Relationships between crystallization behavior and application properties of chemically coupled PAI-PTFE coatings

Poly(tetrafluoroethylene) (PTFE) is well known for its very low friction coefficient and thus widely used for antifriction applications, e.g., sliding lacquers, for many years. Because of the high wear rate and cold flow of the original polymer, PTFE is usually added in higher amounts to other polym...

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Published inJournal of Coatings Technology and Research Vol. 21; no. 2; pp. 623 - 654
Main Authors Gedan-Smolka, Michaela, Jehnichen, Dieter, Malanin, Mikhail, Schmidt, Thomas, Marschner, Anne, Schneider, Antje, Göbel, Michael
Format Journal Article
LanguageEnglish
Published New York Springer US 01.03.2024
Subjects
Chemistry and Materials Science
Corrosion and Coatings
Industrial Chemistry/Chemical Engineering
Materials Science
Polymer Sciences
Surfaces and Interfaces
Thin Films
Tribology
Chemical bonded PAI-PTFE
γ-radiation modified PTFE
compounds
Crystallinity
Reactive extrusion
Sliding lacquers
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Summary:Poly(tetrafluoroethylene) (PTFE) is well known for its very low friction coefficient and thus widely used for antifriction applications, e.g., sliding lacquers, for many years. Because of the high wear rate and cold flow of the original polymer, PTFE is usually added in higher amounts to other polymer matrices as a lubricant. However, the incompatibility of PTFE requires lots of efforts to perform a homogeneous breaking down of agglomerates and particle distribution as well as dispersion stabilization of the physical mixtures during application and curing. PTFE can be functionalized by high energy irradiation and subsequently compatibilized with a polymer matrix by reactive extrusion resulting in chemical bonding of both polymers via suitable reactive groups. In this manner, poly(amide imide) (PAI) was coupled to γ-radiation modified PTFE micro-powder prior to the dispersion procedure. This study deals with the thermal and crystallization behavior of the PTFE lubricant in chemical bonded (cb) PAI-PTFE cb compound thin layers in comparison with those of the plain radiation modified PTFE depending on the cooling rate by DSC, Flash-DSC and WAXS. A morphological characterization of the extrudate as well as the coating gives information about the fragmentation and distribution of the PTFE phase in the PAI matrix. Furthermore, mechanical and surface properties of sliding lacquer films were analyzed after application on steel substrates by varying dry film thickness and curing. Graphical Abstract
ISSN:1547-0091
1935-3804
DOI:10.1007/s11998-023-00845-9