Characterization of Multiblock (Segmented) Copolyurethane- Imides and Nanocomposites Based Thereof Using AFM, Nanotribology, and Nanoindentation Methods

Abstract

This chapter reviews our results on the morphology, tribological, and local mechanical property investigations of new copoly(urethane-imide)s (coPUIs) and nanocomposites based thereof using atomic force microscopy (AFM) and nanoindentation (NI) methods. AFM in the contact mode of lateral forces revealed the presence of different contrast phases on the surface of synthesized films which depends on the chemical structure of monomers used. Single-walled carbon nanotubes (SWCNTs), carbon nanofibers, graphene, tungsten disulfide and tungsten diselenide were introduced into coPUI matrices. Dependencies of microhardness and modulus of elasticity on the depth of indentation have been obtained. It was found that for each synthesized coPUI, there is only one type of carbon nanomateri- als that exerts the greatest influence on their characteristics. The improvement of mechani cal properties is found to mainly depend on the nature of the polymer matrix and filler. Our results showed that effective methods for improving of tribological characteristics can be either modification by SWCNTs (up to 1 wt.%) or heating at 30°C. Synthesized coPUI films and nanocomposites are very promising materials and can be used as thermoplastic elastomers for tribological applications, and their physical-mechanical properties can be controlled both by temperature and by mechanical action. more than twice. Conversely, the initial coPUI (R-AltTDI-R)SOD has a sufficiently low C fr , and the introduction of nanoparticles WS 2 and WSe 2 leads to its almost doubling. The efficiency of multi-pass scanning tests is shown for investigating the tribological prop erties of modified copolymer systems. It is found that coPUI (R-AltTDI-R)SOD and nano composites based thereof with SWCNT have the best tribological properties, while SWCNTs are uniformly distributed in the material and cause homogeneous structuring at the nano-level. As a result of studying the tribological properties of coPUI film surface using AFM method with multi-pass scanning, it has been found that effective methods for improving these properties can be either modification by SWCNTs (up to 1 wt.%) or heating to 30°C. Our results show that synthesized coPUI films and nanocomposites based thereof are very promising materials for tribological applications and their physical-mechanical properties can be controlled both by temperature and by mechanical action.