Kinetics of Crystallization and Thermal Degradation of an Isotactic Polypropylene Matrix Reinforced with Graphene/Glass-Fiber Filler.

Evangelia Tarani,Dimitrios N Bikiaris,Konstantinos Chrissafis,George Z Papageorgiou

doi:10.3390/molecules24101984

Abstract

Polypropylene composites reinforced with a filler mixture of graphene nanoplatelet-glass fiber were prepared by melt mixing, while conventional composites containing graphene nanoplatelet and glass fiber were prepared for comparative reasons. An extensive study of thermally stimulated processes such as crystallization, nucleation, and kinetics was carried out using Differential Scanning Calorimetry and Thermogravimetric Analysis. Moreover, effective activation energy and kinetic parameters of the thermal decomposition process were determined by applying Friedman’s isoconversional differential method and multivariate non-linear regression method. It was found that the graphene nanoplatelets act positively towards the increase in crystallization rate and nucleation phenomena under isothermal conditions due to their large surface area, inherent nucleation activity, and high filler content. Concerning the thermal degradation kinetics of polypropylene graphene nanoplatelets/glass fibers composites, a change in the decomposition mechanism of the matrix was found due to the presence of graphene nanoplatelets. The effect of graphene nanoplatelets dominates that of the glass fibers, leading to an overall improvement in performance.

Highlights

The continuous demand for high-performing materials in the 20th century has led to the development of polymer composites
Isothermal crystallization experiments for neat PP and the corresponding composites were the crystallization of the samples were recorded as a function of time
graphene nanoplatelets (GNP) and Glass fibers (GF) were inserted individually and simultaneously in an isotactic PP matrix; the nucleation, crystallization behavior, and thermal degradation kinetics were studied under a wide variety of conditions

Summary

Introduction

The continuous demand for high-performing materials in the 20th century has led to the development of polymer composites. Polypropylene (PP) is one of the most used semicrystalline polymers It can be found in various applications, such as heating, piping, sanitary, film and rigid packaging, due to its low cost and good physicochemical properties. Glass fibers (GF) are one of these fillers since they can quite efficiently reinforce most polymeric matrices due to their high stiffness and strength, their outstanding fatigue performance, and low cost [6,7,8]. For this reason, GF-reinforced composites are already a commodity in the aerospace, automotive, construction, and sporting industries.

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