大型悬浮PTFE聚合釜爆破片的爆破压力及直径选择对安全性能的影响

近年来，随着我国国内PTFE生产装置的不断扩大，悬浮PTFE聚合釜的规格也随之不断放大。容积从几年前的1000—3000升逐步放大到目前的8000升。据行业内消息，目前已有两个厂家的8000升釜成功投产，每釜聚合量可达1200kg，并有继续扩大的想法。随着聚合釜容积的放大。对于釜的安全性能，     

聚四氟乙烯的加工成型技术

综述聚四氟乙烯（PTFE）的性能特点，以及不同品种PTFE（悬浮聚合PTFE、乳液聚合PTFE和PTFE分散乳液）成型制品所适用的成型工艺。介绍PTFE的模压成型，等压成型，挤压成型，流延成型，热真空成型、热压成型、热吹塑成型及缠绕成型等技术。     

2.0万t／a小本体聚丙烯聚合单元设计优化

对某厂２．０万ｔ／ａ聚丙烯装置聚合釜的数量提出建议，通过计算得出用６台聚合釜代替原设计的８台聚合釜，呵满足设计生产能力要求，节省投资。     

工业聚合反应装置：Ⅲ.均相本体聚合反应器 上

在简述苯乙烯本体聚合反应器选型原理的基础上，介绍和推荐了一些新型装置，如塔式聚合反应器，卧式双轴聚合反应器等。     

聚合体系中添加羧酸对分散PTFE性能的影响

前言专利报导在(NH_4)_S_2O_8过氧化丁二酸高温引发聚合 TFE 的聚合体系中添加羧酸能使制得的 PTFE 制品的收缩率下降。又有专利报导添加-logK(电离常数)在1.5～6.0羧酸能减少凝聚物的形成。在引发剂仅为(NH_4)_2S_2O_8的 TFE 水相分散聚合体系中,添加羧酸是否降低 PTFE 的收缩率?为此在(NH_4)_2S_2O_8-TFE 分散聚合体系结合分散剂、引发剂加入方法的改变,进行了添加-logK 在1.5～6.0的多种脂肪族二元酸和一元酸的试验。用 DSC 对聚合物样品进行分析,并测试了 PTFE 加工制品时的     

吉玛公司20吨／日锦纶6切片聚合装置浅析

本文重要介绍分析了吉玛公司日产２０吨高速纺级锦纶６民用丝切片聚合装置的工艺流程及聚合装置的主要设备结构及性能。     

聚苯胺与苯胺共聚物对聚四氟乙烯膜亲水改性

采用分散聚合的方法在等离子处理的聚四氟乙烯(PTFE)多孔膜上沉积聚苯胺(PANI)或苯胺共聚物进行亲水改性.通过拉曼光谱、扫描电镜、接触角等测试对比研究表明,苯胺共聚物与PANI有类似的化学结构,等离子处理使聚合历程的峰温提高,后期聚合速率增大,但处理时间不宜过长;PANI及其苯胺共聚物在PTFE膜表面的沉积都对PTFE膜亲水性有了良好的改观,苯胺共聚物亲水改性效果优于PANI的.     

辽化HDPE装置浆液化循环技术改造后釜内的聚合过程分析

通过对辽阳石油化纤公司高密度聚乙烯淤浆聚合装置外循环撤热技术改造前后生产ＧＦ７７５０Ｍ牌号产品时聚合过程的工程分析，发现了釜内聚合过程特征的变化，提出了聚乙烯蜡含量的明显上升是引起聚合物粘壁加剧的最直接原因，并通过分析得出了可能导致聚乙烯蜡含量上升的主要因素以及进一步提高装置生产能力的可能性和主要手段。     

化纤公司聚合装置及其发展前景

根据目前世界聚酰胺生产技术现状，针对化纤公司聚合装置实际情况及目前存在的问题，在聚合工艺改进与技术管理上，提出了聚合装置的发展设想。     

工业聚合反应装置 Ⅰ.进展评述

本文是“工业聚合反应装置“系列专论的首报,也是整个系列的导言。文中按聚合方法和设备结构型式,将工业聚合反应装置的核心即反应器分为１０类,并大要地讨论了各类反应器反应工程特性和发展趋势,结合悬浮聚合、乳液聚合、溶液聚合、本体聚合和缩聚等工艺,图示了６种工业聚合反应器。     

Surface grafting polymerization and modification on poly(tetrafluoroethylene) films by means of ozone treatment

Surface modification on polytetrafluoroethylene (PTFE) films was performed with sequential hydrogen plasma/ozone treatments and surface-initiated polymerization. C-H groups were introduced to the surface of PTFE films through defluorination and hydrogenation reactions under hydrogen plasma treatment. The C-H groups then served as ozone accessible sites to form peroxide groups under ozone treatment. Grafting polymerization initiating from the peroxide groups was performed on the PTFE film surface with using acrylamide, acrylic acid, glycidyl methacrylate and 2-(2-bromoisobutyryloxy)ethyl acrylate (BIEA) as monomers. With utilizing the isobutylbromide groups on the surface of PTFE-g-PBIEA film as initiators, sodium 4-styrenesulfonate (NaSS) was polymerized onto the PTFE film surface via atom transfer radical polymerization, to bring arborescent macromolecular structure to PTFE film surface. The chemical structures of the macromolecules on PTFE film surfaces were characterized with FTIR-ATR, SEM-EDX and XPS. The surface hydrophilicities of modified PTFE films were significantly enhanced with the modification.     

辐射引发四氟乙烯聚合的研究进展

辐射引发四氟乙烯（TFE）聚合是一种高纯度PTFE的生产工艺,具有不需要引发剂、反应温度低、聚合过程可以控制的优点。介绍了辐射引发固相TFE、吸附TFE、TFE溶液和TFE乳液聚合方面的研究进展,最后指出,该工艺有助于生产差异化的PTFE。     

Surface modification of poly(tetrafluoroethylene) film by plasma graft polymerization of sodium vinylsulfonate

Poly(tetrafluoroethylene) (PTFE) surface was modified by the graft polymerization of sodium vinylsulfonate, and the chemical composition of the graft-polymerized PTFE surface was analyzed by X-ray photoelectron spectroscopy. Peroxides were formed on the PTFE surface by a combination procedure of argon plasma irradiation and air exposure, and the graft polymerization of sodium vinylsulfonate was initiated by the peroxide groups at 65–80°C. The peroxide concentration is 3 × 10⁺¹³ to 5 × 10⁺¹³ numbers/cm². The average degree of polymerization of the graft polymers was 3.4 × 10³. The graft polymer is distributed over the PTFE surface, but part of the PTFE surface remains uncovered. The coverage with the graft polymer is 43%. The PTFE surface graft polymerized with sodium vinylsulfonate was somewhat hydrophilic, but the hydrophilicity was lower than that of the PTFE surface modified by plasma treatment. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 66: 77–84, 1997     

Emulsion polymerization of tetrafluoroethylene: effects of reaction conditions on the polymerization rate and polymer molecular weight

The emulsion polymerization of tetrafluoroethylene (TFE) was carried out in a semibatch reactor using a chemical initiator (ammonium persulfate) and a fluorinated surfactant (FC-143). The effects of the reaction condition were investigated though the polymerization rate, molecular weight of polytetrafluoroethylene (PTFE), and stability of the dispersion. The emulsion polymerization of TFE was different from conventional emulsion polymerization. The polymerization rate was suppressed when the polymer particles were significantly coagulated. The polymerization rate increased with operating temperature, surfactant concentration, and agitation speed, due to the enhanced stability of the polymer particles. However, once the parameter value was reached, the rate decreased due to the coagulation of the particles. Stable PTFE dispersion particles were obtained when the surfactant concentration was in the range between 3.48 × 10⁻³ and 32.48 × 10⁻³ mol/liter, which is below critical micelle concentration (CMC). The molecular weight of the PTFE obtained was a function of the surfactant and initiator concentrations, and the polymerization temperature. The molecular weight increased as each parameter decreased. This is against the phenomena observed in a conventional emulsion polymerization. A stable PTFE dispersion polymer having a high molecular weight was obtained by optimizing the reaction conditions. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 777–793, 1999     

Plasma‐induced solid‐state polymerization modified poly(tetrafluoroethylene) membrane for pervaporation separation of aqueous alcohol mixtures

Acrylamide (AAm) solid state polymerization was induced using argon plasma to improve the pervaporation performance of poly(tetrafluoroethylene) (PTFE) membranes (PTFE‐g‐PAAm) in aqueous alcohol mixtures. The surface morphology, chemical composition, and hydrophilicity changes in the PTFE and PTFE‐g‐PAAm membranes were investigated using ATR‐FTIR, SEM, AFM, X‐ray photoelectron spectroscopy, and water contact angle measurements. The surface hydrophilicity rapidly increased with increasing Ar exposure time, but decreased after longer Ar exposure time because of the degradation in the PTFE‐g‐PAAm membrane grafted layer. Compared with the hydrophilicity of the pristine PTFE membrane (water contact angle = 120°), the argon plasma induced acrylamide (AAm) solid‐state polymerization onto the PTFE surface (water contact angle = 43.3°) and effectively improved the hydrophilicity of the PTFE membrane. This value increases slowly with increasing aging time and then reaches a plateau value of about 50° after 10 days of storage under air. The pervaporation separation performances of the PTFE‐g‐PAAm membranes were higher than that of the pristine PTFE membrane. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102:909–919, 2006     

Fabricating Janus membranes via physicochemical selective chemical vapor deposition

Membranes with asymmetric wettability-Janus membranes-have recently received considerable attention for a variety of critical applications. Here, we report on a simple approach to introduce asymmetric wettability into hydrophilic porous domains. Our approach is based on the physicochemical-selective deposition of polytetrafluoroethylene (PTFE) on hydrophilic polymeric substrates. To achieve selective deposition of PTFE, we inhibit the polymerization reaction within the porous domain. We prefill the substrates with glycerol, containing a known amount of free radical inhibitor, and utilize initiated chemical vapor deposition (iCVD) for the polymerization of PTFE. We show that the glycerol/inhibitor mixture hinders the deposition of PTFE within the membrane pores. As a result, the surface of the substrates remains open and porous. The fabricated Janus membranes show stable wetting-resistant properties, evaluated through sessile drop contact angle measurements and direct contact membrane distillation (DCMD).     

Emulsifier-free emulsion polymerization of tetrafluoroethylene by radiation. IV. Effects of additives on polymer molecular weight

Poly(tetrafluoroethylene) (PTFE) of high molecular weight, 4.5 × 10⁷, was incidentally obtained at earlier study of an emulsifier-free emulsion polymerization of tetrafluoroethylene by radiation. In order to clarify this phenomenon, the effects of additives, in particular radical scavengers, on the molecular weight of PTFE and its polymerization behavior were studied. It was found that the molecular weight of PTFE is increased by the addition of hydroquinone, benzoquinone, α-pinene, dl-limonene, and ethylenediamine but is decreased by oxygen and triethylamine. A PTFE latex with molecular weight higher than 2 × 10⁷ was obtained in the presence of hydroquinone. It is concluded that additives such as hydroquinone and benzoquinone, which rapidly scavenge the primary radicals (OH·, H·, and e_aq^?) in the aqueous phase but not the growing polymer radicals in PTFE particles, are most effective in increasing the molecular weight.     

Improving hydrophobicity of polyurethane by PTFE incorporation

A simple and facile method was established of incorporating polytetrafluoroethylene (PTFE) on to polyurethane (PU) to improve hydrophobicity of PU by incorporating low levels of fluorine at a molecular level. Nanocomposites were made by preparing PU in the presence of PTFE using seeded miniemulsion polymerization method. The resulting PTFE/PU nanocomposites were characterized by transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectrometry, differential scanning calorimetric, and thermo gravimetric analysis (TGA). FTIR and TEM indicated changes observed in their structure, size and morphology. The water contact angle of PTFE/PU nanocomposite films increased with increasing amount of PTFE and more on blending with silica nanoparticles but a slight decrease in thermal stabilities of SiO₂/PTFE/PU nanocomposites were noticed. The hydrophobicity imparted by PTFE to PU surface was found to be at its best for 1 : 2 PTFE/PU latex film. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42779.     

Microwave dielectric properties of polytetrafluoroethylene‐polyacrylate composite films made via aerosol deposition

Few studies have examined the deposition of polytetrafluoroethylene (PTFE) using additive manufacturing and their subsequent properties in microwave devices. The present study examines polytetrafluoroethylene‐polyacrylate (PTFE‐PA) composite films made via aerosol deposition to assess the potential use of PTFE in additive manufacturing processes. The composites are composed of PTFE‐PA core ? shell nanoparticles, synthesized using a seeded emulsion polymerization, containing various PTFE weight fractions up to 50%. The synthesized nanoparticles were sprayed onto a heated glass substrate and subsequently annealed at a temperature above the glass transition temperature of PA and below that of PTFE, rendering a solid film approximately 40 µm thick. A cavity perturbation resonance technique was employed to determine the complex permittivity of the films. As the volume fraction of PTFE increased, the real part of the permittivity ?′ decreased while the imaginary part of the permittivity ?″ showed little variation. The results demonstrate a promising approach for incorporating PTFE into additive manufacturing processes, particularly for microwave devices. © 2016 Society of Chemical Industry     

Classification of New Melt‐Processable PTFE: Comparison of Emulsion‐ and Suspension‐Polymerized Materials

A new melt‐processable PTFE material is presented and characterized that provides new and economical solutions in polymer technology while bridging the gap between perfluorinated PTFE and fluorothermoplastic materials such as perfluoroalkoxy resins. Thermal transitions, MW and MWD, and microstructures of the melt‐processable PTFE materials are investigated and compared to standard PTFE, modified PTFE, and PFA materials. The influence of the polymerization type used for the preparation of the melt‐processable PTFE (emulsion and suspension polymerization) on the MWD and the comonomer distribution are discussed.