Valorisation of Bagasse Cane by-Product: Effect of Cellulosic Fibers and Coupling Agent on Thermal, Mechanical and Rheological Behaviours of Reinforced Polypropylene

Recently more attentions are growing every day towards the valorisation of industrial by-product especially those generated through agriculture and food industries, as the demands of bio-based resources for the necessary transition from fossil hydrocarbon sources to natural based products are increasing. This paper focuses on the potential effect of chemical treatments and modification as well as fibers loading on the thermal, mechanical, and rheological behaviour of reinforced Polypropylene (PP). During this work, fibers were prepared using alkali and bleaching treatments and then characterized using different analysis such SEM, X-ray, FT-IR and TGA/DTG. The composite materials were elaborated using twin-screw extrusion followed by injection molding by mixing PP with 5 to 10 Wt.% of raw bagasse cane (RBC), alkali bagasse cane (ABC) and bleached cellulose microfibers (BCM) as well as cellulose microfibers with Styrene-(ethylene-butene)-styrene three-block co-polymer grafted with maleic anhydride (SEBS-g-MA) as coupling agent. The result achieved from this study shows that the use of different type of fibers led to significant decrease in thermal degradation of PP. The mechanical results show a significant improvement in Yung’s modulus, tensile strength and hardness of the reinforced PP compared to neat PP. However, a remarkable decrease was obtained in elongation at break and toughness for all reinforced composites compared to neat PP. Besides, higher and low torsion modulus was obtained for PP reinforced with BCM and SEBS-g-MA-BCM, respectively.Statement of Novelty: This study aims to valorise bagasse sugar cane by-product as a lignocellulosic source for the isolation of cellulose fibers. Innovative composite materials were prepared based on polypropylene.

Hydrogen-Bonding-Aided Fabrication of Wood Derived Cellulose Scaffold/Aramid Nanofiber into High-Performance Bulk Material

Preparing a lightweight yet high-strength bio-based structural material with sustainability and recyclability is highly desirable in advanced applications for architecture, new energy vehicles and spacecraft. In this study, we combined cellulose scaffold and aramid nanofiber (ANF) into a high-performance bulk material. Densification of cellulose microfibers containing ANF and hydrogen bonding between cellulose microfibers and ANF played a crucial role in enhanced physical and mechanical properties of the hybrid material. The prepared material showed excellent tensile strength (341.7 MPa vs. 57.0 MPa for natural wood), toughness (4.4 MJ/m3 vs. 0.4 MJ/m3 for natural wood) and Young’s modulus (24.7 GPa vs. 7.2 GPa for natural wood). Furthermore, due to low density, this material exhibited a superior specific strength of 285 MPa·cm3·g−1, which is remarkably higher than some traditional building materials, such as concrete, alloys. In addition, the cellulose scaffold was infiltrated with ANFs, which also improved the thermal stability of the hybrid material. The facile and top-down process is effective and scalable, and also allows one to fully utilize cellulose scaffolds to fabricate all kinds of advanced bio-based materials.

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.

Cellulose Microfibers from Salacca Midrib Fiber Isolated by the Mechanical Treatment

Salacca midrib fibers are abundant natural waste in Turi, Sleman Regency, Daerah Istimewa Yogyakarta. Cellulose Microfibers from the salacca midrib fiber has been isolated by mechanical treatment and successfully has good physical characteristics. Cellulose fibers with micro sizes can strengthen the bond effect between the matrix and the fiber due to the vast contact area. The method for isolated cellulose microfibers by mechanical treatment for speed rotation of 5000, 10000 and 15000 rpm. Mechanical stirrer treatment aims to fibrillation and reduces fiber dimensions because of their high rotation. The characterization by XRD, FTIR, and SEM. The XRD results showed that the mechanical stirrer treatment did not damage the crystallinity index of cellulose microfibers. The crystallinity index of the raw material is 64.3%, increased to 79.1% for the microfiber cellulose crystallinity index. Identification of functional groups using FTIR did not show changes in cellulose compounds resulting from mechanical treatment. Morphological observation of fibers by SEM shows that the diameter cellulose microfibers size obtained from salacca midrib fiber ranges 5-10 µm with 100-300 µm in length. Cellulose microfibers have potential materials as reinforcement in the micro composite and extraction into nanocellulose materials.

Extraction and application of cellulose microfibers from Washingtonia palm as a reinforcement of starch film

This work aims to optimize the industrial extraction conditions of cellulose microfibers (CMFs) from Washingtonia palm fiber for application in starch bio-composite films. The CMF extraction was a mixed process that combines caustic soda treatment with hydrogen peroxide bleaching in a stirred thermostatic bath. To study the yield, whiteness index and α-cellulose content, three variables were selected; NaOH and H2O2 concentrations and treatment time. The optimum was determined using a Response Surface Methodology (RSM) approach for samples treated for 70 min with 5.21% NaOH and 5.54% H2O2. The optimized CMF was used to produce Starch/CMF bio-composite films with higher mechanical and barrier performance, which increased by 300% and 31%, respectively. Moreover, its moisture absorption and water solubility decreased by about 24% and 26%, respectively after adding 20 wt% CMF. In fact, morphological results showed that the higher CMF in the Starch/CMF20 leads to the heterogeneous CMF distribution and agglomerates resulting in weakened starch films. As a result, the extracted CMF can be a competitive nanofabrication filler.