Physical, Mechanical, and Thermal Properties and Characterization of Natural Fiber Composites Reinforced Poly(Lactic Acid): Miswak (Salvadora Persica L.) Fibers

Abstract

7000 years ago, miswak fiber (MF) was used as a toothbrush for oral care. However, since the emergence of plastic materials, it monopolized the oral care industry. The increment of plastic products also promotes accumulation of plastic wastes after its disposal. Thus, many researchers have turn to biodegradable products to reduce this problem. The aim of this study is to investigate the chemical, physical, and mechanical properties of MF as reinforcement in composites that are suitable to replace the toothbrush materials. The MF was reinforced in PLA composite with different weight percentage (0%, 10%, 20%, and 30%) and undergoes several types of testing. The chemical results show that there were high presence of cellulose in the fiber which could act as medium to transfer stress load equally from fiber to matrix. However, the results show low cellulosic contents in MF that affects the poor interfacial bonding between fiber and matrix. Physical properties shows a positive indication to be used as a toothbrush handle. As the fiber content increases, the density also increased. SEM micrographic illustrated the presence of voids as the cause for reduction in mechanical properties of composites. The mechanical results show the proposed material is comparable to the materials used in commercial applications. As for the thermal result, the TGA test melting point of the proposed composite material was comparable to the pure PLA, which means the proposed material can use similar processing temperature as PLA. DSC shows that Tg of PLA/MF composite is found to be similar to Tg in loss modulus of composites. DMA finding found that PLA/MF30 have the highest storage modulus 2062 MPa and the lowest tan δ 0.6 among PLA/MF composites. This concludes that there is a possibility of using these materials as an alternative in composites and increase the fiber strength by using pretreatments and/or compatibilizer.

Manufacture and characterisation of polylactic acid biocomposites with high-purity cellulose isolated from olive pruning waste

“…PLA crystallinity increased from 38.44% to 40.44% with the addition of OTPBH 2 , confirming the role of cellulose as a nucleating agent that promotes PLA crystallisation. 61,62 Also, the extrusion process and the subsequent injection moulding generated an improvement in the orientation of the fibres and in the molecular orientation of the polymer chains, resulting in the improvement of crystallinity. 47 TGA tests were carried out to analyse the thermal degradation of the PLA and the manufactured biocomposites.…”

“…The main degradation event observed in Figure 12 took place in the range 300-400°C, and corresponded mainly to the degradation of the polymer matrix. 55,56,[61][62][63] The thermal stability of the materials represented by onset, maximum and endset degradation temperatures (T onset , T max and T endset , respectively) decreased with the incorporation of the fibres, said decrease being greater in the case of a 15 wt.% reinforcement (Table 6). Some authors have related this reduction by the decrease of molecular weight of PLA during composite processing and to the incorporation of the fibres.…”

Biocomposites Films Based on Polylactic Acid and Olive Wood-Flour: Investigation on Physical, Thermal and Mechanical Properties

“…In DSC heating scans, all PLA/OWF composites showed a faint exothermic peak between 90°C and 120°C, which could be attributed to crystallization. 38 Due to the low mobility of the chains, the crystallization rate of PLA is very slow. Similar findings were reported by R.Z.…”

The Potential of Bio-Based Polylactic Acid (PLA) as an Alternative in Reusable Food Containers: A Review

“…This process occurs faster at a temperature close to the T g of the polymer. For PLA, the T g is 55-63 • C [56], meaning natural aging will occur fastest at these temperatures.…”

“…Mechanical recycling was found to use four times less energy than recycling through a chemical process, although no LCA studies have accounted for the degradation of material properties from mechanical processing and no standard for the resulting quality has been developed; reprocessing may result in various changes in mechanical properties [155]. These changes may include, but are not limited to, a decrease in tensile strength, an increase in brittleness, and altered thermal properties [56]. The environmental impacts of solvent-based recycling have also been considered for post-consumer waste PLA [157].…”