Synthesis, thermal behavior, and kinetics of degradation of alkyl hepta cyclopentyl polyhedral oligomeric silsesquioxanes/polysterene nanocomposites

Abstract

The degradation of polyhedral oligomeric silsesquioxane (POSS)/polystyrene (PS) nanocomposites at different percentages of reinforcement was studied in order to verify their thermal stability in respect to the pristine PS. Analyzed compounds were prepared by in situ polymerization of styrene, in the presence of POSSs and characterized by 1H-NMR. The temperature at 5% mass loss and the activation energy of degradation, determined through kinetics literature methods, were taken into consideration in order to assess both the resistance and the kinetics of degradation. The results obtained for the synthesized polymer and composites were discussed and compared with each other and with those obtained in the past for similar alkyl-POSS/PS nanocomposites. A good improvement of the thermal stability, in respect to neat polymer, was found and showed that the presence of cyclopentyl groups at the vertices of the POSS cage led to a good interaction with the matrix. It was also drawn up a thermal stability classification among the synthesized materials and those studied in the past according to the organic nature of the substituents on the inorganic cage of the composite reinforcement.

Kinetic Study of the Thermal and Thermo-Oxidative Degradations of Polystyrene Reinforced with Multiple-Cages POSS

“…Kinetics data confirmed the key role of multiple-cage POSS in the thermo-oxidative degradation process of the obtained PS composites that let down the degradation rate, and, as demonstrated by the T5% values, enhanced the overall thermal stability of the composites. In an inert environment, the role of When we looked at our previous research regarding the kinetics of the degradation of similar PS/POSS composites but with single- [49][50][51] or double-cage structures [52,53], we observed that the slowdown in degradation kinetics for the triple-cage POSS-reinforced polystyrene was much less pronounced, about 20-30 kJ•mol −1 lower than in the systems studied in the past. This behavior could be attributed to the difficulty of obtaining multiple-cage POSS, which are sterically bulkier than single-cage POSS, to disperse themselves in the polymer matrix.…”

“…When we looked at our previous research regarding the kinetics of the degradation of similar PS/POSS composites but with single- [ 49 , 50 , 51 ] or double-cage structures [ 52 , 53 ], we observed that the slowdown in degradation kinetics for the triple-cage POSS-reinforced polystyrene was much less pronounced, about 20–30 kJ∙mol −1 lower than in the systems studied in the past. This behavior could be attributed to the difficulty of obtaining multiple-cage POSS, which are sterically bulkier than single-cage POSS, to disperse themselves in the polymer matrix.…”

Polyhedral oligomeric silsesquioxane-based aliphatic polyester composites: Synthesis, characterization, and investigation of thermal properties

“…Most of the recent studies have focused on the preparation of organic/inorganic hybrid materials with excellent properties using inorganically developed nanoscale substances such as carbon nanotubes, graphene, and polyhedral oligomeric silsesquioxanes (POSS). 1–5 POSS, a class of unique inorganic compounds having a specific nanostructure, can be incorporated into polymer structures to produce hybrid materials with superior properties. 6–9 The general formula of POSS is showed with ( R SiO 1.5 ) n , ( n ≥ 6).…”

Preparation of PVDF/PAR Composites with Piezoelectric Properties by Post-Treatment

“…Thermoplastic composites have various advantages including high-speed processability and recyclability, besides being environmentally friendly [14]. Therefore, many studies on thermoplastic composite have been completed [15,16]. However, since the matrix resin (PVDF) of thermoplastic composite has a high melt viscosity, the resin is hardly impregnated into the fibers (PAR) [14].…”