1-(反式-4-烷基环己基)-苯基-2-含氟苯基取代乙炔类液晶的合成与性能

以烷基环己酮和溴苯为起始原料,通过格氏反应、氢解、傅克酰化、维格特氧化、乙酰氯加成、脱氯化氢等9步反应,合成了末端为4-F、3,4-F,F、3-F及3,5-F,F基团的4个1-(反式-4-烷基环己基)-苯基-2-含氟苯基取代乙炔类液晶化合物,总收率为6.7%~7.6%,产物结构经IR,1HNMR确认。其中氯代二芳基取代乙烯(Ⅷ)的合成采用简便的乙酰氯加成反应得到,使反应缩短了两步。化合物添加到液晶的基础配方中,能同时改善基础配方的低温和高温性能,提高其双折射率,增加响应速度。     

Fluorinated Pseudopeptide Analogues of the Neuropeptide 26RFa: Synthesis,Biological, and Structural Studies

A series of four fluorinated dipeptide analogues each containing a fluoro‐olefin moiety as peptide bond surrogate has been designed and synthesized. These motifs have been successfully introduced into the bioactive C‐terminal heptapeptide of the neuropeptide 26RFa by conventional SPPS. We then evaluated the ability of the generated pseudopeptides to increase [Ca²⁺]_i in GPR103‐transfected cells. For these fluorinated analogues, greater stability in human serum was observed. Their conformations were also investigated, leading to the valuable identification of differences depending on the position of the fluoro‐olefin moiety in the sequence.     

常温固化氟涂料的制备、性能及发展(上)

常温固化氟涂料具有卓越的性能。本文着重介绍了常温固化氟涂料实现的途径、性能、制备及其发展。     

铀—对氟偶氮氯膦显色反应萃取光度法的研究及应用

较系统地研究了７种不对称变色酸双偶氮氯膦类试剂与铀（Ⅵ）的显色反应,发现其中对氟偶氮氯膦为分光光度法测定铀的较好试剂。在ｐＨ２．５条件下,配合物最大吸收波长为６５５ｎｍ,摩尔吸光系数ε＝４．５８×１０４Ｌ·ｍｏｌ－１·ｃｍ－１。铀（Ⅵ）浓度在０．０～６０μｇ／２５ｍＬ符合比尔定律,相关系数ｒ＝０．９９９４。用磷酸三丁酯－苯萃取分离铀后,将该方法用于测定矿石中铀,结果满意。     

丙烯酸酯橡胶的研究与应用

采用丙烯酸酯类单体通过乳液聚合制备了丙烯酸酯橡胶（ＡＣＭ）。试验研究了ＡＣＭ硫化胶的性能。结果表明,ＡＣＭ引入—ＣＯＯＨ基团,用环氧树脂作硫化剂,可以实现高温快速硫化,且其硫化胶性能良好;增大带有柔性基团的单体（增塑剂）的比例,可以改善ＡＣＭ硫化胶的耐低温性;增大极性大的单体（丙烯腈）的比例,可以改善ＡＣＭ硫化胶的耐油性和耐热性。ＡＣＭ与氟橡胶（ＦＫＭ）并用初步研究结果显示,ＦＫＭ的用量在５０份以上时,并用硫化胶性能接近ＦＫＭ     

二段硫化对氟橡胶性能的提高及耐热性的影响

通过改变不同配方的氟橡胶二段硫化温度和时间，确定了最佳硫化条件。结果表明．氟橡胶经二段硫化后力学性能明显提高；经300℃热空气老化后发现，不同二段硫化条件对氟橡胶的耐热性有着不同的影响。     

Fabrication and Characteristics of Poly(benzimidazole/fluoro/ether/siloxane/amide)/Sulfonated Polystyrene/Silica Nanoparticle-Based Proton Exchange Membranes Doped With Phosphoric Acid

Novel poly(benzimidazole/fluoro/ether/siloxane/amide) (PBFESA) was developed for the formation of hybrid proton exchange membrane. Afterward, phosphoric acid doped PBFESA/PS-S/SiNPs was prepared with PBFESA, sulfonated polystyrene (PS-S), and 0.1–2 wt% silica nanoparticles (SiNPs). Tensile strength of acid doped PBFESA/PS-S/SiNPs nanocomposites increased from 63.9 to 68.1 MPa with increasing SiNPs loading. They had higher ion exchange capacity (IEC) of 2.3–3.3 mmol/g and proton conductivity of 1.9–2.7 S/cm at 80°C (higher than perfluorinated Nafion 117 membrane 1.1 × 10^?1 S/cm). A H₂/O₂ fuel cell using PBFESA/PS-S/SiNPs 2 (IEC 3.3 mmol/g) showed better performance than Nafion 117 at 40°C (30% RH).     

Synthesis of 3′‐Fluoro‐tRNA Analogues for Exploring Non‐ribosomal Peptide Synthesis in Bacteria

Aminoacyl‐tRNAs (aa‐tRNAs) participate in a vast repertoire of metabolic pathways, including the synthesis of the peptidoglycan network in the cell walls of bacterial pathogens. Synthesis of aminoacyl‐tRNA analogues is critical for further understanding the mechanisms of these reactions. Here we report the semi‐synthesis of 3′‐fluoro analogues of Ala‐tRNA^Ala. The presence of fluorine in the 3′‐position blocks Ala at the 2′‐position by preventing spontaneous migration of the residue between positions 2′ and 3′. NMR analyses showed that substitution of the 3′‐hydroxy group by fluorine in the ribo configuration favours the S‐type conformation of the furanose ring of terminal adenosine A76. In contrast, the N‐type conformation is favoured by the presence of fluorine in the xylo configuration. Thus, introduction of fluorine in the ribo and xylo configurations affects the conformation of the furanose ring in reciprocal ways. These compounds should provide insight into substrate recognition by Fem transferases and the Ala‐tRNA synthetases.     

高耐久涂料用交联型氟树脂

介绍了氟化学品及氟聚合物的国内外概况及氟树脂的合成，讲解超耐候建筑外墙涂料、室外钢结构防腐蚀、铝合金建筑型材、卷钢和卷铝用氟碳涂料等所用氟碳树脂的指标、应用及涂料性能。     

ETFE薄膜单向拉伸性能

对3种厚度的ETFE(乙烯-四氟乙烯共聚物)薄膜沿MD及TD方向裁取的试样进行了单向拉伸试验,得到了相应的应力-应变拉伸曲线、抗拉强度及断裂延伸率.通过分析,给出了确定拉伸曲线上2个刚性转折点的方法,由此得到了对应于转折点的屈服应力和应变;给出了ETFE薄膜弹性模量的计算方法,并由拉伸曲线计算得到了切线弹性模量、割线弹性模量、第二和第三弹性模量;借助高精度数字照相方法,测定了ETFE薄膜的泊松比.结果表明,试验中采用的ETFE薄膜材料沿MD及TD方向的单向拉伸特性基本相同.