Structural and Thermal Stability of Polycarbonate Decorated Fumed Silica Nanocomposite via Thermomechanical Analysis and In-situ Temperature Assisted SAXS

Abstract

The inorganic and organic nanocomposites have enticed wide interest in the field of polymer-based composite systems to augment their physiochemical properties like mechanical strength and electrical conductivity. Achieving interfacial interaction between inorganic filler and polymer matrix is a recurring challenge, which has significant implications for mechanical properties of nanocomposites. In this context, the effect of “interfacial zone” on structural and thermal attributes of the melt blended pristine polycarbonate and polycarbonate (PC) decorated fumed silica nanocomposite have been examined from ambient temperature to the glass transition temperature. Thermomechanical characterization and in-situ temperature assisted small angle X-ray scattering technique (SAXS) were used for contemplating quantitative and qualitative molecular dynamics of developed nanocomposites. Though, the FT-IR spectra have demonstrated some extent of interaction between inorganic and organic groups of composite, the reduced glass transition temperature and storage modulus was ascertained in DMA as well as in DSC, which has been further confirmed by in-situ temperature assisted SAXS. It is envisioned that the utilization of in-situ SAXS in addition to the thermomechanical analysis will render the qualitative and quantitative details about the interfacial zone and its effect on thermal and mechanical properties of nanocomposite at varying temperature conditions.

Polycarbonate and activated charcoal-engineered electrospun nanofibers for selective recovery of oil/solvent from oily wastewater

“…147 °C. The weight loss from zone I to zone II is found to be around 68%, which is in line with the developed literature [17][18][19][20][21]35]. From zone II to zone III, the pristine PC, PC + AC(0.5%), and PC + AC(1.5%) nanofibers show weight loss of 8%, 3%, and 6%, respectively.…”

“…Peak at 1223 cm −1 corresponds to asymmetric O-C-O carbonate stretching, while adjacent peaks at 1187 cm −1 , and 1156 cm −1 correspond to stretching of C-O present in polycarbonate structure. The last peak at 824 cm −1 is attributed to the para-substituted phenol rings present in the back bone of the PC polymer structure [17][18][19][20][21][22]35].…”

“…The slightly improved heat stability by PC + AC(0.5%) nanofibers is possibly due to the uniform distribution of the charcoal particles, and their heat sustaining ability (melting temperature > 3000 °C) in the PC matrix. At the end of TGA experiment, pristine PC, and PC + AC(0.5%) nanofibers show complete degradation; however, PC + AC(1.5%) nanofibers show residual mass (uncombusted material) of 9.7%, which is attributed to the higher loading of activated charcoal which binded with PC polymer chains, and prevented their complete degradation [17][18][19][20]38]. In a summary, it was observed that the activated charcoal helped in improving the thermal stability of the PC polymer.…”

“…The electrospinning operation requires extending of fibers moving from needle tip to collector plate, and simultaneously, the evaporation of solvent takes place during movement of the fibers, which leads to generation of micro-sized pores due to escaping of the solvent molecules. After electrospinning operation, PC nanofibers were dried in an air-oven at a temperature of 140 °C (glass transition temperature of 147 °C) for 2 h to facilitate the relaxation PC polymer chains thereby helping the evaporation of any entrapped solvent molecules operation [17][18][19][20]38]. Thus, in addition to pore generation during electrospinning operation, the drying treatment also leads to generation of micro-pores during heating at 140 °C [35,[39][40][41].…”

“…The modification via surface chemistry requires regulation of surface tension between oils (30 mN/m), and organic solvents (18.4 mN/m), and water (72.8 mN/m), thereby allowing only oil/solvent absorption but avoiding water wetting [2,10,12,16]. In present study, the authors have utilized engineering polycarbonate (PC) polymer for oil recovery, as it is mechanically strong (izod impact strength = 600-850 J/m), thermal stability (up to 350 °C), ability to facilitate solution formation, and maintaining its structural rigidity up to its high glass transition temperature (140 °C) [17][18][19][20][21][22]. The activated charcoal was utilized in conjunction with PC polymer, since it exhibits functionalized surface encompassing functional groups like C=O, -CO 3 , O-H, and C-O which facilitates bonding with polymer matrix, and is readily available in commercial market at low cost [23,24].…”