Order–order, lattice disordering, and order–disorder transition in SEBS studied by two-dimensional correlation infrared spectroscopy

Supramolecular Polymer Gel Lubricant with Excellent Mechanical Stability and Tribological Performances

Lubricants performing better in machinery systems would lead to the remarkable reduction of environmental pollution problems and the significant improvement of fuel economy. A new family of supramolecular polymer gel lubricants with urea groups has been successfully prepared via self-assembling noncovalent bonds. These newly designed supramolecular polymer gels were well characterized with field-emission scanning electron microscopy, proton nuclear magnetic resonance, attenuated total reflection-Fourier transform infrared spectroscopy, a rheometer, oscillating reciprocating friction, and a wear tester. Compared to low molecular weight supramolecular gels, the covalent and noncovalent bonds cooperated in the supramolecular polymer gel based on macromolecules. Hence, the mechanical properties and viscoelasticity of gel lubricants are greater than those of the low molecular weight supramolecular gels. Furthermore, owing to the longer chain length of polymer gelators, the thickness of the adsorbed film formed on the surface lubricated by macromolecules is thicker than that on the surface lubricated by low molecular weight supramolecular gels, which positively correlates with the lubricating property, making supramolecular polymer gels based on macromolecules better than low molecular weight supramolecular gels. Excitingly, the supramolecular polymer gels based on macromolecules exhibit more excellent thermal reversibility, creep recovery, and thixotropic properties, which not only achieve the lubricating property but also lead to the remarkable reduction of environmental pollution problems due to oil creeping.

Highly Sensitive Piezoresistive Graphene-Based Stretchable Composites for Sensing Applications

Nanocarbonaceous materials with specific geometries and physicochemical properties allow the development of high-performance polymer-based smart composite materials. Among them, chemical treatments of graphene allow tailoring its electrical conductivity and, therefore, tuning functional response of materials for sensing applications. Polymer-based nanocomposites have been developed from styrene-ethylene-butylene-styrene (SEBS), a high deformation thermoplastic elastomer, and different graphene-based fillers, including graphene oxide (GO), reduced graphene oxide (rGO), and graphene nanoplatelets (G-NPLs). It is shown that the electrical conductivity shows a percolation threshold around 2 wt % for GO and rGO, remaining nearly independent of the filler content for G-NPL filler contents up to 6 wt %. Furthermore, GO/SEBS and rGO/SEBS composites show high piezoresistive sensibility with gauge factors ranging from 15 up to 120 for strains up to 10%. Thus, GO/SEBS and rGO/SEBS composites can represent a new generation of materials for strain sensor applications, as demonstrated in their implementation in a hand glove prototype with finger movement monitoring.

Understanding the crystallization behavior of polyamide 6/polyamide 66 alloys from the perspective of hydrogen bonds: projection moving-window 2D correlation FTIR spectroscopy and the enthalpy

In this study, the crystallization behavior of PA6/PA66 alloys was studied using in situ FTIR spectroscopy, combined with Proj-MW2D correlation analysis and Van't Hoff analysis.

Two-dimensional correlation infrared spectroscopy reveals the detailed molecular movements during the crystallization of poly(ethylene-co-vinyl alcohol)

The key role of hydrogen bonding during the crystallization of EVOH was elucidated from the enthalpy and molecular movements.

Cross-linking process of cis-polybutadiene rubber with peroxides studied by two-dimensional infrared correlation spectroscopy: a detailed tracking

Detailed mechanism of cis-BR cross-linking with peroxides was studied using PCMD2D and 2D correlation FTIR, and a 5-step process was determined.

Separation of the molecular motion from different components or phases using projection moving-window 2D correlation FTIR spectroscopy for multiphase and multicomponent polymers

This study developed a new analytical method called projection moving-window 2D correlation FTIR spectroscopy to separate the molecular motion of groups generated from different components or phases for multiphase and multicomponent polymers.

Hydrogen bond breaking of TPU upon heating: understanding from the viewpoints of molecular movements and enthalpy

Hydrogen bond breaking of TPU based on 4,4′-methylenediphenyl diisocyanate (MDI)/1,4-butanediol (BDO) upon heating was studied and elucidated from molecular movements and enthalpy.