Maximum Decomposition Research Articles

Synthesis, crystal structures, CT-DNA/BSA binding modes and antibacterial activities of Zn(II) and Cr(III) with an acylhydrazone ligand

Two salicylaldehyde-4-hydroxy phenylacetyl acylhydrazone transition metal complexes ZnL2·H2O (I) and [CrL2]NO3·EtOH (II) were synthesized by C15H14N2O3 (HL) with Zn(NO3)2·6H2O and Cr(NO3)3·9H2O. Structures of HL, I and II were characterized by single crystal X-ray diffraction. With the ligand HL belonging to the monoclinic crystal system and the P21/c space group, the coordinating atoms (N and O atoms) in both two complexes I and II exhibited a six-coordinated octahedral geometry centered on the metal ion. Thermal stabilities of the two complexes were analyzed by TG-DTG techniques, which illustrated the maximum thermal decomposition peak temperatures of two complexes were both higher than 170 °C, exhibiting strong thermal stabilities. UV–vis absorption spectroscopy and microcalorimetry were used to determine interaction patterns of I and II with CT-DNA, showing that I and II effectively bound to CT-DNA through the intercalation mode and the interactions processes of I and II with CT-DNA were spontaneous, exothermic entropy reduction reactions. Fluorescence spectroscopy and microcalorimetry were used to determine the interactions of I and II with BSA, presenting that the two complexes can effectively bind to BSA and form non-fluorescent matrix complexes and the interactions processes were spontaneous exothermic and entropy reducing, and each of interaction duration was within 48 min. In addition, the antimicrobial activities of complexes I and II against S. aureus, P. aeruginosa, B. subtilis and E. coli were determined, revealing II exhibited stronger inhibition activity against P. aeruginosa than gentamicin sulfate at 0.5 mg·L-1. Complexes I and II were expected to be used as alternative drugs of gentamicin sulfate in the future.

Preparation and Properties of Phenolic Epoxy Modified Silicone Resin

Phenolic epoxy resin (F51) was first reacted with silane coupling agent (3-aminopropyl)triethoxysilane (KH550) to form a silanized phenolic epoxy resin (SPER); then the SPER was copolymerized with methylphenyl silicone resin (MPS) to synthesize phenolic epoxy modified silicone copolymer (PEMSC). The chemical structure of the PEMSC was characterized by FT-IR. The results of tensile strength and shear strength measurements indicated that the successful introduction of F51 significantly improved the mechanical and adhesive properties of the PEMSC; compared with the PEMSC with 10 phr of F51 added, the tensile strength and shear strength of the PEMSC with 40 phr increased by 8.5 and 3.5 times respectively. The TGA and DTGA analysis showed that the initial thermal decomposition temperature and the residual weight of PEMSC at 800 °C decreased compared to MPS, but the temperature corresponding to the maximum thermal decomposition rate in the second stage increased. Qualitative analysis was conducted on the decomposition products of PEMSC using gas chromatography coupled with mass spectrometry (GC-MS). The results showed that the relative content of aromatic hydrocarbons and their derivatives in the decomposition products of PEMSC was 64.11%, and the relative content of cyclic trimers and higher cyclomers was 20.41%.

Tailored biodegradable films via extrusion blow molding using PBS, PBAT, and TPS

AbstractResearch to replace synthetic polymers with biodegradable polymers is on the rise because common plastics have generated serious ecosystem problems. Films with thermoplastic starch (TPS), poly(butylene succinate) (PBS), poly(butylene adipate‐co‐butylene terephthalate (PBAT), and citric acid (CA) were produced by blown extrusion. They were characterized by blow‐up ratio (BUR), water vapor permeability (WVP), soluble ratio (SR), water sorption isotherm, and thermogravimetric (TG) techniques. Films were uniform and showed BUR > 205%. The different proportions of PBS and PBAT significantly influenced the WVP of the films. All samples had WVP with an order of magnitude similar to other blends with high starch content (10−6 g m−1 day−1 Pa−1). CA efficiently decreased the WVP of the PBS/PBAT/TPS formulations (15/15/70% and 20/10/70% by mass) by 25.2% and 24.7% compared to the acid‐free formulations. There was no significant difference in SR (19.0%–20.1%). These materials were sensitive to moisture since the equilibrium moisture content increased pronouncedly from water activity of 0.5. Films showed good thermal stability, with a maximum decomposition temperature close to pure polyesters. CA did not increase the thermal stability of blends, probably because of the low content used (0.1%). Given the outcomes of this study, these films could be deemed appropriate for applications in food packaging.

High heat Resistance, Strength, and toughness of epoxy resin with cellulose nanofibers and structurally designed ionic liquid

This study investigates the synergistic effects of ionic liquid (IL) and nanofillers on the properties of epoxy resin, aiming to address the issues of brittleness commonly associated with commercial epoxy resins. Starting from molecular structural design, a novel ionic liquid containing amino and phenylboronic acid groups is synthesized via a one-step alkylation reaction. The newly synthesized IL is then synergistically combined with cellulose nanofibers (CNFs) to fabricate a series of IL/CNFs epoxy resin composites. The influence of IL/CNFs content on the thermal properties, mechanical performance, glass transition temperature, and transparency of the composite materials is investigated. Compared to pure epoxy resin (EP), the epoxy composite material with 0.5IL-1.0CNFs exhibits a 50.72 % increase in flexural strength, a 126.94 % increase in elongation at break, and a 97.51 % increase in impact strength. In comparison, both the initial and maximum decomposition temperatures increased (T5% was 374 °C, and Tmax was 400 °C), showing an increase of 6 °C and 4 °C, respectively. Additionally, the epoxy composite material maintains high transparency, with a relatively high level of transmittance in the visible light range (400 nm-760 nm). The transmittance at T500nm increases to 86.8 %, and at T400nm it increases to 69.54 % compared to the pure epoxy resin.

H2 Production from NH3 in a BaTiO3 Moderated Ferroelectric Packed-Bed Plasma Reactor

Plasma decomposition reactions are used for various gas phase chemical processes including the decomposition of ammonia. In this work we show that pure ammonia can be effectively decomposed at atmospheric pressure and ambient temperature using a packed-bed plasma reactor moderated with BaTiO3 ferroelectric pellets without catalyst. The decomposition rate and energy efficiency of this ferroelectric barrier discharge reactor have been monitored as a function of applied voltage (up to a maximum value of 2.5 kV) and flow rate. For each operating condition reaction efficiencies have been correlated with the parameters defining the electrical response of the reactor. It is found that plasma current and volume inside the reactor and hence the energy efficiency of the process and the decomposition rate vary with the applied voltage and the flow of ammonia (a maximum decomposition rate of 14% and an energy efficiency of 150 LH2/kWh has been determined under optimized operation conditions). The role of back reactions (i.e. N2 + 3H2 → 2NH3) in decreasing reactor performance is another key effect affecting the overall efficiency for the ammonia decomposition. The possibilities of ferroelectric barrier discharge reactors to induce the decomposition of ammonia and the importance of keeping the operating temperature below the Curie temperature of the ferroelectric material are highlighted.

Cellulose-Silk Fibroin Composite Particles for Hydrophilic Drug-Controlled Release System: Preparation and Characterization

The objective of this study was to investigate the dissolution of cellulose (C) powder as a potential material for particle formation when combined with a silk fibroin (SF) solution. Each polymer solution as well as a mixture of cellulose and silk fibroin in different ratios were prepared into particles using the solvent emulsion-diffusion method. The particle morphology was characterized by scanning electron microscopy (SEM) and by attenuated reflection Fourier-transformed infrared spectroscopy (ATR-FTIR) and thermogravimetric analyzer (TGA) for the C-SF molecular interaction and thermal properties, respectively. The results showed that the cellulose particles appeared as separate fibers and loosely bound together, while silk fibroin particles were spherical in shape with dense texture and smooth surface. The C/SF mixed particles with different ratios could be formed into spherical particles and a ratio of 1:3 has the most spherical and solid. The ATR-FTIR results indicated the absorption spectra of the main functional groups both cellulose and silk fibroin. Blue dextran helped to enhance the temperature of the maximum decomposition rate (Td,max) of the particles via hydrogen bond interaction between the blue dextran and polymers. A burst release of blue dextran was observed in the first 12 h due to the swelling of particle surfaces and the slowest release found in the silk fibroin particles. The C/SF composite showed different blue dextran- eleased profiles and the particle with a high content of silk fibroin-released blue dextran in slowly rate. The results of this work can be used as a basis for applying C/SF composite particles in a hydrophilic drug release-controlled system.

Synergistic Remediation of Organic Dye by Titanium Dioxide/Reduced Graphene Oxide Nanocomposite.

In this work, nanocomposites based on titanium dioxide and reduced graphene oxide (TiO2@rGO) with different weight percentages of rGO (4, 8, and 16 wt%) were prepared by the hydrothermal/solvothermal synthesis method and thermally treated at 300 °C. The prepared nanocomposites were explored for the removal of methylene blue dye (MB) in the presence of simulated solar illumination as well as natural sunlight. The structural, morphological, chemical, and optical properties of the as-synthesized TiO2@rGO nanocomposites were characterized. The obtained results of the graphene-based nanocomposite materials indicated the existence of interactions between TiO2 and rGO, i.e., the Ti-O-C bond, which confirmed the successful integration of both components to form the TiO2@rGO nanocomposites. The addition of rGO increased the specific surface area, decreased the band gap energy, and increased the photocatalytic degradation efficiency of MB from water compared to TiO2 nanoparticles. The results of photocatalytic activity indicated that the amount of rGO in the prepared TiO2@rGO nanocomposites played a significant role in the application of different photocatalytic parameters, including the initial dye concentration, catalyst concentration, water environment, and illumination source. Our studies show that the reinforcement of the nanocomposite with 8 wt% of rGO allowed us to obtain the maximum photocatalytic decomposition performance of MB (10 mg·L-1) with a removal percentage of 99.20 after 2 h. Additionally, the obtained results show that the prepared TiO2@rGO_8 wt% nanocomposite can be used in three consecutive cycles while maintaining photocatalytic activity over 90%.

Unleashing the power of sunlight: Bi2O3/Sb2S3 photocatalysis for sustainable wastewater remediation of Tetracycline and Rhodamine-B

The use of heterojunction photocatalysts for pollutant decomposition has garnered significant interest in mitigating water contamination and environmental pollution. Our present study focuses on synthesizing Bi2O3/Sb2S3 heterojunction photocatalyst having variable mole ratios by employing a hydrothermal technique. Loading Sb2S3 onto Bi2O3 enables broad-spectrum solar light absorption, efficient segregation of charges, and enhanced surface area, which are excellent traits for photocatalysis. Both Bi2O3 and Sb2S3 showed nano-rod type morphology, while Sb2S3 was present as smaller nano-rods and Bi2O3 as larger ones. The photocatalytic performance of this heterojunction photocatalyst was examined using Rhodamine-B (RhB) and Tetracycline (TC) under solar light illumination for 120 min. Remarkable decomposition efficiency was achieved, with a 98.2% degradation rate observed for RhB having a rate constant of 0.03149 min−1. Similar experiments were conducted using other light sources as well, such as visible light and UV light. However, only 83% and 69% RhB degradation rates were attained with visible and UV light, respectively, indicating that natural sunlight is the superior light source for our catalyst. A 91.5% degradation rate was achieved for TC with the rate constant of 0.01749 min−1, in the presence of sunlight for 120 min. A small amount (0.3 g/L) of 1:3 Bi2O3/Sb2S3 (13BOSBS) photocatalyst was enough to bring such a good result. The photocatalytic activity of our catalyst, that is, 98.2% RhB degradation, is much higher than that of commercially available TiO2–P25 powder, as the latter only achieved 52% RhB degradation. The pH at which the surface of Bi2O3/Sb2S3 has a zero charge (pHpzc) was determined to be 5.37 and the maximum decomposition of RhB was achieved at pH 7. Reusability tests verified the remarkable stability of this catalyst, with about 74.4% of RhB degradation still present after seven consecutive cycles. Scavenger experiments highlighted the crucial role of •OH radicals in the photodecomposition mechanism, as the incorporation of DMSO significantly influenced the photocatalytic efficiency of the 13BOSBS composite, leading to a notable decrease to 37.5% in RhB degradation. For the RhB dye, the 13BOSBS catalyst demonstrated remarkable 90.2% and 85% reductions in COD and TOC, respectively. The commercially available TC powder substantially reduced 84% in COD and 80% in TOC, whereas there was a 78% reduction in COD and 73% in TOC for TC tablets. The degradation of the contaminants was followed by the formation of simpler intermediates, which were discovered using the GC-MS approach. Owing to its excellent attributes and simple synthesis method, the fabricated heterojunction offers a promising solution to prevent the persistent buildup of harmful toxic pollutants in industrial wastewater systems.

Mode and experiments of a straw ditch-burying returning and maturing in cold region of Northeast China

The current agronomic model of returning straw litter to soil (straw returning) involves crushing and mixing the straw with soil, which leads to shallow burial and ineffective decomposition of the straw. To address this issue in the cold region of Northeast China, this study proposed a method of burying and composting rice straw in furrows for returning to the field, and developed a matching machinery. Based on long-term experiments of burying straw in soil in spring and autumn, in this study, the operating parameters, postoperative straw decomposition effects, and influence of soil bulk density were analyzed. The results showed that the straw returning rate was inversely proportional to the forward speed and proportional to the furrow opening rotation speed and exhibited an increasing-then-decreasing trend with increasing collecting rotation speed. Taking into account both straw returning rate and operational efficiency, the recommended optimal operating parameters for the machinery unit were a forward speed of 0.4 m s−1, a raking speed of 180 r min−1, and a ditching speed of 420 r min−1. Under the spring model of burying straw in soil, straw treated with the composting agent was more likely to be fully decomposed in a short period, with a maximum total decomposition rate of up to 97.23%. Burying straw in soil effectively reduced soil bulk density, and straw returning in spring was more conducive to improving soil physical properties than straw returning in autumn. The value of this research lies in the integration of agricultural machinery and agronomy, providing insights for the development and design of related equipment, as well as offering a new approach for the effective treatment and utilization of straw in cold regions.

Green biodegradable dielectric material made from PLA and electron beam irradiated luffa cylindrica fiber: devices for a sustainable future.

The growing prevalence of polymer-based plastics in the environment is an imminent risk to the natural world. As an immediate consequence of this, extensive research has been launched over the course of the past few decades in an effort to reduce the damage that manmade plastics cause to the natural environment. The current study attempts to explore the biodegradability of polylactic acid (PLA), a bio-compatible plastic, by incorporating small amount of electron beam irradiated natural fibers (2 to 10%) derived from luffa cylindrica (LC) at varying irradiation doses (0.5 Gy, 1 Gy, and 2 Gy). Natural fiber surface treatment using electron beam irradiation is effective and environmentally friendly. The biodegradation of composites was studied for 90 days in sand, soil, compost, brackish water, fresh water, salt water, and bacterial and fungal conditions. Maximum decomposition was observed in the composite sample (PLA/10% wt of LC fiber at 2.0 Gy) at 15.42% and 4.73% in bacterial and soil environments. X-ray diffraction (XRD) and Raman spectroscopy validated the fiber and PLAs crystallinity and molecular interaction. The derivative thermo-gravimetric curve (DTGA) showed that electron beam irradiation removed moisture, hemicelluloses, and lignin from hydrophilic fibers. The incorporation of LC fibers into the bio-composites resulted in an increase in the glass transition temperature (Tg), melting temperature (Tm), and crystallization temperature (Tc). Additionally, after LC fiber reinforcement, the composites' dielectric properties were enhanced.

Smart composite nanofibers based on PLA/PEG with the addition of clove oil as thermal regulators

Smart nanofibers based on PLA and PEG with the addition of clove oil (Eugenia caryophyllus) (EO) were obtained using the electrospinning technique. The nanofibers were characterized by SEM, FT-IR, TGA and DSC. For the PLA/PEG/EO composite (mass ratio 2/1/0.25), the temperature of the maximum decomposition rate was approximately 370°C. This composite exhibited good latent heat energy storage (melting enthalpy 77.5 J/g at 34.7°C). Smart nanofibers can be used as thermal regulators in medicine, electronics, and food and textile industries.

Preparation and microstructural and thermal properties of a vulcanized Eucommia ulmoides gum modified asphalt

In this study, a vulcanized Eucommia ulmoides gum modified asphalt (VEUGMA) was prepared using a natural plant-based renewable rubber Eucommia ulmoides gum (EUG) as the matrix. The preparation process and microstructural and thermal properties of VEUGMA were investigated. The results showed that the optimum shearing time for preparing VEUGMA was 45 min, and the optimum development time was 120 min. Moreover, the EUG dosage follows a monotonically decreasing linear relationship with the optimum sulfur dosage. The VEUGMA exhibited a preferable corrugated network structure, and the vulcanization process of EUG in asphalt can be divided into three stages: slight crosslinking, deep crosslinking, and supreme crosslinking. The X-ray diffraction pattern displayed that only new diffraction peaks of ZnO appeared in the VEUGMA, and the EUG and asphalt exhibited better compatibility under the action of vulcanization aids. After EUG was vulcanized in asphalt, the aromatic ring hydrogen in the asphalt was replaced by aliphatic chains. The VEUGMA exhibited a lower glass transition temperature that suggests a better low-temperature crack resistance. Two maximum decomposition temperatures were noted in the thermal decomposition process of VEUGMA. Moreover, the main gases released were CO2, CO, CH4, SO2, NO2, and NO; of which, CO2 and CO exhibited the highest content, whereas the inferior emissions of SO2, NO2, and NO, can be ignored. The VEUGMA can effectively reduce the release of CO2 and CO but has no significant effect on the release of CH4. Further, VEUGMA demonstrated a smaller storage modulus (E'), loss modulus (E”), and loss factor (tanδ), which suggested better flexibility at low temperatures. Therefore, this work demonstrated the preferable modification effect achieved by adding 3.5 wt% EUG and 6 phr (parts per hundred parts of resin) sulfur to the matrix asphalt.

A - 3 Quantifying the Richness of the Boston Process Approach (BPA) Using a Novel Analytic Approach: the Framingham Heart Study.

Neuropsychological (NP) tests are often interpreted with a one test-one domain analytic approach in research, which misrepresents their clinical utility. The Boston Process Approach (BPA) allows for extraction of multi domain features within and across NP tests although its use is hampered by the data complexity and lack of objective quantification methods. In this study, we aim to develop a novel factor analytic approach that quantifies the richness of BPA data in the Framingham Heart Study (FHS). Data included BPA error scores (n = 172) derived from 10 baseline NP tests from 2238 Offspring participants. The outcome variable was dementia diagnosis. Factor analyses were conducted using Kemeny covariance matrix with maximum likelihood decomposition. Dwyer's (1937) method was used to estimate factor loadings for demographic variables (sex, education, and age) and dementia status. Participants' average age was 67.3 ± 9.3years, 54.5% were female, 41.3% had education ≥ college degree, and 92.5% were without dementia. A bifactor model demonstrated adequate fit (TLI = 0.95, RMSEA = 0.03), similar to the best multi-factor model (TLI = 0.95, RMSEA = 0.03), and improved over a single factor model (TLI = 0.87, RMSEA = 0.05). Omega estimates revealed saturation in general factor versus total factor loadings (ratio: 0.90). Dementia status loaded highly on the general factor (0.82, h2 = 0.81), as did sex (0.44, h2 = 0.27). BPA data fit a bifactor model, with most variation accounted for by the general factor. This study quantifies the richness of BPA measures into a single factor score that can be used as a predictor for several outcomes in clinical research.

Sigmoid models in the description of CO₂ evolved from legumes in the soil

The decomposition of legumes in the soil over time can be described by nonlinear sigmoid models. Thus, this study aimedto describe and to compare the fit of the nonlinear sigmoid models, Logistic and Gompertz, to the CO2 mineralization of fourlegume species over time in the soil, and indicate the most suitable model. Furthermore, it is also proposed to evaluate the CO2mineralization of legumes from two different edaphoclimatic conditions when added to the soil under controlled temperatureand humidity conditions. The following legume species used in green manure were evaluated: Arachis pintoi (forage peanut),Calopogonium mucunoides (calopo), Stylosanthes guianensis (Caribbean stylo), and Stizolobium aterrimum (mucuna). Arandomized block design with four replications was used. The soils from both areas are classified as Red-Yellow Latosol andhave a clayey texture. The mineralized carbon was measured at 48, 96, 144, 192, 240, 312, 384, and 480 hours fromthe beginning of incubation. Legumes in different locations had the same amount of potentially mineralizable carbon, andmicroorganisms had the same adaptation time to reach the maximum decomposition rate. The maximum decompositionrate occurs at the beginning of mineralization, and therefore the Gompertz model was more suitable than the Logistic modelin describing the decomposition of the four legumes in the soil.

Biomass intumescent flame retardant polyacrylonitrile composite: flame retardancy, smoke suppression and recycling

A fully biomass intumescent flame retardant (IFR) system was fabricated by combining the reaction product ([email protected]) of phytic acid (PA) and hydrolyzed silk (HS) with potato starch (PS), which was then blended with polyacrylonitrile (PAN) to obtain flame retardant PAN (FR-PAN). The tensile strength and elongation at break for PAN-10%[email protected]/5%PS sample increased by 18.8% and 86.3%. The peak heat release rate (PHRR) and peak smoke production rate (PSPR) decreased by 54.8% and 79.3% respectively, exhibiting excellent flame retardant and smoke suppression performance. Furthermore, the PAN-10%[email protected]/5%PS sample was carbonized to prepare FR-PAN Char (FRPC), which was then used for cellulose and polyvinyl alcohol (PVA) modification. The maximum thermal decomposition rate and PHRR of modified cellulose and PVA were significantly reduced, showing the improved fire safety. This work not only prepared an eco-friendly fully biomass flame retardant PAN composite, but also realized the successful recycling of waste flame retardant PAN materials.

Supercritical carbon dioxide-assisted TiO2/g-C3N4 heterostructures tuning for efficient interfacial charge transfer and formaldehyde photo-degradation

Long exposure to formaldehyde has been a concern for causing respiratory problems and TiO2/g-C3N4 composite is a potential choice to address this issue. This study developed a supercritical carbon dioxide (ScCO2)-assisted method to fabricate TiO2/g-C3N4 composites with two distinct heterostructures. The g-C3N4 nanosheet/TiO2 nanoparticle (denoted as type 1 heterostructure) heterojunction could accelerate electron migration because of its large interfacial surface contact. The ternary TiO2{101}/g-C3N4/TiO2{001} heterojunction (denoted as type 2 heterostructure) was synthesized for the first time, further promoting the separation of photogenerated electron/hole pairs under full-spectrum irradiation because it provided an additional migration channel for photocarriers. By loading different amounts of TiO2, the heterostructures were modulated, thereby influencing the photoactivity of the composites. The TiO2/g-C3N4 composite with 58% TiO2 loading possessed the best photocatalytic performance, achieving the highest rate constant for formaldehyde degradation, approximately 7 times higher than pure bulk g-C3N4 under either visible or full-spectrum light. Under full-spectrum irradiation, the maximum decomposition rate approached nearly 100% within 90 min. The tuned heterostructures facilitated the generation of O2·− and·OH, which were dominant active oxygen radicals responsible for formaldehyde removal under light irradiation. Thus, this study developed a green route to synthesize composites with tunable heterojunctions and enhanced photocatalytic activity that can be used for indoor air pollutant degradation.

3D Printing of sustainable coal polymer composites: Thermophysical characteristics

Recently, there has been a growing interest in enlisting polymer-based additive manufacturing in high-volume structural applications such as wind turbine blade tooling and additive housing construction. However, the availability of sustainable and environmentally friendly 3D printable materials could present a serious challenge, precluding the technology expansion to such applications. This research was focused on developing sustainable and environmentally friendly coal-plastic composites for use in high-volume applications. Polylactic acid, polyethylene terephthalate glycol, high-density polyethylene, and polyamide-12 resins were melt-mixed with bituminous Pittsburgh No. 8 coal at loadings varying from 20 wt % to 70 wt % coal. Thermoplastic composite filaments were extruded and processed with commercial 3D printers. Important thermophysical properties including coefficients of thermal expansion, heat deflection temperatures, glass transition and melt temperatures, specific heat capacities, thermal conductivities, and thermal stabilities of the coal-plastic composites were investigated. Coefficient of thermal expansion values for the composites had an inverse relationship with coal content lending to decreased print warping and consistent 3D printing of high-density polyethylene materials. Coal increased the heat deflection temperature of high-density polyethylene composites while little to no effect was observed for the other plastics. All composites maintained comparable melt temperatures, allowing for processing with commercial equipment. Specific heat capacity and thermal conductivity decreased with coal loading for all composite materials. Thermogravimetric analysis under air showed that the introduction of coal improved the thermal stability of all plastics by increasing the decomposition temperatures at 5 % and 50 % weight loss and by reducing the maximum decomposition rates.

Preparation, characterization and in vitro digestion of octenyl succinic anhydride-modified porous starch with different degrees of substitution

Octenyl succinic anhydride modified porous starch (OSA-PS) with degrees of substitution (DS) from 0.0123 to 0.0427 were prepared by aqueous phase method. From SEM, PS had a porous structure which showed a rough and corrosive surface after esterification with OSA. FT-IR revealed the characteristic peaks of OSA-PS at 1725 cm−1 and 1570 cm−1. From 1H NMR spectra, OSA-PS displayed extra chemical signal peaks at 0.85 ppm, 1.25 ppm and 1.96 ppm. These results fully demonstrated that OSA groups were successfully grafted onto PS. Furthermore, as DS increased, the specific surface area (5.6464 m2/g), pore volume (0.9959 × 10−2 cm3/g) and methylene blue adsorption capacity (24.3962 mg/g) of OSA-PS reached the maximum, while its relative crystallinity (26.8112 %) and maximum thermal decomposition temperature (291.96 °C) were the minimum. In vitro digestion studies showed that with the increase of DS, OSA-PS' contents of rapidly digestible starch and slowly digestible starch decreased from 9.06 % to 6.27 % and 28.38 % to 14.61 %, respectively. In contrast, its resistant starch had an increase in content from 62.56 % to 79.12%. The results provided an effective method for obtaining a double-modified starch with high specific surface area and anti-digestibility, thus broadening the industrial application of starch.

Sustainable cellulose nanocrystal based hydrophobic coatings with excellent self-cleaning and high thermal stability for multi-scenario applications

Paper-based packaging is widely applied for reducing the application of nonbiodegradable fossil-based polymers because of the growing environmental problems. However, paper significantly weakened its mechanical strength in a humid environment because of its hygroscopic nature, and traditional nonbiodegradable polymer coated hydrophobic paper caused microplastics after being discarded. This work developed sustainable cellulose nanocrystals (CNCs) based hydrophobic coatings (DPCs) with self-cleaning properties via self-polymerization of dopamine (DA) and subsequent grafting dodecyltrimethoxysilane (DTMS). The as-produced DPC-3 coating had the highest water contact angle (WCA) of 127.1 ± 1.5° with high water dispersion stability among the other samples because introducing DTMS could significantly transform the hydrophilicity of PDA@CNC to hydrophobicity. Compared to pure CNCs, DPC-3 exhibited excellent thermal stability, and its maximum decomposition temperature (Tmax) improved by 32.5 °C. The obtained DPC-3 powder could be well mixed with chemical solutions and applied to the various substrate surfaces to form hydrophobic and self-cleaning coatings for versatile and promising multi-scenario applications in the waterproofing of paper-based express boxes, fabrics, and paper, as well as self-cleaning of glass. Such improved hydrophobic and high-performance DPCs coatings showed promising choices to reduce the use of nonbiodegradable polymer coating.

Stability of guayulins from Parthenium argentatum, A. Gray during post-harvesting storage for industrial exploitation

BackgroundGuayulins comprise a family of sesquiterpene compounds with potential industrial applications that are extracted from the resinous fraction of the guayule plant (Parthenium argentatum, A. Gray). If a whole industry is to be developed around guayulins, not only their activity should be assessed, but also their stability because the quality of the final products is likely influenced by the time that elapses from harvesting to processing. Thus, the aim of the present study was to evaluate the stability of guayulin compounds from harvested guayule stems or extracted resin after storage at different temperatures to find in which form, stems or resin, is the storage better.ResultsResults showed that, once extracted, the resin could be stored at 20-25 °C for 3 months or more without significant losses of guayulin content. In the case of harvested stems, however, the findings were more complex, with guayulins A and B degrading over time and guayulins C and D showing enrichment. In addition, analysis of the thermal and thermo-oxidative degradation of the resin and guayulins showed that while guayulins A and B showed a maximum decomposition rate around 280 °C, guayulins C and D decomposed at 245 °C. Such thermal differences might be attributed to the observed oxidation of guayulin A and B standards into guayulin C and D, respectively.ConclusionThese findings provide, for the first time, information on the stability of guayulins after harvesting and resin extraction, which could help to the development of an integral industrial process from harvesting to commercializing.Graphical