There is an opportunity to use nanocellulose as an efficient renewable reinforcing filler for polymer composites. There have been many investigations to prove the reinforcement concept of different nanocellulose sources for thermoplastic and thermoset polymers. The present comparative study highlighted the beneficial effects of selecting cellulose nanofibers (CNFs) and nanocrystals (CNCs) on the exploitation properties of vegetable oil-based thermoset composite materials—thermal, thermomechanical, and structural characteristics. The proposed UV-light-curable resin consists of an acrylated epoxidized soybean oil polymer matrix and two different nanocellulose reinforcements. High loadings of up to 30 wt% of CNFs and CNCs in irradiation-cured vegetable oil-based thermoset composites were reported. Infrared spectroscopy analysis indicated developed hydrogen-bonding interactions between the nanocellulose and polymer matrix. CNCs yielded a homogeneous nanocrystal dispersion, while CNFs revealed a nanofiber agglomeration in the polymer matrix, as shown by scanning electron microscopy. Thermal degradation showed that nanocellulose reduced the maximum degradation temperature by 5 °C for the 30 wt% CNC and CNF nanocomposites. Above the glass transition temperature at 80 °C, the storage modulus values increased 6-fold and 2-fold for the 30 wt% CNC and CNF nanocomposites, respectively. In addition, the achieved reinforcement efficiency factor r value for CNCs was 8.7, which was significantly higher than that of CNFs of 2.2. The obtained nanocomposites with enhanced properties show great potential for applications such as UV-light-processed coatings, adhesives, and additive manufacturing inks.

Lignocellulosic fillers have been widely investigated for various polymer resin applications since they have great potential for using wood biomass and recycled plastics. However, besides cellulose nanocrystals (CNC) and nanofibrils (CNF), not much of the other lignocellulose has been used for UV-curing resins. Even more so, none has been used in hybrid lignocellulose combination compositions. In the present work, the effects of hybrid lignocellulose fillers such as lignin (LN)/CNC/CNF/hemicellulose (HC) with ratio-varying compositions on UV-curing biobased resins have been investigated for wood-mimic material coating applications. The hybrid filler effects on the macromolecular chain network, surface morphology, thermomechanical properties, and thermostability were carefully studied. A combination of scanning electron microscopy, DMA Cole–Cole plot, contact angle, etc., allowed getting a sense of hybrid filler distribution and interaction within the polymer matrix. It was identified that an increase in the HC content of up to 38% contributes to more even particle distribution and achieves a maximum double bond conversion rate of about 80%. HC also contributes to porous surface structure, while CNC smooths surface morphology, and, in turn, CNF increases defects. Thermomechanical testing revealed the unique benefit of hybrid reinforcement, showing higher results than single-filler compositions despite the general decrease after incorporation of 5 wt % LN. The storage modulus showed a fourfold increase for 5 wt % LN composition. The observed enormous property enhancement has been attributed to the benefits of hybrid fillers, which mitigate characteristic radical scavenging properties of LN and strongly reduce general filler aggregation, allowing more even filler dispersion while also improving filler–matrix interface synergy. Seventeen different compositions clearly, in comparison to single fillers, show the benefit of hybrid lignocellulosic reinforcement and testify to the ability to precisely tune up material performance and achieve wood structure-mimicking coating materials.

No abstract

No abstract

No abstract