Textiles

Mechanically recycled cotton is heterogeneous, and nep counts obtained from different analytical platforms may not be numerically interchangeable. This study provides a preliminary cross-platform comparison of five industrial batches selected in the original industrial work to span the available production range of total nep count (TotNep). The batches differed in product category, color, supplier/feedstock designation, and production line; Batch was therefore treated as a composite material identity rather than an isolated structural-severity factor. USTER^® Neptester 720 measurements comprised three bales per batch and two technical determinations per bale; USTER^® LVI 920 used the same three bales and three determinations per bale; USTER^® AFIS Pro 2 used one of those bales per batch and ten determinations. Descriptive variability was reported as mean, standard deviation, and coefficient of variation. The primary inferential analysis compared Neptester 720 and LVI 920 on the 15 matched bales. Although the overall mean paired difference was +45.5 neps/g (95% CI: 14.0–76.9; p = 0.0078), batch-specific mean differences ranged from −13.6 to +101.4 neps/g and differed significantly among batches (p = 0.025), showing that +45.5 neps/g is not a transferable correction factor. A secondary exploratory analysis was restricted to the five bales measured by all platforms (one bale per batch). These deliberately range-spanning bales retained the Neptester-defined order (Spearman ρ = 1.00), but the coefficient is descriptive and does not constitute independent validation of cross-platform ranking. Exploratory Bland−Altman mean differences were +32.0, +99.3, and +67.2 neps/g for LVI 920-AFIS Pro 2, Neptester 720-AFIS Pro 2, and Neptester 720-LVI 920, respectively, with wide limits of agreement. Because no reference method was available and each platform was confounded with laboratory, operator, measurement date, and procedural conditions, these values describe cross-platform disagreement rather than instrument-specific measurement bias. The results support ordinal recognition of the selected batches but do not establish validated severity classes, numerical interchangeability, or formal interlaboratory reproducibility. Larger balanced studies using matched bales, documented conditioning, harmonized procedures, and fuller fiber characterization are required.

Ultrasonic bonding offers a promising alternative to traditional sewing and other plastic bonding techniques, with several potential advantages. This paper comprehensively analyzes ultrasonic bond characteristics in PVC-coated hybrid textiles, prevalent in awnings and camping tents. Untreated samples were used as controls to compare the effects of ultrasonic bonding on various characteristics. Developed experimental designs were applied using a 12 mm welding width in a lapped seam, with carefully selected parametric levels to achieve higher bond strength based on preliminary test results. Mechanical properties (tensile, cyclic, and tear strength, including thickness reduction) were thoroughly examined to assess ultrasonic bond seam efficiency. The analysis covered thermal, chemical, morphological, and weight loss aspects before and after ultrasonic welding. Results showed that the weld seam tensile efficiency ranged from 68.27% to 96.13%, indicating enhanced durability. Cyclic efficiency exceeded 95%, tear efficiency surpassed 70%, and both treated and untreated samples showed strengths above standard thresholds. Thermal findings indicated a 3% increase in crystallinity after ultrasonic treatment, enhancing thermal stability with lower weight loss and causing shifts in glass transition and melting temperatures. FTIR spectra revealed that ultrasonic bonding had no significant impact on the material’s chemical properties. Morphological analysis identified pre-existing microvoids, with no significant increase in their number and/or size following ultrasonic treatment. Overall, the study demonstrates the efficacy of ultrasonic welding in improving the mechanical, chemical, and thermal properties of PVC-coated hybrid textiles, providing valuable insights for applications like awnings, camping tents, and roofing materials for short- and long-term use.

The valorization of agricultural residues as alternative lignocellulosic fiber resources may improve biomass utilization. This study comparatively evaluated Corchorus olitorius L. bast fibers recovered from Egyptian Molokhia stem residues using biological water retting, cold alkaline extraction, and manual scraping. The fibers were characterized using scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), chemical composition analysis, elongation-at-break measurements, moisture content determination, extraction-related weight-loss assessment, and thermogravimetric/derivative thermogravimetric analysis (TGA/DTG). Cold alkaline extraction produced the highest measured cellulose content (72.0 ± 3.98%) and the lowest measured lignin content (3.0 ± 1.98%). Biological retting produced the highest empirical Segal crystallinity index (75.2%), whereas chemically extracted fibers exhibited the highest elongation at break (1.8 ± 0.17%). Extraction-related weight loss reached 71.4 ± 0.4% after 21 days of biological retting and 80.7 ± 0.5% after 9 days of cold alkaline extraction; these values reflect overall mass reduction during extraction and should not be interpreted solely as removal of specific non-cellulosic constituents. TGA/DTG showed the highest measured onset degradation temperature and maximum degradation-rate temperature for biologically retted fibers (344.4 and 379.6 °C, respectively), while chemical extraction produced the highest residual mass at 600 °C (9.85%). Overall, the extraction route influenced the measured chemical, morphological, structural, mechanical, and thermal characteristics, with no single method exhibiting the highest values across all evaluated parameters. These findings provide comparative baseline data for further evaluation and optimization of Corchorus olitorius bast fibers recovered from Egyptian Molokhia stem residues.