Investigation of Efficient Alkali Treatment and the Effect of Flame Retardant on the Mechanical and Fire Performance of Frost-Retted Hemp Fiber Reinforced PLA

Abstract

: This research investigates an effective alkali (NaOH) treatment and fire-retardant coating to produce biocomposites from frost-retted hemp fiber and PLA. The fiber surface treatment with various NaOH concentrations was investigated throughout a range of soaking times. The results show that the extracted non-cellulosic fiber content increases with treatment duration and NaOH concentration, while the fraction of targeted components removed remains nearly unchanged after soaking for 1, 2, and 4 h with a 5 wt.% NaOH solution. At the composite level, the treatment with 5 wt.% NaOH solution for 1 h emerged as the most efficient, with tensile strength, Young’s modulus, flexural strength, and flexural modulus of 89.6 MPa, 9.1 GPa, 121.6 MPa, and 9.6 GPa, respectively, using 30 wt.% fibrous reinforcement. The fire performance of the examined batches of biocomposites improved significantly with the novel fire-retardant (Palonot F1) coating. However, the tensile strength notably decreased, while the flexural properties showed only a slight reduction. In most cases, the biocomposites with the alkali-treated hemp fiber had delayed ignition during the 5 min exposure to the cone heater. The findings in this work contribute to studies that will be required to give design guidelines for sustainable building options.

Effect of silane coupling grafted polyethylene terephthalate foam and areca fruit fiber reinforced chitin modified vinyl ester prosthetic composite on thermal and water accelerated aging conditions

“…Moreover the aging slightly induce the flame propagation speed in temperature exposed composites. This is because of thermally broken aged silane molecules allows the composite to capture fire and permits to propagate further 34 . It is noted that the thermally aged composites gives higher propagation speed than the water aged composites.…”

“…This is because of thermally broken aged silane molecules allows the composite to capture fire and permits to propagate further. 34 It is noted that the thermally aged composites gives higher propagation speed than the water aged composites. Composite APR2 gives 12.63 mm/min whereas composite APH2 gives 12.32 mm/min.…”

Influence of Protic Ionic Liquid-Based Flame Retardant on the Flammability and Water Sorption of Alkalized Hemp Fiber-Reinforced PLA Composites

“…For example, a previous study on the hemp fiber used in the current research found no significant difference in the mass loss, ignition time, temperature transfer through depth, basic protection time, or the start of char time for the composites with either untreated or alkali modified fibers [ 14 ], which is primarily due to the hemp fiber’s inherently low lignin content (1.4%) [ 15 ]. Despite this, considerable improvements in the mechanical characteristics [ 15 , 16 ], water absorption, and hygroscopic properties [ 14 ] of the composites were documented following alkali treatment. The biggest issue due to fire-retardant treatments of natural fibers is the loss of mechanical qualities [ 16 ].…”

“…Despite this, considerable improvements in the mechanical characteristics [ 15 , 16 ], water absorption, and hygroscopic properties [ 14 ] of the composites were documented following alkali treatment. The biggest issue due to fire-retardant treatments of natural fibers is the loss of mechanical qualities [ 16 ]. As a result, the challenge is to treat the fibers in a way that delivers both sufficient reaction to fire and mechanical and water sorption durability.…”

Triblock Copolymer Compatibilizers for Enhancing the Mechanical Properties of a Renewable Bio-Polymer

“…Researchers have investigated biodegradable fibers as reinforced composites that exhibit superior performance and suitability for widespread use. Such composites combine the properties of the matrix polymer and reinforced fiber, and are lightweight and high strength [10][11][12]. The matrix material and reinforced fiber must meet the needs of engineering.…”