Low Glass Transition Temperature Research Articles

Bio‐Based and Recyclable Self‐Healing Elastomer for the Application of Self‐Powered Triboelectric Nanogenerator in Low‐Temperature

AbstractThe cracks in flexible triboelectric nanogenerators (TENG) cannot naturally repair themselves during low‐temperature operation, which significantly restricts their practical applications. Yet, the development of elastomers capable of self‐repair at low temperatures has remained a formidable challenge. In this study, a dual dynamic cross‐linking network using multiple hydrogen bonds and β‐hydroxy esters is constructed to fabricate a fully bio‐based elastomer known as PLMBE. This elastomer can be stretched up to an impressive 1200% of its original length and possesses a remarkable autonomous self‐healing capability even under harsh conditions, including low temperatures (−10 °C, 12 h, with a 75% efficiency rate) and exposure to supercooled, high‐concentration saline (10% NaCl solution at −10 °C, 12 h, with a 64% efficiency rate). These remarkable properties are attributed to the elastomer's low glass transition temperature (Tg) of −30 °C and the abundance of hydrogen‐bonded supramolecular interactions. Importantly, this elastomer is highly suitable as a triboelectric layer for creating bio‐based TENG (Bio‐TENG) . These results demonstrate that Bio‐TENG can achieve an impressive output power density of 2.4 W m−2, and the output voltage recovers up to 95% after self‐healing at −10 °C. Consequently, these bio‐based elastomers have promising applications in various fields, including energy storage devices.

Brønsted-Lowry Acid-Based Aqueous Eutectic Electrolyte for Practical Zinc Batteries.

Aqueous highly concentrated electrolytes (AHCEs) have recently emerged as an innovative strategy to enhance the cycling stability of aqueous Zinc (Zn) batteries (AZB). Particularly, thanks to high Zn Chloride (ZnCl2) solubility in water, AHCEs based on ZnCl2 feature remarkable Zn anode stability. However, due to their inherently acidic pH and Cl- anion reactivity, these electrolytes face compatibility challenges with other battery components. Here, an aqueous eutectic electrolyte (AEE) based on Brønsted-Lowry concept is reported-allowing the usage of cheap and abundant salts, ZnCl2, and sodium acetate (NaAc). The reported, pH buffered, AEE displays a higher coordination of water at an even lower salt concentration, by simply balancing the acceptor-donor H─bonding. This results in impressive improvement of electrolyte properties such as high electrochemical stability, high transport properties and low glass transition temperature. The developed AEE displays higher compatibility with vanadium oxide-based cathode with a 50% increase in capacity retention in comparison to sat. ZnCl2. More importantly, the pH buffered AEE solves the incompatibility issues of ZnCl2 toward commonly used aluminium (Al) current collector as well as cellulose separator. This work presents an efficient, simple, and low-cost strategy for the development of aqueous electrolytes for the practical application of Zn batteries.

Effects of elevated-temperature deposition on the atomic structure of amorphous Ta2O5 films

Brownian thermal noise as a result of mechanical loss in optical coatings will become the dominant source of noise at the most sensitive frequencies of ground-based gravitational-wave detectors. Experiments found, however, that a candidate material, amorphous Ta2O5, is unable to form an ultrastable glass and, consequently, to yield a film with significantly reduced mechanical loss through elevated-temperature deposition alone. X-ray scattering PDF measurements are carried out on films deposited and subsequently annealed at various temperatures. Inverse atomic modeling is used to analyze the short and medium range features in the atomic structure of these films. Furthermore, in silico deposition simulations of Ta2O5 are carried out at various substrate temperatures and an atomic level analysis of the growth at high temperatures is presented. It is observed that upon elevated-temperature deposition, short range features remain identical, whereas medium range order increases. After annealing, however, both the short and medium range orders of films deposited at different substrate temperatures are nearly identical. A discussion on the surface diffusion and glass transition temperatures indicates that future pursuits of ultrastable low-mechanical-loss films through elevated temperature deposition should focus on materials with a high surface mobility, and/or lower glass transition temperatures in the range of achievable deposition temperatueres.

Reducing residual stress in photopolymerized composites by grafting high-mobility polymer chains onto the filler-matrix interface

3D/4D printing of thermosets, composites and hydrogels, lithographic procedures and dental resins are important examples of applications that rely on light-driven polymerization supported on substrates. Adhesion between the polymer and substrate during photopolymerization (and even between printed layers) can restrict the usual polymerization shrinkage, leading to the generation of residual stresses. These residual stresses can result in poor-quality products due to the presence of cracks and occurrence of warpage. In this work, silica nanoparticles were incorporated into photopolymerizable dimethacrylate based networks. These nanoparticles had their surface modified by grafting polymer chains with high mobility at usual room temperatures (low glass transition temperature polymer) and with high affinity towards the polymer matrix in order to test the hypothesis that these high-mobility chains could be helpful in dissipating stress and energy generated during photopolymerization in conditions in which the polymerization shrinkage is restricted. The nanoparticles and composites were analyzed via: electron microscopy (SEM), thermal analysis and mechanical bending tests. The evolution of the monomer-to-polymer conversion during photopolymerization was monitored using real-time infrared (FTIR) spectroscopy. To determine the residual stress generated by the polymerization at restricted contraction conditions, a universal mechanical testing machine was adapted and used. The results showed that silica nanoparticles with grafted high-mobility polymer chains that were able to interpenetrate and interact with the dimethacrylate based networks led to the production of composites having higher mechanical properties and lower polymerization stresses than composites containing only silanized nanoparticles and nanoparticles having immiscible polymer grafts towards the dimethacrylate based network. Results indicate that the modifications of the interface of composites developed in this work can be useful in the formulation of materials with improved mechanical properties and stability regarding polymerization shrinkage and residual stress that can lead to higher-quality products obtained in processes that employ light-driven polymerization supported on substrates or that occur on sequential polymerized layers, such as 3D/4D printing, lithography and in dental applications.

Preparation and properties of alcohol‐resistant thermal transfer printing inks for multifunctional label printing via physical blending of resins

AbstractDue to the rise of the logistics industry and the widespread use of ink labels, problems such as the narrow operating temperature range of ink, poor alcohol resistance, and insufficient scratch resistance need to be solved urgently. In this work, creates alcohol‐resistant thermal transfer inks by mixing polypropylene chloride (VP‐365) and epoxidized hydrogenated bisphenol A (P) resin and incorporating them into the ink formulation. The synthetic ink has a lower glass transition temperature (118.2°C), allowing the ink to print at lower temperatures. It has small wetting angles (68°, 63°, 58°, 46°, and 40°) and a large adhesion force (10.44 – 14.4 N) for different labels. Further, to evaluate the printing performance of the ink, the ink was scratched under 1000 g pressure and in the environment of isopropyl alcohol to evaluate its printing performance. The produced ink has high scratch resistance (300 times) and good alcohol resistance (140 times). Moreover, the developed ink showed good printability, printing media versatility, high adhesion, and excellent alcohol resistance. The synthesis method is facile and cost‐effective, which paves a novel way towards high‐performance ink printing and thermal transfer technology industries.

The Study on the Decolorization and Properties of Bismuth Glass

PbO glass has an adverse effect on the environment; the bismuth glass has a high refractive index, low melting temperature, softening temperature, and glass transition temperature (Tg), so that it can be used as a lead-free glass, used in optoelectronics, electronics, optics, and other components, which bismuth glass has been proved to be an important replacement material. Due to the higher melting temperature, Bi3+ ions tend to partially reduce to the low valence state of Bi0, which in turn causes coloration of the glass. In this experiment, the absorption peaks of glass oxidized brown color were observed at about 470 nm at 1,100°C (Bi2O3 = 40, 45 mol%) and 1,000°C (Bi2O3 = 40 mol%) for these three curves. The bismuth glass produced by high-temperature melting is not suitable for optical applications; by adding an oxidant (Sb2O3), which inhibits the reduction reaction of bismuth ions and maintains the ions in the state of Bi3+, the glass becomes more transparent in appearance and the transmittance is also improved and raised to approximately 75%–80%, which proves that appropriate additives are sufficient to greatly improve the application of bismuth glass for optical components. In the research process, the density and molar volume were measured by Archimedes method, Raman analysis was used to explore the influence of its structural changes, UV/Vis spectroscopy was used to measure the transmittance and absorption spectra for analysis and discussion, and TMA was used to observe the thermal properties, in the hope of developing a good optical properties of the glass, and the present experiments have confirmed that the addition of a small amount of Sb2O3 changes the color of the glass from black to a light yellow, which can be better used in the optical glass.

Designing polymeric coating with low coefficient of friction for natural rubber glove application

A layer of polymeric coating with low coefficient of friction (COF) on rubber glove surface is necessary for quick and easy donning. The current study elucidates the effect of varying the composition of soft and hard monomers in novel styrene-butyl acrylate-isoprene (St-BA-Iso) terpolymer on the properties of emulsion and its coating performance on rubber glove substrate. Styrene contributed to the terpolymer’s overall strength and smooth surface. Butyl acrylate, as a soft monomer, imparted flexibility and lower the glass transition temperatures of the coating. Isoprene, another soft monomer, further contributed to the coating’s flexibility and, when combined with butyl acrylate, played a role in maintaining coating adhesiveness. Terpolymers with higher loading of BA and Iso was found to produce films of relatively low glass transition temperature, Tg and higher COF. Meanwhile, high loading of St in the terpolymer resulted with smooth coating surface but exhibited severe delamination from the substrate when stretched due to the high rigidity and poor coating adhesion. St-40 terpolymer with 4 St: 3 BA: 3 Iso composition was able to produce a coating with well-balanced properties, producing smooth film (COF < 0.1) with moderately high Tg (24 °C), while retaining good coating adhesion on the rubber substrate.

Influence of different energetic plasticizers on the performance of NC-RDX nitramine gun propellants

Energetic plasticizers are an essential component of propellants and have a significant impact on their performance, such as energy, combustion, and mechanics. Therefore, there is significant practical value in understanding how plasticizers affect the performance of propellants. In this work, the glass transition temperatures of several energetic plasticizers were compared. By adding energetic plasticizers with good compatibility with the propellant and a low glass transition temperature to the propellant, nitramine gun propellants containing different energetic plasticizers were prepared through a semi-solvent method. The compatibility, thermal behavior, phase structure, composition, mechanical properties, energy, and combustion performance of the nitramine gun propellants were characterized. The influence of plasticizers on the phase structure of the propellant and its mechanism on the combustion performance of the propellant were discussed. Energetic plasticizers GAPE, DNPH, and BuNENA have good compatibility and chemical stability with NC-RDX and display good plasticization. GAPE–NC–RDX, DNPH–NC–RDX, and BuNENA–NC–RDX propellants exhibit stable combustion performance at −40 °C, 20 °C, and 50 °C. Compared with the nitramine gun propellant plasticized with NG, the impact strength of the propellant plasticized with DNPH and BuNENA increased by 108.1 % and 17.2 % at −40 °C, respectively. This work offers a solution to improve the phase structure, mechanical properties, and combustion stability of heterogeneous gun propellants and provides a way to suppress the excessive burning rate and flame temperature of propellants.

Morphological and Thermal Analysis of Poly(L-lactic acid)/ Carboxymethyl Cellulose Bio-composites

Poly (L-lactic acid) (PLLA) and carboxymethyl cellulose (CMC) are derived from renewable resources and both have excellent properties such as biocompatibility and biodegradability. Applications of PLLA are restricted for some of its inadequate physical properties such as low glass transition temperature, relatively low melting point, high crystallization temperature, slow crystallization rate, and poor heat stability. This study aims to prepare and characterize a renewable bio-composite with more adequate properties for applications by solution casting of different PLLA, and CMC ratios. CMC was prepared from microcrystalline cellulose (MCC) of mustard stalks (agricultural wastes) and the yield was about 78%. The samples were analyzed via Fourier transform infrared (FTIR) spectroscopy, differential scanning calorimetric (DSC), wide-angle X-ray diffraction (WAXRD), and scanning electron microscopy (SEM) for spectroscopic and thermal properties characterization. The interaction between carboxylate groups of CMC surfaces and the terminal hydroxyl, terminal carboxyl, and carbonyl groups of PLLA through hydrogen bonds caused the shift and broadening of the band of FTIR spectra. The decomposition temperature of CMC was increased and formed excellent bio composites with PLLA. Composite crystallinity varied with the percentages of the CMC. The fibrous form of CMCs is present in the SEM micrograph indicating cellulose's fibrous structure was not affected by carboxymethylation. In composites, the surfaces of CMC fibers are layered and different from the reported results of SEM micrographs of PLLA/MCC composites. PLLA/CMC performs better in thermal properties but its mechanical characteristics cannot be determined owing to a limitation where the composite was too brittle and not able to undergo tensile testing.

Exfoliation and physico-chemical characterization of novel bioplasticizers from Nelumbo nucifera leaf for biofilm application

Due to the extreme threats as environmental and health issues caused by the petroleum-based leachable plasticizers, researchers among different domains are more interested in finding unique biodegradable plasticizers from natural sources. The present study used Nelumbo nucifera leaf to extract novel biopolymers as viable substitutes for chemical plasticizers. The biopolymers extraction was carried out through chemical means and its physico-chemical and morphological characterization were carried out to confirm its plastic nature. The polymers extracted possess a low glass transition temperature (77.17 °C), good thermal stability (230 °C), low density (0.94 g/cc), good surface roughness (34.154 μm), low crystallinity index (25.1%) and moderate crystallite size (16.36 nm). The presence of an organic polymer with specific chemical groups as olefinic alkenes, epoxide, imino/azo groups, and hydrophobic organic siloxane groups, signify that the material is a condensed phenolic derivative. Furthermore, bio-film was formulated using NLP and poly lactic acid (PLA) matrix to evaluate its plasticizing effect and film-forming ability. Variation in specific properties of film was noted after bio-plasticizer addition, where tensile strength (20.94 ± 1.5 MPa to 19.22 ± 1.3 MPa) and Young's modulus (1.462 ± 0.43 GPa to 1.025 ± 0.52 GPa) was found to be decreased whereas increased the percentage of elongation at break (26.30 ± 1.1% to 39.64 ± 1.6%). In addition, decreased glass transition temperature (Tg) (59.17 °C), good surface compatibility, and increased flexibility of NLP-PLA film in contrast to pure PLA film authorizes the plasticizing effect of bio-plasticizers on PLA. Since the extracted bio-plasticizers could be a suitable replacement to harmful synthetic plasticizers for lightweight packaging applications in bioplastics sector.

Effect of tableting temperature on tablet properties and dissolution behavior of heat sensitive formulations

The tableting process involves the conversion of mechanical to thermal energy. This study evaluated the influence of temperature on the tableting behavior of formulations with different compositions. The tableting machine was equipped with a thermally controlled die to mimic the heat evolution from tableting on an industrial scale. Six formulations containing binders with a comparably low glass transition temperature were examined. Besides the polymer type and concentration, the filler was varied. Paracetamol was chosen as the model active pharmaceutical ingredient. The investigation included alterations in tabletability, disintegration and dissolution. Elevated temperatures led to an enhanced tabletability. The polymer type and concentration were decisive for the extent of alterations. The variation of the filler composition played a minor role due to the high melting points of its components. The results were confirmed in disintegration and dissolution studies. A high binding capacity and a low glass transition temperature resulted in a stronger delay of disintegration. The dissolution was sustained. Increased concentrations of the binding polymer enhanced the effect. If the tableting behavior of a formulation is changed by elevated temperatures during formulation development and production, a change of the binder type or concentration should be considered to ensure a reproducible tablet quality.

Deciphering the Effect of Microstructural Modification in Sodium Alginate-Based Solid Polymer Electrolyte by Unlike Anions.

Microstructure modification in sodium alginate (NaAlg)-based solid polymer electrolytes by the perchlorate (ClO4-) and acetate (CH3COO-) anions of sodium salts has been reported. ClO4- participates in the structure-breaking effect via inter/intramolecular hydrogen bond breaking, while CH3COO- changes the amorphous phase, as evident from X-ray diffraction studies. The larger size and negative charge delocalization of ClO4- have a plasticizing effect, resulting in a lower glass transition temperature (Tg) compared to CH3COO-. Decomposition temperature is strongly dependent on the type of anion. Scanning electron microscopy images showed divergent modifications in the surface morphology in both electrolyte systems, with variations in salt content. The mechanical properties of the NaAlg-NaClO4 electrolyte systems are better than those of the NaAlg-CH3 COONa system, indicating weak interactions in the latter. Although most of the studies focus on the cation influence on conductivity, the interaction of the anion and its size certainly have an influence on the properties of solid polymer electrolytes, which will be of interest in the near future for sodium ion-based electrolytes in energy storage devices.

Construction of eco-friendly multifunctional cashew nut shell oil-based waterborne polyurethane network with UV resistance, corrosion resistance, mechanical strength, and transparency

Vegetable oil-based waterborne polyurethane possesses numerous advantages, including its sustainability, environmental friendliness, and economic benefits. Nevertheless, its application is constrained by inferior mechanical properties and a low glass transition temperature. Hereon, the renewable polyols of sorbitan monooleate/cytidine were incorporated into the anionic cashew nut shell oil-based WPU network through molecular structure design. Series of CNSL-based WPU with outstanding UV resistance, mechanical properties, corrosion resistance, and transparency were successfully synthesized. The effects of Ce/SP content on the performance of CNSL-based WPU dispersions and films were investigated. The results demonstrated a remarkable enhancement in the properties of the modified WPU films. Specifically, the tensile strength and Tg were increased from 9.7 MPa to 23.9 MPa and 1.1 °C to 45.8 °C, respectively, while maintaining a toughness of 26 MJ/m−3, which attained or even surpassed the current vegetable oil-based WPU systems. It was confirmed excellent UV resistance within the UVB and UVC spectrums. Furthermore, with the increase in Ce/SP content, the water contact angle of films increased slightly, enhancing its water resistance. The IE of WPU-Ce and WPU-SP films reached 97.93 % and 98.42 % respectively, indicating outstanding corrosion resistance. This work presented novel strategies for the advancement of high-performance bio-based WPU, which held promising potential in diverse areas including coatings, corrosion protection, inks, and wearable applications.

Designs of ultra-HPHT Electrical Component Packages for Downhole and Geothermal Wellbore Logging Tool Integrations

Conventional dielectric sealing materials (PEEK, glass and glass-ceramic) used for sealing electrical feedthroughs, connectors, interconnectors and bulkheads in electronic packages can provide reliable downhole wellbore long-term logging tool service up to 150C or short-term logging service for greater than/equal 200C, due primarily to low glass transition temperature of the used sealing materials. This paper will demonstrate that the maximum allowable operating pressure and temperature could be from 20KSI to 100KSI and from 200C to 400C with Borosilicate and Bismuth-Boron-Silica (XTS) sealing glasses. Borosilicate glass sealed Inconel-Kovar/Kovar electronic housing could maintain reliability up to the maximum pressures of ~35KSI at 200C or 25KSI at 400C. Similarly, a Bismuth-Boron-Silica XTS glass sealed stainless steel electronic package housing could have a maximum operating pressure of ~100KSI at 150C or ~50KSI at 300C temperature. It has been found that high glass transition temperatures of (440-560)C for Borosilicate glass and (44010)C for Bismuth-Boron-Silicate (XTS) glass are key for making highly reliable ultra-HPHT electronic component packages. It is shown that the tetrahedral diamond-like microstructures of these sealing glasses are keys to ensure water-repelling properties to maintain sufficient electrical insulation resistance regardless of their use in water or moisture-rich wellbores. Moreover, compressive pin stress is found to be additional key for mitigate frequently observed glass seal cracks during logging tool field services.

Impact of the Drying Procedure and Botanical Origin on the Physico-Chemical and Potentially Bioactive Properties of Honey Powders

This study was aimed at researching the impact of the drying procedure (using the most appropriate honey–maltodextrin concentration for each drying technique) and botanical origin of honey on the physicochemical and potentially bioactive properties of honey powders that were made using maltodextrin as a carrier. The research was carried out with thyme, lavender, vetch and multifloral honey dehydrated using vacuum drying and freeze drying. The analysed parameters were moisture, water activity, colour, glass transition temperature, powder recovery, hygroscopic index and rate, tapped density, solubility, and phenolics as well as antiradical (ABTS•+, ROO•, •OH and O2•−), anti-inflammatory and antimicrobial (against Staphylococcus aureus, Escherichia coli and Listeria monocytogenes) activities. Freeze drying provided the highest recoveries. Powders obtained using freeze drying showed higher moisture and solubility as well as lower glass transition temperature, density and hygroscopicity than those obtained using vacuum drying. Hygroscopicity, glass transition temperature and antimicrobial activity against St. aureus depended on the drying procedure–honey concentration. Colour, anti-O2•− activity and antimicrobial activity against L. monocytogenes depended on the botanical origin of the raw honey. Moisture, solubility, density, total phenolic content, anti-ABTS•+ and anti-ROO• activities as well as anti-inflammatory activity and antimicrobial activity against E. coli depended on the drying procedure–honey concentration and botanical origin.

Rheological and thermal properties of an enteral nutrition formula for nutritional support patients using a combined mixture of gelatin and maltodextrin.

Enteral nutrition is a type of nutritional support that provides the necessary sources of energy and protein for patients who suffer from dysphagia, chronic disease, and loss of appetite. In this study, a gelatin-maltodextrin binary biopolymer system has been incorporated into a semi-solid formula. The I-optimal combination design approach was used to create 19 formulations, and the dynamic rheological properties, dynamic laser scattering, and zeta potential responses were evaluated over 30 days of storage at 5°C. Solid viscoelastic behavior has been approved since G' > G″ in the frequency sweep test with no cross-over point. Maltodextrin may interfere within the gelatin network, and increasing the maltodextrin to gelatin (from 0.14 to 1) may lead to a wider linear viscoelastic (LVE) strain range (2.16%), a lower storage modulus at LVE (52%), a lower yield stress (46%), and a lower glass transition temperature (34%). The presence of maltodextrin may reduce the temperature of the sol-to-solid transformation by 48% and enhance its flexibility. In contrast, increasing the gelatin-to-maltodextrin ratio following melting at 37°C led to an increase in the cumulant mean and polydispersity index, indicating a relatively unstable system. The range of zeta potential values between -4.4 and 1.7 mV confirmed a tendency toward coagulation. Microscopic images revealed instability because of irregular or compact chains formed in the gelatin matrix by using higher amounts of maltodextrin. Finally, the best formula had the best rheological stability and was suitable for tube-feeding patients, with a gelatin-to-maltodextrin ratio of 4.35:3.64% w/w on day 17.4.

Synthesis, characterization and performance evaluation of a flame retardant plasticizer for poly(vinyl chloride) derived from biobased vanillic acid

The utilization of biobased resources presents a novel approach for the development of high-performance plasticizers with exceptional flexibility. Nevertheless, the combustibility of flexible poly(vinyl chloride) (PVC) products containing high content plasticizers is frequently disregarded. The development of PVC functional plasticizers requires careful consideration of a good balance between flame retardancy, migration resistance and plasticity through molecular structure design. Currently there is a dearth of biobased plasticizers that exhibit exceptional comprehensive properties. Therefore, a novel biobased flame-retardant plasticizer (VA8-P) has been synthesized from vanillic acid and fully characterized using NMR, IR and MS. The VA8-P plasticized PVC exhibits a lower glass transition temperature and higher low temperature resistance, while its elongation at break is 1141.6% higher than unmodified PVC. Transmittance, haze, cross-sectional SEM and 2D/3D AFM all demonstrate its good optical properties and the compatibility of the plasticizer with polymer matrix. PVC plasticized using VA8-P exhibits better hydrophilicity and especially superior migration resistance than does the same polymer plasticized using DOP. The thermal stability and char residue rate for decomposition of VA8-P plasticized PVC are better than the same parameter of material plasticized with DOP. In cone calorimeter tests, VA8-P plasticized PVC showed excellent heat barrier effect. Additionally, PVC-P3 reached the UL-94 VTM-0 level in the vertical burning test. Its flame-retardant mode of action was also verified by TGA–FTIR analysis. A functional biobased plasticizer with excellent comprehensive properties has been synthesized. This material exhibits greater flexibility than many traditional flame-retardant additives and its use can be expected to improve the fire resistance of flexible PVC.

Surface modification of calcium carbonate by thiol‐ene click reaction and its effect on the performance of PVC composite

AbstractDisposable PVC gloves are cost effective, but their mechanical properties can be compromised at extremely high concentrations of plasticizers. The tensile properties of PVC gloves can be improved by incorporating modified fillers into the PVC matrix. In this research, calcium carbonate (CaCO3) was functionalized with γ‐methacryloxy propyl trimethoxyl silane (KH‐570) and then further modified through a click reaction with n‐Octadecyl mercaptan. Fourier‐transform infrared spectroscopy and X‐ray photoelectron spectroscopy have confirmed that n‐Octadecyl mercaptan‐modified KH‐570 was successfully grafted onto the surface of CaCO3. Composite films were manufactured by blending either pristine CaCO3 or modified CaCO3 with PVC resin paste and their tensile properties, light transmission, moisture permeability, and solvent resistance were evaluated. Compared with CaCO3/PVC and KH‐570‐modified CaCO3/PVC composite films, n‐Octadecyl mercaptan‐modified CaCO3/PVC composite films showed higher light transmittance, lower moisture permeability, and higher tensile properties. Dynamic mechanical analysis revealed that these films had low glass transition temperatures, thus broadening their applicability to low‐temperature conditions.

Chemically recyclable polyolefin-like multiblock polymers.

Polyolefins are the most important and largest volume plastics produced. Unfortunately, the enormous use of plastics and lack of effective disposal or recycling options have created a plastic waste catastrophe. In this work, we report an approach to create chemically recyclable polyolefin-like materials with diverse mechanical properties through the construction of multiblock polymers from hard and soft oligomeric building blocks synthesized with ruthenium-mediated ring-opening metathesis polymerization of cyclooctenes. The multiblock polymers exhibit broad mechanical properties, spanning elastomers to plastomers to thermoplastics, while integrating a high melting transition temperature (Tm) and low glass transition temperature (Tg), making them suitable for use across diverse applications (Tm as high as 128°C and Tg as low as -60°C). After use, the different plastics can be combined and efficiently deconstructed back to the fundamental hard and soft building blocks for separation and repolymerization to realize a closed-loop recycling process.

Structural Characterization and Properties of Deep Eutectic Solvents Plasticized Chitosan Films

In this study chitosan (CS) films were prepared from a deep eutectic solvent (DES) composed of choline chloride and malonic acid by solvent casting, and the influence of DES content on the structure and properties of the CS films was investigated in detail. It was confirmed by the spectral data that hydrogen bonds and ionic bonds were formed between the CS chains and DES. Structural analysis demonstrated that the crystallization of the CS was greatly hampered and the CS chains were stacked disorderly in films with high DES content. Differential scanning calorimetry (DSC) results indicated that DES exerted a significant plasticizing effect. In the case of the plasticized film containing 80 wt% of DES it showed a low glass transition temperature (Tg) of 20 °C. With increasing DES content, the water content of the plasticized films also increased, evidenced by the TGA results. Meanwhile, a structural change from granular to lamellar structure was observed by SEM. In addition, compared with pure CS film, the DES plasticized CS films possessed good fracture toughness and hydrophilicity. These observations suggest that the structure and properties of the CS films can be controlled by changing their DES content.