Antonela Lungu

Integrating traditional textile heritage into contemporary furniture design offers an innovative way to preserve cultural identity through modern materials and decorative techniques. This study investigates the color stability of hybrid decorative plywood panels fabricated using mechanical perforation and sewing techniques inspired by traditional textile motifs. The samples were evaluated using UV-induced artificial aging, alongside color measurements before and after exposure, microscopic analysis, and Fourier Transform Infrared Spectroscopy (FTIR). The approach enables traditional decorative patterns to be transferred onto wood-based materials, creating contemporary furniture decorations, while preserving and reinterpreting the textile heritage. Results revealed distinct aging behaviors depending on the finishing system. Changes in total color difference (ΔE*)—4.36 for red thread, 4.21 for unvarnished reference, 3.34 for oiled, 0.72 for water-based, 2.55 for nitrocellulose-based, and 0.52 for epoxy-coated samples—demonstrated that both the coated plywood substrate and the textile thread were affected by aging after 72 h of UV exposure. Epoxy resin and water-based coatings provided the greatest color surface stability, while oil- and solvent-based finishes exhibited varying degrees of chromatic alteration due to their different responses to ultraviolet radiation and moderate temperature. The stitch technique showed good structural compatibility with plywood and preserved the integrity of heritage-inspired motifs after artificial aging for 72 h of UV exposure relative to long-term furniture use, which is a limitation of the present study. However, the red cotton sewing thread was more sensitive to light exposure, showing a slight UV-induced discoloration, with effects varying according to coating type. FTIR investigations demonstrated that UV aging of the cotton thread resulted in some photo-oxidative degradation of cellulose, which may explain the minor incipient microstructural degradation phenomena observed by SEM.

This study explores the enhancement of Beech wood (Fagus sylvatica L.) surfaces through the laser engraving of motifs inspired by Romanian textile heritage, combining cultural preservation with modern surface design techniques. A digitization and computer-aided design (CAD)-based workflow was employed to accurately transfer traditional motifs onto wood substrates. Engraving was performed using a nitrogen laser at ten different power settings ranging from 10 W to 150 W, followed by color analysis of the engraved areas. The resulting surfaces were evaluated using the International Commission on Illumination (CIELab) system to identify optimal engraving conditions. Based on colorimetric analysis, three laser power settings were selected for final motif reproduction: 30 W, 45 W, and 105 W. The process enabled the accurate rendering of a traditional three-color motif, achieving both visual fidelity and aesthetic appeal. Results demonstrate that color-based laser engraving allows precise, durable, and culturally significant ornamentation of wooden surfaces. The conclusions highlight the potential of this technique to add artistic and commercial value to wood products while preserving and promoting cultural identity.

This study developed sustainable foam-type composites from recycled paper (P), corrugated cardboard (C), and their 1:1 mixture (PC) for use in thermal and acoustic insulation. The materials were produced by water-assisted defibration, gas foaming with sodium bicarbonate and yeast, and oven curing, resulting in lightweight porous panels without synthetic binders. The composites exhibited distinct density and porosity profiles that influenced moisture behavior and stability. Cardboard-based panels absorbed the most water and swelled the most, while paper-based panels were more resistant. Despite these differences, all materials showed uniformly low thermal conductivity, confirming their strong insulation capability. Acoustic performance was enhanced by perforation and multilayer assembly. Cardboard panels with a triple-layer perforated design achieved the highest sound absorption, while mixed paper–cardboard composites provided balanced broadband performance. Microscopy revealed that fiber morphology—coarse in cardboard, fine in paper, and interlaced in mixtures—shaped the porous structure and bonding. Mechanical tests indicated comparable stiffness and strength across all types, with cardboard showing the strongest internal bonding. Overall, the results demonstrate that fiber structure and porosity govern material performance. These foam composites combine effective thermal insulation, competitive sound absorption, and sufficient mechanical strength, positioning them as biodegradable, low-cost alternatives for sustainable construction and acoustic applications.

This paper evaluates the performance of composites made from date palm (Phoenix dactylifera L.) midribs reinforced with carbon fiber. Two types of adhesives—unsaturated polyester and epoxy resin—were used as binder for the experimental panels. The physical properties and mechanical strength of the composites, as a function of fiber types, lamination configuration, as well as adhesive types, were determined. The density levels of the panels made using epoxy and unsaturated polyester resin were found to be 1103 kg/m³ and 1133 kg/m³, respectively. Panels made using polyester adhesive had 6.05% and 3.98% for water absorption and thickness swelling values, respectively. Corresponding values of 3.09% and 6.35% were found for the panels made using epoxy resin. Mechanical properties of the samples revealed that carbon fiber-reinforced epoxy hybrids offer superior mechanical performance, whereas polyester-based hybrids may be more suitable for impact-resistant applications. Stereo-microscopy and vertical density profile (VDP) analysis of the panels resulted in variations in layer adhesion and density distribution. Based on the findings in this work, carbon fiber-reinforced epoxy-bonded hybrid panels exhibited superior mechanical properties, while those panels made using polyester-based binder would be more suitable where impact resistance is desired. The combination of date palm fibers and carbon fiber presents significant potential for sustainable applications, offering a balance of strength and durability.

The evaluation of surface quality is an important criterion to understand the effect of the cutting angle in relation to the grain and of the processing tool on wood. This paper examines, in a comparison, the surface quality of maple cut through by CNC and CO₂ laser, for different angles with regard to the wood grain: 0°, 15°, 30°, 45°, 60°, 75°, and 90° and at different feed speeds of the CNC router: 2; 2.5; 3; 3.5 and 4 m/min. The direction of processing as related to the grain was a more significant factor in comparison with the feed speed when CNC was used, with best options for 0°, 90° and 75° and worst for 15°, where fuzzy grain was predominant, followed in order by 30°, 45°, and 60°, where pull-out material prevailed. The laser smoothed the core roughness, Rk, with no significant differences as related to the wood grain direction and enhanced an anatomical waviness earlywood-latewood, with the earlywood processed deeper. As the cutting advanced from along to across the grain, the laser uncovered more wood anatomical details and with less destruction. No significant differences in Rk between CNC cutting and laser processing were found for angles: 0°, 60°, and 75°, but surfaces processed at 15°, 30°, and 45° were significantly rougher in the case of CNC cutting. Comparative FTIR investigation of surfaces cut by laser and CNC (at 0° and 90°) clearly revealed temperature-induced chemical changes, such as hemicelluloses degradation, possibly demethylation and advanced condensation in the structure of lignin, in the case of laser processing.

The present paper is part of an ongoing research project carried out to find methods to transpose traditional motifs from Romanian textile heritage to furniture ornamentation, as an additional method of preserving the motifs besides conventional conservation. Modern technology, such as Computer Numerical Control (CNC) routing or laser engraving can revive furniture ornamentation, eliminating manual labor and long execution time. Three methods were applied to transpose a bicolored motif from a traditional Romanian blouse from Transylvania onto the surface of maple wood furniture. The first method utilized was nitrogen laser engraving, in which ten power settings between 10 W and 150 W were applied and color measurements were carried out on the resulting engraved surfaces. Following the International Commission on Illumination (CIELab) system analysis, two laser power settings were selected to engrave the ornament on a maple wood surface for an accurate reproduction. The second method employed a staining solution applied on flat wood surface, followed by routing the model on a CNC machine and further coating with lacquer. The third method consisted of CNC routing the model on the wood surface, then coloring the engraved ornament followed by surface sanding to remove color from the flat wood surface and, finally, lacquering. The ornaments transposed onto maple wood surfaces were aesthetically assessed, the technologies were analyzed, and the details of the processed ornaments were highlighted by Stereo Microscope investigation. The conclusions showed that each method adds value to the wood surface by original ornamentation and can be applied as furniture decoration.

This paper presents experimental research on the Computer Numerical Control (CNC) routing of a traditional motif collected from Ţara Bârsei (Transylvania region) using two methods, namely, engraving (Engrave) and carving (V-Carve). The analysis of the CNC router processes includes the calculation of the path lengths, an assessment of the processing time and wood mass loss, and an evaluation of the tool wearing by investigating the tool cutting edge on a Stereo Microscope NIKON SMZ 18 before and after processing the ornament on wood. An aesthetic evaluation of the ornament routed on wood, using both the engraving and carving methods, is also conducted, whilst a microscopic analysis of the processed areas highlights the defects that occurred on the wood surface depending on the tool path.