, high barrier properties to moisture, good optical properties, and ease of processing, low density polyethylene (LDPE) is an ideal material to incorporate with Polyamide-6 for film, container, and many engineering applications. The present study deals with the preparation of Nylon-6 and modified LDPE (MLDPE) blends, varying the MLDPE concentration from 0 to 50 wt%. The objective of this study is to find the effect of maleic-anhydride grafted low-density polyethylaene on various mechanical properties such as tensile, impact, and flexural properties of Nylon-6. There is a decrease in tensile and flexural properties, the notched Izod impact strength increased greatly when the MLDPE content was 20%. It includes the study the effect of MLDPE on thermal properties and morphological properties of Nylon-6. The morphology of PA/MLDPE blends showed dispersed particle in the polymeric matrix.     

Synthesis and nonisothermal crystallization kinetics of thermoplastic polyamide-6 elastomers

Three kinds of thermoplastic polyamide-6 elastomers (TPAEs) with varying polytetramethyleneglycol (PTMG) contents of 10, 20, and 30 wt % were prepared via a one-pot polymerization synthetic route and named as TPAE1, TPAE2, and TPAE3, respectively. First, their structures were investigated by Fourier transform infrared spectroscopy, proton nuclear magnetic resonance spectroscopy, scanning electron microscope, and X-ray diffraction. The obtained results confirmed that targeted TPAEs were successfully synthesized and the unit cell of crystallization in TPAEs with α form was confirmed. Subsequently, the thermal properties of prepared TPAEs were characterized by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) measurements, respectively. DSC curves showed that melting points of synthesized TPAEs were in the range of 209.2–215.9 °C. Moreover, TGA results showed TPAEs possess good thermal stability and cannot be decomposed under 300 °C. Additionally, the modified Avrami's equation, Ozawa's theory, and Mo's method were employed to investigate the nonisothermal crystallization kinetics of prepared TPAEs. It is found that the Mo's method exhibited great advantages in treating the nonisothermal crystallization kinetics of prepared TPAEs. Meanwhile, the crystallization kinetics and halftime are influenced by the contents of PTMG and follows a nonlinear fashion in agreement with the trend inactivation energies calculated by the Kissinger method. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47388.     

基体粘度对PA-6／纳米CaCO3复合体系结构与性能的影响

研究了基体粘度对复合体系力学性能、吸水率和尺寸稳定性的影响。采用扫描电镜和透射电镜分析、观察了不同粘度基体的PA-6／纳米CaCO3复合体系冲击断面的微观形态，及纳米CaCO3粒子在不同粘度基体中的分散状况。结果表明，纳米CaCO3粒子在相对粘度较大的PA-6基体中更易分散，分散均匀性提高，冲击断面呈现韧性断面；适量的纳米CaCO3，能提高PA-6／CaCO3复合体系的冲击强度，特别是对粘度较大(R．V．=2．8dL／g)的基体，复合材料的冲击强度提高了40％。而体系的拉伸强度基本不降低。同时，纳米CaCO3的加入，能降低复合体系的吸水率，提高尺寸稳定性，与基体的粘度无关。     

Effect of the Activator Type and Catalyst/Activator Ratio on Physical and Mechanical Properties of Cast PA-6

The aim of the study is to produce suitable unfilled cast polyamide-6 composition exhibiting optimum mechanical, physical, thermal and electrical properties with anionic polymerization mechanism. Sodium lactamate was used as catalyst at all compositions. Activators used were varied as toluenediisocyanate (TDI), isophronediisocyanate (IPDI), hexamethylenediisocyanate (HMDI) and diphenylmethylenediamine (DPMD). Also, activator and catalyst content were varied between 0.4–0.8% and 1–4% respectively. The best mechanical properties were attained with using TDI as activator at 0.488%. Then, other properties of this composition were determined. Comparison of these properties with other plastics showed that it had the highest abrasion resistance, lower water absorption, higher tensile and flexural strength.     

Synthesis and Structure Characterization of Some Triorganotin Esters of Heteroaromatic Carboxylic Acid and Crystal Structure of Triphenyltin Esters of 6-Hydroxynicotinic Acid and 5-Chloro-6-hydroxynicotinic Acid

Reactions of (R₃Sn)₂O (R=Ph, 2-ClC₆H₄CH₂, 2-FC₆H₄CH₂, 4-CNC₆H₄CH₂) with 6-hydroxynicotinic acid and 5-chloro-6-hydroxynicotinic acid in 1:2 stoichiometry yielded eight triorganotin compounds. These compounds have been characterized by elemental analysis, IR and ¹H NMR spectroscopy. The crystal structures of triphenyltin esters of 6-hydroxynicotinic acid (1) and 5-chloro-6-hydroxynicotinic acid (2) were determined by single crystal X-ray diffraction. In these two compounds the tin atoms are rendered five-coordinate in a trigonal bipyramidal structure by coordination though the three phenyl carbon atoms and two oxygen atoms, one from carboxylate and other from the phenolic hydroxide. The resulting structures are two one-dimensional linear polymers through an interaction between the O atoms of phenolic hydroxide and tin atoms of an adjacent molecule.     

浸萃联合法制取硼酸新工艺

以盐酸为分解剂,异辛醇为萃取剂,煤油为稀释剂,采用浸取萃取联合的方法对辽宁宽甸的低品位硼镁矿进行工艺处理以制备硼酸。采用离子交换分离-酸碱滴定法和络合滴定法分别对试样中硼和镁的含量进行测定。通过系列实验获得了优化工艺参数如下:反应温度95℃,反应时间60min,油相:水相:固相=4∶3∶1,酸量为1.05倍的理论酸量,萃取级数4～6级,稀释剂∶萃取剂=1∶1。在该工艺参数下,MgO和B2O3的分解率可达到95%以上,硼酸四级萃取率达到90%以上。     

Structure and Tribological Performance of Monomer Casting Nylon-6/Colloidal Graphite Composites Synthesized through in Situ Polymerization

A series of monomer casting nylon-6/colloidal graphite composites were synthesized through in situ anionic ring-opening polymerization. It was found that colloidal graphite layers modified with titanate coupling agent had a uniform distribution in the matrix, and the molecular weight of monomer casting nylon-6 decreased slightly below 5?wt% titanate coupling agent-colloidal graphite content. The crystallizing ability was much improved at lower titanate coupling agent-colloidal graphite content, indicating the nucleation effect of titanate coupling agent-colloidal graphite on monomer casting nylon-6. The notched charpy impact strength of the composites increased by addition of 0.5–1?wt% titanate coupling agent-colloidal graphite, and the obvious ductile fracture characteristics was presented. Meanwhile the storage modulus and the glass transition temperature (T_g) increased, and the loss factor (tan δ) decreased by addition of titanate coupling agent-colloidal graphite, indicating the toughening effect of titanate coupling agent-colloidal graphite on monomer casting nylon-6 matrix and improvement of the stiffness of the composites. Compared with neat monomer casting nylon-6 specimen, the composites presented a remarkable lower friction coefficient at the initial friction stage, and the wear resistance of monomer casting nylon-6/4?wt% titanate coupling agent-colloidal graphite specimen was enhanced by more than 10-fold. For neat monomer casting nylon-6, the melting and crystallization temperature, and crystallinity of the worn surface were obviously higher than that of the bulk part, indicating that the surface was fully annealed and the crystallizing ability was improved under produced friction heat, resulting in a poor anti-wear performance with abrasive wear form. For monomer casting nylon-6/titanate coupling agent-colloidal graphite composite, the annealing degree of the surfaces exhibited much lower than that of neat monomer casting nylon-6, due to the protective effect and suppression effect of titanate coupling agent-colloidal graphite layers and reduction of friction heat, resulting in the formation of uniform transfer film and a significant improvement of the wear resistance of the composites with the adhesive wear form.     

尼龙6纤维酸性染料染色性能的研究现状及进展

从尼龙6纤维的酸性染料染色机理出发,讨论了影响纤维酸性染料染色性能的因素,包括热处理条件、pH值、温度等;并在此基础上,提出了改善尼龙6纤维酸性染料染色性能的方法,如加入匀染剂或其他助剂、引入特殊的结构基团、提高末端胺基含量、加入稳定剂、超声波处理和氧化还原处理等。     

2,6-萘二甲酸及其酯的制备和应用

本文介绍了 2 ,6 -萘二甲酸及其酯的各种制造方法、应用及国内外发展概况     

Modified Nonconventional Synthesis of New Terpoly(Aniline,o-Anthranilic Acid and o-Phenylenediamine)/Bentonite Composites

Terpolymers of aniline, anthranilic acid and o-phenylenediamine/Hydrophilic bentonite composites were synthesized using a 1:1:1 molar ratio of the respective monomers with different percentages of clay via modified in situ chemical terpolymerization. The spectral characteristics upon incorporation of anthranilic acid units into the copoly(aniline o-phenylenediamine) backbone in absence and in presence of bentonite nanoparticles were investigated. Moreover, terpolymer/bentonite composites were thermally more stable than pure terpolymer under nonoxidative condition. On the basis of surface morphological studies of terpolymer composites, a platy network texture can be explained, and it can be clearly seen in the SEM photomicrographs.     

Vilsmeier氯代制备三氯蔗糖-6-乙酸酯反应机理及氯代废液治理方法的研究

本文根据Vilsmeier试剂氯代反应制备三氯蔗糖-6-乙酸酯的机理,揭示该氯代反应必须经过升温氯代和碱催化水解两步反应完成。并对氯代废液中的主要残余物质,包括DMF、二甲胺、氯盐、甲酸盐等回收处理进行了探讨。     

Mutations of Glucose-6-Phosphate Dehydrogenase Durham,Santa-Maria and A+ Variants Are Associated with Loss Functional and Structural Stability of the Protein

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is the most common enzymopathy in the world. More than 160 mutations causing the disease have been identified, but only 10% of these variants have been studied at biochemical and biophysical levels. In this study we report on the functional and structural characterization of three naturally occurring variants corresponding to different classes of disease severity: Class I G6PD Durham, Class II G6PD Santa Maria, and Class III G6PD A+. The results showed that the G6PD Durham (severe deficiency), and the G6PD Santa Maria and A+ (less severe deficiency) (Class I, II and III, respectively) affect the catalytic efficiency of these enzymes, are more sensitive to temperature denaturing, and affect the stability of the overall protein when compared to the wild type WT-G6PD. In the variants, the exposure of more and buried hydrophobic pockets was induced and monitored with 8-Anilinonaphthalene-1-sulfonic acid (ANS) fluorescence, directly affecting the compaction of structure at different levels and probably reducing the stability of the protein. The degree of functional and structural perturbation by each variant correlates with the clinical severity reported in different patients.     

Modelling of the Hydrolysis of Benzylpenicillin to 6-Aminopenicillanic Acid and Phenyl Acetic Acid by an Immobilised Penicillin Amidase in a Small Pilot Plant Batch Recirculated Reactor

This paper deals with the modelling of the hydrolysis of benzylpenicillin to 6-aminopenicillanic acid (6-APA) and phenyl acetic acid (PAA) in a small pilot plant batch recirculated reactor by an immobilised penicillin amidase preparation. By using the following linearised form for an integrated Michaelis-Menten equation Et/V₀X=α+β| In (1-X)/X| where α and β are reaction kinetic parameters, good correlations are obtained of α and β with linear velocity across the reactor, substrate concentration and temperature of operation. A process to determine α and β from initial velocity measurements is outlined. The applicability of the above equation to published data is also analysed.     

重组结核杆菌Ag85a-ESAT6融合蛋白的原核表达、纯化及其生物活性

目的原核表达、纯化重组结核杆菌Ag85a-ESAT6融合蛋白,并检测其生物活性。方法将Ag85a-ESAT6融合基因片段插入pET-28a(+)载体中,构建重组质粒pET-28a-Ag85a-ESAT6,转化大肠杆菌BL21(DE3),IPTG诱导表达。表达产物在变性条件下经Ni-琼脂糖凝胶层析柱纯化复性后,在体外对经5种不同类型的表达结核杆菌Ag85a和ESAT6的重组痘苗病毒免疫的小鼠脾淋巴细胞进行刺激,以MTT法检测脾淋巴细胞的增殖反应。结果重组质粒pET-28a-Ag85a-ESAT6经双酶切及测序鉴定证明构建正确;表达的重组融合蛋白相对分子质量约41000,主要以包涵体形式表达,表达量占菌体总蛋白的55.65%;纯化复性的重组融合蛋白纯度达95%以上,表达量约为1.2g/L发酵液,且具有良好的反应原性;与空痘苗病毒或生理盐水免疫的小鼠相比,5种重组痘苗病毒免疫的小鼠脾淋巴细胞与Ag85a-ESAT6融合蛋白共培养后,增殖活性明显升高(P<0.01)。结论成功利用原核系统表达了结核杆菌Ag85a-ESAT6融合蛋白,纯化复性的Ag85a-ESAT6融合蛋白具有生物学活性。     

2, 3-吡嗪-二甲酸二顺6-壬烯酯的合成，热裂解分析及其卷烟加香应用

以顺6-壬烯醇和2, 3-吡嗪-二甲酸为原料,以环己基碳二亚胺（DCC）为缩水剂,在4-二甲氨基吡啶（DMAP）催化作用下,合成了2, 3-吡嗪-二甲酸二顺6-壬烯酯。其结构经IR, 1H NMR, 13C NMR, HRMS图谱对比得到验证,并对其进行了热裂解和卷烟加香实验。结果表明：(1)合成产物为目标产物;（2）裂解温度对合成产物的热裂解产物的种类和含量有较大影响,随着裂解温度的升高,裂解程度愈来愈剧烈;（3）目标产物在卷烟中的适宜用量为0.01%,目标产物加入到卷烟中后能够明显改善卷烟的吸食品质,协调烟香,减少刺激性和杂气,改善余味。     

Evaluation of 6-Hydroxydopamine and Rotenone In Vitro Neurotoxicity on Differentiated SH-SY5Y Cells Using Applied Computational Statistics

With the increase in life expectancy and consequent aging of the world’s population, the prevalence of many neurodegenerative diseases is increasing, without concomitant improvement in diagnostics and therapeutics. These diseases share neuropathological hallmarks, including mitochondrial dysfunction. In fact, as mitochondrial alterations appear prior to neuronal cell death at an early phase of a disease’s onset, the study and modulation of mitochondrial alterations have emerged as promising strategies to predict and prevent neurotoxicity and neuronal cell death before the onset of cell viability alterations. In this work, differentiated SH-SY5Y cells were treated with the mitochondrial-targeted neurotoxicants 6-hydroxydopamine and rotenone. These compounds were used at different concentrations and for different time points to understand the similarities and differences in their mechanisms of action. To accomplish this, data on mitochondrial parameters were acquired and analyzed using unsupervised (hierarchical clustering) and supervised (decision tree) machine learning methods. Both biochemical and computational analyses resulted in an evident distinction between the neurotoxic effects of 6-hydroxydopamine and rotenone, specifically for the highest concentrations of both compounds.     

Fatty Acids of Abyssal Echinodermata,the Sea Star Eremicaster vicinus and the Sea Urchin Kamptosoma abyssale: A New Polyunsaturated Fatty Acid Detected, 22:6(n-2)

Fatty acids (FA) of two species of abyssal Echinodermata—the sea star (Asteroidea) Eremicaster vicinus and the sea urchin (Echinoidea) Kamptosoma abyssale—from the Kuril–Kamchatka Trench, collected at depths of 5210 and 6183 m, were analyzed. Lipids of these deposit-feeding animals showed similar FA compositions: 20.05–16.08% saturated, 42.20–39.50% monoenoic, and 37.75–44.42% polyunsaturated FA, respectively. The contents of odd- and branched-chain FA were 17.35% and 8.80%, respectively. A significant part of FA was represented by uncommon FA such as 21:4(n-7), 22:4(n-8), 22:5(n-5), and 23:4(n-9), earlier discovered in deep-sea foraminifera. Also, the newly found acid, related to the ω2 family, Δ5,8,11,14,17,20–22:6(n-2), amounted 1.60% and 0.33% of total FA, respectively, for the two species. Such unusual FA composition of these abyssal species can be explained by the transfer and modification of FA from consumed foraminifera, which in turn, feed on bacteria.