Editorial Type:
Article Category: Research Article
 | 
Online Publication Date: 03 Dec 2020

Bioenveloping Inorganic Filler-Based Eggshell Wastes for Enhancing the Properties of Natural Rubber Biocomposites

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Page Range: 315 – 331
DOI: 10.2346/tire.20.20002
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ABSTRACT

In this study, eggshell (ES) wastes were used as a renewable reinforcing material in natural rubber (NR) composite to limit carbon production. Long bio-alkyd resin (LAR) was also used to envelope the inorganic ES particles and to aid in dispersing the filler in the NR matrix. The effect of the coated ES filler (ESR) in the rubber mix on the morphology, mechanical properties, and swelling was investigated. The ES filler and its biocomposites were characterized by X-ray fluorescence, scanning electron microscopy, Fourier transform infrared imaging microscope (FT-IR-IM), differential scanning calorimetry (DSC), and thermogravimetric analysis. The morphological data reveal that the resin enhances the dispersion of the ES filler in the NR matrix. These data were confirmed by the results obtained from FT-IR-IM. The swelling and mechanical properties were significantly improved when the coated filler was used in NR matrix, especially at 20 wt.% ESR. DSC thermograms revealed that the increase in the resin caused the glass transition temperature (Tg) to be shifted to a lower temperature. The obtained results show that the bioenveloping ESR can be used as potential alternative for green tire and vehicle applications rather than conventional petroleum-based filler.

Keywords: natural rubber; eggshell filler; renewable reinforcing; bio-alkyd resin; FT-IR microscope; mechanical properties
FIG. 1 —
FIG. 1 —

SEM images of neat NR and its filled biocomposites by untreated and treated ES containing 20 wt.% filler content.

SCHEME 1 —
SCHEME 1 —

Schematic representation of the preparation of ESR and its processing with NR to obtain highly compatible NR/ESR biocomposites.

FIG. 2 —
FIG. 2 —

FT-IR-IM analysis of neat NR, NR/ES-20, and NR/ESR-20 biocomposites at magnification of 8× and 64 scans.

FIG. 3 —
FIG. 3 —

Schematic diagram represents the proposed reaction mechanism of pristine NR with bio-alkyd soybean resin (LAR).

FIG. 4 —
FIG. 4 —

DSC thermographs for neat NR and its filled biocomposites with different contents of untreated and treated ES bio-fillers during heating ramp.

FIG. 5 —
FIG. 5 —

Tensile versus strain curves for pristine NR and its biocomposites with various ratios of ES (a) and ESR (b).

FIG. 6 —
FIG. 6 —

Increase in tensile strength and strain at break percentages as a function of ES and ESR filler contents.

FIG. 7 —
FIG. 7 —

Swelling ratio at equilibrium and crosslink density (1/Mc) as a function of NR composites at ambient temperature for 72 hours in toluene.

FIG. 8 —
FIG. 8 —

TGA curves for ES powder, NR, and their biocomposites based on unmodified ES (a) and modified ESR (b) in nitrogen atmosphere. a* and b* represent the derivative thermogravimetry of the samples.

Contributor Notes

1  Polymer Metrology & Technology Department, National Institute of Standards (NIS), Tersa Street, El Haram, P.O. Box 136, Giza 12211, Giza, Egypt
2 Corresponding author. Email: hesham.moustafa21@gmail.com
3 Packaging Materials Department, National Research Centre, 33 El Bohouth St. (former El Tahrir St.), P.O. Box 12622, Dokki, Giza, Egypt
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