Nanofibril reinforced unsaturated polyester nanocomposites: Morphology, mechanical and barrier properties, viscoelastic behavior and polymer chain confinement

Nanostructured biocomposites based on unsaturated polyester resin and a cellulose nanofiber network

“…At a relative humidity of 50%, the reinforcement effects are strong -modulus and ultimate strength increase as the CNF content increases. The mechanical performance of composites based on CNF and UP have been reported to increase up to a certain CNF content (typically a few wt%), after which the dispersion of the CNF becomes a problem -both strength (and occasionally modulus) begin to drop when CNF content increases [9,13]. In the present work, the strength and modulus increase continuously with the addition of the CNF network, indicating that CNF agglomeration is limited even at 45 vol% CNF.…”

“…Increased T g indicates constrained molecular mobility in the UP network due to the proximity of high specific surface area CNF fibrils. In the present system, carbonyl groups from UP may interact with the surface hydroxyls of CNF via hydrogen bonding and other secondary interactions [9]. The CNF/UP interface has an important role in determining the composite properties, as will be discussed in the coming sections.…”

“…Existing literature on CNF/UP composites primarily focuses on low content of CNF (up to 20%). Chirayil et al [9,10] studied UP composites with CNF content up to 5 wt% and observed that the mechanical properties were favorable at 0.5 wt%. The drop in properties at higher CNF content is usually due to agglomeration of the fibrils, and the agglomerates initiate premature failure.…”

Cross‐Linkable Modified Nanocellulose/Polyester Resin‐Based Composites: Effect of Unsaturated Fatty Acid Nanocellulose Modification on Material Performances

“…The broad peak at about 3479 cm −1 and the low‐intensity peak at 700 cm −1 originate from hydroxyl (OH) groups' stretching vibrations. An increase in intensity and width of the OH groups' stretching vibrations peak in the FTIR spectra of cured UPe/m‐NC(b) nanocomposites is observed due to hydrogen bonding ( Figure ) between the UPe macromolecular chains and m‐NC . The highest extent of hydrogen bonding interaction appears at 1.0 wt% of NC modified with methyl esters of FAs via MA/EDA cross‐linker due to its better dispersibility and larger contact area between filler surface and UPe chains.…”

Microfibrillated-cellulose-modified urea-formaldehyde adhesives with different F/U molar ratios for wood-based composites

“…[4] In a previous study, it was reported that the composites prepared from unsaturated polyester adhesive containing the MFC had the ability to transfer stress from the adhesive to the MFC and they showed good tensile values compared to neat adhesive. [25] The improvement in the modulus and strength of the LVLs could be explained by the fact that the incorporation of the MFC into the UF adhesive decreased the stress concentrations along the bond line of the UF adhesive between the veneers.…”