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Microplastic fibers (MPFs) have been found to be a major form of microplastics in freshwaters, and washing of synthetic textiles has been identified as one of their main sources. The aim of this work was to use a panel of 12 different textiles of representative fibers and textile types to investigate the source(s) of the MPF during washing. Using standardized washing tests, textile swatches tailored using five different cutting/sewing methods were washed up to 10 times. The MPF quantity and fiber length were determined using image analysis. The 12 textiles demonstrated great variability in MPF release, ranging from 210 to 72,000 MPF/g textile per wash. The median MPF length ranged from 165 to 841 μm. The number of released MPF was influenced by the cutting method, where scissor-cut samples released 3–21 times higher numbers of MPF than the laser-cut samples. The textiles with mechanically processed surfaces (i.e., fleece) released significantly more (p-value < 0.001) than the textiles with unprocessed surfaces. For all textiles, the MPF release decreased with repeated wash cycles, and a small continuous fiber release was observed after 5–6 washings, accompanied by a slight increase in the fiber length. The decrease in the number of MPF released is likely caused by depletion of the production-inherited MPFs trapped within the threads or the textile structure. The comparison of MPF release from laser-cut samples, which had sealed edges, and the other cutting methods allowed us to separate the contributions of the edge- and surface-sourced fibers from the textiles to the total release. On an average, 84% (range 49–95%) of the MPF release originated from the edges, highlighting the importance of the edge-to-surface ratio when comparing different release studies. The large contribution of the edges to the total release offers options for technical solutions which have the possibility to control MPF formation throughout the textile manufacturing chain by using cutting methods which minimize MPF formation. © 2020 American Chemical Society. ISSN:0013-936X ISSN:1520-5851

Poly(hydroxybutyrate-co-3-hexanoate) (PHBH) is a biodegradable thermoplastic polyester with the potential to be used in textile and medical applications. We have aimed at developing an upscalable melt-spinning method to produce fine biodegradable PHBH filaments without the use of an ice water bath or offline drawing techniques. We have evaluated the effect of different polymer grades (mol% 3-hydroxy hexanoate, molecular weight etc.) and production parameters on the tensile properties of melt-spun filaments. PHBH monofilaments (diameter < 130 µm) have been successfully melt-spun and online drawn from three different polymer grades. We report thermal and rheological properties of the polymer grades as well as morphological, thermal, mechanical, and structural properties of the melt-spun filaments thereof. Tensile strengths up to 291 MPa have been achieved. Differences in tensile performance have been correlated to structural differences with wide-angle X-ray diffraction and small-angle X-ray scattering. The measurements obtained have revealed that a synergetic interaction of a highly oriented non-crystalline mesophase with highly oriented α-crystals leads to increased tensile strength. Additionally, the effect of aging on the structure and tensile performance has been investigated.

The inconsistency of available methods and the lack of harmonization in current microplastics (MPs) analysis in soils demand approaches for extraction and quantification which can be utilized across a wide variety of soil types. To enable robust and accurate assessment of extraction workflows, PET MPs with an inorganic tracer (Indium, 0.2% wt) were spiked into individual soil subgroups and standard soils with varying compositions. Due to the selectivity of the metal tracer, MPs recovery rates could be quickly and quantitatively assessed using ICP-MS. The evaluation of different methods specifically adapted to the soil properties were assessed by isolating MPs from complex soil matrices by systematically investigating specific subgroups (sand, silt, clay, non-lignified and lignified organic matter) before applying the workflow to standard soils. Removal of recalcitrant organic matter is one of the major hurdles in isolating MPs for further size and chemical characterization, requiring novel approaches to remove lignocellulosic structures. Therefore, a new biotechnological method (3-F-Ultra) was developed which mimics natural degradation processes occurring in aerobic (Fenton) and anaerobic fungi (CAZymes). Finally, a Nile Red staining protocol was developed to evaluate the suitability of the workflow for non-metal-doped MPs, which requires a filter with minimal background residues for further chemical identification, e.g. by μFTIR spectroscopy. Image analysis was performed using a Deep Learning tool, allowing for discrimination between the number of residues in bright-field and MPs counted in fluorescence mode to calculate a Filter Clearness Index (FCI). To validate the workflow, three well-characterized standard soils were analyzed applying the final method, with recoveries of 88% for MPs fragments and 74% for MPs fibers with an average FCI of 0.75. Collectively, this workflow improves our current understanding of how to adapt extraction protocols according to the target soil composition, allowing for improved MPs analysis in environmental sampling campaigns., Environmental Pollution, 311, ISSN:0269-7491, ISSN:1878-2450, ISSN:1873-6424

This data article presents fitting results of wide-angle x-ray diffraction (WAXD) patterns of melt-spun polymer fibers from amorphous materials (polycarbonate (PC), cyclo-olefin polymer (COP), copolyamide (coPA), polyethylene terephthalate glycol (PETG)) and semi-crystalline materials (polyethylene terephthalate (PET), poly-3-hydroxybutyrate(P3HB)). The data was fit using the fitting algorithms, previously described in the publication by Perret and Hufenus ‘Insights into strain-induced solid mesophases in melt-spun polymer fibers’ [1] . Fitting results of WAXD data and details about azimuthal, equatorial, meridional or off-axis profiles are presented in sections 1.1-1.2. SAXS patterns of fibers, melt-spun from amorphous materials, are shown in section 1.3. Fiber production parameters are given in section 2.1, and a description of the WAXD measurements and fitting details, e.g., the chosen fitting parameters, are given in section 2.2.

This article summarizes synchrotron wide-angle x-ray diffraction (WAXD) patterns, polarized attenuated Fourier transform infrared spectroscopy (ATR-FTIR) data and differential scanning calorimetry (DSC) data of differently stress-annealed poly(3-hydroxybutyrate) (P3HB) fibers. Additionally, in-situ polarized ATR-FTIR data has been measured under tensile drawing of pre-annealed P3HB fibers under low annealing stress. Modifications to the ATR-FTIR setup and sample holders for performing measurements on P3HB fibers are explained in the experimental section. For more information see ‘Reversible mesophase in stress-annealed poly(3-hydroxybutyrate) fibers: A synchrotron x-ray and polarized ATR-FTIR study' [1] .

Interfacial interactions in biphasic polymeric fluids confined in a nanochannel are studied by using dissipative particle dynamics. The effects of an arrested nanotube at the interfaces of short-ch...

The increased use of synthetic textiles in the last decades, coupled with recent emphasis on the accumulation of (micro)plastic across multiple environmental compartments, has garnered interest into how microplastic fibers are released into the environment. In particular, polyester textiles washed in the home have shown to release microplastic fibers but challenges with microplastic fiber analysis, including time and difficulty of sample preparation and measurement, has limited mechanistic studies on fiber fate and transport studies. In this study, we provide a method to synthesize fibers with an embedded inorganic (In) fingerprint which can be used as a tracer for ease of analysis and show the utility of this approach to assess the affinity for heteroaggregation between microplastic fibers and other particles in a heterogeneous suspension, as well as approximate the fate of microplastic fibers in batch studies using activated sludge from a municipal wastewater treatment plant (WWTP). Total In content in the fibers was measured to be 0.2 % by weight, which was low enough to not change fiber dynamics for fate and transport studies (e.g. density, etc.) but provided sensitive detection limits by ICP-MS. Fiber length was 510 μm ± 410 μm and 30 μm in diameter. The incorporated metal remained stable inside the polymer when suspended in water and in activated sludge, with < 0.1 % In leaching over two months. In batch experiments, the majority of fibers were associated with the sludge ( > 99.9 %), with a mass balance of > 95 % recovery achieved on average across batches. Fiber removal linearly increased with contact times of up to 10 min, suggesting interactions between plastics and organic matter is a metric that should be considered closely in this and other environmental contexts for fate and transport. ISSN:0043-1354 ISSN:1879-2448

Melt-polymer processing is conventionally employed for thermoplastic polymeric materials. The rheological behaviour of the polymer is then of critical importance to correctly accomplish the process. The effect of pressurized fluid additives (PFA), such as CO2 and N2, has been investigated in this work to determine the extension of their beneficial plasticization effect on PLA. In-line measurements performed by a custom-designed slit-die rheometer were conducted at different temperatures and PFA concentrations, and the viscosity values of PLA/PFA mixtures were experimentally determined and compared to those obtained when adding a commercial plasticizer, acetyltributylcitrate (ATBC), to PLA. Our results suggested that a twofold reduction of PLA viscosity is achievable using addition of 2.65 wt% pressurized CO2 respect to similar contents of ATBC. Furthermore, a decrease of 10 °C of the processing temperature could be attained when adding 1.70 wt% of CO2. This work aims at shedding light on the rheological behaviour that PLA experiences during assisted-melt extrusion processing, and on how more favourable energetic processing could be achieved by lowering temperature, if the appropriate type and concentration of PFA is employed during processing.

At elevated temperatures, polyethylene terephthalate (PET) is known to undergo a cascade of interconnected chemical reactions, in particular oxidative crosslinking, which can lead to severe limitations in processability, product properties, and recyclability. To control such undesired reactions, a newly synthesized phosphorus-based additive with promising flame retardant properties (T. Stelzig et al. Dopo-Based Hybrid Flame Retardants. EP2921498 (A1), 2015), by the chemical name 6-((1-oxido-2,6,7-trioxa-1-phosphabicyclo[2.2.2]octan-4-yl)methoxy)dibenzo[c,e][1,2]oxaphosphinine 6-oxide (DOPO-PEPA, or simply DP), was added to PET in different concentrations. To assess the miscibility of DP and PET at the nanoscale, a multiscale simulation scheme was developed by combining molecular dynamics and dissipative particle dynamics. DP showed a prominent inter-chain lubrication effect in PET in extrusion experiments. To replicate the heating cycles during repeated recycling, the thermal stability of PET melts was assessed on extended timescales using rheological measurements. Time-resolved frequency sweep experiments were conducted with or without the novel DP additive, under air and nitrogen atmospheres. By combining various chemical analysis techniques, a chemical stabilizing mechanism could be proposed that describes how the DP molecule intervenes with the degenerative chemical reactions of PET chains in the melt processing phase. The proposed mechanism outlines trace-release from DP involving the formation of phosphorus radicals including DOPO•, PEPA•, and PO•. Such radicals scavenge the oxygen radicals from air and can thus protect the linearity of PET chains. The results underline the synergistic effects of DP on the processing of high performance PET. Together with flame retardancy of the original product, the environmental-friendly DP chemically-protects and lubricates PET during subsequent recycling of the waste.

Three novel alkyl sulfone bridged phosphorus (P) compounds namely 6,6′-(sulfonylbis(ethane-2,1-diyl))bis(dibenzo[c,e][1,2]oxaphosphinine 6-oxide) (SEDOPO), sulfonylbis(ethane-2,1-diyl))bis(diphenylphosphine oxide) (SEDPPO), and tetraphenyl (sulfonyl bis(ethane-2,1-diyl)) bis(phosphonate) (SEDPP) (i.e. phosphine oxide, phosphinate and phosphonate, respectively) were synthesized via a Michael addition reaction with good yields (≥ 85%) at a 200-g scale. They exhibited thermal stability above 250 °C, which allowed them to be melt-processed with polypropylene (PP) and formed into thin films (~ 0.6 mm). Rheological measurements of the PP blends exhibited a typical shear thinning behavior and provided evidence for the synthesized compound's thermo-oxidative stabilizing effect. This was also confirmed by thermal analysis showing that the thermo-oxidative stability of PP-SEDOPO and PP-SEDPPO blends was higher (~25 °C) than the blank PP; however, PP-SEDPP had a smaller impact. Small scale fire tests of the PP-FR blends confirmed the flame retardant efficacy of the new P-compounds. Cone calorimetry on PP-SEDOPO blends showed a reduction in the heat release rate (HRR) (~48%) compared to blank PP. Further thermal and evolved gas analysis of the PP blends confirmed that the new P-compounds are primarily active in the gas-phase.

A flexible hollow polypropylene (PP) fiber was filled with the phase change material (PCM) polyethylene glycol 1000 (PEG1000), using a micro-fluidic filling technology. The fiber&rsquo, s latent heat storage and release, thermal reversibility, mechanical properties, and phase change behavior as a function of fiber drawing, were characterized. Differential scanning calorimetry (DSC) results showed that both enthalpies of melting and solidification of the PCM encased within the PP fiber were scarcely influenced by the constraint, compared to unconfined PEG1000. The maximum filling ratio of PEG1000 within the tubular PP filament was ~83 wt.%, and the encapsulation efficiencies and heat loss percentages were 96.7% and 7.65% for as-spun fibers and 93.7% and 1.53% for post-drawn fibers, respectively. Weak adherence of PEG on the inner surface of the PP fibers favored bubble formation and aggregating at the core&ndash, sheath interface, which led to different crystallization behavior of PEG1000 at the interface and in the PCM matrix. The thermal stability of PEG was unaffected by the PP encasing, only the decomposition temperature, corresponding to 50% weight loss of PEG1000 inside the PP fiber, was a little higher compared to that of pure PEG1000. Cycling heating and cooling tests proved the reversibility of latent heat release and storage properties, and the reliability of the PCM fiber.

Mechanical properties of as-spun, aged and stress-annealed melt-spun poly(3-hydroxybutyrate) (P3HB) fibers are presented in section 1.1. Section 1.2 presents tables with stress/temperature conditions and exposure times during insitu laboratory WAXD and SAXS experiments, and section 1.3 presents azimuthal profiles of the corresponding WAXD patterns with extracted orientation factors of the alpha-crystals. Section 1.4 presents the extracted long-spacings, coherence lengths and crystal sizes from SAXS patterns. The corresponding fits of meridional and transversal SAXS profiles are shown in sections 1.5 and 1.6, respectively. In-situ synchrotron measurements during tensile drawing of differently pre-annealed P3HB fibers are presented in section 1.7. A detailed description of the tensile, SAXS/WAXD measurements and analysis is given in the experimental section 2. The laboratory SAXS/WAXD measurements during stress annealing were performed with a Bruker Nanostar U diffractometer (Bruker AXS, Karlsruhe, Germany) and a heating stage H + 300 (Bruker AXS, Germany). Different weights were attached to the fibers during heating to apply stress. The synchrotron measurements during tensile drawing were performed at the cSAXS beamline at the Swiss Light Source of the Paul Scherrer Institute in Switzerland. The fibers were drawn with a TS 600 tensile stage (Anton Paar GmbH, Austria) using a 5 N load cell. For more information see 'Structural response of melt-spun poly(3-hydroxybutyrate) fibers to stress and temperature' [1] . (c) 2020 The Author(s). Published by Elsevier Inc. This is an open access article under the CC BY license. ( http://creativecommons.org/licenses/by/4.0/ )

Rheological and thermal properties of the poly(epsilon-caprolactone) (PCL) polymer are presented in Section 1.1. Section 1.2 summarizes results of melt-spun PCL filaments. Specifically, we show the necking point stabilization during high-speed online drawing in Section 1.2.1, filament morphology in Section 1.2.2, wide-angle X-ray diffraction (WAXD) fitting results in Section 1.2.3, WAXD patterns of aged fibers in Section 1.2.4, crystallinity analysis in Section 1.2.5 and small-angle X-ray scattering (SAXS) analysis results in Section 1.2.6. Details about the materials, experimental and analytical methods are given in Section 2. Of particular interest may be the simulation and fitting procedures of 2D WAXD patterns, which are summarized in Section 2.7.2. For more information see the publication by Selli et al. 'Mesophase in melt-spun poly(epsilon-caprolactone) filaments: structure-mechanical property relationship' [1]. (C) 2020 The Authors. Published by Elsevier Inc.

Safety workwear often requires antistatic protection to prevent the build-up of static electricity and sparks, which can be extremely dangerous in a working environment. In order to make synthetic antistatic fibers, electrically conducting materials such as carbon black are added to the fiber-forming polymer. This leads to unwanted dark colors in the respective melt-spun fibers. To attenuate the undesired dark color, we looked into various possibilities including the embedding of the conductive element inside a dull side-by-side bicomponent fiber. The bicomponent approach, with an antistatic compound as a minor element, also helped in preventing the severe loss of tenacity often caused by a high additive loading. We could melt-spin a bicomponent fiber with a specific resistance as low as 0.1 &Omega, m and apply it in a fabric that fulfills the requirements regarding the antistatic properties, luminance and flame retardancy of safety workwear.

We have investigated the structural response of melt-spun poly-3-hydroxybutyrate (P3HB) fibers to stress and temperature and its impact on the mechanical properties. Low-stress (= 32 MPa), however, lead to fibers with a higher tensile strength (182 MPa) and with a lower elongation at break (22%). These significant differences in the tensile properties are closely related to structural changes, which we have studied with in-situ wide-angle x-ray diffraction (WAXD) and small-angle x-ray scattering (SAXS) experiments. A highly oriented non-crystalline mesophase (P-nc), which is located in-between orthorhombic alpha-crystals is growing during high-stress annealing but disappears during low-stress annealing. However, it is possible to restore the mesophase by post-drawing. The viscoelastic hysteresis behavior of low-stress annealed fibers is explained by a reversible transformation of a-crystals into mesophase and back.

Fine poly(ϵ-caprolactone) (PCL) filaments (diameter: 59–92 μm) were successfully melt-spun with modified drawing setups to prevent draw instabilities. Depending on the production parameters, different mechanical properties were obtained (tensile strength: 302–456 MPa, elongation at break: 69–88%). These variations are related to subtle structural differences, which we have analyzed with wide-angle x-ray diffraction (WAXD) and small-angle x-ray scattering (SAXS). SAXS was used to determine crystal widths and the spacing between crystals along the filament axis. Additionally, 2D WAXD patterns were simulated and WAXD profiles were fitted. The detailed 2D WAXD analysis revealed that a highly-oriented non-crystalline mesophase is present in drawn PCL filaments, which is most-likely situated in-between PCL crystals. A large amount of this mesophase (>16%), combined with high crystalline orientation and perfect crystals, led to higher tensile strength values. We also confirmed that PCL chains pack with non-planar chain conformations in the unit cell.

Microplastic fibres (MPFs) and nanoplastics (NPs) have the potential to be hazardous to soil organisms. Understanding uptake into organisms is key in assessing these effects, but this is often limited by the analytical challenges to quantify smaller-sized plastics in complex matrices. This study used MPFs and NPs containing inorganic tracers (In, Pd) to quantify uptake in the earthworm Lumbricus terrestris. Following seven days exposure, tracer concentrations were measured in earthworms and faeces. Earthworms exposed to 500 μg MPFs/g soil retained an estimated 32 MPFs in their tissues, while at 5000 μg MPFs/g earthworms retained between 2 and 593 MPFs. High variation in body burdens of MPFs was linked to soil retention in earthworms and reduced faeces production, suggesting egestion was being affected by MPFs. NPs uptake and elimination was also assessed over a more extended time-period of 42 days. After 1 day, NPs were no longer detectable in faeces during the elimination phase. However, some retention of NPs in the earthworms was estimated, not linked to retained soil, indicating not all NPs were eliminated. MPFs and NPs uptake can be quantified in earthworms and both particle types can be retained beyond the depuration period, suggesting the potential for longer-term accumulation. ISSN:0048-9697 ISSN:1879-1026

Poly(ethylene terephthalate) (PET) has wide usage in packaging and fiber industries thanks to its superior mechanical, thermal, and barrier properties. It is also one of the "big five" recyclable plastics with well-established procedures. In many textile and film products, flame retardants (FRs) are added to PET for fire-safe applications. However, PET/FR products are often not designed for recycling, and downgrade during thermomechanical recycling due to polymer degradation. To address this issue, we study the behavior of PET containing phosphorus FRs during and after thermomechanical recycling. Two phosphorus FRs, namely DOPO-PEPA (DP) and Aflammit PCO 900 (AF), are added to PET by extrusion. The compounds are then studied by a comprehensive set of thermal, rheological, and chemical experiments to investigate their thermal, thermo-oxidative, and thermo-mechanical degradation mechanisms. The results indicate the high potential of DP to add enhanced lubrication, and control melt rheology over long periods by stabilization. On the other hand, AF can boost chain extensions and branching in PET, which can counter chain scissions to some extent. A chemical mechanism is proposed suggesting that both FRs can release active radicals and moieties that either quench other radicals such as oxygen radicals, or initiate a reaction with the PET chains leading to chain scissions and/or branching. Finally, a thermomechanical recycling process is simulated by reprocessing the PET compounds in extrusion and injection molding. The mechanical performance of the compounds before and after recycling is studied in tensile experiments. PET/DP samples preserve their ductile tensile behavior after recycling, whereas PET/AF samples become completely brittle. This work motivates future research on the synthesis of new phosphorus FRs based on mixed chemical characteristics of DP and AF for improved recyclability of PET/FR products.

Surface properties of monofilaments can be tailored with radial structural gradients, which is of specific interest for technical textile applications. Radial gradients in fine (≤40 μm thick) poly(ethylene terephthalate) monofilaments have been studied with high-resolution Raman mapping and one-dimensional microbeam small-angle x-ray scattering tomography. Filaments have been melt-spun by using online and offline drawing techniques. Radial structural gradients are strongly affected by the drawing method. Raman mapping revealed that offline drawn filaments have a higher crystallinity in the core than in the surface region, whereas the opposite is the case for online drawn filaments. The molecular alignment was the highest in the core for all filaments. Microbeam SAXS tomography revealed that the long-spacing between crystals, in the direction of the fiber axis, increases towards the fiber surface. Fibers that have been drawn to a larger extent, resulting in improved tensile strength, have been found to have a larger long-spacing.

In this work we have performed a comprehensive study on synthesis, processing, detailed material characterization and preliminary assessment of toxicity of relatively new flame retardant (FR) additives as a key for developing environmentally friendly fire safe polyesters. Two 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) based FR additives were synthesized using principles of green chemistry and incorporated via thermal processing in high temperature polyesters such as polyethylene terephthalate (PET) and polybutylene terephthalate (PBT). The green synthesis strategies included (i) the use of N-chlorosuccinimide as a sustainable chlorinating agent for DOPO and (ii) a solvent and catalyst free microwave-assisted synthesis. Atomistic molecular dynamics (MD) simulations were employed in order to calculate the solubility parameters of these additives so as to estimate their compatibility in the polyesters. Detailed rheological measurements of the polyester/FR blends were carried out and the results indicated a clear difference in all three additives tested. Based on these analyses, 6H-dibenz[c,e][1,2]oxaphosphorin,6-[(1-oxido-2,6,7-trioxa-1-phosphabicyclo[2.2.2]oct-4-yl)methoxy]-, 6-oxide (DOPO-PEPA) exhibited the highest compatibility with both polyesters and their blends and showed the highest thermal-oxidative stability guaranteeing stable and steady processing at high temperatures. All polyester/FR formulations exhibited higher flame retardancy compared to the virgin polyesters in the small scale fire tests. The FR additives were evaluated for their potential toxicity using a well-established in vitro platform. Our results indicate no acute cytotoxic potential for all FRs analyzed in two different cell types (the human lung epithelial cell line A549 and macrophages derived from the monocytic cell line THP-1) and under the chosen experimental conditions.

Functional polymer composites based on hybrid carbon nanoparticles (CNPs) offer synergistic properties and have recently received a lot of attention for various applications including photovoltaic cells. In this context, the size dispersity inherent in CNPs such as carbon nanotubes (CNTs) is still a controversial topic in light of new experimental findings when it comes to the formation of percolating networks. Here, we show how nanotube models with different aspect ratios (ARs) dispersed in polyamide 12 (PA12) matrix differ in their equilibrium nanostructures. To this end, large-scale dissipative particle dynamics simulations are carried out, and CNPs with different ARs representing fullerene-like isomers up to realistic CNTs are studied separately or in hybrids. The continuous pathways in the CNP nanostructures are further assessed in Monte Carlo calculations by random electrons transporting through the network quantifying its continuity for electrical conductivity. The results confirm that the morpholo...

The core – sheath interfacial interactions in a bicomponent thermoplastic filament have been analyzed by means of an adapted micro-mechanical approach for interfacial pull-out. The method relies on a specimen preparation procedure that selectively removes a segment of the sheath component while leaving the core intact. This adaptation of the classical pull-out method enables the controlled extraction of the exposed core from the embedded bicomponent segment. Using linear low density polyethylene (LLDPE) – polyamide 6 (PA6) filaments with a diameter of approximately 100 μm, it has been shown that the addition of 2–5 weight % maleic anhydride grafted polyethylene (MAPE) significantly increases the surface energy of LLDPE, which results in substantial improvements in the mean interfacial shear strength and work to debond. Use of 10 % wt. MAPE leads to the formation of voids which are detrimental to the mechanical properties of the core – sheath interface, despite a further enhancement of surface energy.

This data in brief article summarizes structural data obtained from monocomponent melt-spun and offline drawn poly(ethylene terephthalate) (PET) monofilaments, as well as from melt-spun bicomponent core-sheath PET-polyamide 6 (PA6) filaments. The diameters of the single filaments range from 27 µm to 79 µm. Presented analysis techniques and results thereof are (i) Raman mapping of filament cross-sections: 2D maps of peak positions, widths, peak area ratios; (ii) attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR): ATR-FTIR spectra and extraction of surface crystallinity; (iii) wide-angle x-ray diffraction (WAXD): WAXD patterns and extraction of average crystallinity; (iv) small-angle x-ray scattering (SAXS): SAXS patterns and determined crystallite sizes and long-spacings; (v) differential scanning calorimetry (DSC): thermograms and extracted average crystallinity as well as thermal properties; (vi) atomic force microscopy (AFM): AFM image of the surface of an embedded fiber cross-section. For more information, see the publication by E. Perret et al. 'High-resolution 2D Raman mapping of mono- and bicomponent filament cross-sections' [1] .

This article provides an overview of strain-induced solid mesophases in polymer fibers, melt-spun from amorphous (polycarbonate, cyclo-olefin polymer, copolyamide, polyethylene terephthalate glycol) and semi-crystalline materials (polyethylene terephthalate, poly-3-hydroxybutyrate). The discussed mesophases are made of stretched, conformationally disordered macromolecules that are highly oriented along the fiber axis, and that reveal variations in their lateral spacing. Fitting algorithms for respective wide-angle x-ray diffraction (WAXD) patterns are put forward, and are directly tested on fibers melt-drawn from amorphous as well as semi-crystalline polymers. Equatorial, meridional, off-axis and azimuthal profiles are extracted from WAXD patterns and are simultaneously fitted. Best fit parameters contain detailed structural information, and lead to simulated 2D WAXD patterns, which in turn can be used to quantify the phases that are present in the fibers. We postulate that mesophases, which lead to broad equatorial reflections in WAXD patterns, can be found in all types of drawn melt-spun polymer fibers.

A high-resolution Raman mapping method has been developed in order to obtain 2D information about structural anisotropies (crystallinity, molecular alignment) in thin filament cross-sections (diameters between 27 μm and 79 μm). Cross-sections of melt-spun, hot-drawn poly (ethylene terephthalate) (PET) filaments and bicomponent core-sheath PET-polyamide 6 (PA6) filaments have been scanned through a laser beam (spatial resolution

Polymer optical fibers (POFs) have been utilized in several applications since the late 1950s. Adding photoluminescence (PL) to the fiber considerably widens the optical functionality of POFs and opens new application fields. In recent years, the availability of laboratory-scale production methods with industrialization potential has triggered a surge of new studies and developments in the promising area of PL-POFs. These applications, profiting from the addition of PL to fibers, are identified in this review as: light harvesting, sensing, color illumination, anti-counterfeiting, and random lasing. Progress in these fields is foreseen to generate a need for larger quantities of fibers, therefore large-scale manufacturing and processing methods are becoming more relevant. This review thus provides an overview of the most important developments in this emerging area, together with a description of the key parameters describing PL-POF performance and efficiency.

Poly(3-hydroxybutyrate) (P3HB) is a thermoplastic, biocompatible, and truly biodegradable polyester produced by bacteria and characterized by a high degree of crystallinity due to its isotactic nature. In order to tackle the challenges of its processability at the time of developing new green materials, the use of biodegradable additives is highly recommended. In this work, the biodegradable and biocompatible semicrystalline multiblock copolyester poly(butylene succinate-butylene dilinoleate) (PBS:DLA), shortly abbreviated as CoPo, is used to produce new P3HB blends. The hard:soft segment ratio of the copolymer can be selected as desired during its synthesis. Two different copolymers, namely, CoPo70 (70:30) and CoPo50 (50:50), were blended with P3HB at different concentrations, i.e., 5, 10, and 20 wt %, to investigate the phase behavior of blends. Furthermore, the effect of CoPo segmental composition and its content was evaluated experimentally as well as by dissipative particle dynamics (DPD) simulations...

Rock climbing ropes tend to suffer catastrophic failure when dynamically loaded over a sharp edge. Seeking to gain a better understanding of this phenomenon, a testing methodology based on a pendulum tear tester has been developed to quantify the cut resistance of polymer-based core-sheath climbing ropes in a reliable and reproducible manner. Experimental measurements indicate that the specific energy required to cut a rope is directly proportional to the linear density of the sheath component in the rope, where a high coefficient of determination between the two parameters is observed. Field tests under actual rock climbing conditions involving a granite sharp edge confirm the practical relevance of the developed laboratory methodology. An analysis of failure modes by means of scanning electron microscopy indicates that cut resistance is inversely proportional to the amount of frictional heating introduced at the point of contact between rope and sharp edge.

Melt spinning and drawing of amorphous cyclo-olefin and co-polyamide polymeric materials were performed to develop mono-component continuous filaments. Raman spectroscopy was employed to assess the effect of a static bending deformation on the microstructure of the filaments. Spectra stemming from the fiber regions under tensile and compressive loading do not show any appreciable shift of their vibrational bands as a function of applied strain. The bent filaments manage to redistribute strains without any stretching or buckling of polymer chains associated with peak shifting in the Raman spectrum. The influence of fiber draw ratio on the degree of molecular ordering was demonstrated by means of polarized Raman spectroscopy. An increase in draw ratio leads to a variation of the polarization ratio for spectroscopic bands located along the polymer backbone. We observed a correlation between the polarization ratio of these vibrational bands and the macroscopic tensile modulus of the material.

We demonstrate the continuous production of liquid-filled polymeric fibers in a stable melt-spinning process at the pilot plant scale. Different polymers and liquids could successfully be combined over a wide range of core-sheath dimensions. The ability to produce a continuous liquid-core fiber (LCF) is attractive since post-filling of a hollow fiber with similar dimensions is not practical. We characterized the mechanical properties of the LCF's with particular attention to their damping properties. A LCF can exhibit significantly enhanced damping properties compared to plain polymeric filaments of same dimensions. Some possible damping mechanisms are discussed. This new type of fiber could find future applications in the enhancement of the damping factor of fiber-reinforced lightweight structures. Keywords: Bicomponent melt-spinning, Liquid-core fiber, Energy dissipation, Damping factor, Fiber-reinforced composite

The development of thermoplastic fibers containing a liquid core is described. Internal morphology analysis confirms that the liquid-containing core is composed of a continuous cylindrical microchannel of constant diameter. Microfluidic experiments on both liquid core and reference hollow fibers were conducted by pumping distilled water through several filaments simultaneously. The observed fluid motions are satisfactorily described by the Hagen-Poiseuille law, indicating that the hollow and liquid core fibers have internal diameters of 31.6 and 14.8 µm, respectively. Flushing the liquid core fibers with a surfactant solution efficiently removes the saturated ester initially used during the melt spinning of the fiber.

A novel approach for the development of ultra-light, fully-thermoplastic fiber reinforced composites is presented. The composite material consists of a polyolefin plastomer (POP) matrix reinforced with ultra-high molecular weight polyethylene (UHMWPE) fibers. The interfacial affinity of both polyolefins is enhanced by the deposition of a nanometer-scale polar functional plasma polymer film on the surface of the filaments within a reel-to-reel continuous process. The activated UHMWPE yarn is subsequently coated with a layer of the matrix material using a modified wire coating process in order to produce a hybrid yarn. The improved adhesion between the two materials is demonstrated by means of a specially developed yarn pull-out method that measures the UHMWPE–POP interfacial shear strength. The combination of the two techniques employed in the development of the hybrid yarn largely maintains tensile strength as well as the crystalline structure of the UHMWPE yarn as determined by wide angle X-ray diffraction. Alternate layers of woven hybrid yarn and woven pure UHMWPE yarn are then stacked and the lay-up is consolidated by hot compaction, resulting in a composite laminate with a fiber volume fraction of 0.54 and a density of 0.93 g/cm3. Keywords: UHMWPE, Thermoplastic composite, Plasma polymerization, Extrusion

Promising effects of DOPO-PEPA (DP), an environmental-friendly flame retardant, on the processing of polyethylene terephthalate (PET) are studied via rheological experiments. DP reveals profound melt stabilization and lubrication effects even at low concentrations (~1 wt%). Mechanical characterization of PET films confirms that the direct addition of DP powder to PET during extrusion has no adverse effects even if the films are exposed to elevated temperatures for prolonged periods. This property is particularly interesting for high-temperature applications, for instance flexible power electronics, where mechanical flexibility should not be compromised by using a melt process stabilizer.

In recent years, several studies have investigated the flux of particulate plastic through municipal waste water treatment plants (WWTP). Challenges related to time consuming analytical methods have limited the number of sampling points and detection limits have hampered quantification of nanoplastic and microplastic fiber fluxes through WWTPs. By synthesizing nanoplastic particles and microplastic fibers labeled with a rare metal (Pd and In, respectively) which can be measured as a proxy for the plastic itself, we have circumvented major analytical pitfalls associated with (micro)plastic measurements. In this study, we spiked the labeled materials to a pilot WWTP mimicking the activated sludge process (nitrification, de-nitrification and secondary clarification). Using a mass flow model for WWTP sludge, we assessed the behavior of particulate plastic in relation to the removal of organic matter. Triplicate samples were collected from the mixed liquor and from the effluent at least twice weekly over the entire experimental run time of 40 d. Our findings show that in discrete grab samples during steady state conditions, at least 98% of particulate plastics were associated with the biosolids. A positive correlation between total suspended solids (TSS) and plastic concentrations was observed in the sludge as well as in the effluent. Because of the strong association between particulate plastic and TSS, TSS removal is likely a good indicator of plastic removal in a full scale WWTP. Therefore, additional process steps in a full-scale WWTP which further reduce the TSS load will likely retain nanoplastic particles and microplastic fibers effectively and consequently increase the removal rates. ISSN:0043-1354 ISSN:1879-2448

Microplastic fibers (MPF) are often detected in waste water treatment plants and environmental samples, which implies a pathway of MPF release from domestic washing of textiles into the environment. Although there are many textile washing/release studies, it is still unclear to what extent the liberated MPFs originate from processes during washing (e.g. abrasion) or rather from processes earlier in the textile supply chain. Understanding the origin of MPFs is important since different MPF formation mechanisms would lead to different mitigation strategies. Therefore, the aim of our study was to investigate the presence of MPFs in various intermediate and finished polyester textiles products. In this study, we developed a sonication extraction method to quantify and characterize extractable MPFs already present in the textiles (i.e. manufacturing related MPFs). To identify the manufacturing process responsible for the MPF formation, this study included 18 representative products along the textile production line. The extraction dynamics of MPFs for all materials were investigated by ultrasonication. The number of extracted MPFs ranged from 15 MPF/g for a filament to 45′400 MPF/g for a scissor-cut microfiber textile. We found that a rotor yarn exhibited an elevated number of extracted MPFs (4′310 MPF/g) compared to other types of yarns (160–230 MPFs/g), suggesting that the rotor spinning may be a critical step responsible for MPF formation. On average, five times more MPFs could be extracted from textiles with processed surfaces (such as Fleece, Plain brushed and Microfiber) compared to those with unprocessed surfaces. This suggests that abrasive friction during production may be another critical factor for MPF formation. Furthermore, scissor-cut textiles demonstrated three to 31 times higher number of extracted MPFs than laser-cut textiles, enabling us to quantitatively discriminate between the contribution of MPFs from the textile surface opposed to those originating from the textile edges. The majority of the extracted MPFs were found to be between 100 and 800 μm in length. The results of this study may help to reduce the MPF release from textiles by modifications throughout the production and finishing process. © 2020 Elsevier Ltd. ISSN:0959-6526

A simple one-step solventless in-situ reduction method was developed to prepare silver nanoparticle (AgNP) based polymer composites using different silver precursors and thermoplastic polymers. This method utilizes the mild reducing environment of thermoplastic polymer melts to convert silver precursors to AgNPs during the extrusion process. Complete reduction of Ag2O with broad AgNP size distribution (20 ± 18 nm) in polyamide 6 (PA6) was obtained after 5 min processing. For same matrix, the uniformity of AgNPs improved significantly after 10 min processing time, associated with a slight increase in the particle diameter (26 ± 9 nm). No significant impact of in-situ AgNP synthesis method on chemical and macromolecular characteristics of polyamide 6 was detected. When this method was used to synthesize AgNPs in polylactic acid and polypropylene, the influence of surface energy of polymer melt was evident. Reduction of Ag2O in polylactic acid (at 165 °C) was slower compared to PA6 and 95 ± 3% Ag2O reduction was achieved after 10 min of processing. When polypropylene was used as the matrix, only 60% reduction of Ag2O was achieved, possibly due to poor wetting of the silver precursor, owing to the low surface energy of polypropylene. AgNP-PA6 composites were also successfully prepared using Ag2CO3 and Ag-palmitate as precursors. To demonstrate the potential application of such composites in food packaging, the silver release and antibacterial activity of AgNP-PA6 composite were also studied. Though the composites released 500 times less silver compared to the permitted limits of different safety standards, they exhibited an excellent antibacterial activity against a typical food pathogen (Listeria monocytogenes) already at a low level of AgNP loading i.e. 0.5 wt%.

This study addresses three very important aspects of sustainable development of new flame re-tardant material, i.e. in situ solvent free synthesis of flame retardant macromolecules during thermal processing of polymers, their leaching behavior from the polymer matrix and their preliminary toxicity assessment. Polyamide 6 (PA6) was functionalized by a novel reactive extrusion process. In situ synthesis of phosphine oxide based macromolecules was obtained via Michael addition reaction of divinyl phenyl phosphine oxide (DVPPO) and piperazine during the reactive extrusion process. The formation of phosphine oxide macromolecules (oligomers and low molecular weight polymers) were confirmed by NMR study of the modified PA6 polymer and UPLC-MS analysis of extracts from PA6 samples. Elemental analysis of the modified PA6 after the extraction with chloroform and water confirmed retention of majority of phosphorus species, confirming the beneficial effect of large macromolecular additives. This non-leaching behavior of modified PA6 is an important requirement for thin walled substrates like fibers and films where long-term durability is very important. The reactive extruded PA6 was successfully processed into textile fibers via melt spinning process in a laboratory spinning plant. The presence of phosphine oxide macromolecules in PA6 matrix had a lubricating effect, which has influence in the thermal processing and final properties of the fiber. The modified PA6 was evaluated for fire performance in small-scale fire tests where it showed improved fire performance. Moreover, the preliminary toxicity assessment of the relatively unknown DVPPO, via a well-established in vitro platform showed no adverse effects on cell viability.

A continuous and efficient production process of polymer optical fibers with varying core geometries is presented, along with mechanical and spectral characterization of prepared devices. Results are supported with finite element analysis.

Bacterial poly-3-hydroxybutyrate (P3HB) is a thermoplastic polyester with perfectly isotactic structure; it has the potential of being melt-spun to fibers, and it is thus interesting for textile applications. Aiming at developing an upscalable melt-spinning method to produce high-strength fibers, we have investigated P3HB as native polymer with the additives tri- n -butyl citrate (TBC) as plasticizer, and boron nitride (BN) as nucleating agent, to evaluate their effect on the melt-spinning performance of P3HB. In addition, the draw-off unit has been modified in order to enhance primary crystallization to the extent that secondary crystallization is suppressed. The such drawn fibers are dominated by longitudinally oriented lamellae rather than spherulitic structures. This allows obtaining P3HB fibers which contain domains of highly oriented molecules between crystallites, exhibiting promising tensile strengths up to 215 MPa. The wide-angle X-ray diffraction (WAXD) data suggest that besides the oriented crystalline α-phase, a highly oriented amorphous phase is present.