The Effect of Various Polyhedral Oligomeric Silsesquioxanes on Viscoelastic, Thermal Properties and Crystallization of Poly(ε-caprolactone) Nanocomposites

Abstract

Polyhedral oligomeric silsesquioxane POSS nanoparticles can be applied as reinforcing additives modifying various properties of biodegradable polymers. The effects of aminopropylisobutyl POSS (amine-POSS), trisilanolisooctyl-POSS (HO-POSS) and glycidyl-POSS (Gly-POSS) on the viscoelastic, thermal properties and crystallization of biodegradable poly(ε-caprolactone) PCL were studied. The analysis of the viscoelastic properties at ambient temperature indicated that aminopropylisobutyl POSS (amine-POSS) and glycidyl-POSS (Gly-POSS) enhanced the dynamic mechanical properties of PCL. The increase in the storage shear modulus G′ and loss modulus G″ was observed. The plasticizing effect of trisilanolisooctyl POSS (HO-POSS) due to the presence of long isoctyl groups was confirmed. As a result, the crystallization of PCL was facilitated and the degree of crystallinity of χc increased up to 50.9%. The damping properties and the values of tan δ for PCL/HO-POSS composition increased from 0.052 to 0.069. The TGA results point out the worsening of the PCL thermal stability, with lower values of T0.5%, T1% and T3%. Both HO-POSS and Gly-POSS facilitated the relaxation of molten PCL. The presence of Gly-POSS influenced the changes that occurred in the viscoelastic properties of the molten PCL due to the thermo-mechanical degradation of the material; a positive impact was observed.

Advancement in Biosensor Technologies of 2D MaterialIntegrated with Cellulose—Physical Properties

“…Flexibility: Combining the unique properties of nanocellulose with flexible and durable 2D materials makes them an ideal choice for developing wearable biosensors suitable for real-time health monitoring [ 97 ].…”

Research on the Interaction Capability and Microscopic Interfacial Mechanism between Asphalt-Binder and Steel Slag Aggregate-Filler

“…Usually, when the interactions are strong, the flow capacity of the asphalt mortar becomes weak, with its complex shear modulus G* and complex viscosity η* increasing in magnitude-and vice versa for weak interactions [65]. Therefore, the G* and η* rheological parameters were assumed to potentially reflect and indirectly be used as quantitative indicators of the asphalt-binder-filler interactions.…”

SiO2 Nanostructure-Based Aerogels with High Strength and Deformability for Thermal Insulation

“…To meet the needs of a new generation of lightweight and high-strength materials, polyhedral oligomeric silsesquioxane (POSS), a polyhedral nanostructure hybrid system, was developed by the Technology Advancement Committee of the US Air Force Research Laboratory in the mid-1990s of the last century. − POSS has a hexahedral core formed by alternating Si–O bonds, which is the structural support that gives it high strength, and Si atoms at the eight top corners are connected to functionalized groups that exhibit different physicochemical properties. − Therefore, the SiO 2 aerogel prepared by using the Si–O–Si hexahedral cores in POSS as the strength support part and establishing a certain length of molecular chain between the cores for connection theoretically has high strength and excellent deformability, which are expected to overcome the poor mechanical properties. Based on this research idea, we used hexaphthalic acid as a flexible multilink molecular chain to connect the −Si–O–Si– hexahedral hard cores in the synthesized octa­(aminophenyl)-T8-POSS and successfully realized a special SiO 2 aerogel constructed alternately with −Si–O–Si– hard cores and double flexible chains.…”