Styrene plasma-polymerized

A number of typical polymer-forming monomers have been polymerized using plasma polymerization including tetrafluoroethylene, styrene, acrylic acid, methyl methacrylate, isoprene, and ethylene. Polymerization of many nontypical monomers has also occurred including toluene, benzene, and simple hydrocarbons. 

The deposition of polymeric films by plasma polymerization of styrene in a 800 kHz discharge was investigated by Lam et al. . It was proposed that the observed deposition kinetics could be explained by a scheme in which the initiation of monomers by electron impact is followed by propagation and termination, as in conventional polymerization. This scheme is summarized by the following three reactions ... 

Model 4. As a result Lam et al. concluded that Model 3 best describes the plasma polymerization kinetics of styrene. 

Akovali and Ulkem [33] reported the surface modification of carbon black by plasma polymerization of styrene and butadiene. The effect of such plasma-coated carbon black was studied in a SBR matrix. A slight increase in the tensile strength was observed for the plasma-polymerized styrene-coated carbon black. This was explained by a decrease in the interfacial tension, as the result of the similarities between the treated filler and the matrix at the interface. They also concluded that the plasma coating obtained on carbon black is so thin that no blockage of the pores occurred and that there was no decrease in the original absorptive capacity. 

Plasma-polymerized phenylacetylene, styrene, PVC, merocyanine dyes and other materials [323-328] were also photoconductive in various spectral ranges. Most of them made Schottky type barriers with electrodes. As a rule, electrophotographic properties attracts attention to polymeric films possessing them. 

Two component spectra of plasma polymerized styrene (PPS) observed above 50 QC were interpreted in terms of a mesh-like crosslinked network structure. Broad and narrow components are attributed to the protons in crosslinked regions and oligomeric structures (which act as plasticizers), respectively 3i). 

A multi-microsensor array of potentiometric MIP chemosensors has been devised for determination of a serotonin neurotransmitter [180]. In the toluene porogenic solvent solution, the MAA functional monomer and the EGDMA cross-linker were polymerized in the presence of the serotonin hydrochloride template (Table 6). Subsequently, the resulting MIPs were immobilized on a plasma polymer layer by swelling and polymerization. Plasma polymerization was performed using styrene or ethylbenzene as the monomer. The chemosensor fabricated that way was appreciably responsive to serotonin while selectivity to serotonin analogues, like acetaminophen... 

Because of the unique growth mechanism of material formation, the monomer for plasma polymerization (luminous chemical vapor deposition, LCVD) does not require specific chemical structure. The monomer for the free radical chain growth polymerization, e.g., vinyl polymerization, requires an olefinic double bond or a triple bond. For instance, styrene is a monomer but ethylbenzene is not. In LCVD, both styrene and ethylbenzene polymerize, and their deposition rates are by and large the same. Table 7.1 shows the comparison of deposition rate of vinyl compounds and corresponding saturated vinyl compounds. 

An example of plasma copolymerization of gases is the incorporation of N2 in the plasma polymer of styrene. N2 mixed with styrene was consumed in plasma polymerization [12]. In a closed-system experiment, pressure measurement is a very useful tool for investigating plasma polymerization, particularly when the monomer used does not produce gaseous by-products. The pressure changes observed in a closed-system plasma reactor with mixtures of N2 and styrene are shown in... 

The effects of the discharge power on the distribution of polymer deposition in a tubular reactor (Fig. 20.1) are shown in Figures 20.19-20.22. Figure 20.19 depicts the change in polymer deposition pattern due to the discharge power observed in the plasma polymerization of styrene at a fixed flow rate of 5.6 seem. 

Figure 6. Rates of plasma polymerization of styrene as a function of pressure for various power inputs...

There has been a great deal of interest in the study of the electrical properties of plasma polymerized films. Early data on the dielectric and conductivity of the films has been reviewed by Mearns ( ). More recently, the dielectric properties of plasma polymerized styrene (69-71), acrylonitrile (72), hexamethyldisiloxane (73-75), tetrafluoroethylene... 

Attempts have recently been made to determine the dominat electric conductivity mechanism using the results of measurements of the current flow across asymmetric systems, such as metal -polymer-metalo (Me -P-Mc2) and metal-polymer-semiconductor (M-P-Sj such studies involved plasma-polymerized styrene (2 ), silo-xane and silazane ( ). The possibility of tunnel-... 

Figure 1. Monomer—copolymer composition relationship for the plasma-initiated copolymerization of methyl methacrylate with styrene. Plasma-initiated polymerization (%) NMR, (x) elemental analysis. Thermal polymerization (O) NMR, (Aj elemental analysis, (—) theoretical curve, tmma = 0.46 =...

In order to modify favorably the interaction balance at PE/PS contacts, mica was subjected to LMP treatments using E and S monomers in sequence. In principle, the generation of plasma-polymerized ethylene (PPE) and styrene (PPS) on the mica surface might... 

System Dependent Phenomena. Perhaps the most important aspect of plasma polymers is that their method of formation, plasma polymerization, is highly system dependent. For example, a monomer will not yield a well defined polymer, but a variety of polymers can be formed from a monomer depending on how plasma polymerization is used. This is definitely different from conventional polymerization. For instance, styrene can be polymerized by many different polymerization techniques, but the products can always be identified as polystyrene. This is because the polymerizations are essentially molecular processes, and, consequently, the chemical structure of the monomer is retained within the resulting polymer in a very predictable manner. 

Because of the contribution of atomic polymerization, the plasma polymer of styrene in its most practical and useful form is distinctly different from polystyrene. This is exactly why plasma polymers can be used to improve the wear resistance of other polymers. If the plasma polymerization of styrene did produce a conventional polystyrene, one could not expect any improvement in the wear resistance of polystyrene by using plasma polymerization. Because the plasma polymer of styrene is not polystyrene, the deposition of the plasma polymer of styrene on the surface of polystyrene can produce a remarkable improvement. 

Because of the system dependent aspect of plasma polymerization, there is no material that can be adequately described as the plasma polymer of a particular monomer, e.g., the plasma polymer of styrene, the plasma polymer of tetrafluoroethylene, and so on. The factors that influence the system dependent aspect of plasma polymerization are operational parameters, such as flow rate, discharge power, system pressure, and substrate temperature, and the design factors of the reactor, such as its size and shape, mode of electric discharge, and location of the substrate. 

It is believed that a considerable number of residual radkals are present in the plasma-polymerized thin films, and that these radicals often induce the oxidation of the films to give carbonyls and hydroxyls by contact with the ambient air. The residual radicals formed in plasma-polymerized styrene (PPS) thin films have been investigated by ESR measurements [54]. An asymmetrk singlet line characteristic of oxide radicals with anisotropic g-valnes (gj = 2.008, g = 2.006, and gj = 1.993) was obsaved in PPS produced under oxygen carrier gas, whereas a symmetric line was observed in PPS produced under nitrogen carrier gas. 

Extensive investigation of the electrical properties of plasma polymeric films using a wide variety of monomers has been carried out and many interesting results have been achieved [79-82]. Also, many studies on the photoconduction of plasma polymeric films have been carried out [83, 84]. Pender and Fleming have obtained plasma polymeric films from styrene, acetykne, benzene, etc., which showed a iMstaUe switching effect [85]. An elastic electron tunneling effect was observed in plasma-... 

The structures that have evolved for ablative-mode optical discs make use of interference effects to minimize the reflectance (R) of the disc in the absence of a hole. A typical ablative-mode optical disc has the structure shown in Figure 5.51. The substrate is an optically transparent material such as polycarbonate, poly(methyl methacrylate), poly(ethylene terephthalate), or poly(vinyl chloride), topped by a subbing layer to provide an optically smooth (to within a fi-action of a nanometer) surface for the recording layer. A metal reflector (typically aluminum) is then incorporated next to a transparent dielectric medium such as spin-coated poly(a-methyl styrene) or plasma-polymerized fluoropolymers. This dielectric spacing layer serves both to satisfy the quarter-wave (2/4) antireflection conditions and to insulate thermally the A1 reflector from the top absorbing layer where the information pits are created. 

Aizawa H, Kurosawa S, Kobayashi K, Kashima K, Hirokawa T, Yoshimi Y, Yoshimoto M, Hirotsu T, Miyake J, Tanaka H (2000) Turning of contact angle on glass plates coated with plasma-polymerized styrene, allylamine and acrylic acid. Mater Sci Eng C 12 49-54... 

Wu et al. (1992) treated the surfaces of the hydrophilic porous membranes, such as cellulose acetate, by radiation graft polymerization of styrene to increase their hydrophobicity and to reach the MD membrane characteristics. Kong et al. (1992) employed a cellulose nitrate membrane modified via plasma polymerization of both vinyltrimethylsilicone and carbontetrafluoride and octafluorocyclobutane for the preparation of MD membranes. Fujii et al. (1992) prepared tubular membranes from PVDF polymer dopes by using the dry-jet wet-spinning technique. Ortiz de Zarate et al. (1995) and Tomaszewska (1996) reported on PVDF flat-sheet membranes prepared for MD by the phase inversion method. 

On the other hand, coating techniques do have less influence on the fibre surface. Nevertheless, brittle coatings such as SiC deteriorate mechanical properties of the fibres. As an example, reactive sputtered SiC layers improve the interfacial shear strength of carbon fibre reinforced epoxy resin /3/. Recently, Dagli and Sung 141 reported about the coating of carbon fibres by plasma polymerization of acrylonitrile and styrene using an inductively coupled plasma. 

The purpose of this study is to explore the effects of plasma polymerized styrene (PPS) butadiene coating on carbon black in SBR matrices. 

MWCNTs were modified by grafting with PS using plasma polymerization of styrene mraiomer [166]. The modified MWCNTs were characterized by FTIR, dispersion test, TEM, SEM, and Raman analysis. TEM images of unmodified and modified MWCNTs are shown in Fig. 15. After plasma-induced grafting polymerization, the MWCNTs had a less-tangled organization, which demonstrated that the grafted styrene molecule efficiently promoted dispersal of the MWCNTs. 

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