Characterization and properties of cellulose microfibers from water hyacinth filled sago starch biocomposites

Nanocellulose reinforced polyvinyl alcohol-based bio-nanocomposite films: improved mechanical, UV-light barrier, and thermal properties

This study reported the development and characterisation of bio-nanocomposite films based on the polyvinyl alcohol (PVA) reinforced with cellulose nanofibres (CNFs) of different concentrations (1-5 wt%), isolated from pineapple leaf fibre via high-shear homogenisation and ultrasonication. The PVA film and bio-nanocomposite were prepared using a solution casting method. The PVA film and bio-nanocomposite samples were characterized using FE-SEM, XRD, FTIR spectroscopy, UV-vis spectroscopy in transmission mode, TGA, and DTG. Mechanical properties (tensile strength and strain at break) were also determined and statistical analysis was applied as well. With the incorporation of CNFs, the mechanical properties of the bio-nanocomposite were found to be significant (p ≤ 0.05), particularly the 4 wt% CNF bio-nanocomposite showed optimum properties. The tensile strength, CI, and thermal stability of this film were 28.9 MPa (increased by 28.2%), 78.7% (increased by 5.2%), and 341.8 °C (increased by 1.6%), respectively, compared to the pure PVA film. These characteristics imply that the bio-nanocomposite film has prospects as a promising material for biopackaging.

Valorization of guinea grass seed (Megathyrsus maximus): Synthesis and utilization of cellulose microfiber to reinforce esterified and cross-linked guinea starch films

The present study extracts starch from guinea grass seed and fiber from the starch extraction residue. The fibrous residue was chemically converted into cellulose microfiber (CMF) and used to reinforce the native, esterified and crosslinked guinea starch films. The films were developed with 5 % starch, 40 % glycerol and 0, 2.5, 5, and 10 % CMF based on the dry matter of starch. SEM images of all film samples showed good compatibility of CMF with starch molecules, and no fractures or pores were observed. Adding filler materials to modified starch films slightly increased the film thickness (0.24 to 0.30 mm) due to the high dimensions of CMF, which comprise a significant amount of the composite's volume. A synergetic effect of starch modification and CMF in films decreased the moisture content (21.98 to 9.21 %), water solubility (25.65 to 15.47 %), water vapor permeability (6.96×10-7 to 1.65×10-7g∙mm2∙day∙Pa), and elongation at the break (33.51 to 16.79 %) while increasing the tensile strength (1.84 to 3.85 MPa) and Young's modulus (5.49 to 22.93 MPa). The L* and a* values of the films decreased, and the b* and opacity values of the films increased with the addition of CMF. The XRD graph showed that all films have semicrystalline structures with peaks at 18°, 20°, and 22°, and the degree of crystallinity increases (32.3 to 55.1 %) with CMF. All film samples showed good thermal stability up to 315 °C. In conclusion, esterified starch-based films exhibited superior barrier properties and flexibility. On the contrary, cross-linked starch films demonstrated higher tensile strength and lower water solubility.

Limonene and its derived oligomer as bioactive additives in starch/coffee husks biocomposites for food packaging applications

In this study, antioxidant, and antimicrobial starch-based biocomposite films reinforced with coffee husks (S/CH) were developed by incorporating either limonene (LM) (S/CH/LM) or its oligomer derivative, poly(limonene) (PLM) (S/CH/PLM), at different concentrations (5-10 % w/w of starch). Through a comprehensive assessment of film properties, morphology, and structure, a comparative analysis between the two additives was proposed. Scanning electron microscopy (SEM) revealed some defects throughout the polymer matrix after additive incorporation. The tensile strength (TS) and modulus of elasticity (ME) showed a decrease upon the inclusion of both LM and PLM, while the elongation at break (E) increased. Notably, PLM exhibited outstanding antioxidant capacity, enhancing the films by 108 % over control samples. Additionally, at just 5 % concentration, PLM effectively inhibited the growth of Escherichia coli ATCC 11775 (35.33 ± 2.52 mm) and demonstrated an impressive UV-Vis barrier, comparable to the highest amount of LM incorporated. Therefore, this research highlights the potential of coffee husk-reinforced starch biocomposites with limonene-derived additives as a promising solution for food packaging applications. The comparative analysis sheds light on the advantages of using the PLM in terms of antioxidant and antimicrobial properties, contributing to the advancement of active packaging technologies.

Biodegradation behavior of acetylated lignin added polylactic acid under thermophilic composting conditions

Acetylated lignin (AL) can improve compatibility with commercial plastic polymers compared to existing lignin and can be used as an effective additive for eco-friendly biocomposites. For this reason, AL can be effectively incorporated into polylactic acid (PLA)-based biocomposites, but its biodegradation properties have not been investigated. In this study, biodegradation experiments were performed under mesophilic and thermophilic conditions to determine the effect of AL addition on the biodegradation characteristics of PLA-based biocomposites. As a result, the PLA-based biocomposite showed a faster biodegradation rate in a thermophilic composting environment, which is higher than the glass transition temperature of PLA, compared to a mesophilic environment. 16S rDNA sequencing results showed that differences in microbial communities depending on mesophilic and thermophilic environments strongly affected the biodegradation rate of lignin/PLA biocomposites. Importantly, the addition of AL can effectively delay the thermophilic biodegradation of PLA biocomposites. As a result of tracking the changes in physicochemical properties according to the biodegradation period in a thermophilic composting environment, the main biodegradation mechanism of AL/PLA biocomposite hydrolysis. It proceeded with cleavage of the PLA molecular chain, preferential biodegradation of the amorphous region, and additional biodegradation of the crystalline region. Above all, adding AL can be proposed as an effective additive because it can minimize the decline in the mechanical properties of PLA and delay the biodegradation rate more effectively compared to existing kraft lignin (KL).

Starch biocomposites based on cellulose microfibers and nanocrystals extracted from alfa fibers (Stipa tenacissima)

Cellulose-based biopolymers have emerged as one of the most promising components to produce sustainable composites as a potential substitutes to fossil-based materials. Herein, the aim of this study is to investigate the reinforcing effect of cellulose microfibers (CMFs) and cellulose nanocrystals (CNCs), extracted from alfa fibers (Stipa tenacissima), on the properties of starch biopolymer extracted from potato. The as-extracted CMFs (D = 5.94 ± 0.96 μm), CNCs (D = 14.29 ± 2.53 nm) and starch were firstly characterized in terms of their physicochemical properties. Afterwards, CMFs and CNCs were separately dispersed in starch at different concentrations, and their reinforcing effects as well as the chemical, thermal, transparency and mechanical properties of the resulted starch-based films were evaluated. Thus, CMFs and CNCs incorporation into starch resulted in a minor impact on the films thermal stability, while a considerable impact on the transparency property was observed. In terms of mechanical properties, the addition of up to 20 wt% CMFs reduced the film's elongation but drastically increased its stiffness by 300 %. On the other hand, in the case of CNCs, a loading of 10 wt% was found to be the most effective in increasing film stiffness (by 57 %), while increasing the loading up to 20 wt% CNCs enhanced the film's ductility (strain-to-failure) by 52 %. This study showed that introduction of cellulosic fibers having different sizes into starch can produce biocomposite materials with a wide range of properties for food packaging application.

Optimization of the Formulation of Sago Starch Edible Coatings Incorporated with Nano Cellulose Fiber (CNF)

This study aimed to produce new edible coatings based on the mixture of sago starch, cellulose nanofiber (CNF), glycerol, and tween-80.The effect of sago starch (5–10 g of starch/100 ml of distilled water), CNF (0.5–20% w/w), glycerol (10–30% w/w), and tween-80 (0.5–10% w/w) based on sago starch concentration on contact angle (CA), water vapor permeability (WVP), oxygen permeability (PO2) and tensile strength (TS) properties of the edible coatings were optimized using factorial experimental design (2k).The result showed that the linear model for all independent variables was significant (<i>P</i><0.05) on all responses (dependent variable).The sago starch concentration depicted a significant (p < 0.001) positive effect on contact angle; CNF showed a statistically significant effect on WVP, PO2, and TS; tween-80 showed a significant effect on all dependent variables, whereas glycerol only affected WVP. The optimum concentrations of sago starch, CNF, glycerol, and tween-80 were predicted to be 5 g/100 ml distilled water, 20% w/w, 10% w/w, and 0.5% w/w based on sago starch, respectively to obtain the minimum contact angle, WVP, PO2, and the maximum TS. The predicted data for the optimized coating formulation were in good agreement with the experimental value. This work revealed that the potential of sago starch/CNF based coating formulation could be effectively produced and successfully applied for coating of food.

Facile Preparation of Cellulose Bioplastic from Cladophora sp. Algae via Hydrogel Method

Bioplastic has been widely studied in the past decades as a replacement for non-biodegradable and non-environmentally friendly plastic. One of the promising materials to produce bioplastic is cellulose. However, it is rarely used as the main component for bioplastic production. This study reports a facile process to prepare bioplastic using the pure cellulose content of Cladophora sp. algae via the hydrogel method. The effect of epichlorohydrin (ECH) concentrations as the cross-linking agent was investigated toward the biodegradability, thermal, and mechanical properties of the cellulose bioplastic obtained. The results showed that ECH concentrations affected the properties of the cellulose bioplastic produced due to the number of cross-links formed during the process. The cellulose bioplastic possessed relatively high thermal and mechanical properties. The cellulose bioplastic performed excellent biodegradability, as it was degraded by more than 40% within five days. Thus, the cellulose of Cladophora sp. algae has the potential to be developed as the main component for bioplastic application.

Composite cassava starch/chitosan/Pineapple Leaf Fiber (PALF)/Zinc Oxide (ZnO): Bioplastics with high mechanical properties and faster degradation in soil and seawater

Biopolymers based on starch, cellulose and proteins extracted directly from biomass with or without modification have been widely used as the natural resources to produce biodegradable plastic. Starch has several disadvantages: strong hydrophilic behavior and inferior mechanical properties when compared with synthetic polymers. Starch is also mostly soluble in water and will be decomposed before undergoing the gelatinization process. To provide resistance and mechanical strength of starch, several fillers (reinforcement) in the form of metal and natural materials are usually added to the polymer matrix. Zinc oxide (ZnO) nanoparticle and natural fiber as a lightweight material that is biocompatible, nontoxic, cost-effective and exhibit strong antibacterial activity can be considered as a reinforcement of starch-based bioplastic. The present study, the reinforcing effect of ZnO on the mechanical, antibacterial, and physical properties of bioplastic films in the form of cassava starch/chitosan/pineapple leaf fiber (PALF)/ZnO. The highest value of elongation at break is for 16 % ZnO-bioplastics which could be completely decomposed only 21 days in ordinary soil and only 18 days in seawater. The packaging tests using slice bread showed antimicrobial properties with no fungal growth for 30 days of bioplastic coatings with 10, 13, and 16 % ZnO NPs. The results in this study indicated that, the ZnO and PALF plays an important role in reinforcing the physical, mechanical, and antibacterial properties of starch/chitosan/PALF-based bioplastic.

Isolation and characterization of cellulose nanofibers from Agave gigantea by chemical-mechanical treatment

Nanocellulose is a renewable and biocompatible nanomaterial that evokes much interest because of its versatility in various applications. This study reports the production of nanocellulose from Agave gigantea (AG) fiber using the chemical-ultrafine grinding treatment. Chemical treatment (alkalization and bleaching) removed non-cellulose components (hemicellulose and lignin), while ultrafine grinding reduced the size of cellulose microfibrils into nanocellulose. From the observation of Transmission Electron Microscopy, the average diameter of nanocellulose was 4.07 nm. The effect of chemical-ultrafine grinding on the morphology and properties of AG fiber was identified using chemical composition, Scanning Electron Microscopy, X-ray Diffraction, Fourier Transform Infrared, and Thermogravimetric Analysis. The bleaching treatment increased the crystal index by 48.3% compared to raw AG fiber, along with an increase in the cellulose content of 20.4%. The ultrafine grinding process caused a decrease in the crystal content of the AG fiber. The crystal index affected the thermal stability of the AG fiber. The TGA results showed that AG fiber treated with bleaching showed the highest thermal stability compared to AG fiber without treatment. The FTIR analysis showed that the presence of CH vibrations from the ether in the fiber. After chemical treatment, the peaks at 1605 and 1243 cm-1 disappeared, indicating the loss of lignin and hemicellulose functional groups in AG fiber. As a result, nanocellulose derived from AG fiber can be applied as reinforcement in environmentally friendly polymer biocomposites.

Valorization of Rice Straw into Cellulose Microfibers for the Reinforcement of Thermoplastic Corn Starch Films

In the present study, agro-food waste derived rice straw (RS) was valorized into cellulose microfibers (CMFs) using a green process of combined ultrasound and heating treatments and were thereafter used to improve the physical properties of thermoplastic starch films (TPS). Mechanical defibrillation of the fibers gave rise to CMFs with cumulative frequencies of length and diameters below 200 and 5–15 µm, respectively. The resultant CMFs were successfully incorporated at, 1, 3, and 5 wt% into TPS by melt mixing and also starch was subjected to dry heating (DH) modification to yield TPS modified by dry heating (TPSDH). The resultant materials were finally shaped into films by thermo-compression and characterized. It was observed that both DH modification and fiber incorporation at 3 and 5 wt% loadings interfered with the starch gelatinization, leading to non-gelatinized starch granules in the biopolymer matrix. Thermo-compressed films prepared with both types of starches and reinforced with 3 wt% CMFs were more rigid (percentage increases of ~215% for TPS and ~207% for the TPSDH), more resistant to break (~100% for TPS and ~60% for TPSDH), but also less extensible (~53% for TPS and ~78% for TPSDH). The incorporation of CMFs into the TPS matrix at the highest contents also promoted a decrease in water vapor (~15%) and oxygen permeabilities (~30%). Finally, all the TPS composite films showed low changes in terms of optical properties and equilibrium moisture, being less soluble in water than the TPSDH films.

Valorization of Aquatic Weed and Agricultural Residues for Innovative Biopolymer Production and Their Biodegradation

In this work, water hyacinths, bagasse and rice straw were valorized to produce an innovative biopolymer. Serial steps of extraction, bleaching and conversion of cellulose to be carboxymethylcellulose (CMC) as well as the last steps of blending and molding were performed. The CMC was mixed with tapioca starch solution by a ratio of 9:18, and a plastic sizer of glycerol was varied at 2%, 4% and 6% by volume. In addition, bioplastic sheets were further determined in their properties and biodegradation. The results revealed that bioplastics with 6% glycerol showed a high moisture content of 23% and water solubility was increased by about 47.94% over 24 h. The effect of temperature on bioplastic stability was found in the ranges of 146.28–169.25 °C. Furthermore, bioplastic sheets with 2% glycerol could maintain their shape. Moreover, for texture analysis, the highest elastic texture in the range of 33.74–38.68% with 6% glycerol was used. Moreover, bioplastics were then tested for their biodegradation by landfill method. Under natural conditions, they degraded at about 10.75% by weight over 24 h after burying in 10 cm soil depth. After 144 h, bioplastics were completely decomposed. Successfully, the application of water, weed and agricultural wastes as raw materials to produce innovative bioplastic showed maximum benefits for an environmentally friendly product, which could also be a guideline for an alternative to replace synthetic plastics derived from petroleum.

Recent Advances in Microfluidically Spun Microfibers for Tissue Engineering and Drug Delivery Applications

In recent years, the unique and tunable properties of microfluidically spun microfibers have led to tremendous advancements for the field of biomedical engineering, which have been applied to areas such as tissue engineering, wound dressing, and drug delivery, as well as cell encapsulation and cell seeding. In this article, we analyze the most recent advances in microfluidics and microfluidically spun microfibers, with an emphasis on biomedical applications. We explore in detail these new and innovative experiments, how microfibers are made, the experimental purpose of making microfibers, and the future work that can be done as a result of these new types of microfibers. We also focus on the applications of various materials used to fabricate microfibers, as well as their many promises and limitations.

Removal of Methylene Blue Dye from Wastewater Using Periodiated Modified Nanocellulose

The study was focused on the preparation and characterizations of sodium periodate-modified nanocellulose (NaIO4-NC) prepared from Eichhornia crassipes for the removal of cationic methylene blue (MB) dye from wastewater (WW). A chemical method was used for the preparation of NaIO4-NC. The prepared NaIO4-NC adsorbent was characterized by using X-ray diffraction (XRD), Fourier transform infrared (FTIR), scanning electron microscope (SEM), energy-dispersive X-ray (EDX), and Brunauer–Emmett–Teller (BET) instruments. Next, it was tested to the adsorption of MB dye from WW using batch experiments. The adsorption process was performed using Langmuir and Freundlich isotherm models with maximum adsorption efficiency (qmax) of 90.91 mg·g−1 and percent color removal of 78.1% at optimum 30 mg·L−1, 60 min., 1 g, and 8 values of initial concentration, contact time, adsorbent dose, and solution pH, respectively. Pseudo-second-order (PSO) kinetic model was well fitted for the adsorption of MB dye through the chemisorption process. The adsorption process was spontaneous and feasible from the thermodynamic study because the Gibbs free energy value was negative. After adsorption, the decreased values for physicochemical parameters of WW were observed in addition to the color removal. From the regeneration study, it is possible to conclude that NaIO4-NC adsorbent was recyclable and reused as MB dye adsorption for 13 successive cycles without significant efficient loss.

Adsorptive Removal of Cd(II) Ions from Wastewater Using Maleic Anhydride Nanocellulose

In this study, both pristine cellulose nanocrystalline (CNC) and maleic anhydride functionalized cellulose nanocrystalline (MA-CNC) were prepared from the stems of Eichhornia crassipes weed by the sulfuric acid hydrolysis method. The as-prepared adsorbents were characterized by using X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), energy-dispersive X-ray (EDX), and Brunauer–Emmett–Teller (BET) instruments. These materials were applied for the removal of Cd(II) ions from WW. The uptake mechanism was fixed to both Langmuir and Freundlich adsorption isotherms with a maximum Cd(II) ion uptake capability (qmax) of 75.76 and 215.52 mg g−1 by CNC and MA-CNC adsorbents, respectively. Pseudo-second-order (PSO) kinetic model was well fitted to the uptake process. The adsorbent regeneration study was done after desorption of Cd(II) ions from the adsorbent by HCl washing. Results exhibited that the adsorbent was reused for the removal of Cd(II) ions from real WW after successive 13th cycle.

Improvement of Biocomposite Properties Based Tapioca Starch and Sugarcane Bagasse Cellulose Nanofibers

Biocomposite based tapioca starch (TS) and sugarcane bagasse cellulose nanofibers (SBCN) was made through casting method. SBCN was prepared by chemical and ultrasonication process. It was successfully displayed by transmission electron microscope (TEM) in range 20 - 45 nm. Meanwhile, particle size analysis (PSA) also supported the distribution diameter of SBCN for 59.75 ± 10.84 nm. SBCN and glycerol were used as reinforcement and plasticizer, respectively. The amount concentration of SBCN was varied from 0 to 8 wt%. Biocomposite was characterized by using scanning electron microscopy (SEM) and tensile test. SEM image displays SBCN is in good interfacial bonding with the matrix. The highest tensile strength of biocomposite was in TS/4SBCN sample for 20.84 MPa. These results showed that SBCN fiber become potential candidate as reinforcement in biocomposite application.