This is an editorial article. It has no abstract.

Particulate matter (PM) has been always a significant environmental and public health concern due to its adverse effects on air quality and respiratory health. This study evaluates the efficiency of hydrophobic nanostructured bioaerogels as PM filters under both normal and high-humidity conditions. Bioaerogels were prepared using nanocellulose and chitosan and modified with varying concentrations of tetraethyl orthosilicate (TEMS). At normal humidity, the 3% TEMS-modified bioaerogel demonstrated the highest average PM removal efficiency of 91.6%, attributed to its optimized balance of hydrophobicity, porosity, and mechanical strength. Under high-humidity conditions, the unmodified 0% TEMS bioaerogel exhibited a significant decline in performance due to water absorption, reducing its efficiency by over 15% after prolonged exposure. Conversely, the hydrophobic 3% TEMS bioaerogel maintained its efficiency at 91.4%, highlighting its ability to resist water-induced degradation. This study provide valuable insights into the design of bioaerogel-based filters for realworld applications where variable humidity poses a challenge.

Natural fiber composites (NFC) have emerged as promising sustainable alternatives to conventional synthetic materials due to the increasing environmental concerns and unsustainable reliance on depleting petroleum resources. NFCs offer various advantages, such as reduced costs, low density, biodegradability, and good specific mechanical properties. However, their impact resistance remains a crucial factor that greatly influences their suitability for sectors like automotive, construction, and aerospace, where impact loading is prevalent. This review comprehensively analyzes the impact resistance of NFCs, aiming to elucidate the factors governing their behavior under varying impact loading conditions. The study delves into the influence of key parameters such as fiber type, matrix properties, and fiber-matrix adhesion on the impact response of NFCs. Different impact loading methods, including low-velocity impact and high-velocity impact, are examined, highlighting their distinct effects on NFC failure mechanisms. Furthermore, the review investigates the effectiveness of various methods employed to enhance the impact strength of NFCs. Finally, it identifies current challenges and limitations associated with impact-resistant NFCs and outlines potential future research directions to overcome these obstacles and unlock the full potential of these sustainable materials.

In this work, a PDMS spinning technique is developed and enables the continuous production of a filament with a circular cross-section (~500 μm diameter). The production of continuous silicone polymer filaments can be useful in the textile field to provide new properties in applications such as weaving, knitting or composite reinforcement. The method involves injecting the pre-polymer and curing agent mixture into a heated oil bath (202–215 °C) to simultaneously shape and cure the PDMS. The morphological and mechanical properties of the filament are studied regarding the production parameters (formulation, needle diameter, bath temperature, conveyor belt speed). The most homogeneous filament is produced at the highest temperature (215°C) and conveyor belt speed (13.6 m∙min^–1). When subjected to cyclic mechanical stress, the PDMS filament produced exhibits stable mechanical behavior, making it suitable for a wide range of applications.

The kinetics of polycyclotrimerization of cyanate ester resin (CER), viz. dicyanate ester of bisphenol E (DCBE), was studied by DSC method during its molecular design at ultra-low content (0.1 wt%) of two types of nanofillers: reactive aminopropylisobutyl polyhedral oligomeric silsesquioxane (APIB-POSS) or inert fullerene C₆₀ having inorganic closed cage structure of nanomolecules. The polycyclotrimerization of DCBE was significantly accelerated in the presence of APIBPOSS, and its nanoparticles were covalently incorporated into the structure of the growing polycyanurate (PCN) matrix to form a hybrid organic-inorganic PCN/APIB-POSS network. Using FTIR, ¹H NMR and ¹³C NMR spectroscopy for the DCBE/APIB-POSS (50/50 wt%) reactive blend the chemical interaction between the NH₂ groups of APIB-POSS and the –OC≡N groups of DCBE was confirmed even from the beginning of mixing of the components at T ≈20°C. In contrast, the distribution of inert C₆₀ nanoparticles in DCBE slowed down its polycyclotrimerization, but, unexpectedly, this led to the formation of a PCN/C₆₀ nanocomposite with increased glass transition temperature (T_g) reaching 277°C, which is 24°C higher than the T_g of unfilled PCN. The nanocomposites developed are characterized by high thermal stability (Т_d5% > 440°C).

Freeze-thaw (F-T) poly(vinyl alcohol) (PVA) as a soft network and ionic-crosslinked sodium carboxymethyl cellulose (CMC) as a hard network were applied to fabricate a double network (DN) gel using a one-step process. Mechanical properties of the DN gel using a high degree of hydrolysis PVA (PVA-CMC of 60-1) were significantly improved compared to that of a single network gel of PVA. The tensile strength of ~0.55 MPa and elongation at break of 179% could be achieved. The mechanical properties of PVA-poly(acrylic acid) DN gel were lower than that of PVA-CMC samples. Fourier-transformed infrared (FTIR) spectroscopy results showed less compatibility between polyacrylic acid (PAA) and PVA compared to that of CMC. The solution made from the lower hydrolysis degree PVA (PVA1788) could form a strong gel after being treated with NaOH 1 M. The FTIR result showed the disappearance of acetate groups. A large melting peak in differential scanning calorimetry (DSC) results showed high crystallinity of the hydrolyzed-PVA1788. The effect of various multivalent cations on the mechanical properties of PVA1788-CMC DN gel was performed. The properties of the samples followed the order: Fe³⁺<Co²⁺<Ni²⁺<Cu²⁺<Zn²⁺<Ca²⁺~Ba²⁺<Al³⁺. The tensile strength of DN gel fabricated using AlCl3 solution could reach 0.87 MPa, and the elongation at break was 330%.

Polyimide (PI) fiber is a promising and high-performance polymer fiber with high temperature resistance and low density; however, much energy is needed during the thermal imidization process. Here, PI fiber with excellent mechanical properties and high-temperature resistance was fabricated via the dry-jet wet spinning method for polyamic acid (PAA) precursor fiber, followed by stretching and thermal imidization reaction at a lower temperature. With the increase of the stretching ratio, the mechanical properties of the PI fiber increase significantly. When the stretching was twice as long, the tensile strength and initial modulus of the fiber were as high as 6.23 and 114.13 cN·dtex^–1, respectively. Fourier transform infrared results revealed that all samples were completely imidized at 260 °C. The resulting PI fibers exhibit only 5% weight loss at 539.53 °C, and its limiting oxygen index (LOI) can reach up to 32.6%, showing excellent high temperature resistance and flame-retardant properties as well as commendable mechanical performance, which compare favorably with those of other imidization methods.

This study presents for the first time a sustainable approach to hydrophobic modification of nanocellulose/chitosan bioaerogels using beeswax emulsion. The incorporation of beeswax into the aerogel matrix resulted in increasing the density from 35.1 to 298 mg/cm³, while the porosity decreased from 96.4 to 62%. Fourier transform infrared spectroscopy (FT-IR) analysis confirmed the successful integration of beeswax into the nanocellulose/chitosan matrix, with distinct peaks corresponding to the characteristic functional groups of beeswax, such as C–H stretching vibrations, further validating the hydro - phobic modification. The mechanical properties showed increased hardness, from 0.24 to 0.95 N/mm², indicating that higher beeswax content enhanced the rigidity of the aerogels. Contact angle measurements confirmed a dramatic improvement in hydrophobicity, with angles increasing from 47.68 to 134.40 and 128.11° for NC/CH 60-40-15. Water absorption capacity decreased from 17.5 g/g in the control sample to 8 g/g at the highest beeswax concentration, while oil absorption increased significantly, with fresh engine oil absorption rising from 3 to 45 g/g and used engine oil absorption from 2.5 to 40 g/g respectively. These results confirm the successful green modification of bioaerogels using beeswax, providing a sustainable and eco-friendly approach that enhances hydrophobicity, mechanical strength, and selective absorption properties.