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[Display omitted] Polysiloxanes are becoming new trend in self-cleaning (oil- and water‐repellent) applications due to their low-cost and environmentally friendly nature. Lower phase separation of polysiloxanes in coating matrix is critical to obtain excellent self-cleaning properties. We hypothesize that telechelic polysiloxanes can bind to coating matrix at both ends and thus will suppress phase separation of polysiloxane as compared to hemi-telechelic analog and thus will offer excellent self-cleaning properties. Eight PDMS additives were prepared via the free-radical polymerization of telechelic and hemi-telechelic methacryloxypropyl-based PDMS precursors with methylmethacrylate (MMA) and glycidylmethacrylate (GMA). The compositions of the prepared polysiloxane additives were optimized to obtain excellent self-cleaning performance. Our breakthrough development confirms that telechelic polysiloxanes (PDMS-T) incorporated into epoxy-based anti-smudge coatings outperform hemi-telechelic polysiloxanes (PDMS-HT) by offering excellent repellency against difficult to repel liquids. These breakthrough findings will vertically advance Science and innovations in the self-cleaning field by offering robust guidelines for choosing suitable polysiloxane for self-cleaning applications. [ABSTRACT FROM AUTHOR]

The current open-loop practices employed to render paper substrates water- and oil-repellent for packaging and non-packaging applications have generated ocean pollution and have placed daunting burdens on landfills. In this study, we report a green, unique and facile approach for the fabrication of grease- and water-resistant paper products with 100% recyclability of the paper pulp. Low surface energy polydimethylsiloxane (PDMS) was grafted onto a biobased chitosan polymer via urea linkages to prepare the graft copolymer chitosan-graft-polydimethylsiloxane (chitosan-g-PDMS). Chitosan-g-PDMS was then applied as a coating onto an unbleached Kraft paper substrate from an aqueous solution. The coated paper substrates exhibited good hydrophobic properties with a water contact angle of 120.53 ± 0.96° and a Cobb 60 value of 9.89 ± 0.32 g m−2. The coated paper substrates also showed good oil-resistance as evident from the kit rating value of 11.7/12. The tensile strength, crushing resistance, bending stiffness, and internal tearing resistance of the paper before and after coating treatment was determined. Scanning electron microscopy (SEM) analysis was used to characterize changes in the porosity of the paper before and after the coating. The pulp recyclability of the coated paper was validated by subjecting the coated paper samples to repulping and washing treatment. This novel and practical approach can provide significant environmental benefits by offering plastic-free, fluorine-free and fully-recyclable water- and grease-resistant paper; thus promoting sustainability due to its unique closed-loop nature. [ABSTRACT FROM AUTHOR]

Conventionally, low-surface-tension fluorinated reagents are incorporated into anti-smudge (oil- and water-repellent) coatings for oil repellency. However, fluorinated compounds are expensive and an environmental concern because of their high stability and bioaccumulation. These factors limit their widespread application. We report herein the development of fluorine-free anti-smudge polyurethane coatings that are clear at thicknesses up to tens of micrometers and are able to sustain extensive surface damage. We demonstrate that these coatings can be applied readily onto a diverse range of substrates. [ABSTRACT FROM AUTHOR]

Conventionally, low-surface-tension fluorinated reagents are incorporated into anti-smudge (oil- and water-repellent) coatings for oil repellency. However, fluorinated compounds are expensive and an environmental concern because of their high stability and bioaccumulation. These factors limit their widespread application. We report herein the development of fluorine-free anti-smudge polyurethane coatings that are clear at thicknesses up to tens of micrometers and are able to sustain extensive surface damage. We demonstrate that these coatings can be applied readily onto a diverse range of substrates. [ABSTRACT FROM AUTHOR]

Clear anti-smudge coatings with a thickness of up to tens of micrometers have been prepared through a graft-copolymer-based approach from commercial precursors. The coatings repel water, diiodomethane, hexadecane, ink, and an artificial fingerprint liquid. In addition, they can be readily applied onto different substrates using different coating methods. These coatings could find applications in protecting hand-held electronic devices from fingerprints, windows from stains, and buildings from graffiti. [ABSTRACT FROM AUTHOR]

Clear anti-smudge coatings with a thickness of up to tens of micrometers have been prepared through a graft-copolymer-based approach from commercial precursors. The coatings repel water, diiodomethane, hexadecane, ink, and an artificial fingerprint liquid. In addition, they can be readily applied onto different substrates using different coating methods. These coatings could find applications in protecting hand-held electronic devices from fingerprints, windows from stains, and buildings from graffiti. [ABSTRACT FROM AUTHOR]

Factors affecting the grafting of fluorinated diblock copolymers onto silica particles and the repellency of films prepared from the coated silica particles were investigated. The three copolymers used for silica coating were of the poly[3-(triisopropyloxysilyl)propyl methacrylate]- block -poly[2-(perfluorooctyl)ethyl methacrylate] (PIPSMA- b -PFOEMA) family possessing different relative block lengths. They were grafted onto silica under acidic conditions via the sol–gel chemistry of the PIPSMA block in binary solvent mixtures that solubilized the PFOEMA block but not necessarily the PIPSMA block. Depending on the solvent property, the silica type, the polymer composition, and the acid catalyst used, the coated silica could be non-dispersible or dispersible. The morphology of the coating on silica could be lumpy, smooth, or bumpy. Further, the amount of polymer grafted was also affected by these parameters. The various experimental results and observations were rationalized. In addition, the coated silica was cast to yield either smooth or rugged particulate films. The water and oil repellency or amphiphobicity of the films improved as the particle coating was changed from being smooth to bumpy, as the relative PFOEMA-to-PIPSMA block length of the coating polymer was increased, or as the roughness of the particulate film increased. [ABSTRACT FROM AUTHOR]

Two linear triblock terpolymers weresynthesized and used to coatcotton textiles. These copolymers consist in sequence of a water-solublepoly(ethylene glycol) (PEG) block, a highly water- and oil-repellantpoly[2-(perfluorooctyl)ethyl methacrylate] (PFOEMA) block, and a photo-cross-linkablepoly(2-cinnamoyloxyethyl methacrylate) (PCEMA) block. The PEG blockbonds to PFOEMA via a redox-cleavable disulfide junction (-S2-). To prepare the copolymers, monomethoxyPEG (PEG-OH) was derivatized to yield a PEG chain bearing one terminalthiol group (PEG-SH). Atom transfer radical polymerization and deprotectionchemistry were used to prepare Py-S2-PFOEMA-b-PHEMA, where PHEMA and Py-S2- denote poly(2-hydroxyethyl methacrylate) and a terminal pyridin-2-yldisulfanylgroup, respectively. Reacting PEG-SH with Py-S2-PFOEMA-b-PHEMA via a thiol–disulfideexchange reaction yielded PEG-S2-PFOEMA-b-PHEMA, and the cinnamation of the PHEMA block producedPEG-S2-PFOEMA-b-PCEMA.PEG-S2-PFOEMA-b-PCEMAdispersed in water and plasticized by a trace amount of dimethyl phthalatewas then used to coat cotton textiles, and this coating was securedby photo-cross-linking the PCEMA domains. Treating the coating withdithiothreitol cleft the disulfide junction and thus the PEG block,revealing the hidden PFOEMA block and its water- and oil-repellantproperties. Aqueous solutions of these copolymers could thus be appliedonto a substrate to provide amphiphobic coatings. [ABSTRACT FROM AUTHOR]

Commercially feasible self-cleaning surfaces are highly desirable for various technological applications. However, the current approaches are challenging to scale up and often lack the desirable performance. The synthesis of novel siloxane-based additives for the oversimple fabrication of surfaces with excellent self-cleaning properties is reported herein. These siloxane-based additives are synthesized by the free-radical polymerization of methacryloxypropyl-terminated polydimethylsiloxane (PDMS) with tetrahydrofurfuryl acrylate (THFA) monomer at various compositions, and these additives were subsequently incorporated into UV curable coatings. In total, four novel additives and 16 different compositions are evaluated in this study for their water, oil, and hexadecane repellent properties, as well as for their anti-ink performance. The surface roughness and textures of these coatings are characterized via atomic force microscopy (AFM) analysis and scanning electron microscopy (SEM), while X-ray photoelectron spectroscopy (XPS) was employed to map the surface chemical compositions of these coatings. [Display omitted] • Commercially feasible self-cleaning surfaces are highly desirable for various technological applications. • Facile synthesis of novel siloxane-based additives from telechelic polydimethylsiloxane (PDMS) with tetrahydrofurfurylacrylate (THFA) monomer. • Four novel additives and 16 different compositions are evaluated in this study for their self-cleaning performance toward UV curable coatings. • Prepared additives have imparted excellent water, vegetable oil and hexadecane repellencies to UV cured omniphobic coatings with exceptional optical clarity. • Reported facile one-step approach offers a readily scalable method for large size fabrication of fluorine-free UV self-cleaning coatings [ABSTRACT FROM AUTHOR]

Reported are the preparation and application of a triblockterpolymer poly(ethylene oxide)-ONB-poly[2-(perfluorooctyl)ethylmethacrylate]-block-poly(2-cinnamoyloxyethyl methacrylate)(PEO-ONB-PFOEMA-b-PCEMA). Here PEOis water-soluble, PCEMA is photo-cross-linkable, PFOEMA is of lowsurface tension, and ONBdenotes a photocleavable o-nitrobenzyl unit at the junction of the PEO and PFOEMAblocks. To prepare the copolymer, a macroinitiator bearing an ONBunit between PEO and the initiating site was first synthesized.FOEMA and 2-trimethylsilyloxyethyl methacrylate (HEMA-TMS) were thensequentially polymerized by atom transfer radical polymerization (ATRP)to yield the triblock copolymer PEO-ONB-PFOEMA-b-P(HEMA-TMS). Removal of the trimethylsilyl groups fromthe P(HEMA-TMS) block and cinnamation of the resultant poly(2-hydroxyethylmethacrylate) block with cinnamoyl chloride resulted in the targetedtriblock copolymer. PEO-ONB-PFOEMA-b-PCEMA formed micelles in tetrahydrofuran/water at the water volumefraction of 80%, in which only the PEO block was soluble. Upon photolysis,the micellar PCEMA cores were cross-linked and the micellar coronalPEO chains were cleft, resulting in the precipitation of cross-linkedPFOEMA-b-PCEMA nanoparticles. Films of the nanoparticleswere water- and oil-repellent due to the exposure of the initiallyhidden PFOEMA block. [ABSTRACT FROM AUTHOR]

Glycidyl-based chain extenders are broadly used as processing aids to enhance the physical properties of polyesters, but glycidyl-containing compounds have severe toxicity concerns. Reported herein are glycidyl-free chain extenders produced via the grafting of 9-(oxiran-2-yl)nonyl methacrylate (EAT) and 8-(3-octyloxiran-2-yl)octyl methacrylate (EAI) on biodegradable poly(e-caprolactone) (PCL). EAI and EAT were grafted onto PCL via free radical grafting using melt extrusion to produce PCL-epoxy-grafted PCL-g-EAI and PCL-g-EAT. The obtained PCL-g-EAI and PCL-g-EAT were characterized by 1H nuclear magnetic resonance (NMR) spectroscopy, intrinsic viscosity measurements, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and size exclusion chromatography (SEC). Using reactive melt extrusion, PCL-g-EAI and PCL-g-EAT were tested as potential chain extenders for poly(lactic acid) (PLA). PCL-g-EAI showed comparable or better mechanical properties than those of the commercial chain extender Joncryl ADR. A cytotoxicity assay has been conducted on PLA samples with the new chain extender and showed the absence of cytotoxicity in all samples. The outcomes reported in this paper offer new opportunities for the development of safer chain extenders. [ABSTRACT FROM AUTHOR]

Polyethylene-, polyvinylidene chloride-, and per- and polyfluoroalkyl substance-coated paper generate microplastics or fluorochemicals in the environment. Here, we report an approach for the development of oil-resistant papers using an environmentally friendly, fluorine-free, water-dispersible poly(dimethylsiloxane) (PDMS) coating on kraft paper. Carboxylic-functionalized PDMS (PDMS-COOH) was synthesized and subsequently neutralized with ammonium bicarbonate to obtain a waterborne emulsion, which was then coated onto kraft paper. The water resistance of the coated paper was determined via Cobb60 measurements. The Cobb60 value was reduced to 2.70 ± 0.14 g/m2 as compared to 87.6 ± 5.1 g/m2 for uncoated paper, suggesting a remarkable improvement in water resistance. Similarly, oil resistance was found to be 12/12 on the kit test scale versus 0/12 for uncoated paper. In addition, the coated paper retained 70–90% of its inherent mechanical properties, and more importantly, the coated paper was recycled via pulp recovery using a standard protocol with a 91.1% yield. [ABSTRACT FROM AUTHOR]

There is an urgent need for coatings that exhibit both self-healing as well as self-cleaning properties as they can be used for a wide range of applications. Herein we report a novel approach toward fabricating polyurethane thermosets possessing both self-cleaning and self-healing properties. The desired coating was achieved via casting a bottom layer of self-healable polyurethanes comprised of reversible phenolic urethane bonds followed by a subsequent dip-coating of the prepared layer in a solution of bis(3-aminopropyl)-terminated polydimethylsiloxane (PDMS-NH2). The PDMS was used to impart self-cleaning properties to the coating. While the self-healing behavior of the bottom polyurethane layer is achieved through phenolic urethane chemistry, via the exchange of phenolic urethane moieties. The prepared coatings were tested for their optical, mechanical, self-healing, and self-cleaning properties using a variety of characterization methods, which confirmed the successful fabrication of novel self-cleaning and self-healing clear urethane coatings. [ABSTRACT FROM AUTHOR]

The melt-reprocessing of thermosets such as polyurethanes (PUs) and epoxy network materials has been a constant technical challenge. Here we report, for the first time, melt-reprocessing of mixed PUs made of aliphatic and aromatic feedstocks. Our methodology consists of using Zn(II) catalysts combined with a slight excess of diols. The use of diols was sufficient to partially reverse the gel-point and reclaim the melt-processability as demonstrated for aliphatic, aromatic, and mixed PUs. Zinc acetate was not effective in imparting melt-processability to PU samples. Furthermore, the mixed PU samples were successfully melt-processed in an extruder on a large scale. This work holds the promise to facilitate the recycling of post-consumer mixed PUs with immense benefits for science, the economy, and the environment. This work has the capability to divert multi-million tons/year of waste PUs into valuable feedstock for manufacturing, thus saving energy and chemicals that are used to generate virgin PUs. Consequently, this work fits the very first principle of green chemistry, which is the prevention of waste creation. [ABSTRACT FROM AUTHOR]

Reported herein is a comparative study of the synthesis of indane via ring contraction reaction, mediated by iodine(III) and thallium(III). A series of protected 1,2-dihydronaphthalenes were synthesized and subjected to hydroxy(tosyloxy)iodobenzene (HTIB) and thallium(III) nitrate trihydrate (TTN) in trimethyl orthoformate (TMOF) to compare the percent yields provided by both oxidizing agents. The yields of the ring contracted products (indanes) were in the range of 61–88% for reactions performed with TTN·3H2O in TMOF. However, the yields were found to be significantly lower (e.g., 18–34%) when using HTIB in TMOF with some addition products. This study provides an important development related to the efficacy of the two oxidizing agents for ring contraction reaction. [ABSTRACT FROM AUTHOR]

• Mapping the intricate correlation between the three-phase structure and hydrolysis temperature. • The hydrolysis process induces transformations in the three-phase structure. • Temperatures induce diverse effects on the hydrolysis rate of semicrystalline PLA. • High-crystalline PLA rapidly hydrolyzes at sub-glass transition temperatures. • Immobilized rigid amorphous phase accelerated hydrolysis near glass transition temperatures. Hydrolysis significantly influences both the properties and degradability of poly(lactic acid), PLA. This work investigates the hydrolysis kinetics of PLA films as affected by degree of crystallinity and temperatures by considering the three-phase model structures (i.e., mobile amorphous, rigid amorphous, and crystalline). Molecular weight and three-phase fraction analyses were performed during hydrolysis to estimate the kinetic rates using phenomenological models. Results revealed that temperature significantly impacted PLA degradation, with distinct characteristics observed for each of these three phases. Above the glass transition temperature, the hydrolysis rates of PLA were comparable among samples with different crystallinity due to rapid water-induced crystallization of the amorphous phases, coupled with accelerated hydrolysis. In contrast, at below the glass transition temperature, the higher crystallinity sample exhibited a faster hydrolysis rate attributed to the presence of the rigid amorphous fraction. An increase in crystallinity introduced more defects due to limited mobility in the rigid amorphous fraction, influencing hydrolysis. The study provides valuable insights into the crucial relationship between temperature, crystallinity, and hydrolysis kinetics which are expected to be useful for predicting PLA degradation behavior during its intended applications and at its end of life. [Display omitted] [ABSTRACT FROM AUTHOR]

Catalytic liquefaction is an effective method for bio-crude production, but the development of efficient catalysts remains a challenge. Bifunctional Co/HZSM-5, Zn/HZSM-5 and Co-Zn/HZSM-5 catalysts were integrated with zinc hydrolysis to produce upgraded bio-crude. Co or Zn modified HZSM-5 catalysts improved the yields of bio-crude and gas compared to no catalyst treatment. Co or Zn modified HZSM-5 catalysts decreased the contents of oxygenated compounds including ketones, acids, alcohols and phenols. Co or Zn loaded HZSM-5 catalysts improved the hydrocarbons contents. Compared to monometallic Co/HZSM-5 and Zn/HZSM-5, bimetallic Co-Zn/HZSM-5 generated bio-crude with higher quality due to the synergistic effect of Co and Zn on HZSM-5 support. Co-Zn/HZSM-5 produced the highest bio-crude yield at 67.38 wt%, and the highest hydrocarbons content of bio-crude produced was 18.59%. [ABSTRACT FROM AUTHOR]

The cover page of the journal "Angewandte Chemie" is presented.

Macrocycles with ultra dense functionalities are very useful but are difficult to synthesize. In this study, we report six novel macrocycles bearing a pincer ligand alone or a combination of pincer-calixarenes, and pincer-fluorene moieties. Click chemistry was utilized to synthesize the desired macrocycles in good yields. These macrocycles were fully characterized using mass spectrometry (EI-MS, ESI-MS, and MALDI-TOF MS), and NMR spectroscopy. These macrocycles are under investigations as size-selective and recyclable catalysts for various chemical transformations. [ABSTRACT FROM AUTHOR]

The use of plant oil-coated paper could provide a greener approach to develop packaging materials in contrast to reliance on synthetic polymer-coated paper such as that coated by nylon, polystyrene (PS), polyethylene (PE), polytetrafluoroethylene (PTFE), polypropylene (PP), epoxy (commonly known as plastic), including plastic−paper hybrid materials. As described herein, we have successfully demonstrated the use of acrylated epoxidized soybean oil (AESO) for paper coating applications. It was found that the AESO-coated paper exhibited excellent oil and water resistance as reflected by kit rating (12/12) and Cobb 1800 (~2 g/m2) analysis. The coating steps include doctor-blade casting of AESO and 2 wt% of photoinitiator (2-hydroxy-2-methylpropiophenone) onto paper substrates followed by UV curing that yields highly crosslinked polymeric coating on the surface of paper. Fourier-transform infrared (FTIR) data confirms the crosslinking of AESO monomers, where the C C stretching frequency (~1638 and 809 cm−1) disappears after UV treatment. Mechanical property measurements show retention of >80 % in tensile index in the coated sample as compared to the uncoated paper. Further analysis such as ring crush test, bending stiffness, and internal tearing resistance measurements demonstrate that AESO-coated paper offers a significant improvement over the uncoated paper in terms of mechanical stability. Thermogravimetric analysis indicates that the crosslinked AESO-matrix is stable even at an elevated temperature (~340 °C), which demonstrates the stability of this polymeric material on paper substrates, thus increasing its utility in food packaging by mitigating the risk of the coating material leaching into food at high temperatures. [Display omitted] • Successful demonstration of using acrylate epoxidized soybean oil (AESO) for paper coating applications using UV curing • Excellent kit rating (12/12) and Cobb 1800 (~2 g/m2) for AESO-coated paper • AESO-coated paper is thermally stable at elevated temperatures, thus making it suitable for food packaging [ABSTRACT FROM AUTHOR]

Hollow polymer-based particles are useful for the encapsulation, protection, and release of active compounds. Adding a metal-organic coordination framework shell to nanocontainers is an attractive goal because it should help control their stability and permeability while yielding new properties and functions. We have discovered that polymer capsules with a Prussian blue analogue inner shell can be synthesized by emulsion-induced assembly of a metalcontaining amphiphilic block ionomer. The capsules are selectively permeable and were used as nanocontainers to encapsulate and release a model compound. Further, these nanomaterials are tunable in size and organize into 2-D closepacked arrays in the solid state. Potential applications for these materials include the encapsulation and nanopatterning of pharmaceutical, biological, and catalytic compounds. [ABSTRACT FROM AUTHOR]

Coatings exhibiting both self-cleaning and self-healing properties are envisioned for a wide range of applications. Herein we report a simple fabrication approach toward poly(urea-urethane) (PU) coatings having self-healing and self-cleaning properties. The self-cleaning component is a poly(dimethylsiloxane) (PDMS), which is affordable in cost and also has a lower environmental footprint relative to its fluorinated counterpart. The self-healing properties are imparted by dynamic urea bonds of the matrix. The obtained surfaces are evaluated for their anti-smudge properties such as water-, oil- and ink-repellency, as well as optical properties. The self-healing properties of these coatings are evaluated by making scores with a doctor blade and monitoring the healing under different conditions using optical microscopy. The resultant coatings are also investigated for their good mechanical properties. The surface chemical compositions are determined x-ray photoelectron spectroscopy, while atomic force microscopy is used for microstructural analysis of these coatings. [ABSTRACT FROM AUTHOR]

This work estimates that if the growth of polymer production continues at its current rate of 5% each year, the current annual production of 395 million tons of plastic will exceed 1000 million tons by 2039. Only 9% of the plastics that are currently produced are recycled while most of these materials end up in landfills or leak into oceans, thus creating severe environmental challenges. Covalent adaptable networks (CANs) materials can play a significant role in reducing the burden posed by plastics materials on the environment because CANs are reusable and recyclable. This review is focused on recent research related to CANs of polycarbonates, polyesters, polyamides, polyurethanes, and polyurea. In particular, trends in self-healing CANs systems, the market value of these materials, as well as mechanistic insights regarding polycarbonates, polyesters, polyamides, polyurethanes, and polyurea are highlighted in this review. Finally, the challenges and outlook for CANs are described herein. [ABSTRACT FROM AUTHOR]

Hydrodeoxygenation (HDO) is an effective route to upgrade bio-oil to hydrocarbon bio-oil, but the development of efficient catalysts for bio-oil HDO still remains a challenge. In this study, non-sulfided Fe-Co/SiO 2 catalysts were used to upgrade bio-oil using HDO. A series of Fe-Co/SiO 2 catalysts with different Fe/Co mole ratios were prepared, characterized and evaluated. The Fe and/or Co loading did not change SiO 2 crystalline structure. The Fe and/or Co metals increased the amount and strength of Fe-Co/SiO 2 catalyst acidity. Physicochemical properties of upgraded bio-oils produced using Fe-Co/SiO 2 catalysts such as water content, total acid number, viscosity and higher heating values improved in comparison to raw bio-oil. Bimetallic Fe-Co/SiO 2 catalysts resulted in better HDO performance than monometallic Fe/SiO 2 or Co/SiO 2 catalysts. This was due to the synergistic effect of Fe and Co occurring on the SiO 2 support. Fe-Co/SiO 2 catalyst having medium amount of acidity was more effective for bio-oil upgrading. The highest hydrocarbons content produced using Fe-Co(1)/SiO 2 catalyst was 22.44%. The mechanism of bio-oil HDO on Fe-Co/SiO 2 catalysts is proposed. [ABSTRACT FROM AUTHOR]

Chemical recycling of poly (ethylene terephthalate) is a long-lasting challenge in the realm of plastic recycling and circularity. Glycolysis of poly (ethylene terephthalate) to its parent monomer, bis(2-hydroxyethyl) terephthalate, is a popular method that can be facilitated with a variety of catalysts, especially zinc-containing catalysts. Herein, we report the effect of using a catalyst and diols during the melt-treatment of poly (ethylene terephthalate) and subsequent glycolysis. Primarily, it has been found that pretreatment effectively eliminates the crystallinity barriers that hinder depolymerization. Additionally, the presence of the catalyst and additive during pretreatment reduced the chain length of the polymer, while creating active sites that accelerate the rate of depolymerization within the structure of the polymer. Depolymerized products were analyzed using in-line FTIR spectroscopy to monitor the reaction along with 1H NMR and liquid chromatography-mass spectrometry to quantify the compounds in the crude product. Results suggest that the addition of zinc 2-ethyl hexanoate as the internal catalyst and cyclohexanedimethanol as the additive diol during pretreatment shortened the depolymerization time from ∼7 h to only 9 min at 180 °C, thus providing a monomer yield of ∼85.4% [Display omitted] • Use of catalyst and diols during melt-extrusion of post-consumer PET significantly accelerate the depolymerization process. • The presence of catalysts and diols promotes chain scission. • Pretreated PET samples in the presence of diols have a low degree of crystallinity (<5%), as compared to the untreated PET >28% crystallinity. [ABSTRACT FROM AUTHOR]

A novel fluorescent bis-calix[4]arene macrocycle 9 incorporating metal-binding pockets was successfully prepared. The structure of macrocycle 9 and its precursors were characterized via EI-MS, MALDI-TOF-MS, ESI-MS, 1 H NMR, 13 CNMR, 2D NMR, and X-ray crystallography. The macrocycle 9 displayed selective fluorescence quenching after interacting with Cu 2+ in the presence competing metal cations including Mg 2+ , Ca 2+ , Ba 2+ , Ag + , Zn 2+ , Ti 4+ ,Cd 2+ , Hg 2+ , Pb 2+ , In 3+ , La 3+ , Cr 3+ , Ni 2+ , Sb 3+ , V 5+ , Fe 3+ , Co 2+ , Sn 2+ , Sn 2+ , and Tl + . The Cu 2+ limit of detection was found to be 40 nM much lower than its threshold level (∼20 μM) in drinking water permitted by the U.S Environmental Protection Agency (EPA). Furthermore, drinking water samples from Karachi University (Pakistan) spiked with Cu 2+ were analysed with the sensing system and the results showed an excellent agreement with the fluorescence quenching phenomenon of macrocycle 9 examined in deionized water. Importantly, the chemosensor 9 could be used to detect Cu 2+ in living cells [ABSTRACT FROM AUTHOR]

Reported herein is a simple strategy for the fabrication of phenolic polyurethane coatings with self-healing and anti-smudge properties as well as good mechanical strength and optical clarity. Polydimethylsiloxane (PDMS) is incorporated to impart anti-smudge performance into urethane matrix comprised of biobased propyl gallate, hexamethylene diisocyanate trimer, and polytetrahydrofuran prepolymer. Propyl gallate is used as a reversible crosslinker to impart the self-healing properties to the coating. The reaction products were confirmed by Fourier transform infrared spectroscopic studies. Optical microscopic analysis was used to observe the self-healing behavior of polymer films. The contact angle and sliding angle tests were used to evaluate the anti-smudge ability of these polymers. Tensile test, hardness, and abrasion test were used to validate the mechanical properties of the coatings. The obtained coatings showed excellent anti-smudge properties as evident from their water, oil, ink, and hexadecane repellencies. Also, these coatings showed excellent optical clarity approach 100% transmittance. Furthermore, these coatings exhibit promising self-healing properties, which recover from 40 μm cuts in ∼10 min at 120 ℃ and in 1 h at 80 ℃. As this approach offers a simple route towards multi-functional coatings, therefore, real-world applications are anticipated for the coatings reported in this study. [ABSTRACT FROM AUTHOR]

The preparation of renewable polyesters with good barrier properties is highly desirable for the packaging industry. Herein we report the synthesis of high molecular weight polyesters via an innovative use of an in situ drying agent approach and the barrier properties of the films formed from these polyesters. High number average molecular weight (Mn) semiaromatic polyesters (PEs) were synthesized via alternating ring-opening copolymerization (ROCOP) of phthalic anhydride (PA) and cyclohexene oxide (CHO) using a salen chromium(III) complex in the presence of 4-(dimethylamino)pyridine (DMAP) cocatalyst. The use of a calcium hydride (drying agent) was found to enhance the number Mn of the synthesized PEs, which reached up to 31.2 ku. To test the barrier properties, PE films were prepared by solvent casting approach and their barrier properties were tested in comparison poly(lactic acid) films. The PE films showed significantly improved water vapor and oxygen barrier properties compared to the commercial poly(lactic acid) (PLA) film that suggests the potential use of these PEs in in the food packaging industry. [ABSTRACT FROM AUTHOR]