Direct milling: Efficient, facile, and green method for processing fibrillated cellulose/polymeric nanocomposites with boosted thermomechanical and rheological performance

Alternative proton exchange membrane based on a bicomponent anionic nanocellulose system

As integral parts of fuel cells, polymer electrolyte membranes (PEM) facilitate the conversion of hydrogen's chemical energy into electricity and water. Unfortunately, commercial PEMs are associated with high costs, limited durability, variable electrochemical performance and are based on perfluorinated polymers that persist in the environment. Nanocellulose-based PEMs have emerged as alternative options given their renewability, thermal and mechanical stability, low-cost, and hydrophilicity. These PEMs take advantage of the anionic nature of most nanocelluloses, as well as their facile modification with conductive functional groups, for instance, to endow ionic and electron conductivity. Herein, we incorporated for the first time two nanocellulose types, TEMPO-oxidized and sulfonated, to produce a fully bio-based PEM and studied their contribution separately and when mixed in a PEM matrix. Sulfonated nanocellulose-based PEMs are shown to perform similarly to commercial and bio-based membranes, demonstrating good thermal-oxidative stability (up to 190 °C), mechanical robustness (Young's modulus as high as 1.15 GPa and storage moduli >13 GPa), and high moisture-uptake capacity (ca. 6330 % after 48 h). The introduced nanocellulose membranes are shown as promising materials for proton-exchange material applications, as required in fuel cells.

Thermomechanical Properties of Polymers and Their Composites with Other Materials: Advances in Thermal and Mechanical Properties of Polymeric Materials (2nd Edition)

Progress in the engineering of polymeric materials, including the search for innovative polymer composites with specific properties, has resulted in an expansion of their application areas, especially in the automotive, construction, energy, packaging, and medical industries [...].

Improvement in the Thermomechanical Properties and Adhesion of Wood Fibers to the Polyamide 6 Matrix by Sequential Ball Milling Technique

The engineering thermoplastics industry has largely limited the use of natural fiber reinforcements due to their susceptibility to low-onset thermal degradation and water absorption. Therefore, in order to utilize these economically viable and environmentally friendly materials effectively through common composite fabrication methods such as hot pressing, safeguarding them from thermal degradation becomes essential. This work presents a viable industrially technique called sequential ball milling for processing unbleached softwood kraft pulp fibers (PF) with an engineering thermoplastics polyamide 6 (PA6) with high melting temperatures (>220 °C). An additional eco-friendly modification step that employs ball milling and cellulose nanocrystal (CNC) has been implemented in this study to enhance the mechanical properties of the composites. Special attention is given to fine-tuning key variables, such as milling duration and PF particle size, to produce optimal composites. Leveraging the ability of sequential ball milling to evenly distribute pulp fibers into PA6, a 160% increase in Young's modulus was achieved with the incorporation of 30 wt % PF. Importantly, the introduction of a 5 wt % CNC modifying agent elevated Young's modulus to 4.3 GPa, marking a 187% improvement over unmodified PA6. Diverse techniques, including rheological analyses, thermomechanical evaluations, morphological examinations, and assessments of moisture absorption, were utilized to validate the efficiency of the suggested processing approach and the modification phase.

The impact of esterified nanofibrillated cellulose content on the properties of thermoplastic starch/PBAT biocomposite films through ball-milling

To enhance the mechanical properties and interfacial compatibility of thermoplastic starch (TPS) highly filled poly(butylene adipate co-terephthalate) (PBAT) composite films, esterified NFC was innovatively fabricated and introduced into the composite system. The influences of NFC content and ball-milling treatment were thoroughly investigated. Interestingly, the amphiphilic esterified NFC provided a "bridge-like" effect between TPS and PBAT interfaces, which significantly improved the interfacial compatibility and mechanical properties. Notably, the tensile properties of the composite films reached their maximums at a 7 wt% NFC content, displaying a tensile strength of 6.2 MPa and an elastic modulus of 263 MPa. These values corresponded to a 59 % and 180 % increase, respectively, compared to the composition without NFC. More importantly, ball-milling contributed to uniform dispersion and surface activation of NFC, preventing starch retrogradation, and enhancing the tensile strength and elastic modulus by 30.3 % and 56.6 %, respectively. Additionally, the film exhibited excellent UV-blocking, foldable, writable, and transparent performance. These findings provide valuable data supporting the expanded applications of starch-based composite films.