Preparation and CO₂ Sorption/Desorption of <i>N</i>-(3-Aminopropyl)Aminoethyl Tributylphosphonium Amino Acid Salt Ionic Liquids Supported into Porous Silica Particles

To search for robust CO₂ capture materials, several <i>N</i>-(3-aminopropyl)­aminoethyl tributylphosphonium amino acid salts ([apaeP₄₄₄]­[AA])-type task specific ionic liquids (TSILs) were synthesized and immobilized into porous silica support through a facile impregnation–vaporization method. The ILs and thus prepared sorbents, Sorb-AA, were well characterized, and their CO₂ sorption and desorption behaviors under temperature- and vacuum-swing conditions were investigated. The ILs can be immobilized facilely into silica up to 1/1 IL/SiO₂ weight ratio. After IL loading, the sorbents retain reasonably high specific surface area and porosity and therefore exhibit rapid sorption and desorption rates as well as excellent sorption capacity and selectivity and can be used repeatedly. Among them, Sorb-Lys has the highest CO₂ sorption capacity. It can capture 1.54 mmol or 67.9 mg CO₂ per gram sorbent from a simulated flue gas containing 14% CO₂ in each cycle of sorption and desorption. Sorb-Gly has slightly less CO₂ sorption capacity, 1.37 mmol or 60.4 mg CO₂ per gram sorbent from the simulated flue gas, and much better long-term durability. It is estimated that it can retain 90% sorption capacity even after 1.38 × 10³ cycles. These robust sorbents, especially Sorb-Gly, exhibit excellent potential in CO₂ capture applications

High Molecular Weight Polyesters Derived from Biobased 1,5-Pentanediol and a Variety of Aliphatic Diacids: Synthesis, Characterization, and Thermo-Mechanical Properties

High molecular weight aliphatic polyesters were synthesized from biobased 1,5-pentanediol and aliphatic diacids with 4, 5, 6, 9, 10, or 12 carbon atoms via melt polycondensation. The poly­(1,5-pentylene dicarboxylate)­s were characterized with intrinsic viscosity, gel permeation chromatography (GPC), nuclear magnetic resonance (NMR), differential scanning calorimetry (DSC), wide-angle X-ray diffraction (WAXD), thermogravimetric analysis (TGA), and tensile testing. The effects of dicarboxylate chain length on crystalline structure and thermo-mechanical properties were investigated. All the polyesters had weight-average molecular weight over 100,000 g/mol or intrinsic viscosity over 1.05 dL/g except poly­(1,5-pentylene adipate) (PPeA), which was less thermally stable than others. As semicrystalline polymers, they have a polyethylene-like crystal structure and crystallize rapidly except poly­(1,5-pentylene succinate) (PPeS). As a whole, the crystallizability and melting temperature (<i>T</i>_m) increase with dicarboxylate chain length, and the “even–odd” effect exists to a certain extent. Among them, poly­(1,5-pentylene azelate) (PPeAz), poly­(1,5-pentylene sebacate) (PPeSe), and poly­(1,5-pentylene dodecanedioate) (PPeDo) have <i>T</i>_m of 50–62 °C, good thermal stability, and exhibit comparable or even superior tensile properties in comparison with polyethylene and the well-known biodegradable copolyester, poly­(butylene adipate-<i>co</i>-terephthalate) (PBAT). These biobased and potentially biodegradable polyesters appear to be promising materials for practical applications

Potential for Using Simple 1,2,4-Triazole Salt Solutions as Highly Efficient CO₂ Absorbents with Low Reaction Enthalpies

Simple solutions of alkali metal salts of 1,2,4-triazole (TrizM) in polyethyelene glycol (PEG) and dimethylsulfoxide (DMSO) were prepared and assessed for CO₂ capture. These aprotic heterocyclic anions (AHAs) containing solutions exhibit excellent CO₂ capture performances. The TrizM salts absorb CO₂ chemically in a 1:1 stoichiometry. What is more attractive is that the CO₂ chemical absorption enthalpies are as low as −33 ∼ −21 kJ mol^–1, close to that of physical absorption by traditional ionic liquids (ILs). This makes regeneration of the absorbents highly energy-saving. The TrizM-PEG solution has a steady CO₂ capture performance due to the nonvolatility of PEG, and therefore, it is durable for CO₂ capture. In comparison, the TrizM-DMSO solution has a higher absorption capacity (120 mg/g solution) because of the higher solubility of TrizM. Such simple and inexpensive solutions show new potential as promising candidates for highly efficient, energy-saving, and economical CO₂ catchers

Biodegradable and High-Performance Poly(butylene adipate-<i>co</i>-terephthalate)–Lignin UV-Blocking Films

Renewable and biodegradable UV-blocking films are in high demand for the increasing need of sustainable environment. Lignin can offer significant UV absorption, but it deteriorates the mechanical properties of films at a high content. In this effort, biobased 10-undecenoic and oleic acids were successfully grafted on soda lignin via solvent- and catalyst-free processes, as confirmed by ³¹P and ¹H NMR and Fourier transform infrared (FTIR). The resulting lignin ester derivatives and neat lignin were then melt-blended with a biodegradable poly­(butylene adipate-<i>co</i>-terephthalate) (PBAT) to prepare UV-protective films. The incorporation of the modified lignins into the PBAT matrix exhibited good dispersion of lignin particles with almost unaffected tensile properties as well as good thermal stability for up to 20 wt % loading of lignin derivatives. The resulting films showed excellent UV-barrier property with 10 wt % lignin loading, having full protection in the whole UV-irradiation range (280–400 nm). The UV protection of prepared films proved persistent even after UV irradiation for 50 h, and their transparency was evidently enhanced. This work demonstrates a very promising procedure to produce high-performance and biodegradable PBAT–lignin UV-blocking films

Synthesis and CO₂ Capture Behavior of Porous Cross-Linked Polymers Containing Pendant Triazole Groups

Porous cross-linked polymers containing pendant triazole groups were synthesized from glycidyl methacrylate (GMA) in the presence of divinylbenzene via high internal phase emulsion (HIPE) templating method followed by functionalization with sodium 3-amino-1,2,4-triazole (ATANa). They were characterized with FTIR, SEM, BET, and mercury intrusion and assessed as CO₂ adsorbents. With interconnected hierarchical porous structure and abundant triazole groups which absorbed CO₂ chemically in 1:1 stoichiometry, the adsorbents exhibited high CO₂ adsorption capacity (3.6 mmol g^–1, at 25 °C and 1 atm) and rate, and good CO₂/N₂ selectivity (∼30). The adsorbents also displayed easy CO₂ desorption with medium desorption heat (58 kJ/mol CO₂), acceptable moisture endurance, and excellent recyclability. The results suggest that these functionalized porous polymers are potential adsorbents for CO₂ capture

Enhancement of Water Vapor Barrier Properties of Biodegradable Poly(butylene adipate-<i>co</i>-terephthalate) Films with Highly Oriented Organomontmorillonite

Low water vapor permeability is highly demanded for biodegradable packaging and agricultural film applications. However, biodegradable poly­(butylene adipate-<i>co</i>-terephthalate) (PBAT) films demonstrate poor water vapor barrier properties. A series of nanocomposite (NC) films composed of organically modified montmorillonite (OMMT) dispersed at levels ranging from 0 to 13 wt % in PBAT were thus generated using both film blowing and biaxial orientation. Films were characterized with wide-angle X-ray diffraction, transmission electron microscopy, thermal analysis and mechanical testing (static and dynamic), and their water vapor permeation (WVP) values were determined. The WVP of PBAT-OMMT NC films relative to that of the pure PBAT dropped and began leveling at the maximum OMMT concentrations tested. NCs for which OMMT layers better aligned with film surfaces, in this case those generated via biaxial orientation, provided for faster and more substantial decreases in WVP values relative to those produced with film blowing. The WVPs can be predicted using the Bharadwaj model, which accounts for OMMT aspect ratio, concentration, as well as orientation. The experimental results are in good agreement with the prediction values of the model. The addition of 13 wt % OMMT more than doubled the Young’s modulus, but resulting in a decrease of film tensile strength. The elongation at break was found to initially climb up to OMMT levels of about 6 wt % but declines sharply with higher concentrations. Results demonstrate the viability of reducing WVP levels of PBAT using orientated OMMT addition and provide insights on key structural parameters

Synthesis and Thermomechanical and Rheological Properties of Biodegradable Long-Chain Branched Poly(butylene succinate-co-butylene terephthalate) Copolyesters

Biodegradable long-chain branched (LCB) poly­(butylene succinate-co-butylene terephthalate) (PBST) copolyesters were prepared via a two-step direct esterification and melt polycondensation process, using a small amount (0–2 mol %) of diglycidyl 1,2,3,6-tetrahydrophthalate (DGT) as an in situ branching agent (BA). The chemical structures of LCB PBSTs were characterized and the thermal, mechanical, and rheological properties were investigated. With increasing DGT loading, PBSTs with higher branching degree, broader molecular weight distribution, and lower melt flow index were synthesized in shorter polycondensation time. The branching of PBSTs results in a slight decrease in crystallizability, melting, and Vicat softening temperatures, but leads to an obvious decrease in elongation at break. On the other hand, the existence of LCB greatly improved the rheological properties of PBSTs. PBST with higher branching degree possesses higher storage and loss modulus, higher zero-shear viscosity, longer relaxation time, more obvious shear-thinning, and lower loss angle tangent. The Han plot of the rheological data also indicates higher elasticity of LCB PBSTs

Biobased Epoxy Resin with Low Electrical Permissivity and Flame Retardancy: From Environmental Friendly High-Throughput Synthesis to Properties

Recent years have witnessed significant advances in biobased epoxy resins to replace their petroleum-based counterparts, especially diglycidyl ether of bisphenol A type epoxy resin (DGEBA). However, for meeting a great variety of the requirements, long-standing challenges include environmentally friendly preparation of epoxy resin with few toxic byproducts and improving their properties. Herein, we report a facile method to synthesize new silicone-bridged difunctional epoxy monomers in high yield. They are derived from naturally occurring eugenol by introducing the methylsiloxane and phenylsiloxane linkers of different chain lengths into their molecular backbones. These synthesized liquid epoxy monomers have definitive molecular structure with high purity. These silicone-bridged difunctional epoxy monomers exhibit much lower viscosity (<2.5 Pa s) than commercial DGEBA epoxy (10.7 Pa s) suitable for composites and prepregs. After curing, they exhibit a dielectric permittivity as low as 2.8 and good intrinsic flame retardancy with LOI value higher than 31, far outperforming DGEBA. All these advantages are stemmed from their siloxane-contained segments characterized by low polarity, very high dissociation energy, helical molecular structure, and high molecular volume. Overall, this work provides a very facile and scalable route access to a family of the multifunctional eugenol-based epoxy monomers with low dielectric constant and enhanced flame retardancy

Investigation and evaluation of contamination in dredged reclaimed land in China

<p>Large-scale reclamation projects have been developing rapidly in China’s coastal lands since 2000. In this study, the scale and pollutant contents of reclaimed lands were collected from published data and field surveys. Over 80% of the gross area was formed using hydraulic reclaimed technology. The pollution index, geoaccumulation index, and Nemerow integrated pollution index (NIPI) of 13 pollutant types were calculated based on the collected data. The potential pollution within major newly reclaimed lands was evaluated with valid pollutant data from sediments of the neighboring water. All reclaimed lands larger than 30 km² were slightly to seriously polluted with Cu, Pb, Zn, Cd, Cr, Hg, As, and Ni according to NIPI. The reclaimed fields in Hengsha Island, Binhai Tower, and Lingang New City of Shanghai were selected as verification sites for the pollution evaluations. The Cu, Pb, Zn, Cd, Cr, As, and Ni concentrations in dredged soils determined through inductively coupled plasma mass spectrometry showed a generally good soil quality within the typical reclaimed fields. Principal component and hierarchical clustering analyses indicated that the relatively high As content in the reclaimed soils was due to the internal pollutants of dredging fills and originated from anthropogenic sources.</p

Design of Multistimuli-Responsive Shape-Memory Polymer Materials by Reactive Extrusion

Shape-memory polymers (SMPs) are a class of stimuli-responsive materials that have attracted tremendous attention in various applications, especially in the medical field. While most SMPs are thermally actuated, relating to a change of thermal transition (e.g., melting temperature), SMPs that can be actuated upon exposure to light are emerging. Recently, there has been new interest into multiple stimuli-responsive SMPs in order to cover the range of applications for these smart materials. In this work, poly­(ester-urethane)­s (PURs) made of heating-responsive poly­(ε-caprolactone) (PCL) segments of various degrees of crystallinity and photoresponsive <i>N</i>,<i>N</i>-bis­(2-hydroxyethyl) cinnamide (BHECA) monomer were successfully prepared using reactive extrusion technology to design dual-stimuli-responsive SMPs (DSRSMP). In order to tune the SMP properties (temperature or light), the crystallinity of the PCL segment was finely adjusted by the copolymerization of ε-caprolactone with para-dioxanone in bulk at 160 °C using tin­(II) octoate. The resulting polyester segments were then coupled with BHECA using <i>n</i>-octyl diisocyanate at 130 °C. The SMP properties of resulting PURs were correlated with DSC and DMTA measurements. Further addition of di- and tetracinnamate PCL segments into these SMPs was also studied in order to enhance the photoactuated SMP properties