Reactively compatibilised 80/20 PA6/ABS blends: effect of various compatibilisers on morphology, dynamic mechanical analysis, crystallisation and thermal degradation kinetics

Author(s):  
Bhagwan F. Jogi
2011 ◽  
Vol 17 (2) ◽  
pp. 141-151 ◽  
Author(s):  
Shahryar Pashaei ◽  
S Siddaramaiah ◽  
Mansouji Avval ◽  
Ahmed Syed

Nylon 6 is extensively used in engineering application because of its unique characteristics such as low price, low viscosity, high toughness, shelf lubricating behaviour and high chemical resistance. The nanocomposites based on PA-6 were prepared by melt extrusion and an adjacent injection moulding process. Mechanical and thermomechanical properties have been investigated by tensile testing and dynamic mechanical analysis. To evaluate the potential of crysnano nanoclays as a new candidate in the class of nanofillers, the properties of the crysnano nanoclays nanocomposites has been compared to those of glass fiber. Thermal characteristics were performed using thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA). As increase in filler loading the enthalpy of melting (?Hm) obtained from DSC curves was reduced as compared to pristine nylon 6. All the nanocompsoites were stable upto 205?C. Degradation kinetic parameters have been calculated for thermal degradation processes using the composites using three mathematical models namely, Horowitz-Metzger, Coats-Redfern and Broido?s methods.


2021 ◽  
pp. 002199832110082
Author(s):  
Azzeddine Gharsallah ◽  
Abdelheq Layachi ◽  
Ali Louaer ◽  
Hamid Satha

This paper reports the effect of lignocellulosic flour and talc powder on the thermal degradation behavior of poly (lactic acid) (PLA) by thermogravimetric analysis (TGA). Lignocellulosic flour was obtained by grinding Opuntia Ficus Indica cladodes. PLA/talc/ Opuntia Ficus Indica flour (OFI-F) biocomposites were prepared by melt processing and characterized using Wide-angle X-ray scattering (WAXS) and Scanning Electron Microscope (SEM). The thermal degradation of neat PLA and its biocomposites can be identified quantitatively by solid-state kinetics models. Thermal degradation results on biocomposites compared to neat PLA show that talc particles at 10 wt % into the PLA matrix have a minor impact on the thermal stability of biocomposites. Loading OFI-F and Talc/OFI-F mixture into the PLA matrix results in a decrease in the maximum degradation temperature, which means that the biocomposites have lower thermal stability. The activation energies (Ea) calculated by the Flynn Wall Ozawa (FWO) and Kissinger Akahira Sunose (KAS) model-free approaches and by model-fitting (Kissinger method and Coats-Redfern method) are in good agreement with one another. In addition, in this work, the degradation mechanism of biocomposites is proposed using Coats-Redfern and Criado methods.


Molecules ◽  
2021 ◽  
Vol 26 (6) ◽  
pp. 1597
Author(s):  
Iman Jafari ◽  
Mohamadreza Shakiba ◽  
Fatemeh Khosravi ◽  
Seeram Ramakrishna ◽  
Ehsan Abasi ◽  
...  

The incorporation of nanofillers such as graphene into polymers has shown significant improvements in mechanical characteristics, thermal stability, and conductivity of resulting polymeric nanocomposites. To this aim, the influence of incorporation of graphene nanosheets into ultra-high molecular weight polyethylene (UHMWPE) on the thermal behavior and degradation kinetics of UHMWPE/graphene nanocomposites was investigated. Scanning electron microscopy (SEM) analysis revealed that graphene nanosheets were uniformly spread throughout the UHMWPE’s molecular chains. X-Ray Diffraction (XRD) data posited that the morphology of dispersed graphene sheets in UHMWPE was exfoliated. Non-isothermal differential scanning calorimetry (DSC) studies identified a more pronounced increase in melting temperatures and latent heat of fusions in nanocomposites compared to UHMWPE at lower concentrations of graphene. Thermogravimetric analysis (TGA) and derivative thermogravimetric (DTG) revealed that UHMWPE’s thermal stability has been improved via incorporating graphene nanosheets. Further, degradation kinetics of neat polymer and nanocomposites have been modeled using equations such as Friedman, Ozawa–Flynn–Wall (OFW), Kissinger, and Augis and Bennett’s. The "Model-Fitting Method” showed that the auto-catalytic nth-order mechanism provided a highly consistent and appropriate fit to describe the degradation mechanism of UHMWPE and its graphene nanocomposites. In addition, the calculated activation energy (Ea) of thermal degradation was enhanced by an increase in graphene concentration up to 2.1 wt.%, followed by a decrease in higher graphene content.


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