Chemical recycling of polymer contaminated poly(ethylene terephthalate) by neutral hydrolysis.

Plastic recycling is gaining traction to reduce the demand for fossil resources for plastic production. Poly(ethylene terephthalate) (PET), mainly used in the packaging and textile sectors, is often isolated in the sinking fraction during the density-based separation of mixed plastic waste streams. The heterogeneity of the sinking fraction makes direct mechanical recycling of PET impossible.

A direct comparison of a next generation hyperspectral camera to state-of-the-art.

Hyperspectral camera technology is advancing rapidly, and this paper seeks to compare a state-of-the-art industrial dual-camera setup to a single-camera system employing the latest chip technology (IMX990 from Sony). The hyperspectral cameras are compared over both the Visual and Short-Wave Infrared range (400-1700 nm) of the electromagnet spectrum. The spectral range and resolution, as well as spatial parameters and spectroscopic information are quantified with comparable optics, electronics, and test targets.

Recommendations for strain elastography of the uterine cervix.

Purpose: Conventional vaginal strain ultrasound elastography, not based on shear-wave elastography imaging, can assess the biomechanical properties of the uterine cervix. This assessment may inform the risks of preterm birth and failed induction of labor. However, there is considerable variation in the approaches to strain elastography, including the placement of the region of interest (ROI).

Quantification of aluminium trihydrate flame retardant in polyolefins via in-line hyperspectral imaging and machine learning for safe sorting.

The extensive use of aluminium trihydrate (ATH) flame retardant in plastics poses challenges and hazards in plastic waste recycling, thus it is crucial to accurately identify ATH. This study demonstrates the effectiveness of an industrial in-line shortwave infrared (SWIR) hyperspectral imaging system and principal component analysis (PCA) for detecting and quantifying ATH in low-density polyethylene (LDPE) and polypropylene (PP). The samples were characterized by elemental analysis, ATR-FTIR, DSC, and TGA.

Identification of black plastics with terahertz time-domain spectroscopy and machine learning.

Several optical spectroscopy and imaging techniques have already proven their ability to identify different plastic types found in household waste. However, most common optical techniques feasible for plastic sorting, struggle to measure black plastic objects due to the high absorption at visible and near-infrared wavelengths. In this study, 12 black samples of nine different materials have been characterized with Fourier-transform infrared spectroscopy (FTIR), hyperspectral imaging, and terahertz time-domain spectroscopy (THz-TDS).

In-line quantitative estimation of ammonium polyphosphate flame retardant in polyolefins via industrial hyperspectral imaging system and machine learning.

Due to developments in European legislation, several halogenated flame retardants are banned due to their toxicity, and the use of phosphor-based flame retardants in plastics is increasing. A revision of ammonium polyphosphate (APP) flame retardant revealed that it is an eye irritant and toxic, thus posing a health issue. Hence APP identification is needed for enabling safe recycling of plastic waste streams.

Transdisciplinary pragmatic melioration for the plastic life cycle: Why the social, natural, and technical sciences should prioritize reducing harm.

Plastics underpin modern society but also threaten to choke it. Only 9 % of all plastic waste is recycled, usually with loss of quality ("downcycling"); the rest is landfilled or dumped (79 %) or incinerated (12 %). Put bluntly, the "plastic age" needs a "sustainable plastic culture.

Quantitative strain elastography of the uterine cervix assessed by the GE Voluson E10 system in combination with a force-measuring device.

Objective: During pregnancy, the stiffness of the cervical tissue decreases long before the cervical length decreases. Therefore, several approaches have been proposed in order to ensure a more objective assessment of cervical stiffness than that achieved by digital evaluation. Strain elastography has shown promising results.

In-line identification of Pb-based pigments in fishing nets and ropes based on hyperspectral imaging and machine learning.

Fishing lines, nets, and ropes represent a significant portion of plastic pollution in marine environments, and can contain hazardous additives. The development of less laborious and faster methods aiming at identifying plastic-related additives is therefore needed, in order to facilitate effective recycling. This work aims to develop an industrial inline method to identify lead-based pigments in fishnets by an industrial hyperspectral imaging (HSI) system working in visible-near-infrared spectral range (Vis-NIR, 450 to 1050 nm) and machine learning.

A force-measuring device combined with ultrasound-based elastography for assessment of the uterine cervix.

Introduction: In this feasibility study, we hypothesize that the evaluation of cervical biomechanical strength can be improved if cervical length measurement is supplemented with quantitative elastography, which is a technique based on conventional ultrasound elastography combined with a force-measuring device. Our aims were to: (a) develop a force-measuring device; (b) introduce a cervical elastography index (CEI) and a cervical strength index (CSI; defined as cervical length × CEI); (c) evaluate how these indexes assess the cervical softening that takes place during normal pregnancy; and (d) how these indexes predict the cervical dilatation time from 4 to 10 cm.

Material And Methods: An electronic force-measuring device was mounted on the handle of the transvaginal probe, allowing for force measurement when conducting elastography.

Streptococcus agalactiae do not penetrate human chorioamniotic membranes in vitro but alter their biomechanical properties.

Introduction: Vaginal colonization with Streptococcus agalactiae (group B streptococci) is hypothesized to constitute a risk factor for preterm prelabor rupture of membranes. In vitro studies have shown that S. agalactiae strains isolated from infants with neonatal sepsis adhere to chorion cells of the human chorioamniotic membrane.

Constraints on CaCO precipitation in superabsorbent polymer by aerobic bacteria.

Microbially induced CaCO precipitation (MICP) can give concrete self-healing properties. MICP agents are typically bacterial endospores which are coated into shelled granules, infused into expanded clay, or embedded into superabsorbent polymer (SAP). When small cracks appear in the cured concrete, the encapsulation is broken and the metabolic CO production from the germinated bacteria causes healing of the cracks by precipitation of CaCO.

Recyclable carbon fibre composites enabled by cystine containing epoxy matrices.

Recyclable composites are of industrial relevance and benefits the environment, which initiates research towards more sustainable solutions. In this study, a commercial epoxy thermoset, modified by a bio-based additive is used as an infusion resin making recyclable carbon fibre composites. The matrix fractionation process was investigated and optimized with respect to additive & solvent concentration, and temperature.

Highly Efficient Rubber-to-Stainless Steel Bonding by Nanometer-Thin Cross-linked Polymer Brushes.

Stainless steel (SS) surfaces were grafted with poly(glycidyl methacrylate) (PGMA) brushes that were post-modified using allylamine, diallylamine, and propylamine as reagents. Likewise, poly[2-(diethylamino)ethyl methacrylate] brushes were synthesized. All samples were compression molded with uncured ethylene-propylene-diene M-class rubber and dicumyl peroxide and vulcanized for 12 min at 170 °C.

Accelerated physical ageing of poly(1,4-cyclohexylenedimethylene--2,2,4,4-tetramethyl-1,3-cyclobutanediol terephthalate).

Successfully evaluating plastic lifetime requires understanding of the relationships between polymer dynamics and mechanical performance as a function of thermal ageing. The relatively high ( = 110 °C) of poly(1,4-cyclohexylenedimethylene--2,2,4,4-tetramethyl-1,3-cyclobutanediol terephthalate) (PCTT) renders it useful as a substituent for PET in higher temperature applications. This work links thermal ageing and mechanical performance of a commercial PCTT plastic after exposure to 40-80 °C for up to 2950 h.

Epoxy Matrices Modified by Green Additives for Recyclable Materials.

Epoxy-based thermosets are one of the most popular matrix materials in many industries, and significant environmental benefits can be obtained by developing a recyclable variant of this widely utilized material. Incorporation of a bio-based disulfide additive within a commercial epoxy system leads to a cross-linked material that can be fractionated under mild and environmentally benign conditions. The material has been analyzed by FTIR and solid-state NMR.

Tailoring Membrane Nanostructure and Charge Density for High Electrokinetic Energy Conversion Efficiency.

The electrokinetic energy conversion (EKEC) of hydraulic work directly into electrical energy has been investigated in charged polymeric membranes with different pore charge densities and characteristic diameters of the nanoporous network. The membranes were synthesized from blends of nitrocellulose and sulfonated polystyrene (SPS) and were comprehensively characterized with respect to structure, composition, and transport properties. It is shown that the SPS can be used as a sacrificial pore generation medium to tune the pore size and membrane porosity, which in turn highly affects the transport properties of the membranes.

Improved adhesion between PMMA and stainless steel modified with PMMA brushes.

In this work, various lengths and densities of poly(methyl methacrylate) (PMMA) brushes were synthesized on stainless steel (SS) surfaces via surface initiated atom transfer radical polymerization. Subsequently, the joints between the bulk PMMA and the PMMA brushed stainless steel were obtained by injection molding, and for these the degree of adhesion was assessed by tensile testing. Several conditions are required to facilitate the mixing between the brushes and the bulk polymer and to reduce the residual stress at the interface: preheating of the SS samples before the injection molding; a long packing time; and a mold temperature above the glass transition temperature (Tg) of PMMA during the injection molding.

Electrochemical polymerization of allylamine copolymers.

We describe for the first time the electro-oxidative synthesis and passivating properties of surface films of poly(allylamine) and copolymers of allylamine and diallylamine. Cyclic voltammetry and impedance spectra show that the films exhibit high charge-transfer resistance and that the addition of diallylamine causes improvements in the compactness and stability toward swelling of the films when compared to both allylamine and diallyamine, leading to coatings with high charge-transfer resistance up to 70 MΩ. We also show that removing oxygen before the polymerization further improves the films' passivating properties.

Redox grafting of diazotated anthraquinone as a means of forming thick conducting organic films.

Thick conductive layers containing anthraquinone moieties are covalently immobilized on gold using redox grafting of the diazonium salt of anthraquinone (i.e., 9,10-dioxo-9,10-dihydroanthracene-1-diazonium tetrafluoroborate).

On surface-initiated atom transfer radical polymerization using diazonium chemistry to introduce the initiator layer.

This work features the controllability of surface-initiated atom transfer radical polymerization (SI-ATRP) of methyl methacrylate, initiated by a multilayered 2-bromoisobutyryl moiety formed via diazonium chemistry. The thickness as a function of polymerization time has been studied by varying different parameters such as the bromine content of the initiator layer, polarity of reaction medium, ligand type (L), and the ratio of activator (Cu(I)) to deactivator (Cu(II)) in order to ascertain the controllability of the SI-ATRP process. The variation of thickness versus surface concentration of bromine shows a gradual transition from mushroom to brush-type conformation of the surface anchored chains in both polar and nonpolar reaction medium.

Nitrophenyl groups in diazonium-generated multilayered films: which are electrochemically responsive?

Various nitrophenyl-containing organic layers have been electrografted to glassy carbon surfaces using diazonium chemistry to elucidate the extent by which the layer structure influences the solvent (i.e., acetonitrile) accessibility, electroactivity, and chemical reactivity of the films.