Transformation of polymers in a stream of low‐temperature arc discharge plasma

Abstract

SYNOPSISSpraying of polymer materials in a low-temperature plasma stream is a very efficient way of depositing polymer coatings on large surfaces. The deposition of powdered polymers by an arc discharge plasma flow and spraying from the bulk have been compared. The properties of powdered polymers do not change considerably during transportation by the stream because of the short residence of the particles in the plasma. When spraying from the bulk, polymers are transported in the form of melt droplets (polyethylene, polycarbonate) or in gaseous phase (polytetrafluoroethylene); autohesion of the droplets or secondary polymerization occurs, respectively, on the substrate surface. This process offers high-quality thin films and coatings whose structure depends significantly on the characteristics of the substrate as well as on the structure of the source polymer. Obtained polymer coatings contain nitrogen and oxygen entrapped from the atmosphere as well as (on the glass surface) the products of glass etching. This fact enables one to vary widely the properties of the coatings. Furthermore, the problem of obtaining combined protective coatings in which polymer melt fills the pores between metal particles can be solved successfully in a united techno- I NTRO DUCT1 0 NWhen one speaks about plasma application for polymer coatings deposition, glow discharge plasma is usually implied. However, the possibilities of this method are limited by natural factors: a discontinuous coating process, small size of workpieces being treated, thin coatings obtained, and a relatively long time required for the polymer deposition. A t the same time, the protection and reclamation of largesized articles (in particular, those working in corrosive media) remains a problem of high priority. To solve this problem, the deposition of protective coatings by a stream of arc discharge plasma is used. Traditionally, only inorganic coatings ( metallic, ceramic) are obtained in this way because the conditions in a high-enthalpy flow are believed to be too hard for organic polymers. However, ceramic and metallic coatings deposited by an arc discharge

Nylon 11/silica nanocomposite coatings applied by the HVOF process. I. Microstructure and morphology

“…Materials that have been deposited include: polyetheretherketone (PEEK) and polyphenylenesulphide (PPS), 10, 11 polyethylene terephtalate (PET), 12,13 polyester (PES) and polyethylene (PE), 14 -18 polyvinylidene fluoride (PVDF), 15,16 polypropylene (PP), 17 polycarbonate (PC), polysulfone (PSF), 18 polyamides, [15][16][17]19 polymethylmethacrylate (PMMA), 20 and polytetrafluorethylene (PTFE) and its copolymers. 15,17,18 There have been some reports on spraying composites, mainly micron-sized filled polymers, including Al 2 O 3 , SiO 2 -filled epoxy, 21 Al 2 O 3 , and NiCr-filled EMMA, 22 glass, Al 2 O 3 , SiO 2 -filled nylon 11.…”

“…15,17,18 There have been some reports on spraying composites, mainly micron-sized filled polymers, including Al 2 O 3 , SiO 2 -filled epoxy, 21 Al 2 O 3 , and NiCr-filled EMMA, 22 glass, Al 2 O 3 , SiO 2 -filled nylon 11. 20 Filler dispersion was reported to be a strong function of the powder injection angle and the filler size.…”