等离子体聚合

<正> 一、等离子体聚合和应用的进展等离子体聚合是利用等离子体实现的聚合反应。它是等离子体化学的重要组成部分。由等离子体聚合得到的聚合物与常规化学聚合物有很大的不同,严格地讲由等离子体聚合的聚合物应称为等离子聚合物。例如由等离子体聚合的乙烯聚合物应称为等离子聚乙     

CO2和苯乙烯非平衡态等离子体连续引发聚合反应

利用自制等离子体引发聚合装置进行了ＣＯ２和苯乙烯（Ｓｔ）的等离子体连续引发聚合反应，并采用红外光谱、Ｘ射线光电子能谱和核磁共振谱对聚合产物的结构进行了表征。对比ＣＯ２／Ｓｔ等离子体引发聚合产物和常规方法聚合得到的聚苯乙烯的红外光谱图可以发现，前者在１...     

等离子体聚合物薄膜的性质及应用进展

概述了利用低温等离子体技术制备的有机聚合物薄膜特性、主要合成方法及研究现状，简要讨论了等离子体聚合条件对薄膜结构和性质的影响；介绍了现代分析技术对聚合物薄膜结构的表征；阐述了近年来对低温等离子体聚合物薄膜的物理性质(包括表面性质、渗透性、电学和光学性质等)的研究新进展，并描述了其在工业生产上的一些应用。     

反相微乳液聚合

介绍了反相微乳液聚合方法的建立及体系组成、乳化剂选择、聚合过程及聚合物的表征、聚合反应动力学及机理,以及反相微乳液聚合的特点及应用。指出,提高反相微乳液聚合体系中的固含量将是今后的重点及难点。     

反相微乳液聚合

介绍了反相微乳液聚合方法的建立及体系组成、乳化剂选择、聚合过程及聚合物的表征、聚合反应动力学及机理，以及反相微乳液聚合的特点及应用。指出，提高反相微乳液聚合体系中的固含量将是今后的重点及难点。     

活性自由基聚合反应与多种结构聚合物的制备

介绍了原民移自由基聚合反应这一新型的活性自由基聚合方式,并综述了利用这种聚合方法制备的多种结构的聚合物,包括嵌段共取物,交替共聚物,接枝共聚物,星形聚合物,超支化聚合物,梳形聚合物等。     

高吸水树脂的等离子体引发聚合反应制备研究进展

介绍了等离子体引发聚合反应的特点;综述了等离子体引发聚合反应在制备高吸水树脂领域的研究进展,包括等离子体引发乙烯基系列单体聚合制备高吸水树脂、等离子体引发乙烯基系列单体接枝共聚制备高吸水树脂、等离子体引发制备有机-无机复合高吸水树脂等;最后指出了等离子体引发制备高吸水树脂研究需要加强的几个方向:即加强对等离子体引发聚合制备高吸水树脂反应机理的研究;加强天然产物接枝系列、有机-无机复合系列高吸水树脂以及多功能高吸水树脂的等离子体引发聚合制备研究等。     

环氧丙烷的脉冲等离子体聚合及其聚合物的稳定性

以环氧丙烷为单体进行了脉冲等离子体聚合,研究了脉冲占空比,聚合时间对聚合动力学的影响,并以红外(FT-IR)、扫描电镜(SEM)和接触角等方法研究了等离子体聚合物的结构与性能。结果表明:高占空比和长的聚合时间有利于聚合量的增加,环氧丙烷的等离子体聚合物中含有酯,羧基,直链醚,环醚,羟基等官能团并存在支化,交联的结构,聚合物中保留的环氧基团可以与乙二胺反应,并能进一步提高表面的稳定性。     

聚合过程强化技术的发展

聚合过程强化技术是实现聚合过程效能最大化、聚合物产品结构可控化以及聚合过程和产品绿色化的有效技术手段。本文综述了聚合过程强化技术的国内外进展,从流动与混合强化、传热与传质强化、反应耦合过程强化、超临界流体强化、外场强化等方面重点分析了不同聚合过程强化技术的特点,并对聚合过程强化技术中存在的问题进行了探讨。指出聚合过程强化应注重聚合动力学特性和设备特性的有效耦合,基于聚合反应特性的过程强化方法是今后的发展方向。     

烯烃聚合中负载型催化剂及初生聚合物颗粒形貌的表征评述

介绍了应用于烯烃聚合反应中催化剂和初生聚合物颗粒形貌的几种表征方法,包括普通光学显微镜、扫描电子显微镜、透射电子显微镜、激光扫描共聚焦荧光显微镜、视频显微镜以及拉曼光谱与显微镜联用,并对每种表征方法的优缺点进行了分析和评价。     

等离子体优化修饰技术在固定化酶载体材料中的应用进展

运用等离子体聚合或表面处理技术改变载体材料的表面性质,进而固定酶蛋白的方法主要有4类:等离子体表面处理、等离子体聚合、等离子体接枝共聚和等离子体化学气相沉积。综述了近年来用等离子体优化修饰技术处理载体材料进行固定化酶研究的新进展,指出今后应加强等离子体体系表面改性规律及机理、等离子体单体气体种类、放电条件及底衬材料等方面的研究。     

The initiation of in situ polymerization of vinyl monomers in polyester by glow discharge

Glow discharge initiation of in situ polymerization of acrylic acid and other vinyl monomers incorporated in PET films was investigatigated. The influence of glow discharge conditions such as the gas used, plasma power, discharge current, and plasma treatment time on polymerization yield was determined. Though glow discharge effects are limited to the film surface, in situ polymerization of the vinyl monomers took place and the vinyl polymer could be found all through the film cross section. At short plasma treatment time only surface modification took place, while at longer treatment time bulk modification occurred, too. Good polymerization yields were obtained. Gel effect behavior was observed. Mechanical properties of the modified PET film were not changed, while the contact angle with water improved when polar vinyl monomers were used.     

Hexafluoropropylene plasmas: Polymerization rate–reaction parameter relationships

Plasma polymerization generates thin, pinhole-free, and highly adhering films and is often described by the ratio of power to mass flow rate (energy per mass). This research explores the relationships between plasma reactor parameters such as monomer flow rate, plasma power, and reactor pressure and the rates of polymerization, etching, and deposition. The chemical structure of the amorphous, crosslinked plasma polymerized hexafluoropropylene consists largely of similar amounts of C*-CF, CF, CF₂, and CF₃ groups and some C-C groups. A dimensionless plasma parameter (E) proportional to power and inversely proportional to flow rate cubed was derived. E, reflecting both plasma energy and residence time, was used to describe various aspects of the plasma reactions. A dimensionless exponential expression successfully described the dependence of pressure on E with a master curve. An expression for polymerization efficiency (polymer conversion) derived in part through a mass balance was also successfully related to E using an exponential master curve. The rate of deposition was described as the difference between the rates of polymerization and etching. The deposition efficiency maximum and plateau were successfully described by the difference between polymerization and etching efficiencies, each related exponentially to E. The technique used to derive parameters to describe the dependence of plasma reactions on plasma operating conditions can be applied to any monomer/reactor system.     

The plasma polymerization of vinyl monomers. II. A detailed study of the plasma polymerization of styrene

A study has been made on the plasma polymerization of styrene monomer in a cold, low-power, inductively coupled RF plasma. Styrene monomer yielded an insoluble, crosslinked film which was slightly colored. A kinetic study is reported for styrene. The effects of power level, bleed rate of monomer, pressure, and reactor geometry on the rate of polymer formation are reported. A mechanism is postulated for plasma polymerization. It was found that the initiation step was the rate controlling step and that the reaction followed a cationic polymerization scheme. Both crosslinking and discoloration of the polymers occur at the time of polymerization and are not a result of exposure of the reacted polymer to the plasma. The polymerization was shown to take place in the bulk phase as well as on the reaction wall surfaces.     

Hydrocarbon barrier performance of plasma-surface-modified polyethylene

Plasma modifications were applied on the inner surfaces of high-density polyethylene bottles. The methods applied include Ar gas plasma treatment, plasma polymerization with tetrafluoroethylene (TFE), trimethylsilane (TMS) + O₂ (1:4), CH₄, and C₂H₂ monomers, plasmainduced acrylic acid grafting polymerization, and C₂H₂ plasma polymerization plus acrylic acid plasma polymerization. Solvent weight-loss data are reported primarily for the n-hexane/HDPE bottle system. The best permeation reduction factor of 0.03 was obtained with C₂H₂ plasma polymerization at a high energy level followed by acrylic acid plasma polymerization at a low energy level. C₂H₂ plasma polymerization at an energy level of 10¹⁰ J/kg and C₂H₂ plasma polymerization followed by acrylic acid grafting polymerization offer a similar permeation reduction factor of 0.07. A combination of improved surface polarity and tightness of the surface is responsible for remarkable reductions in permeation rates. © 1996 John Wiley & Sons, Inc.     

Plasma surface modification of silica and its effect on properties of styrene–butadiene rubber compound

The effects of surface modification of silicas by plasma‐polymerization coating, together with modification using a silane coupling agent for a comparison on the dispersion and physical properties of styrene–butadiene rubber (SBR) are reported. The chemical compositions of the plasma‐polymerization coating were characterized using FTIR and Auger spectrometer and it was found that the plasma coating was composed of C?C and C? H bonds. The surface modification of silica by either plasma polymerization or silane greatly improved the dispersion of silica particles in SBR vulcanizates. The plasma‐polymerization modification of silica improved the tensile modulus of SBR vulcanizates without deterioration of important basic properties such as tensile strength and elongation at break. © 2002 Society of Chemical Industry     

Thin‐film plasma‐polymerized iso‐t‐pentinol and its postpolymerization properties

Thin films of plasma polymer were prepared from unsaturated precursor with one triple bond, iso‐t‐pentinol. This precursor was injected either in a vapor state itself or using argon as a carrier gas, bubbled through a precursor. These polymers were prepared under different fixed conditions when only one parameter of plasma polymerization among all the others was changed in each measurement during the process of polymerization (i.e., power in a matched reactor, precursor partial pressure, total pressure in reactor, electrode gap, and polymerization time). The samples were deposited on thin solid substrate having oxygenless molecules. Infrared Spectroscopy, IRS, Electron Spectroscopy for Chemical Analysis, ESCA (XPS), and Electron Paramagnetic Resonance (EPR) were used for analyses of these samples. The results of analyses proved generation and growth of oxygen‐containing groups by plasma polymerization (IRS); they also proved that C O group concentration increased and CO group concentration decreased in polymer surface layers during 24 h after plasma polymerization (ESCA). A drop of free radical concentration (measured by EPR) was steep from the end of plasma polymerization to 60 min and mild later on (to approximately 215 h). Amount of free radicals depended on the power in reactor. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 677–686, 1999     

Plasma etching and plasma polymerization coating of carbon fibers. Part 1. Interfacial adhesion study

Unsized AS-4 carbon fibers were etched by RF plasma and then coated via plasma polymerization in order to enhance their adhesion to vinyl ester resin. Gases utilized for plasma etching were Ar, N₂ and O₂, while monomers used in plasma polymerization coating were acetylene, butadiene and acrylonitrile. Plasma etchings were carried out as a function of plasma power (30–70 W), treatment time (1–10 min) and gas pressure (20–40 mtorr). Plasma polymerizations were performed by varying the treatment time (15–60 s), plasma power (10–30 W) and gas pressure (20-40 mtorr). The conditions for plasma etching and plasma polymerization were optimized by measuring interfacial adhesion with vinyl ester resin via micro-droplet tests. Plasma etched and plasma polymer coated carbon fibers were characterized by SEM, XPS, FT-IR and α-Step, dynamic contact angle analyzer (DCA) and tensile strength measurements. In Part 1, interfacial adhesion of plasma etched and plasma polymer coated carbon fibers to vinyl ester resin is reported, while characterization results including tensile strength of carbon fibers are reported in Part 2. Among the treatment conditions, a combination of Ar plasma etching and acetylene plasma polymer coating provided greatly improved interfacial shear strength (IFSS) of 69 MPa, compared to 43 MPa obtained from as-received carbon fiber. Based on the SEM analysis of failure surfaces and load-displacement curves, the failure was found to occur at the interface between plasma polymer coating and vinyl ester resin.     

UV protecting layers on PVC made by plasma polymerization

UV protection is necessary for many plastics if they are to be used for outdoor applications. Plasma polymerization, a new surface coating technology, permits the depositing of thin polymer layers on plastics as UV and weather protection. With these layers, even the UV resistance of polyvinylchloride (PVC) containing a conventional UV stabilizer can be improved; After a QUV panel test of 5000 h the plasma polymerized films show a decrease in the degree of yellowing by a factor of 3 compared to the uncoated samples. Different types of monomers and other process parameters of the plasma polymerization apparatus show a significant influence on deposition rates, surface chemistry, and UV protecting properties.     

Preparation of reverse osmosis membranes by plasma polymerization of organic compounds

The plasma polymerization of organic compounds was used to prepare a composite reverse osmosis membrane which consists of an ultrathin semipermeable membrane formed by plasma polymerization of an organic compound or compounds and a porous substrate. Many nitrogen-containing compounds (aromatic amines, heteroaromatic compounds, aliphatic amines, and nitriles) were found to yield excellent reverse osmosis membranes by plasma polymerization directly onto porous substrates such as Millipore filters, porous polysulfone filters, and porous glass tubes. Factors involved in the preparation of reverse osmosis membranes by plasma polymerization were investigated and discussed. The plasma polymerized membranes have the following unique features: (1) very stable performance independent of salt concentration and applied pressure (practically no water flux decline was observed with many membranes): (2) salt rejection and water flux both increase with time in the initial stage of reverse osmosis (consequently, the performance of the membrane improves with time of operation); (3) very high salt rejection (over 99%) with high water flux (up to 38 gfd) can be obtained with 3.5% NaCl at 1500 psi (membranes perform equally well under conditions of sea water conversion and brakish water treatment).