STUDY OF VARIOUS QUALITY CHARACTERISTICS OF POLYESTER FIBERS OBTAINED ON THE BASIS OF PRIMARY AND SECONDARY POLYETHYLENE TEREPHTHALATE

The aim of study is comprehensive determination of various quality characteristics of polyester fibers obtained on the basis of primary and secondary polyethylene terephthalate. The analysis of the raw material base of pre-oriented yarns (POY) threads has been carried out. The technological, physicomechanical properties, as well as the structure of the primary and secondary polyethylene terephthalate used in the production of the threads have been studied. The structure and properties of polyethylene terephthalate changed: the properties were worse, the structure were amorphous, the molecular weight decreased. The structure of recycled polyethylene terephthalate changed as a result of technological conversions in the production of POY fibers. This is due to a change in the thermophysical characteristics and structure of secondary polyethylene terephthalate under the influence of heat, moisture, and shear stresses. A comparative analysis of the physicomechanical properties of POY yarns obtained from primary and secondary polyethylene terephthalate has been carried out.

Morphology, Chemical Characterization and Sources of Microplastics in a Coastal City in The Equatorial Zone With Diverse Anthropogenic Activities (Fortaleza City, Brazil)

The aim of the present study was to perform morphological and chemical characterizations of microplastics (MPs) found in seawater samples from the coast of the city of Fortaleza (CE) using Fourier-transform infrared (FTIR) spectroscopy, Raman spectroscopy and differential scanning calorimetry (DSC). Sampling was performed using a neuston sampler. MPs were separated based on the difference in density. MPs with varied morphologies were found. Fibers and fragments were the most abundant (57% and 36.2%, respectively). FTIR, Raman spectroscopy and DSC confirmed the presence of polyurethane and alkyd resin, polyethylene, polypropylene, polystyrene, polyamide blends, thermoplastic rubber and polyester fibers. Many studies have chemically characterized plastic materials using FTIR, Raman spectroscopy and DSC and common MPs, such as polyethylene, polypropylene, polyamide and polyester, have been characterized. However, characterization becomes more complex when MPs are less common particles, weathered particles and blends of polymers and additives. There is also less information on these types of MPs in commercial polymer databases. Therefore, the MP spectra obtained in this study can serve as a database to compare and characterize common as well as less common, more complex MPs.

The Toxicity of Polyester Fibers in Xenopuslaevis

Microplastics are practically ubiquitous and pose a serious survival challenge for many species. Most of the exposure experiments for determining the toxicological effects of microplastics were performed with a microplastic varying little in shape and size (often purchased microplastic beads), but few studies deal with non-homogeneous samples. We analyzed the effect on Xenopuslaevis larva on the early development of polyester fibers, PEFs, taken from a dryer machine in which 100% polyester fabrics were dried after washing. Three concentrations were tested. The results showed that the gastrointestinal tract, GIT, was the most affected system by PEFs which modified the normal shape of the intestine with an EC50 96 h value of 6.3 µg mL−1. Fibers were observed to press against the digestive epithelium, deforming the normal architecture of the gut, sometimes pushing deep into the epithelium until piercing it. Physical GIT occlusion was observed in a concentration-dependent manner. However, no other damages were registered. No mortality was observed, but PEF-exposed larvae showed a significant reduction in their mobility. The results of the present paper suggest that environmental samples with their heterogeneity may have adverse effects on X. laevis development.

Mathematical modeling of equivalent ellipse radii of Raman spectra for identification of gold nanoparticles

To ensure the biomedical, therapeutic and protective properties of textile materials using gold nanoparticles, there is a need to apply the convergence of nano-, bio-, info -, cognitive sciences and technology. It is proposed to evaluate the accuracy of identification of colloidal gold nanoparticles on organic fibers based on the multidimensional correlation components of the Raman spectra under control by the polarization characteristics. The aim of the work is to improve the accuracy of identification of gold nanoparticles in nanostructured biological objects during mathematical modeling based on the components of Raman spectrograms.The paper analyzes the Raman spectra of polyester fibers with and without gold nanoparticles in different ranges. A method for solving a system of multidimensional equations with differentiation in X and Y is proposed, according to which the coordinates of the intersection points of ellipses are determined under conditions of equality of equivalent radii and probability densities of two-dimensional distributions. The sensitivity to the concentration of gold nanoparticles of the developed method under various conditions is estimated. The research carried out in this work will improve the accuracy of identification of gold nanoparticles on various biological objects, as well as solve a wide range of problems related to increasing the reliability of control of metal nanoparticles

Development of Sustainable and Functional Fabrics from Recycled and Nanocomposite Polyester Fibers

Antimicrobial knitted and woven fabrics were developed from recycled polyester (PET) and silver nanocomposite (SNC) fibers. Two different fabrics were produced from two different blend proportions of the fibers. The antimicrobial properties of fabrics were tested against those of the S. aureus (Gram-positive) and E. coli (Gram-negative) bacterial natures, and their yarn properties and hand-related characteristics were investigated. The results show uneven fabrics properties such as irregularity in thickness and SNC-recycled PET fiber ratio increase, and the tensile strength decreases while the NEP number increases. This implies that fabrics made from a blend with higher SNC-recycled PET fiber ratios have higher surface roughness levels, higher bending rigidity, and harder texture. As a consequence, the antimicrobial efficiency of the fabrics was improved as the percentage of SNC increased. The recycled PET fiber within the blended yarn shows a good antimicrobial property (above 90%) observed in all fabrics. The reduction of bacterial colonies was constantly exceeding 90% for both E. coli and S. aureus in all fabric samples.

Exposure to microplastic fibers does not change fish early life stage development of three-spined sticklebacks (Gasterosteus aculeatus)

Microplastic fibers are frequent contaminants of aquatic ecosystems. Early life stages of aquatic organisms are predicted to be especially vulnerable to microplastic pollution. We hypothesized that microplastic fibers in the water column might interfere with fertilization and embryonic development of fish. We tested this with an in vitro fertilization system with three-spined sticklebacks. Six egg clutches were divided and one half was fertilized and bread out in water with polyester fibers (PET fibers; mean diameter 9.7 ± 2.3 μm; mean length 245.6 ± 163.1 μm) at a concentration of 1 × 104 fibers/L while the other half served as control without fibers.Observation with a dissection microscope revealed that some polyester fibers stuck to the outside of the eggs in the fiber treatments. Yet, overall 67.4 ± 12.9% eggs were fertilized from which 97.2 ± 4.2% larvae hatched without any significant difference between treatments. Mortality and abnormal development of larvae was low and was not changed by microplastic fibers, as was the heart rate of developing embryos five days post fertilization.The present study illustrates that polyester fibers, even at concentrations three to four orders above levels reported from the environment, do not impair fertilization success, embryonic and early larval development of sticklebacks. Accordingly, concentrations of microplastic fibers currently observed in aquatic habitats do not appear to be harmful to early live stages of fish.