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To develop bio-nanocomposites using natural biopolymers, nanocomposite films were prepared based on sodium alginate and kapok nanofibrils (CNFs). CNFs when subjected to TEMPO-mediated oxidation gave rise to cellulose nanocrystals (TOCNCs), with carboxyl groups at the surface (Ka/Kb = 3.64). The differences between the two types of nanocelluloses (nanofibrils and nanocrystals) and their impact in the preparation of bio-nanocomposites, were studied. When incorporated in the matrix, the CNFs particles have the tendency to form surface aggregation (Ka/Kb = 2.37), distorting the alginate network, creating heterogeneous films, with high surface roughness (Sa = 29.37 nm), porosity (Dp = 0.087 cm2/min) and vulnerability to heat. The TOCNCs present good dispersion creating a 3D network, which forms uniform (Dp = 0.122 cm2/min) and homogeneous films, with smooth surface (Sa = 16.83 nm). The ultrasonication treatment facilitated the dispersion improving the interfacial interaction between the reinforcing phase and the matrix. The results show the reinforcement potential of kapok nanocellulose in an industrially and medically important biopolymer, sodium alginate, especially when TOCNCs and ultrasonication were used.

Cellulose produced by bacteria (BC) is considered a promising material for the textile industry, but the fragile and sensitive nature of BC membranes limits their broad applicability. Production of all-cellulose biocomposites, in which the BC is cultivated in situ on a cotton fabric, could solve this problem, but here a new issue arises, namely poor adhesion. To overcome this challenge, cotton fabric was modified with low-pressure oxygen plasma in either afterglow, E-mode, or H-mode. All-cellulose biocomposites were prepared in situ by placing the samples of cotton fabric in BC culture medium and incubating for 7 days to allow BC microfibril networks to form on the fabric. Modification of cotton fabric with oxygen plasma afterglow led to additional functionalization with polar groups, and modification with oxygen plasma in H-mode led also to etching and surface roughening of the cotton fibers, which improved the adhesion within the biocomposite. In addition, these biocomposites showed higher deformation capacities. Modification of the cotton fabric over a longer period in E-mode was found to be unsuitable, as this caused strong etching, which led to the defibrillation of cotton fibers and poor adhesion of BC. This study highlights the potential of low-pressure plasma treatment as an environmentally friendly method to improve the performance of cellulose-based biocomposites.

This study identifies the optimal combination of active and passive thermoplastic materials for producing multi-material programmable 3D structures. These structures can undergo shape changes with varying radii of curvature over time when exposed to hot water. The research focuses on examining the thermal, thermomechanical, and mechanical properties of active (PLA) and passive (PRO-PLA, ABS, and TPU) materials. It also includes the experimental determination of the radius of curvature of the programmed 3D structures. The pairing of active PLA with passive PRO-PLA was found to be the most effective for creating complex programmable 3D structures capable of two-sided transformation. This efficacy is attributed to the adequate apparent shear strength, significant differences in thermomechanical shrinkage between the two materials, identical printing parameters for both materials, and the lowest bending storage modulus of PRO-PLA among the passive materials within the activation temperature range. Multi-material 3D printing has also proven to be a suitable method for producing programmable 3D structures for practical applications such as phone stands, phone cases, door hangers, etc. It facilitates the programming of the active material and ensures the dimensional stability of the passive components of programmable 3D structures during thermal activation.

Flammability testing of undergarments is a topic that is often overlooked and rarely on the list of textiles to be tested for fire safety. However, it is particularly important for professionals exposed to fire risk to investigate the flammability of underwear as its direct contact with the skin can be critical to the extent and degree of skin burns. This research focuses on the suitability of affordable blends of 55 wt.% modacrylic, 15 wt.% polyacrylate, and 30 wt.% lyocell fibres that have the potential to be used for flame-resistant underwear. The influence of modacrylic fibre linear density (standard and microfibres), ring spinning processes (conventional, Sirospun, and compact), and knitted structure (plain, 2:1 rib, 2:1 tuck rib, single pique, and triple tuck) on their properties required for thermal comfort in high-temperature environments was investigated. Scanning electron and optical microscopy, FT-IR spectroscopy, mechanical testing, moisture regain, water sorption, wettability, absorption, DSC, TGA, and flammability were tested to assess the desired suitability. The wetting time (5-14.6 s) and water absorption time (4.6-21.4 s) of the knitted fabrics have shown excellent ability to transport and absorb water compared to the knitted fabrics created from a conventional blend of 65% modacrylic and 35% cotton fibres. The afterflame and afterglow times of less than 2 s met the criteria for non-flammability of the knitted fabrics according to the limited flame spread test method. The results show that the investigated blends have the potential to be used for affordable flame-retardant and thermally comfortable knitted fabrics for underwear.

In this study, the mechanical and thermal properties of poly(lactic acid) (PLA) blends with an addition of poly(ε-caprolactone) (PCL) and fumed silica (SiO 2 ) were evaluated to research the possibility of their use as relief printing plates for embossing processes. PCL and nano-silica were added to the PLA matrix at different concentrations. Morphological, thermal and mechanical analyses were performed to determine the properties and possible functional characteristics of the studied blends. SEM micrographs showed that unmodified PLA/PCL blends exhibit a morphology typical of incompatible blends with clearly visible spherical domains of dispersed PCL in PLA. In particular, the results of the hardness tests showed that the selected blends have the optimal hardness (between 65 SH D and 75 SH D) for use in the embossing process. The tensile tests showed that the addition of nano-silica to neat PLA and to the PLA/PCL blends 50/50 and 60/40 improved the mechanical properties of the blends, especially stiffness and toughness. The DMA results showed that the addition of smaller amounts of SiO 2 can contribute to an increase in storage modulus, which is due to good dispersion and distribution of SiO 2 in the matrix. DSC analysis showed that the addition of PCL to PLA polymer increased the thermal stability of PLA and that the addition of nano-silica increased the degree of crystallinity of PLA. The TGA results showed that the addition of nano-silica improved the thermal degradation behavior of the studied blends, especially for blends modified with 3 wt% nano-silica. The results show that it is possible to optimize the mechanical and thermal properties of the blends with the aim of using them in the embossing process.

The aim of the study was to analyse the colour fastness of 3D printed samples that could be used as decorative or household items. Such items are often fabricated with 3D printing. The colour of filaments affects not only the mechanical properties, but also the appearance and user satisfaction. Samples of biocomposite filaments (PLA and PLA with added wood and hemp fibres) were used. First, the morphological properties of the filaments and 3D printed samples were analysed and then, the colour fastness against different agents was tested (water, oil, detergent, light and elevated temperature). Finally, the dynamic mechanical properties of the filaments and 3D printed samples were determined. The differences in the morphology of the filaments and 3D printed samples were identified with SEM analysis. The most obvious differences were observed in the samples with wood fibres. All printed samples showed good resistance to water and detergents, but poorer resistance to oil. The sample printed with filaments with added wood fibres showed the lowest colour fastness against light and elevated temperatures. Compared to the filaments, the glass transition of the printed samples increased, while their stiffness decreased significantly. The lowest elasticity was observed in the samples with wood fibres. The filaments to which hemp fibres were added showed the reinforcement effect. Without the influence on their elasticity, the printed samples can be safely used between 60 and 65 °C.

Polylactic acid (PLA) is one of the most suitable materials for 3D printing. Blending with nanoparticles improves some of its properties, broadening its application possibilities. The article presents a study of composite PLA matrix filaments with added unmodified and lignin/polymerised lignin surface-modified nanofibrillated cellulose (NFC). The influence of untreated and surface-modified NFC on morphological, mechanical, technological, infrared spectroscopic, and dynamic mechanical properties was evaluated for different groups of samples. As determined by the stereo and scanning electron microscopy, the unmodified and surface-modified NFCs with lignin and polymerised lignin were present in the form of plate-shaped agglomerates. The addition of NFC slightly reduced the filaments' tensile strength, stretchability, and ability to absorb energy, while in contrast, the initial modulus slightly improved. By adding NFC to the PLA matrix, the bending storage modulus (E') decreased slightly at lower temperatures, especially in the PLA samples with 3 wt% and 5 wt% NFC. When NFC was modified with lignin and polymerised lignin, an increase in E' was noticed, especially in the glassy state.

Studies of the production of fiber-forming polyamide 6 (PA6)/graphene composite material and melt-spun textile fibers are scarce, but research to date reveals that achieving the high dispersion state of graphene is the main challenge to nanocomposite production. Considering the significant progress made in the industrial mass production of graphene nanoplatelets (GnPs), this study explored the feasibility of production of PA6/GnPs composite fibers using the commercially available few-layer GnPs. To this aim, the GnPs were pre-dispersed in molten ε -caprolactam at concentrations equal to 1 and 2 wt %, and incorporated into the PA6 matrix by the in situ water-catalyzed ring-opening polymerization of ε -caprolactam, which was followed by melt spinning. The results showed that the incorporated GnPs did not markedly influence the melting temperature of PA6 but affected the crystallization temperature, fiber bulk structure, crystallinity, and mechanical properties. Furthermore, GnPs increased the PA6 complex viscosity, which resulted in the need to adjust the parameters of melt spinning to enable continuous filament production. Although the incorporation of GnPs did not provide a reinforcing effect of PA6 fibers and reduced fiber tensile properties, the thermal stability of the PA6 fiber increased. The increased melt viscosity and graphene anti-dripping properties postponed melt dripping in the vertical flame spread test, which consequently prolonged burning within the samples.

In the material extrusion of the thermoplastic filaments, known as Fused Deposition Modelling, usually, pure thermoplastic polymers are used. Recently, the focus of the research is given to the development of new biocomposite thermoplastic materials. In our research, 3D printable biocomposite filaments, made with the addition of 50 wt.% of cardboard dust to the HDPE and PLA polymer matrix were studied. The influence of the added cardboard dust on structural, morphological and mechanical properties of the 3D printable biocomposite filaments was investigated. With the addition of the corrugated cardboard dust into the HDPE and PLA polymer matrix the changes in density, uniformity, chemical structure and transition temperatures of the samples were detected. The addition of the cardboard dust into the HDPE polymer matrix lead to low tenacity, toughness, deformability resulting in brittleness of the 3D printable biocomposite filament, whereas the addition of the cardboard dust into the PLA polymer matrix lowered tensile properties, but didn't affected bending toughness and has even improved compression strength of the 3D printable filament.