Development of waste tire‐derived graphene reinforced polypropylene nanocomposites with controlled polymer grade, crystallization and mechanical characteristics via melt‐mixing

Abstract

In the present work, single layer graphene nanoplatelets (GNPs) derived from waste tires by recycling and upcycling approaches were integrated in homopolymer (Homo-) and copolymer (Copo-) polypropylene (PP) matrices by fast and efficient mixing in the melt phase. The effect of GNP content on crystallization and mechanical behaviors was investigated in detail at different loading levels. Regarding isothermal and non-isothermal crystallization experiments, GNPs significantly accelerated the nucleation and growth of crystallites, and the crystallization degree in Homo-PP nanocomposites was slightly higher than that of Copo-PP based nanocomposites. Also, there was significant improvement in mechanical and thermal properties of GNP reinforced polymers compared to neat polymers. As the GNP concentration increased from 1 to 5 wt%, there was a gradual increase in flexural modulus and strength values. In tensile tests, an increase in GNP content in both polymer grades led to a slight increase in yield strength coming from the proper distribution of nano-reinforcement by creating stress concentration sites. After the yield point, Homo-PP based nanocomposites showed higher strain hardening than GNP reinforced Copo-PP owing to a high crystallization degree and linear chains of Homo-PP. This work showed that functionalized graphene can act as both nucleating and reinforcing agent in the compounding process and its exfoliation through polymer chains is much better in homopolymers at a faster and high shear rate.

Experimental and Numerical Investigation of Flow and Alignment Behavior of Waste Tire-Derived Graphene Nanoplatelets in PA66 Matrix during Melt-Mixing and Injection

“…Figure 2 shows the flexural stress/strain curves of neat PA66 and its nanocomposites with different loadings after ISO 178 three-point bending tests. Flexural strength gives insight into a material’s resistance to fracture, while flexural modulus indicates a material’s tendency to bend [ 54 ]. It can be seen that the addition of GNP increased the flexural modulus with the increase of GNP loadings and also improved flexural strength except for 0.2 wt% loading.…”

Scalable fabrication of high‐performance graphene/polyamide 66 nanocomposites with controllable surface chemistry by melt compounding

“…In Table 2, the values of tensile strain at break of composites by incorporating graphene reinforcements were decreased since graphene leads to a decrease in ductility resulting in an increase in brittleness of composites and thus the formation of fractures in TEGO and rGO based composites before deforming much under a tensile load of neat PA 66 37 …”

“…35,36 In Table 2, the values of tensile strain at break of composites by incorporating graphene reinforcements were decreased since graphene leads to a decrease in ductility resulting in an increase in brittleness of composites and thus the formation of fractures in TEGO and rGO based composites before deforming much under a tensile load of neat PA 66. 37 Furthermore, it is well known that the dispersion state of graphene in the matrix greatly affects the mechanical performance of graphene based polymeric composites.…”

An Industrial Case for Polypropylene Nanocomposite Foams: Lightweight, Soundproof Exterior Automotive Parts

“…The magnitude of improvement showed consistency with empirical and theoretical studies regarding graphene-polypropylene nanocomposites in the literature [ 30 , 31 , 32 ]. The improvement of the modulus for copolymer-based nanocomposites was lower than that of homopolymer-based nanocomposites due to crystallinity degree [ 33 , 34 ]. The flexural property of nanocomposites showed an analogy with tensile properties.…”