Revaluation of Australian palm residues in polypropylene composites: Statistical influence of fiber treatment

Abstract

Australian palm residues are generated by palm heart industry in large quantities and are considered an underused material with a composition rich in lignocellulosic structures. This residue is generally utilized as briquettes for energy or sheep feed; however, few works investigate this residue as composite fillers. This work aimed to revalue Australian palm residues (PR) by preparing polypropylene composites through melt mixing, using different fiber contents (0, 5, 10, 20, and 30 wt%), and evaluate the statistical influence of fibers (residues) alkali treatment (MPR) in composites mechanical properties. PR and MPR were evaluated by FTIR, XRD, SEM, TGA, and composites were assessed using thermal and mechanical analysis, in which ANOVA statistical analysis was applied. The residues addition increased the mechanical properties and their treatment enhanced the stiffness of the composites compared to pristine PP. However, ANOVA demonstrated that at low residues contents, surface treatment does not increase fiber-matrix interactions effectively, then tensile properties were statistically similar to PP. Considering tensile properties, 20% MPR showed statistically distinct properties, with significative enhancements; no filler contents dependence was verified. Flexural properties were more sensitive to residue loading, and composites with 30% PR and MPR presented superior mechanical performance. This difference is associated with a higher sensitivity of tensile stress towards fiber-matrix interactions, which was improved with fiber treatment. Also, the residues content and treatment influenced the composites' thermal stability, with better results for PP-MPR. Results indicate that palm residue is an excellent filler for improving composites' thermal and mechanical properties, with a greener character.

Development and Characterization of a 3D Printed Cocoa Bean Shell Filled Recycled Polypropylene for Sustainable Composites

“…Residual char and ash content about 35% was found after 600 °C. Even though the thermogravimetric behavior of natural fillers depends on their chemical constituents [ 49 ], the thermal behavior obtained in this study coincides with the report for other lignocellulosic fibers such as flax, hemp, sugar cane, bamboo, coconut, among others [ 49 , 50 , 51 , 52 ].…”

Adoption of cleaner production in a pupunha palm heart factory: a systematic literature review and a case study

“…The Australian royal palm is an endemic tree in eastern Australia; however, it has developed well in Brazil, as the country's tropical climate provides an ideal temperature range (between 20 and 30 °C) for plant germination (Zanini et al, 2020). This specimen can reach up to 25 meters in height, producing viable seeds, having good resistance to diseases, and providing high-quality palm heart.…”

“…When analyzing the agribusiness exploitation and the processes related to the industrialization of the pupunha palm heart, it is possible to observe the residual generation of large quantities of barks and their respective external sheaths, which, if not adequately cared for and discarded, can cause environmental problems (Silva et al, 2009). According to Zanini et al (2020), high palm production results in significant amounts of waste during palm heart extraction. For each palm, approximately 400 g of commercial palm heart is collected.…”

“…Palm residues are found in large quantities in several countries, mainly in Brazil, and are considered low-cost, biodegradable, and easy to handle waste (Zanini et al, 2020). Besides, pupunha palm heart can be sold through simplified processing steps.…”

Experimental analysis of tensile properties and essential work of fracture of fumed silica filled polypropylene toughened with thermoplastic polyolefin elastomer

“…Polypropylene (PP) is one of the most common thermoplastic polymers which widely utilized in home appliances, medical equipment, automotive industries, etc. 1 PP is known to be sensitive to notch and has brittle behavior under some situations such as rapid impact force or low temperature. Combining PP with ductile polymers by melt mixing or copolymerization with flexible polymers are efficient strategies to increase its toughness.…”