POSS‐inducedrheological and dielectric modification of polyethersulfone

Abstract

Polyhedral oligomeric silsesquioxane (POSS) nanostructured chemicals, when incorporated at low levels in thermoplastics, provide processability enhancement and viscosity reduction without compromising other bulk physical properties. POSS has been relatively unexplored in high performance polymers, and there is incomplete understanding of the mechanisms by which POSS produces flow improvements. In this study, polyethersulfone (PES) was melt‐blended with trisilanolphenyl (TSP)‐POSS and dodecaphenyl (DP)‐POSS; and rheological, dielectric spectroscopy, and scanning electron microscopy evaluations were conducted to identify structure/property/processing relationships. TSP‐POSS yielded greater processability improvements and viscosity reductions than DP‐POSS, suppressed low temperature relaxations to a larger extent, and displayed a greater degree of nanoscale dispersion in the polymer matrix. The findings are evaluated in terms of competing theories of POSS viscosity reduction.

Why POSS-Type Compounds Should Be Considered Nanomodifiers, Not Nanofillers—A Polypropylene Blends Case Study

“…The effect of the other additives may be explained on the basis of intermolecular interactions, where CS molecules diffuse between polymer chains and reduce the polymer chain–chain interaction in favor of chain–CS molecule interaction, which also increases the polymer void volume. This hypothesis has been proposed in a number of other reports on silsesquioxane-containing polymer materials [ 27 , 76 ]. Also, i Bu 7 SSQ-3OH showed a strong lubricating effect at 1% loading, which confirms that the amorphous products of its thermal condensation are more susceptible towards interaction with the polymer matrix.…”

“…They may also be used as antioxidants [ 23 ] or nanoparticle dispersants for plastics [ 24 , 25 ]. Cage siloxanes have been studied as functional and processing additives for polyolefins, e.g., polyethylene or polypropylene [ 26 ], as well as other thermoplastics, including PES [ 27 ], PPS [ 28 ], PEO [ 29 ], or different grades of polyamide (PA) [ 30 ]. The effect of these additives on the properties of the base polymer is highly dependent on the level of dispersion of the additive within the polymer matrix and the CS–matrix interactions (either macroscopic or molecular level ones).…”

β-Phase Crystallinity, Printability, and Piezoelectric Characteristics of Polyvinylidene Fluoride (PVDF)/Poly(methyl methacrylate) (PMMA)/Cyclopentyl-Polyhedral Oligomeric Silsesquioxane (Cp-POSS) Melt-Compounded Blends

“…The hybrid structure of POSS enables enhanced thermal stability, mechanical robustness, wear resistance, and oxidative stability through the robust inorganic cage, while the tunable organic corona promotes favorable interactions and compatibility with a polymer matrix. At low loadings, POSS has been shown to provide a lubricating effect in multiple polymer blends, by our group and others. − In many semicrystalline polymers, POSS has also been shown to act as a nucleating agent which aids in increasing the overall degree of crystallinity as well as the rate of crystallization. − Most reports to date of PVDF/POSS have involved fluoroalkyl-substituted POSS solution blends with PVDF, in which improvements in mechanical, crystalline, and dielectric properties were observed. − Limited reports of PVDF/nonfluorinated POSS melt blends have appeared. Martins and co-workers studied blends prepared in a batch melt mixer of PVDF with up to 5 wt % methacrylate-substituted POSS and reported viscosity reductions at all loading levels .…”

Flame retardancy of carboxylated polyhedral oligosilsesquioxane modified layered double hydroxide in the process of leather fatliquoring

“…[15][16][17] Polyhedral oligomeric silsesquioxane (POSS) has a typical cubic octamer structure. It is a clathrate compound composed of silicon-oxygen bridges containing nano-sized cages surrounded by organic group R. 18 Its rigid structure makes it able to block combustible gas during the combustion process, and the alternately linked silicon-oxygen framework enable to form a dense char layer to isolate the heat. 19 And its active functional groups can improve the compatibility of the POSS with other matrix.…”