Renewable Natural Fiber Research Articles

Strong, bacteriostatic and transparent polylactic acid-based composites by incorporating quaternary ammonium cellulose nanocrystals

Renewable natural fibers (e.g., cellulose nanocrystals (CNCs)) are being applied for reinforcing bio-based polylactic acid (PLA). For improvement in the interfacial compatibility between CNCs and PLA and the dispersibility of CNCs, a quaternary ammonium salt-coated CNCs (Q-CNCs) hybrid was prepared in this study based on an esterification self-polymerization method, and such hybrid was further utilized as a new strengthening/toughening nanofiller for producing the Q-CNCs-reinforced PLA composite. The results confirmed that quaternary ammonium salt coatings could efficiently enhance CNCs/PLA interfacial compatibility via mechanical interlocking and semi-interpenetrating networks. Attributing to the synergistic effect of quaternary ammonium salts and CNCs, a considerable enhancement in processing, mechanical, and thermal properties was gained in the obtained Q-CNCs-reinforced PLA composite. With the addition of 0.5 wt% Q-CNCs, the tensile strength, Young's modulus, and elongation at break of the Q-CNCs-reinforced PLA composite was raised by approximately 23 %, 37 % and 18 %, respectively; compared with pure PLA, the obtained composite had excellent bacteriostatic properties and good transparency. This work discusses the development of high-performance, low-cost and sustainable PLA-based composites on a potential application in packaging materials.

Geopolymeric Composites Containing Industrial Waste Reinforced with Arundo donax Fibers

Traditional Portland cement-based composites have a great environmental impact. Alkali-activated binders can offer an alternative, particularly if they can be obtained even partially from waste. Two residuals derived from the finishing steps of the traditional ceramic industry have been used as possible polymerizable sources mixed with metakaolin. Moreover, to contrast the low dimensional stability of alkali-activated materials and their mechanical brittleness, natural fibers derived from the Arundo donax plant have been added to the mortars. The use of renewable natural fibers instead of synthetic ones can contribute a further environmental advantage. The fresh (consistency) and cured (mechanical) properties of composite materials prepared with residuals and metakaolin were analyzed here. For comparison’s sake, a reference set of composite materials not loaded with fibers but with an identical binder/sand and liquid/binder ratio was cast. A room-temperature curing condition was selected that, although inadequate to promote the short-time reactivity of the wastes, has a minimal energy requirement and allows on-site applications. A small-scale decrease in the properties in the compression mode tests was observed in the waste-modified mortars, while the Arundo addition improved their flexural strength and dimensional stability.

Synergistic Enhancement of the Mechanical Properties of Epoxy-Based Coir Fiber Composites through Alkaline Treatment and Nanoclay Reinforcement

This study explores the synergistic effects of incorporating coir fibers and nanoclay into epoxy resin composites. Coir, a renewable and cost-effective natural fiber, undergoes an alkaline treatment to influence its ability to form strong interfacial bonding with the epoxy matrix. To further enhance the mechanical properties of the composite, montmorillonite nanoclay, surface-modified with aminopropyltriethoxysilane and octadecyl amine, is introduced. The research investigates different combinations of coir fiber content (20, 30, and 40 wt%) and nanoclay loading (0, 2, and 4 wt%) with epoxy resin. The composites are fabricated through an open molding process, and the mechanical properties are evaluated using tensile and flexural tests according to the ASTM D638 and D7264 standards, respectively. The tensile and flexural strengths of the 40 wt% coir fiber-reinforced epoxy composite are found to be 77.99 MPa and 136.13 MPa, which are 44% and 23% greater than pure epoxy, respectively. Furthermore, the strengths displayed a 23% improvement in tensile strength with 4 wt% and a 31.4% improvement in flexural strength with 2 wt% nanoclay as additional reinforcement. Scanning electron microscopy is employed for fractographic analysis of the fractured specimens from the tensile test. The study underscores the importance of understanding the interplay between natural fibers, nanoclay, and epoxy resin for optimizing the composite’s performance in real-world applications.

Effect of Modified Cow Dung Fibers on Strength and Autogenous Shrinkage of Alkali-Activated Slag Mortar.

Alkali-activated slag (AAS) presents a promising alternative to ordinary Portland cement due to its cost effectiveness, environmental friendliness, and satisfactory durability characteristics. In this paper, cow dung waste was recycled as a renewable natural cellulose fiber, modified with alkali, and then added to AAS mortar. The physico-chemical characteristics of raw and modified cow dung fibers were determined through Fourier transform infrared (FTIR), X-ray diffraction (XRD), and Scanning electron microscope (SEM). Investigations were conducted on the dispersion of cow dung fibers in the AAS matrix, as well as the flowability, strength, and autogenous shrinkage of AAS mortar with varying cow dung fiber contents. The results indicated that modified fiber has higher crystallinity and surface roughness. The ultrasonic method showed superior effectiveness compared to pre-mixing and after-mixing methods. Compared with raw cow dung fibers, modified fibers led to an increase of 11.3% and 36.3% of the 28 d flexural strength and compressive strength of the AAS mortar, respectively. The modified cow dung fibers had a more significant inhibition on autogenous shrinkage, and the addition of 2 wt% cow dung fibers reduced the 7 d autogenous shrinkage of the AAS paste by 52.8% due to the "internal curing effect." This study provides an alternative value-added recycling option for cow dung fibers as a potential environmentally friendly and sustainable reinforcing raw material for cementitious materials, which can be used to develop low autogenous shrinkage green composites.

High-Performance Calcium Silicate Board Reinforced by Microfibrillated Cellulose/Microsilica

The use of microfibrillated cellulose (MFC) derived from renewable natural plant fibers and microsilica (Ms) derived from industrial byproducts in calcium silicate boards (CSBs) is consistent with current trends favoring the use of green building materials. Herein, MFC and Ms synergistically reinforced CSBs were prepared by filling the pores between the MFC and the matrix using Ms to strengthen the MFC–matrix bond. The results show that adding Ms promotes the formation of calcium silicate hydrate. Furthermore, increasing the Ms content decreases the cumulative pore size of the plate, resulting in a denser structure. In addition, when the MFC and Ms contents were 0.3 and 12%, respectively, the flexural strength of the CSB reached 35.96 MPa, which is 37.4% greater than that in the absence of Ms (26.17 MPa). Moreover, a flexural strength of 25.03 MPa was retained after 25 freeze–thaw cycles, demonstrating excellent freeze–thaw resistance.

Performance Enhancement of Asphalt Mixtures Enabled by Bamboo Fibers and Acrylated Epoxidized Soybean Oil

Bamboo fibers (BFs) have attracted much attention as a potential sustainable reinforcement material for asphalt pavements due to their high specific strength and modulus, low cost, renewability, and biodegradability. However, the key challenge of using BFs in asphalt mixtures is the weak interfacial adhesion between intrinsically hydrophilic BFs and the hydrophobic asphalt matrix. Therefore, this study proposed a surface modification method of BFs using acrylated epoxidized soybean oil (AESO) and 4,4-methylenediphenyl diisocyanate (MDI) to improve the fiber–matrix adhesion of the BFs/asphalt mixture. Fourier transform infrared spectroscopy and nuclear magnetic resonance analyses confirmed that the modified BF surface was grafted with AESO, and both of them were linked by MDI, thereby leading to the formation of a hydrophobic layer on the fiber surface. The water absorption of BFs significantly decreased after modification, and the interfacial adhesion between the modified BFs and the asphalt matrix remarkably improved. Adding the modified BFs to the mixture improved its mechanical properties, high-temperature stability, and low-temperature cracking resistance and decreased its moisture susceptibility. The work provides a feasible and industrial-scale method to enhance the road performance of the asphalt mixture by using renewable natural fibers and vegetable oils as modifying materials.

Influence of flax fiber orientation on mechanical, thermo-mechanical and interfacial adhesion properties of epoxidized methyl ricinoleate modified epoxy composite: A sustainable green composite for cleaner production

Renewable natural fibers have been better eco-friendly reinforcing agents for plant oil toughened epoxy composites in order to achieve the desired properties for structural applications. In the current work, epoxy methyl ricinoleate (EMR) synthesized from castor oil was used to modify epoxy to tailor the stiffness-toughness balance. For the first time, an epoxy/EMR blend has been used to fabricate the composite. The fiber pull-out test showed a 17% increment in interfacial shear strength on adding 20% EMR to epoxy and hence this modified epoxy was reinforced with UD (Unidirectional) mat at three different orientations i.e. [0/0], [0/90] and [90/90]. The [0/0] orientation laminates displayed the highest tensile, flexural, and impact strength with an increment of 120%, 151% and 858% respectively as compared to epoxy/EMR copolymer, whereas [0/90] orientation laminates showed superior translaminar fracture toughness and critical strain energy release rate with an increment of 216.5% and 494% respectively. Different theoretical models and a combination of classical lamination theory and modified rules of mixture were adopted to fit with the obtained experimental tensile strength and modulus values of appropriate laminates. Thermogravimetric and dynamic mechanical analysis confirmed the desired thermal stability and damping ability of the composites. Scanning electron microscope (SEM) morphology of the fractured surface and Water Contact Angle (WCA) of the surface of composites were studied to explain the fiber-matrix interface mechanism and wettability of the samples respectively. The results demonstrated that the EMR Modified Epoxy Composite can be an alternative to synthetic epoxy composites in automobile and structural applications. • Less viscous and reactive epoxy methyl ricinoleate (EMR)bio-resin is synthesized • High performance bio-composite using 20%EMR/epoxy as matrix was fabricated. • Effect of fiber inter-ply orientation on various mechanical properties was studied. • Failure mechanisms were validated with by Scanning Electron Microscope (SEM).

Facile Synthesis of Metal Oxide Decorated Carbonized Bamboo Fibers with Wideband Microwave Absorption.

Aiming at the disadvantages of high cost, complex processes, low yield, and narrow bandwidth of carbon-based microwave absorbing materials, this paper provides a novel and efficient method for synthesizing metal oxide/carbonized bamboo fibers using renewable natural bamboo fibers as a carbon source. The results suggested that the metal oxides such as NiO and Fe3O4 were uniformly dispersed on the carbonized bamboo fibers and proved that the dielectric component NiO and magnetic component Fe3O4 can significantly improve the microwave absorption performance of the carbonized bamboo fibers. As expected, the NiO/carbonized bamboo fibers showed excellent microwave absorption performance due to the appropriate complex permittivity, high impedance matching, and attenuation coefficient. A wide effective bandwidth of 6.4 GHz with 2.2 mm thickness is achieved, covering the entire Ku-band. Remarkably, the reflection loss (RL) values less than -10 dB covered the whole X-band at a thickness of 3.0 mm. This work reveals the potential of carbonized bamboo fibers-based composite as an economic and broadband microwave absorbent and offers a new strategy for designing promising microwave absorption materials.

Mechanical and durability properties of natural fiber-reinforced geopolymers containing lead smelter slag and waste glass sand

• Properties of natural fiber-reinforced FA/GGBS geopolymers containing different waste-based sands (NS, LSS, and WGS) were evaluated. • Geopolymers containing WGS experienced highest strength and lowest water absorption compared to the geopolymers containing NS and LSS. • LSS modified geopolymers exhibited lowest drying shrinkage compared to the geopolymers prepared with NS and WGS. • Natural fiber-reinforced geopolymers exhibited highest strength and lowest drying shrinkage compared to unreinforced geopolymers. • Natural fibers and waste-based sands can be used to prepare sustainable and durable geopolymers for structural applications. Owing to the low tensile properties of concrete, the use of internal fibers received significant attention in concrete production. In recent years, using renewable and eco-friendly natural fibers has become a viable alternative to synthetic fibers. Toward this direction, the behavior of natural fiber-reinforced geopolymers containing industrial by-products and waste-based sands is presented in this study. Industrial by-products, namely fly ash (FA) and ground granulated blast furnace slag (GGBS), were used as binders and waste-based sands, namely lead smelter slag (LSS) and waste glass sand (WGS), were used as fine aggregates in geopolymer mortars reinforced with natural fibers (i.e., 1% coir, ramie, sisal, hemp, jute and bamboo fibers, as well as 2% ramie fiber by volume fraction of fine aggregates). The flowability, mechanical properties (i.e., compressive strength and direct tensile strength), durability properties (e.g., water absorption), and drying shrinkage of the mortars were investigated. The results reveal that, at a given binder and fiber type, geopolymers containing WGS experience higher strength and lower water absorption than those containing LSS and natural river sand (NS). LSS-incorporated geopolymers exhibit a lower drying shrinkage when compared to the geopolymers prepared with WGS and NS. It is also found that geopolymers containing 1% ramie, hemp and bamboo fiber, and 2% ramie fiber exhibit higher compressive and tensile strengths and a lower drying shrinkage than unreinforced geopolymers, with those containing 1% ramie fiber exhibiting the highest strength and lowest drying shrinkage. These findings are promising and have significant potential for the use of natural fibers in the development of structural-grade construction materials, in which binder and aggregate are replaced with industrial by-products and waste-based materials.

Numerical and Experimental Assessment of Mechanical Properties of Biobased Epoxy Reinforced by Flax Fibres and Seashell Nanoparticles for Prosthetic Socket

Chronic diseases such as peripheral vascular and arteriosclerosis, wars, terrorist attacks, natural disasters, and traffic collisions are the major causes of the high demand for prostheses. The inadequacy of the typically used materials at reasonable prices and the high stiffness of these materials, which can negatively influence socket-limb load transfer, imply an urgent need to find alternatives to the existing prosthetic sockets. This work aims to use renewable, low-hazard, and low-cost natural flax fibres and seashell nanoparticles as substitutes for conventional reinforcement materials for prosthetic sockets. Seashell nanoparticles of 1, 3, and 5 weight fractions and 3 layers of flax fibres were integrated into biobased epoxy. Tensile and flexural properties of modified and unmodified specimens were assessed, and the finite element technique (ANSYS-20) was utilised to analyse and evaluate the mechanical characteristics of the specimens by observing the stress and total deformation. Here, all fabricated nanocomposites provided tensile and flexural strength higher than that of additive-free biobased epoxy. In addition, hybrid nanocomposites fabricated from 3 layers of flax fibres and 3 wt% of seashell nanoparticles were revealed to have the highest mechanical properties compared with unmodified resin and biobased epoxy filled with other percentages of the reinforcement. These findings were further validated numerically in which the total deformation was shown to decrease after the addition of 3 wt% of these nanoparticles within the nanocomposites. Moreover, the antibacterial activity proved its superb antimicrobial performance against various pathogenic microorganisms, namely, Staphylococcus aureus and E. coli. Accordingly, the fabricated composite systems are suggested to be an appropriate candidate for forming prosthetic sockets. These composites have promising mechanical and antibacterial properties, and they are made of affordable and available materials, which can be a suitable option, particularly in poor countries due to the fact that advanced technologies may require a substantial amount of money for equipment, surgery fees, and medical care.

Development of sandwich using low-cost natural fibers: Alfa-Epoxy composite core and jute/metallic mesh-Epoxy hybrid skin composite

Alfa grass is one of the most abundant and renewable natural fiber resources in North Africa. In this regard, this work aimed to valorize this plant by preparing a sandwich panel composed of Alfa fiber-based core and a hybrid polymer matrix composite (jute and metallic mesh) as skin. The mechanic properties of the parts (the core, skin and whole sandwich composite) were evaluated by bending, tensile and non-destructive tests. Thanks to Alfa fiber-based core, the resulting sandwich performance was higher compared to other bio-based ones such as cork-based sandwiches but had higher density. The hybridization of the jute improves the rigidity of the skin (about 65% of Young and flexural modulus, respectively) but decries the tensile strength by about 23%. The sandwich breaking was strongly influenced by the stacking sequence of the skin, the presence of metallic mesh at the interface core/skin led to delamination, which reduces the mechanical properties of the sandwich. Overall, this sandwich could find useful application as a non-structural component in building materials (separation or roofs panels).

Genome-wide identification and expression profile of GhGRF gene family in Gossypium hirsutum L.

BackgroundCotton is the primary source of renewable natural fiber in the textile industry and an important biodiesel crop. Growth regulating factors (GRFs) are involved in regulating plant growth and development.MethodsUsing genome-wide analysis, we identified 35 GRF genes in Gossypium hirsutum.ResultsChromosomal location information revealed an uneven distribution of GhGRF genes, with maximum genes on chromosomes A02, A05, and A12 from the At sub-genome and their corresponding D05 and D12 from the Dt sub-genome. In the phylogenetic tree, 35 GRF genes were divided into five groups, including G1, G2, G3, G4, and G5. The majority of GhGRF genes have two to three introns and three to four exons, and their deduced proteins contained conserved QLQ and WRC domains in the N-terminal end of GRFs in Arabidopsis and rice. Sequence logos revealed that GRF genes were highly conserved during the long-term evolutionary process. The CDS of the GhGRF gene can complement MiRNA396a. Moreover, most GhGRF genes transcripts developed high levels of ovules and fibers. Analyses of promoter cis-elements and expression patterns indicated that GhGRF genes play an essential role in regulating plant growth and development by coordinating the internal and external environment and multiple hormone signaling pathways. Our analysis indicated that GhGRFs are ideal target genes with significant potential for improving the molecular structure of cotton.

Study of mechanical behaviour on jute fiber and rice straw reinforced hybrid silica filled composite material

World is focusing on alternate material resource that are environment friendly and recyclable in nature. Now-a-days, renewable natural fibers provide an alternative polymer composite material instead of synthetic fibers. With several natural fibers such as wheat grass, rice straw fiber, timber powder, jute, hemp is widely used natural fiber for its advantage of ease of availability, low density fiber, low production costs, material properties and the equipment. This study introduces the effect of synthetic filler on silica with natural fiber such as jute fiber and natural fiber as Rice straw Hybrid composites have better properties than single reinforced fiber which is a composite and applied to the application such as Home appliances like(Door), Bed Headboard, Mattress, Panel board for interior walls, Reusable shopping bags. Though the hybrid composite have better strength when compared to single fiber composites. By combining Natural Fiber with synthetic filler which strengthened the fiber matrix interface. The test were taken on sample by means of mechanical test such as Tensile test, Hardness test, morphological study on X ray Diffraction Analysis and Scanning Electron Microscope is done and results were found 90.1Mpa and 78.8Mpa for Tensile and Hardness test by adding 4 % of silica.

Review on properties of banana fiber reinforced polymer composites

The fast moving world is very much concerned about the environmental ecology and new regulations from government agencies. Due to this scientists and researchers are looking for biodegradable and renewable natural fiber reinforced composites as an alternate material. The fiber obtained from natural resources has indubitable benefits over the synthetic fibers such as low density, comparable strength, non-toxicity, low cost and minimum waste disposal problems. A lot of research has been done by researchers to explore the potential applications of natural fibers. But fibers such as banana, jute, bagasse, sisal have gained importance in this decade. Banana fibers are plant native to Southeast Asia, they are obtained from the steam of the banana tree which are considered as waste material after the harvest of fruit. Banana fibers as a reinforcing material have exhibited significant improvement in physical, chemical and mechanical properties of the polymer composites. The present study gives an extensive review of the banana fiber reinforced composites with its potential applications. Various aspects which affect the behavior of banana fiber reinforced polymer composites such as fiber length, its orientation and configuration, moisture content, temperature and surface treatments of fibers are discussed in this work.

Sustainable and Renewable Bio-Based Natural Fibres and Its Application for 3D Printed Concrete: A Review

The concept of sustainability and the utilization of renewable bio-based sources have gained prominent attention in the construction industry. Material selection in construction plays a significant role in design and manufacturing process of sustainable building construction. Several studies are being carried out worldwide to investigate the potential use of natural fibres as reinforcement in concrete with its noticeable environmental benefits and mechanical properties. 3D printed concrete (3DPC) is another emerging technology, which has been under-developed for the past decade. The integration of reinforcement is one of the major challenges in the application of this new technology in real-life scenario. Presently, artificial fibres have been used as a reinforcement material for this special printable concrete mixture. However, natural fibre composites have received significant attention by many 3DPC constructions due to their lightweight energy conservation and environmentally friendly nature. These benchmarking characteristics unlock the wider area of natural fibres into the composite sector and challenge the substitution of artificial fibres. Hence, this paper presents a comprehensive review on the current practice and advantages of natural fibres in conventional concrete construction. Subsequently, with a view to the future efficient 3DPC construction, the potentials of natural fibres such as eco-friendly, higher impact, thermal, structural, and fire performance over the artificial fibres were highlighted, and their applicability in 3DPC as composites was recommended.

Flexural Properties and Microstructure Mechanisms of Renewable Coir-Fiber-Reinforced Magnesium Phosphate Cement-Based Composite Considering Curing Ages.

As a renewable natural plant fiber, Coir fiber (CF) can be used to as an alternative to improve poor toughness and crack resistance of magnesium phosphate cement (MPC), replacing such artificial fibers as steel fiber and glass fiber and thereby reducing huge energy consumptions and large costs in artificial fibers’ production and waste treatment. Aiming at examining the effects of CF volume concentrations on MPC flexural properties, this study employed a typical three-point bending test, including thirty cuboid specimens, to investigate the flexural strength, load-deflection behavior, and flexural toughness of MPC with different CF volume concentrations from 0% to 4% at the curing age of seven days and 28 days. Results demonstrated that CF presented similar effects on MPC’s properties at two curing ages. At both curing ages, as CF grew, flexural strength increased first and then decreased; specimen stiffness, i.e., MPC elastic modulus, displayed a decreasing trend; and flexural toughness was improved continuously. Additionally, modern microtesting techniques, such as, scanning electron microscopy (SEM) and energy dispersive X-ray detection (EDX), were adopted to analyze the microstructure and compositions of CF and specimens for explaining the properties microscopically.

A genome-wide identification of the BLH gene family reveals BLH1 involved in cotton fiber development

BackgroundCotton is the world’s largest and most important source of renewable natural fiber. BEL1-like homeodomain (BLH) genes are ubiquitous in plants and have been reported to contribute to plant development. However, there is no comprehensive characterization of this gene family in cotton. In this study, 32, 16, and 18 BLH genes were identified from the G. hirsutum, G. arboreum, and G. raimondii genome, respectively. In addition, we also studied the phylogenetic relationships, chromosomal location, gene structure, and gene expression patterns of the BLH genes.ResultsThe results indicated that these BLH proteins were divided into seven distinct groups by phylogenetic analysis. Among them, 25 members were assigned to 15 chromosomes. Furthermore, gene structure, chromosomal location, conserved motifs, and expression level of BLH genes were investigated in G. hirsutum. Expression profiles analysis showed that four genes (GhBLH1_3, GhBLH1_4, GhBLH1_5, and GhBLH1_6) from BLH1 subfamily were highly expressed during the fiber cell elongation period. The expression levels of these genes were significantly induced by gibberellic acid and brassinosteroid, but not auxin. Exogenous application of gibberellic acid significantly enhanced GhBLH1_3, GhBLH1_4, and GhBLH1_5 transcripts. Expression levels of GhBLH1_3 and GhBLH1_4 genes were significantly increased under brassinosteroid treatment.ConclusionsThe BLH gene family plays a very important role in many biological processes during plant growth and development. This study deepens our understanding of the role of the GhBLH1 gene involved in fiber development and will help us in breeding better cotton varieties in the future.

Flexural Properties of Renewable Coir Fiber Reinforced Magnesium Phosphate Cement, Considering Fiber Length.

Coir fiber (CF), a renewable natural plant fiber, is more competitive in improving poor toughness and crack resistance of magnesium phosphate cement (MPC) than artificial fibers, due to its slight energy consumptions and low costs in production and waste treatment. In this paper, a typical three-point bending test was carried out to study the effects of CF length on MPC flexural properties. A total of forty-two cuboid specimens were employed to investigate the flexural strength, load-deflection behavior, and flexural toughness of MPC, with CF lengths varying from 0 to 30 mm at the curing age of 7 days and 28 days. Results showed that, at both two curing ages, MPC flexural strength first increased with CF length increasing, and then deceased when CF length exceeded the threshold. However, with the increase of CF length, MPC flexural toughness increased continuously, while MPC elastic modulus displayed a decreasing trend. Additionally, Modern micro testing techniques, such as scanning electron microscope (SEM) and X-ray diffraction (XRD), were also used to study the microstructure and phase compositions of specimens for further explaining the themicroscopic mechanism.

Preparation, characterization, and functionality of bio-based polyhydroxyalkanoate and renewable natural fiber with waste oyster shell composites

This paper reports the fabrication process for a new composite of modified polyhydroxyalkanoate (MPHA), treated renewable pineapple leaf fiber (PLF), and waste oyster shell powder (OSP), with antibacterial, cytocompatibility, and biodegradability properties. PLF and OSP were thermally processed in a solar energy tube as a filler for MPHA-based green composites. The compositions and structures of composites were characterized using Fourier transform-infrared spectroscopy and X-ray diffraction. Tensile and morphological analyses revealed enhanced adhesion and improved compatibility between OSP/PLF and MPHA in composites, compared with polyhydroxyalkanoate (PHA)/OSP/PLF composites. MTT assay and cell adhesion tests revealed that the relative growth rate of human foreskin fibroblasts cells increased with OSP/PLF content, indicating that the composites were not cytotoxic. OSP enhanced the antimicrobial properties of MPHA/OSP/PLF composites. PHA/OSP/PLF composites absorbed more water than MPHA/OSP/PLF composites. The weight loss of composites after being buried in soil compost indicated that both were biodegradable, especially at high levels of OSP/PLF substitution.

Study on the Compressive Properties of Magnesium Phosphate Cement Mixing with Eco-Friendly Coir Fiber Considering Fiber Length.

Coir fiber (CF), an eco-friendly and renewable natural fiber, was introduced into magnesium phosphate cement (MPC) mortar to improve its crack resistance. A total of 21 specimens were employed to investigate the failure pattern, compressive strength, stress–strain curve, and energy absorption of MPC with varying CF lengths (0, 5, 10, 15, 20, 25, and 30 mm) after a curing period of 28 days through a static compressive test. The results demonstrated that compressive strength, elastic modulus, and secant modulus decreased with the increase in CF length. However, energy absorption presented a convex curve, which increased to the maximum value (77.0% relative to the value of the specimen without CF) with a CF length of 20 mm and then declined. A series of modern micro-tests were then carried out to analyze the microstructure and composition of specimens to explain the properties microscopically.