Improving mechanical properties of ramie/poly (lactic acid) composites by synergistic effect of fabric cyclic loading and alkali treatment

Abstract

Natural cellulose fiber reinforced biopolymer composites have attracted increasing attention due to environmental concerns. However, these fibers have relatively low mechanical properties and poor interfacial adhesion with matrices, limiting their composite mechanical properties. This study investigates the synergistic effect of two recently developed techniques to maximize the mechanical performance of ramie/poly (lactic acid) laminated composites, namely alkali treatment to loosen fiber molecular structure and to increase fiber surface roughness and subsequent cyclic loading treatment to fabrics to increase their tensile strength and modulus. The results show that the treated fabrics have increased crystallinity and crystal orientation factor as well as better orientation of fibers and more uniform structures, leading to 11% improvement in fabric tensile strength and 57% enhancement of tensile strength (90.9 MPa), 48% higher tensile modulus (5.6 GPa), 18% higher flexural strength (149.4 MPa), and 91% higher flexural modulus (8.2 GPa) for the corresponding composites. Meanwhile, postmortem analysis shows that better interfacial adhesion is achieved using this approach.

Tensile Strength Improvements of Ramie Fiber Threads through Combination of Citric Acid and Sodium Hypophosphite Cross-Linking

“…In the future, the ramie fiber, which crosslinked with CA in optimum condition, should be recommended for application for Natural Fiber Reinforced Polymer Composite (NFRPC). The bio-composites of NFRPC are categorized into complete and partial green composites [ 39 , 40 , 41 , 42 ]. There has been much research completed on some of the significant advancements related to NFRPCs materials that can replace synthetic fibers in numerous applications, including the car manufacturing industry, which has advantages such as being more efficient in terms of production costs, lighter in weight, has an excellent mechanical quality, has biodegradability properties so it is more environmentally friendly, and has economic perspective.…”

Interfacial modified unidirectional wheat straw/polylactic acid composites

“…Thus, it was difficult for WS to adhere and bond to the resin, which can affect the interface and mechanical properties of the composites. Alkali treatment had been an effective method for removing wax from the surface of natural fibers [1,16,[22][23][24][25]. Huda et al [16] used alkali and silane to treat kenaf fibers.…”

Biodegradation properties and thermogravimetric analysis of 3D braided flax PLA textile composites

“…However, its use in many applications is limited by low thermal stability, brittleness and low barrier properties [10,13]. Hence, it is important to alter the brittle nature and enhance the impact strength, thermal stability and other mechanical properties by adding natural fiber as reinforcement in the PLA matrix [14][15][16][17]. Natural fibers such as sisal, jute, elephant grass, kenaf, hemp, bamboo, coir and flax reinforced PLA composites are developed by using injection moulding and hot-press compression moulding methods [18][19][20][21].…”