Synthesis and Characterization of Fluorine-containing Polyacrylate Emulsion with Core-Shell Structure

A fluorine-containing polyacrylate copolymer emulsion was synthesized by a seed emulsion polymerization method, in which methyl methacrylate （MMA） and butyl acrylate （BA） were used as main monomers and hexafluorobutyl methacrylate （HFMA） as fluorine-containing monomer. The structure and properties were characterized by Fourier transform infrared spectrum （FT-IR）, transmission electron microscopy （TEM）, particle size analysis, X-ray photoelectron spectroscopy （XPS）, contact angle （CA）, differential scanning calorimetry （DSC） and thermogravimetry （TG） analysis. The FTIR and TEM results showed that HFMA was effectively involved in the emulsion copolymerization, and the formed emulsion particles had a core-shell structure and a narrow particle size distribution. XPS and CA analysis revealed that a gradient concentration of fluorine existed in the depth profile of fluorine-containing emulsion film which was richer in fluorine and more hydrophobic in one side. DSC and TG analysis also showed that a clear core-shell structure existed in the fluorine-containing emulsion particles, and their film showed higher thermal stability than that of fluorine-free emulsion.

SYNTHESIS AND THERMAL PROPERTIES OF POLYBENZOXAZOLE FROM SOLUBLE PRECURSOR WITH HYDROXY-SUBSTITUTED POLYENAMINONITRILE

Aromatic polybenzoxazole (PBO) precursor, hydroxy-substituted polyenaminonitrile, was prepared by direct polycondensation of 1,4-bis(1-chloro-2,2-dicyanovinyl)benzene (CCB) and 4,6-diaminoresorcinol dihydrochloride (DAR) using pyridine and N,N-dimethylacetamide as condensing agent and solvent. The precursor has good solubility in polar aprotic solvent which is due to the strong dipolar nature of the main chain. The soluble precursor was subjected to thermal cyclization in an inert atmosphere to convert it into the corresponding PBO, which has its 5% weight loss temperature at The fully cyclized PBO were characterized by FT-IR and TGA. The introduction of 10% mol 1,3,5- benzenetricarboxylic chloride (BTC) into the main chain not only has little effect on the solubility of PBO precursor but also raises its 5% weight loss temperature to 552°C and char yield at 700°C for the cyclized PBO with BTC.

Research progress on preparation and purification of fluorine-containing chemicals in lithium-ion batteries

With the development of digital products,electric vehicles and energy storage technology,electronic chemicals play an increasingly prominent role in the field of new energy such as lithium-ion batteries.Electronic chemicals have attracted extensive attention in various fields.Characteristics of high-end electronic chemicals are high purity and low impurity content,which requires a very strict separation and purification process.At present,crystallization is a key technology for their separation and purification of electronic chemicals.In this work,the representative fluorine-containing compounds in cathode and anode materials,separator and electrolyte of lithium-ion batteries are introduced.The latest technologies for the preparation and purification of four kinds of fluorine-containing battery chemicals by crystallization technology are reviewed.In addition,the research prospects and suggestions are put forward for the separation of fluorine-containing battery chemicals.

SYNTHESIS AND CHARACTERIZATION OF A NOVEL FLUORINE-CONTAINING HYDROPHOBICALLY ASSOCIATING POLYMER

In this article, the synthesis and characterization of a novel fluoromonomer and its copolymer with acrylamide is reported. 2-perfluoroamyl-4-hydroxylquinoline 2 was synthesized from ethyl 2, 2-dihydroperfluoroheptanoate in high yields. The monomer 4 was then synthesized from 2 in two steps readily in high yields. Synthesis and characterization of copolymers of acrylamide (AM) and the fluoromonomer were investigated. The composition and intrinsic viscosity of these copolymers were studied. It was found that the rheological properties of aqueous solutions of polyacrylamide were modified significantly when a small proportion of the fluoromonomer 4 was incorporated on investigating the viscosity-concentration profiles, pseudoplasticity of these solutions and the effect of the presence of surfactant. These results could be explained by the hydrophobic association of the fluorocarbon segments in the aqueous solutions of these copolymers.

Design and Synthesis of Novel Fluorine-containing Acrylates

A series of novel fluorine-containing acrylates 6a-6g were synthesized via the condensation of ethyl cyanoacetate and trifluoroacetic anhydride, followed by chloridization and the coupling reaction with amines. These new compounds exhibited some biological activity as preliminary bioassay indicated. A plausible reaction mechanism was outlined and discussed.

Preparation and Characterization of Aromatic Polybenzoxazoles Copolymers Containing 2,6-Naphthalene Units

A series of polybenzoxazoles(co)polymers bearing crankshaft units in the main chain was synthesized by the conventional solution polycondensation of 4,6-diaminorescinol dihydrochloride, terephthalic acid(TA) and 2,6-naphthalene dicarboxylic acid(NDA). All of the polymers show lyotropic liquid crystal behavior in polyphosphoric acid(PPA) and methanesulfonic acid(MSA). The polybenzoxazoles exhibit an excellent thermal resistance although the crankshaft monomer has been introduced into the polymer backbone. The temperature for the 5% weight loss of all the polymers is above 600 ℃.The X-ray diffraction analysis results show that the series of the polymers has a high crystallinity. The introduction of NDA makes a slight decrease in the thermal resistance of the polymers. The maximum absorption peak in the UV-Vis spectra can be adjusted according to the amount of 2,6-naphthalene units in the polymers, which indicates the potential application of the polymers as optoelectric materials.

Michael Addition of Nitroalkanes to CF_3CCl_2COCH=CHPh: A Facile Route to Fluorine-containing γ-Nitro Ketones

Nitroalkanes react smoothly with CF_3CCl_2COCH=CHPh via Michael addition in the presence of inorganic bases such as KF/Al2O3 or K2CO3, giving fluorinecontaining γ-nitro ketones in good yields.

Synthesis and Characterization of Fluorine-containing Poly(ether ether ketone)s

Poly（ether ether ketone）s（PEEK） are a class of high performance engineering thermoplastics known for their excellent thermal, mechanical, and electrical properties. This class of advanced materials has currently received considerable attention for potential application in aerospace, electronics, automobile and other high technology fields. However, it is difficult for PEEK to be processed because of their high melting temperature and poor solubility.

A CONVENIENT SYNTHESIS OF FLUORINE-CONTAINING QUINOLINES

2-Fluoroalkyl-4-hydroxy-quinolines were easily obtained from the reactions of 2-(F-alkyl)acetates with aromatic amines in the presence of Et_3N,followed by cyclization of the intermediates with PPA.

PBO fibers/fluorine-containing liquid crystal compound modified cyanate ester wave-transparent laminated composites with excellent mechanical and flame retardance properties

Bisphenol A dicyanate ester resins modified by fluorine-containing liquid crystal compound(LCFE)are applied as polymer matrix(LCFE-BADCy),poly(p-phenylene-2,6-benzobisoxazole)(PBO)fibers as rein-forcements,and fluorine/adamantane PBO precursor(pre FABPBO)as interfacial compatibilizer to prepare the corresponding PBO fibers/FABPBO/LCFE-BADCy wave-transparent laminated composites.LCFE could improve the order degree of BADCy cured network,in favor of enhancing the wave-transparent perfor-mance,mechanical properties,and intrinsic thermal conductivity.The dielectric constant and dielectric loss of PBO fibers/FABPBO/LCFE-BADCy composites are highly temperature(25–200℃)and frequency(10^(4)–10^(7) Hz and 8.2–12.4 GHz)stable with the value of 2.49 and 0.003 under 10^(6) Hz at 25℃,and the corresponding wave transmission efficiency is 95.0%,higher than that of 92.5%for PBO fibers/BADCy com-posites.The interlamellar shear strength and flexural strength are respectively 50.7 MPa and 682.5 MPa,38.1%and 16.2%higher than those of PBO fibers/BADCy composites.Besides,the volume resistivity,breakdown voltage,heat resistance index,glass transition temperature,flame retardant grade,and ul-timate oxygen index of PBO fibers/FABPBO/LCFE-BADCy composites are respectively 5.3×10^(15)Ωcm,29.75 kV/mm,217.2℃,245.7℃,V-1 grade,and 33.6%,expected to be performed as a new generation of“lightweight/loading/wave-transparent”electromagnetic window materials in advanced military weapons and civil communication base station.

The action mechanisms and structures designs of F-containing functional materials for high performance oxygen electrocatalysis

Non-renewable fossil fuels have led to serious problems such as global warming,environmental pollution,etc.Oxygen electrocatalysis including oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)plays a central role in clean energy conversion,enabling a number of sustainable processes for future air battery technologies.Fluorine,as the most electronegative element(4.0)not only can induce more efficient regulation for the electronic structure,but also can bring more abundant defects and other novel effects in materials selection and preparation for favorable catalysis with respect to the other nonmetal elements.However,an individual and comprehensive overview of fluorine-containing functional materials for oxygen electrocatalysis field is still blank.Therefore,it is very meaningful to review the recent progresses of fluorine-containing oxygen electrocatalysts.In this review,we first systematically summarize the controllable preparation methods and their possible development directions based on fluorine-containing materials from four preparation methods.Due to the strong electron-withdrawing properties of fluorine,its control of the electronic structure can effectively enhance the oxygen electrocatalytic activity of the materials.In addition,the catalytic enhancement effect of fluorine on carbonbased materials also includes the prevent oxidation and the layer peeling,and realizes the precise atomic control.And the catalytic improvement mechanism of fluorine containing metal-based compounds also includes the hydration of metal site,the crystal transformation,and the oxygen vacancy induction.Then,based on their various dimensions(0D–3D),we also have summarized the advantages of different morphologies on oxygen electrocatalytic performances.Finally,the prospects and possible future researching direction of F-containing oxygen electrocatalysts are presented(e.g.,novel pathways,advanced methods for measurement and simulation,field assistance and multi-functions).The review is considered valuable and helpful in exploring the novel designs and mechanism analyses of advanced fluorine-containing electrocatalysts.

Fluorine-containing drugs approved by the FDA in 2021

Nine new fluorine-containing drugs have been approved by the US Food and Drug Administration(FDA)in 2021,which are presented in this review article.These small molecular drugs feature aromatic fluorine,trifluoromethyl and chlorodifluoro groups.The therapeutic areas of these fluorine-containing drugs include multiple myeloma,lymphoma,HIV,chronic heart failure,chronic myeloid leukemia,(ANCA)-associated vasculitis,migraines,von Hippel-Lindau disease,and non-small cell lung cancer.The brief biological activities and the synthetic methods have been discussed in this review for each of these nine drugs.

Low dielectric constant and highly intrinsic thermal conductivity fluorine-containing epoxy resins with ordered liquid crystal structures

Epoxy resins with a high dielectric constant and low intrinsic thermal conductivity coefficient cannot meet the current application requirements of advanced electronic and electrical equipment.Therefore,novel fluorine-containing liquid crystal epoxy compounds(TFSAEy)with fluorinated groups,biphenyl units,and flexible alkyl chains are first synthesized via amidation and esterification reactions.Then,4,4′-diaminodiphenylmethane(DDM)is used as a curing agent to prepare the corresponding fluorine-containing liquid crystal epoxy resins.The obtained dielectric constant(ε)and dielectric loss(tanδ)values of TFSAEy/DDM at 1 MHz are 2.54 and 0.025,respectively,which are significantly lower than those of conventional epoxy resins(E-51/DDM,3.52 and 0.038).Additionally,the intrinsic thermal conductivity coefficient(λ)of TFSAEy/DDM is 0.36 W/(m⋅K),71.4%higher than that of E-51/DDM(0.21 W/(m⋅K)).Meanwhile,the corresponding elastic modulus,hardness,glass transition temperature,and heat resistance index of TFSAEy/DDM are 5.73 GPa,0.35 GPa,213.5◦C,and 188.7℃,respectively,all superior to those of E-51/DDM(3.68 GPa,0.27 GPa,107.2℃,and 174.8℃),presenting potential application in high-heating electronic component packaging and printed circuit boards.

高相对分子质量PBO的聚合及其高性能纤维的成型

以自行合成的4,6-二氨基间苯二酚盐酸盐(DAR)和商品对苯二甲酸(TPA)为单体原料,以多聚磷酸(PPA)为溶剂,制备了高相对分子质量PBO聚合物．研究了PBO聚合过程中TPA单体的粒径、溶剂的浓度以及搅拌器,聚合前脱除HCl的方式对PBO聚合和所得产物分子质量的影响．结果表明,TPA粒径小、聚合结束时PPA中P2O5的浓度维持在84％左右,有利于得到高相对分子质量的PBO聚合物．新型双螺带搅拌器能提高搅拌的效果,加压脱除HCl的工艺能有效地实施聚合的稳定控制,利用双螺杆挤出机同时完成了后聚合和液晶纺丝,得到了特性粘度([η])达到20-30 dL/g的PBO聚合物,采用干喷湿法成型制备出的金黄色的PBO纤维手感柔软、拉伸强度达到4．38 GPa．

液晶态高分子量PBO的合成工艺及性能研究

通过改进的三氯苯合成路线合成高纯度的4.6-二氨基间苯二酚盐黢盐,使用红外光谱和核磁共振氢谱对得到的产物进行了表征分析,证明得到了纯度很高的4.6-二氨基间苯二酚盐酸盐。使用合成的单体聚合得到了高分子量的聚对苯撑苯并二(?)唑(PBO)。在聚合过程中脱察到了明显的爬杆现象和搅拌乳光。对得到的聚合物进行推膜,并进行了红外光谱和热失重法分析,证明得到了热稳定性高的离分子量PBO。

一种新的4,6-二氨基间苯二酚盐酸盐的制备方法及与对苯二甲酸的缩合聚合

以间苯二酚为原料 ,通过乙酰化、肟化、 Beckmann重排、水解反应制备 4,6-二胺基间苯二酚盐酸盐( DAR· 2 HCl) ,并用 FTIR,MS,元素分析 ,1 H NMR和 1 3C NMR等对 DAR· 2 HCl及中间体进行了表征 .同时 ,将 DAR· 2 HCl和对苯二酸 ( TPA)成盐 ,然后进行缩聚得到具有较高分子量的 PBO.通过 FTIR和固体 1 3C NMR表征了 PBO的结构 ,并研究了

聚苯并噁唑(PBO)的合成及其应用研究

聚苯并噁唑(PBO)因其具有的强度大、耐高温、耐氧化、耐潮湿以及优良的热稳定性等特点,自20世纪80年代以来一直是人们关注的热点之一。综述了PBO的合成方法,如多磷酸法、中间相聚合法、三甲基硅烷基化法、对羟基苯甲酸酯法,并介绍了PBO纤维的性质,对其应用前景作了展望。

聚苯并噁唑树脂的合成及其应用

介绍了聚苯并噁唑树脂的发展概况以及合成聚苯并噁唑树脂的主要单体和聚合工艺;阐述了聚苯并噁唑的性能和推广应用的前景。

液晶芳族聚苯唑的热稳定性及应用

溶致液晶性芳香族聚苯唑是指大分子链上含有噻唑环、唑环或咪唑环等的一类全芳族杂环高聚物。最典型的代表是聚对苯撑苯并二噻唑（ＰＢＴ）和聚对苯撑苯并二唑（ＰＢＯ），它们的分子结构式分别为：芳族聚苯唑大分子链的高度芳香性，使其具有明显的液晶性能、优异的力...