All-cellulose composite laminates prepared from pineapple leaf fibers treated with steam explosion and alkaline treatment

Abstract

Pineapple leaf fibers with diameters of 43 ± 0.1 µm were treated by two different approaches: the alkaline treatment and the combination of the steam explosion and alkaline treatment. The observations revealed the steam explosion process efficiently provided 3.4 µm diameter fibers with a less amount of lignin and a higher proportion of cellulose, compared with the alkaline-treated fibers. The steam-exploded fibers showed higher crystallinity and more thermal stabilities than the alkaline-treated fibers. No structural change from cellulose I to cellulose II was detected from both treated pineapple leaf fibers. Subsequently, all-cellulose composite laminates were prepared from these two types of treated pineapple leaf fibers mats. The higher tensile strength and modulus were obtained from the steam-exploded pineapple leaf fibers composite laminates due to larger surface areas of the fibers interacted with the cellulose matrix. Fracture morphology of the composites was studied after tensile deformation. The combination mechanism of fiber breakage and fiber pull-out deformation was observed from the steam-exploded pineapple leaf fibers composite laminates, whereas only fiber pull-out mechanism was found from the alkaline-treated pineapple leaf fibers composite laminates. The fiber width and amounts of the matrix filling in pores in a mat were found to dominate the mechanical properties of the all-cellulose composites.

Mechanical Properties of Gigantochloa Scortechinii Bamboo Particle Reinforced Semirigid Polyvinyl Chloride Composites

“…The factors controlling the composite strengths are interface adhesion between fibre and matrix, hydrogen bonding, fibre size, stress-strain transfer between fibre and matrix and fibre dispersion [6,30]. The tensile strength and tensile modulus of SE-alkalitreated BP/semirigid PVC is higher than that of untreated BP/semirigid PVC; this result is consistent with that reported in [6] because of the small sizes and large surface areas of the particles which can interact with the matrix. The increased tensile strength and tensile modulus may be due to the good adhesion between the particle and the matrix (Figure 4h).…”

“…However, many factors should be considered when using natural fibre; these factors include incompatibility between fibre and polymer due to polarity, high level of moisture absorption, poor wettability and inadequate level of adhesion between untreated fibre and nonpolar polymer which leads to a weak interface between fibre and matrix [4][5]. The poor adhesion between fibre and matrix indirectly hinder stress transfer in composites [6]. The previous study [7] observed many small voids and broken fibres, thereby indicating the weak adhesion between fibre and matrix in the case of sugarcane bagasse fibre-filled Polyamide 6.…”

“…Most of the natural fibres possess highly hydrophilic nature due to the presence of hydroxyl groups in lignocellulosic structure [8]. Previous research has used many techniques in modifying the surface properties of natural fibre to enhance the adhesion between matrix and natural fibre; these techniques include acetylation and stearation [1], alkali [9], chitosan [10], sulfuric acid [11], silane coupling agent [12] and SE [6].…”

Cellulose Nanocomposites of Cellulose Nanofibers and Molecular Coils

“…Two common methods of producing ACCs are infiltrating a cellulose solution in pre-aligned cellulose fibers [9][10][11], and in situ dissolution of cellulose fibrils to partially amorphized cellulose for binding remainder fibers [12][13][14]. Other routes for production of cellulose composites have been experimented through either incorporating fibers to cellulose solutions or partially dissolving fibers using solvents including N-methyl morpholine N-oxide (NMMO) [15], ionic liquids [16][17][18], N,N-dimethyl acetamide (DMAc) and LiCl [13,[19][20][21], or others [22,23], followed by coagulation to regenerate cellulose II, resulting in cellulose composites containing a myriad of structures resulting in interlinked bulk and interfacial properties [12,[23][24][25][26].…”

Fibra de sisal modificada com óxido de alumínio hidratado para emprego como reforço em compósitos de matriz resina epóxi

“…. Publicações apresentam pesquisas que avaliam o tratamento alcalino em FVL aplicado juntamente com outros tratamentos(ARPITHA et al, 2017;TANPICHAI;WITAYAKRAN, 2017).…”