A New Agent for Modification of the Teflon Surface

Abstract

The possibility of preparing modification solutions from sodium naphthalenide wastes and their effect on Teflon adhesion were studied.Organometallic complexes of alkali metals (Li, Na, K) and aromatic hydrocarbons (diphenyl, naphthalene, anthracene, etc.) are widely used to enhance adhesion of inert polymers, including Teflon [1,2]. Wastes remaining after modifying the Teflon surface with Na-naphthalene complex comprise more than 70% of the initial active solution. The spent inactive solution containing various toxic compounds after neutralization is discharged into industrial sewage and pollutes the environment.Arene complexes of metals are unstable; they are prepared under the anaerobic conditions [1,3]. Previously [4], we attempted to prepare arene complexes of metals at room temperature in air using ethers [tetrahydrofuran (THF), dimethyl ethylene glycol, dimethyl diethylene glycol, diethyl diethylene glycol] and obtained dark solutions whose color was determined by the kind of metal and aromatic hydrocarbon.In this study we examined by ESR solutions of sodium and naphthalene in THF, prepared at room temperature. We also examined the possibility of reusing the spent inactive solution of sodium naphthalenide to enhance the Teflon adhesion. EXPERIMENTALThe ESR spectra were recorded on a Bruker ESR-300 spectrometer at T = 298 K. The g-factor in the ESR spectra of the solution in question agrees with that of the naphthalene radical anion [5].We attempted to reuse the spent inactive solution.On adding sodium and naphthalene into the spent solution, its color changed from yellowish to dark brown; according to ESR data, this solution is diamagnetic.

Multi‐featured epoxy composites filled with surface‐modified PTFE powders treated by Na‐naphthalenide system

“…They reported that peroxy‐radicals formed when the powders were exposed to O 2 in the air during the surface modification process. They also reported these peroxy‐radicals were converted to hydroxyl and other functional groups by the process of washing with H 2 O 42 …”

“…The reaction mechanism of surface modification of poly (tetrafluoroethylene) (PTFE) powders with Na-naphthalenide system. 34,42,46 properties and IZOD impact resistance. As shown in Figure 4, the addition of the surface-modified PTFE powders into the epoxy system increased both the ultimate tensile and flexural strength values by up to 10 wt%.…”

“…Ayurova et al 42 modified PTFE surfaces with an active Na‐naphthalenide system in an air conditioned setting, and they observed various functional groups such as radicals on C atoms, as well as hydroxyl groups. They reported that peroxy‐radicals formed when the powders were exposed to O 2 in the air during the surface modification process.…”

“…The large decreases in the contact angle values of the surface-modified PTFE in the range between 50 and 60 confirmed this situation. [41][42][43] Apart from Ayurova et al, 42 other researchers such as Miller et al, 44 Borisova et al, 45 Dake and Bhoraska, 46 Jansta et al, 47 and Roina 34 reported functional groups such as conjugated C C unsaturation points, carbonyl groups, and hydroxyl groups available on the surfaces of PTFE treated with Na-naphthalenide systems.…”

“…A Na‐naphthalenide system is also very effective in promoting the adhesion of fluoropolymers. Ayurova et al 42 modified PTFE surfaces with active Na‐naphthalenide in THF in atmospheric conditions at room temperature. They reported that hydroxyl groups formed on the surface of the PTFE treated with the Na‐naphthalenide system.…”