Silica aerogel (SA) was used as fillers in the sugar palm/polyester composite (SPF/PE). Their influence on tensile, flexural, and impact properties of the composite was determined by varying the additive concentration from 1-5 wt% in the resin. The findings from the study indicate that both the strength and modulus of SPF/PE improved significantly by adding SA. Maximum tensile, flexural, and impact strength occurred at an optimum filler concentration of 2-3 wt%. Similarly, the highest tensile and flexural modulus was achieved with 5 wt% and 2 wt%, respectively. The microstructure of SA-infused composites revealed less fiber pullout/slippage compared to the composites without filler.
Natural fibers possess many advantages in comparison to the synthetic fibers like biodegradability, economical production, and least environmental impacts throughout the commercial life cycle [
SPF existing in the naturally woven state was obtained from the Negeri Sembilan region in Malaysia. Reversol P9509 PE resin with Methyl Ethyl Ketone Peroxide (MEKP) and SA was procured from Bintang Timur Sdn Bhd and Maerotech Sdn Bhd, Malaysia. SA derived from the rice husk was purchased from Maerogel Sdn Bhd, Malaysia. SA used in this study had a high specific surface area of 900 m2/g, average nanoscale size of 20-50 nm, and melting point of 1700°C [
Initially, the obtained SPF layers were stacked together and pressed in the hot press at 80°C for 10 minutes to form the compressed fiber mat. SA at 1-5 wt% concentration was introduced slowly in the resin and mixed with the mechanical stirrer at a constant speed of 500 rpm for 60 minutes. The resin mixing process with SA was performed in the air-conditioned atmosphere at 22°C temperature and 50% humidity.
The composite samples with different weight concentration of SA were prepared by the layup and hot press technique as shown in Figure
Fabrication process of SA-infused SPF/PE composite.
Table
Notation of SPF/PE composite with various SA concentrations.
Notation | SPF (wt%) | PE (wt%) | SA (wt%) |
---|---|---|---|
0% SA | 30 | 70 | 0 |
1% SA | 30 | 69 | 1 |
2% SA | 30 | 68 | 2 |
3% SA | 30 | 67 | 3 |
4% SA | 30 | 66 | 4 |
5% SA | 30 | 65 | 5 |
Tensile, flexural, and impact properties were determined for composites infused with SA at different concentrations and compared to the composite without filler. 5 specimens cut from the fabricated sample with different SA concentrations were tested, and their average results were reported in accordance with ASTM D3039, ASTM D790, and ASTM D6110, respectively. Tensile and flexural test was carried out with 5 KN Blue hill INSTRON. Strength at maximum load and Young’s modulus was measured automatically and recorded by the machine interface. The Charpy impact test was performed on V-notched specimens, and the impact energy was recorded. Impact strength was calculated using
The fractured specimen from the impact test was gold sputtered and observed under HITACHI S-3400N to study the morphological changes and their failure behavior.
Table
Mechanical properties of SPF/PE with and without SA.
Properties | SPF/PE composite | |||||
---|---|---|---|---|---|---|
0% SA | 1% SA | 2% SA | 3% SA | 4% SA | 5% SA | |
Tensile strength (MPa) | ||||||
Tensile modulus (GPa) | ||||||
Flexural strength (MPa) | ||||||
Flexural modulus (GPa) | ||||||
Impact strength (KJ/m2) |
From Table
It could be observed from Table
In case of the impact properties, a notable increase of impact strength up to 21% was observed for 3% SA in comparison to the composite without SA (Table). Zhang et al. [
Figures
SEM images of SPF/PE (a) 0% SA composite and (b) 3% SA-infused composite.
0% SA composite (Figure
SA-infused composite showed higher strength and modulus at their optimum concentrations due to the better fiber-matrix adhesion, lower lengths of fiber breakage, less fiber pullout, and increased degree of roughness in the matrix. The enhancement in properties obtained with the addition of SA will help to increase the usability of otherwise wasted sugar palm fibers as a potential reinforcement for composites in the tertiary structures and household applications.
The data used to support the findings of this study are available from the corresponding author upon request.
The authors declare that they have no conflicts of interest.