Processing and characterization of polystyrene nanocomposites based on CoAl layered double hydroxide

AbstractThe present work deals with the development of polystyrene (PS) nanocomposites through solvent blending technique with diverse contents of modified CoAl layered double hydroxide (LDH). The prepared PS as well as PS/CoAl LDH (1–7 wt.%) nanocomposites were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), rheological analysis, thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The XRD results suggested the formation of exfoliated structure, while TEM images clearly indicated the intercalated morphology of PS nanocomposites at higher loading. The presence of various functional groups in the CoAl LDH and PS/CoAl LDH nanocomposites was verified by FTIR analysis. TGA data confirmed that the thermal stability of PS composites was enhanced significantly as compared to pristine PS. While considering 15% weight loss as a reference point, it was found that the thermal degradation (Td) temperature increased up to 28.5 °C for PS nanocomposites prepared with 7 wt.% CoAl LDH loading over pristine PS. All the nanocomposite samples displayed superior glass transition temperature (Tg), in which PS nanocomposites containing 7 wt.% LDH showed about 5.5 °C higher Tg over pristine PS. In addition, the kinetics for thermal degradation of the composites was studied using Coats-Redfern method. The Criado method was ultimately used to evaluate the decomposition reaction mechanism of the nanocomposites. The complex viscosity and rheological muduli of nanocomposites were found to be higher than that of pristine PS when the frequency increased from 0.01 to 100 s−1

Enhanced mechanical and thermal properties of polystyrene nanocomposites prepared using organo-functionalized NiAl layered double hydroxide via melt intercalation technique

The article reports upon the preparation and characterization of organo-functionalized NiAl layered double hydroxide (LDH)-polystyrene (PS) nanocomposites. Initially, pristine NiAl LDH was synthesized via the co-precipitation technique and was subsequently treated using sodium dodecyl sulfate to obtain organo-functionalized NiAl LDH (ONiAl LDH). PS nanocomposites were fabricated by melt intercalation using a twin screw extruder in presence of ONiAl LDH nanofiller (1, 3, 5, and 7 wt.%). The PS nanocomposites were characterized for their structural, thermal and mechanical properties. The dispersion and morphology of the obtained PS nanocomposites were investigated by X-ray diffraction (XRD) and transmission electron microscopy (TEM). Mechanical and thermal properties of the PS nanocomposites as a function of LDH content were examined by tensile tests, thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The XRD and TEM results revealed the formation of an exfoliated structure of the PS nanocomposite with 1 wt.% ONiAl LDH loading. The maximum improvements of the mechanical and thermal properties of the nanocomposites with ONiAl LDH loading over pristine PS included tensile strength = 34.5% (1 wt.%), thermal decomposition temperatures (T15%) = 27.4 °C (7 wt.%), and glass transition temperature (Tg) = 4.3 °C (7 wt.%). The PS nanocomposites possessed higher mechanical strength and thermal degradation resistance compared to the pristine PS. The activation energy (Ea) and reaction mechanism with respect to thermal degradation of the pristine PS and its nanocomposites were evaluated by the Coats-Redfern and Criado model, respectively

A simple solvent blending coupled sonication technique for synthesis of polystyrene (PS)/multi-walled carbon nanotube (MWCNT) nanocomposites: Effect of modified MWCNT content

The influence of carboxylic acid functionalized multi-walled carbon nanotubes (cMWCNTs) content on the properties of polystyrene (PS) nanocomposite (NC) films was investigated. The NC films were produced by a simple sonication assisted solvent blending technique. The interaction between the matrix (PS) and well dispersed filler (cMWCNT) was evaluated by different techniques involving Fourier transform infrared spectroscopy, Raman spectroscopy and X-Ray diffraction. Morphological images of the NCs were collected from Transmission electron microscopy. The thermal characteristics of the PS were found to be improved by the incorporation of the cMWCNTs, which was evident from the Thermogravimetric analysis (TGA) data. The thermal degradation activation energy evaluated by Coats-Redfern method and integral procedural decomposition temperature determined by Doyle's method supported the thermal stability proposed by TGA of the NCs. The reaction mechanism of thermal degradation of neat PS and respective NCs was successfully predicted using Criado method. The rheological properties and hardness were found to be upgraded by the inclusion of nanotubes to the PS matrix