Total Release Research Articles

Preparation and properties of bio‐based flame‐retardant rigid polyurethane foams with soybean oil polyols containing phosphorus

AbstractTwo types of bio‐based RPUFs (RPUF‐P and RPUF‐PPOA) were prepared that contained ethanol‐modified polyols (Polyol‐E) and one contained an epoxidized polyol modified with phosphoric acid (Polyol‐P), and the other contained epoxidized polyol modified with phenylphosphonic acid (Polyol‐PPOA). The cell morphologies, thermal and mechanical properties, and flame retardancy characteristics of the RPUF, RPUF‐P, and RPUF‐PPOA were studied by scanning electron microscopy (SEM), thermogravimetric analysis(TGA), compression tests, limiting oxygen index (LOI), and cone calorimetry test (CCT). The porous structures revealed that the cell sizes of both RPUF‐P and RPUF‐PPOA increased first and then decreased, and the number of pores decreased first and then increased. Furthermore, the apparent density showed a similar trend of increasing before decreasing. The compressive strengths of the RPUF‐P and RPUF‐PPOA were higher than that of the RPUF, and the compressive strength of the RPUF‐P was better than that of the RPUF‐PPOA, because the hydroxyl value of the Polyol‐P was much higher than that of the Polyol‐PPOA. The crosslinking density of the RPUF‐P prepared by the PM‐200 reaction was much higher than that of the RPUF‐PPOA. The LOI values of the RPUF‐P4 and RPUF‐PPOA4 were 21.68 and 23.10, respectively. Furthermore, the value of the peak of the heat release rate (HRR) was reduced by 40.3% compared with that of pure RPUF. The total heat release (THR), smoke produce rate (SPR), and total smoke release (TSR) decreased with increased Polyol‐P and Polyol‐PPOA addition. The flame‐retardancy residues micrographs showed that the carbon layers generated from the combustion of the RPUF‐P4 and the RPUF‐PPOA4 lacked perforated structures and exhibited better densification than the pure RPUF. Based on the analysis and discussion, the flame retardancy of RPUF‐P and RPUF‐PPOA were improved mainly through a condensed and gas phases mechanism.

Not all soil carbon is created equal: Labile and stable pools under nitrogen input.

Anthropogenic activities have raised nitrogen (N) input worldwide with profound implications for soil carbon (C) cycling in ecosystems. The specific impacts of N input on soil organic matter (SOM) pools differing in microbial availability remain debatable. For the first time, we used a much-improved approach by effectively combining the 13C natural abundance in SOM with 21 years of C3-C4 vegetation conversion and long-term incubation. This allows to distinguish the impact of N input on SOM pools with various turnover times. We found that N input reduced the mineralization of all SOM pools, with labile pools having greater sensitivity to N than stable ones. The suppression in SOM mineralization was notably higher in the very labile pool (18%-52%) than the labile and stable (11%-47%) and the very stable pool (3%-21%) compared to that in the unfertilized control soil. The very labile C pool made a strong contribution (up to 60%) to total CO2 release and also contributed to 74%-96% of suppressed CO2 with N input. This suppression of SOM mineralization by N was initially attributed to the decreased microbial biomass and soil functions. Over the long-term, the shift in bacterial community toward Proteobacteria and reduction in functional genes for labile C degradation were the primary drivers. In conclusion, the higher the availability of the SOM pools, the stronger the suppression of their mineralization by N input. Labile SOM pools are highly sensitive to N availability and may hold a greater potential for C sequestration under N input at global scale.

The Effects of TMR® Fab 6 on Hamstring Flexibility in Healthy Subjects; An Exploratory Observational Investigation.

Stretching programs are designed to improve hamstring flexibility by attempting to mechanically increase the length of the target tissue. However, other manual treatment approaches such as those utilized in Total Motion Release (TMR®), could be beneficial by identifying body asymmetries to assess and treat soft tissue impairments leading to diminished extensibility. The purpose of this study was to determine the effectiveness of the TMR® Fab 6 assessment and treatment to increase hamstring flexibility in healthy participants following one session of TMR®. Observational Cohort study. A convenience sample of 20 healthy participants (10 males, 10 females) were recruited from three institutions. Following collection of demographic information and a brief medical history, each participant performed a five minute warm-up on the stationary bike at a moderate intensity (80-90 RPMs) followed immediately by the bilateral performance of the Active Knee Extension Test (AKET) and Passive Straight Leg Raise (PSLR) to assess hamstring muscle length. Participants were randomly placed in the TMR® or control group. The TMR® group completed the "Fab 6" evaluation and treatment, while the control group performed one repetition of standing active hip flexion every 30-seconds for 15-minutes with both knees in full extension. Upon completion of treatment, control and TMR® groups were immediately re-evaluated on the AKET and the PSLR in the same order and fashion as baseline testing. Participants were asked to return in 24-hours for the same objective measurements as previously described. A significant time by group interaction was identified across all variables (p ≤ 0.001) for AKET and PSLR except the PSLR preferred leg from post-treatment to 24hr follow-up. The most significant increase in the AKET occurred in the TMR® group between baseline and post-treatment of the non-preferred leg (12.15°±2.94) when compared to the control group (7.15°±1.56). The results of the study suggest that implementing a regionally interdependent treatment approach like TMR® results in significant improvements in hamstring extensibility and hip ROM compared to the control group. 3.

Construction of Fire Safe Thermoplastic Polyurethane/Reduced Graphene Oxide Hierarchical Composites with Electromagnetic Interference Shielding.

Incorporating outstanding flame retardancy and electromagnetic interference shielding effectiveness (EMI SE) into polymers is a pressing requirement for practical utilization. In this study, we first employed the principles of microencapsulation and electrostatic interaction-driven self-assembly to encapsulate polyethyleneimine (PEI) molecules and Ti3C2Tx nanosheets on the surface of ammonium polyphosphate (APP), forming a double-layer-encapsulated structure of ammonium polyphosphate (APP@PEI@Ti3C2Tx). Subsequently, flame-retardant thermoplastic polyurethane (TPU) composites were fabricated by melting the flame-retardant agent with TPU. Afterwards, by using air-assisted thermocompression technology, we combined a reduced graphene oxide (rGO) film with flame-retardant TPU composites to fabricate hierarchical TPU/APP@PEI@Ti3C2Tx/rGO composites. We systematically studied the combustion behavior, flame retardancy, and smoke-suppression performance of these composite materials, as well as the flame-retardant mechanism of the expansion system. The results indicated a significant improvement in the interface interaction between APP@PEI@Ti3C2Tx and the TPU matrix. Compared to pure TPU, the TPU/10APP@PEI@1TC composite exhibited reductions of 84.1%, 43.2%, 62.4%, and 85.2% in peak heat release rate, total heat release, total smoke release, and total carbon dioxide yield, respectively. The averaged EMI SE of hierarchical TPU/5APP@PEI@1TC/rGO also reached 15.53 dB in the X-band.

Expanded charring flame retardant effect of caged polysilsesquioxane containing Schiff base structure on poly(ethylene terephthalate) combustion

Via a hydrolytic condensation reaction, we successfully synthesized polyhedral oligomeric silsesquioxane containing Schiff base structures (NSPOSS). These were then incorporated into the PET matrix through melt blending, aiming to bolster the flame retardancy of poly(ethylene terephthalate) (PET). The interaction force between NSPOSS and PET was analyzed by simulation of NSPOSS pulling out in PET via MS8.0. Additionally, NSPOSS exhibits excellent flame retardancy and smoke suppression. For PET-10wt%NSPOSS, the peak heat release rate (pk-HRR), the total heat release (THR), the total smoke release (TSR), peak smoke release rate (pk-RSR), and the highest smoke density peak (Ds max) decreased by 60%, 14%, 57%, 42% and 59%, respectively, compared to neat PET. Moreover, PET-NSPOSS composites exhibit char expansion during combustion, for which we propose a charring mechanism. The newly prepared NSPOSS can be applied in various resin matrices, offering promising prospects for practical applications.

A comprehensive enhancement of the optical, mechanical, low dielectric, and flame-retardant characteristics of epoxy resin by the incorporation of multifunctional additive

Epoxy resin is widely utilized but faces the drawback of flammability. However, adding flame retardants often results in the compromise of other properties, such as mechanical and optical characteristics. In this study, a phosphorus-nitrogen multifunctional flame retardant named DPVPI was successfully synthesized. The resulting epoxy resin containing DPVPI demonstrated good transparency and low dielectric constant. Furthermore, the unique structure of DPVPI led to additional enhancements in the mechanical properties of EP composite. The tensile strength of EP composite was increased by 33 %, and the impact strength was improved from 13.61 kJ/m² to 25.74 kJ/m². Remarkably, the composites with Only 4wt% DPVPI can achieve a V-0 rating in the UL-94 test and the maximum limiting oxygen index (LOI) of it reached 32.6 %. The cone calorimeter test showed that the peak heat release of the composites with a 5 wt% addition decreased by 35 %, the total smoke release decreased by 37 %, and the char yield doubled. This research presents a novel strategy for subsequent synthesis endeavors about multifunctional flame retardants.

Enhancing flame retardant wood’s versatility and adjustable properties through multi-scale micro-coating strategy

Wood, a naturally renewable material with a porous structure and breathability, rendering it a green construction material that can absorb sound, isolate heat and regulate moisture. Efforts to enhance wood’s resistance to combustion while maintaining its porous nature are hindered by the potential impact of physical and chemical treatments on its porous structure, posing a challenge in achieving flame-retardant wood that retains its breathability. Inspired by the multi-layer coating decoration method used on walls of various rooms in frame structure buildings, the study applies multi-scale micro-coating strategy to the multi-scale microstructure of wood. This strategy applied polyamino polyether methylene phosphonate (PAP), metal ions (Al3+/ Mg2+/ Ca2+), and alkali solutions to create a persistent multifunctional protective coating for the multi-scale wood structure. This coating effectively preserved the wood’s vessel, ray tissue, cell cavity, and pit structure, protecting its permeability. The modified wood demonstrated an increased limited oxygen value from 19.7 % to 38.4 % and a 55.9 % decrease in the total smoke release compared to natural wood, obtaining high fire safety. Furthermore, the modified wood exhibited adjustable antibacterial, photoaging-resistant and corrosion resistance properties depends on the type of metal. This strategy demonstrated proven reliability, versatility, and durability in the treatment of various metal ions, enabling the production of functional wood with tailored properties.

Echogenic Gold Nanorod Incorporated Hybrid Poly(2-oxazoline) Nanocapsules for Real-Time Ultrasound/Fluorescent Imaging and Targeted Cancer Theranostics.

In recent years, various nanocarrier systems have been explored to enhance the targeting of cancer cells by improving the ligand-receptor interactions between the nanocarrier and cancer cells for selective cancer cell imaging and targeted delivery of anticancer drugs. Herein, we report multifunctional hydrogen-bonded multilayer nanocapsules functionalized with both folic acid-derived quantum dots (FAQDs) and gold nanorods (AuNRs) for targeted cancer therapy and cancer cell imaging using fluorescence microscopy and medical-range ultrasound imaging systems. The encapsulation efficiency of nanocapsules was found to be 49% for 5-fluorouracil (5-FU). The release percentage reached a plateau at 37% after 1 h at pH 7.4 and increased to 57% after 3 h when the release pH was decreased to pH 5.5 (i.e., the pH of the tumor environment). Under ultrasound irradiation, the release was significantly accelerated, with a total release of 52% and 68% after only 6 min at pH 7.4 and pH 5.5, respectively. While the sonoporation process plays an important role in anticancer activity experiments under ultrasound exposure by generating temporary pores, the targeting ability of FAQDs brings the capsules closer to the cell membrane and improves the cellular uptake of the released drug, thereby increasing local drug concentration. In vitro cytotoxicity experiments with HCT-116 and HEp-2 cells demonstrated anticancer activities of 96% and 98%, respectively. The nanocapsules showed enhanced ultrasound scattering signal intensity and bright spots under ultrasound exposure, most likely caused by high scattering ability and internal reflections of preloaded AuNRs in the interior structure of the nanocapsules. Hence, the demonstrated nanocapsule system not only has the potential to be used as an integrated system for early- stage detection and treatment of cancer cells but also has the ability for live tracking and imaging of cancer cells while undergoing treatment with chemotherapy and radiation therapy.

In vitro evaluation of ethyl cellulose and polyvinyl pyrrolidone composite nanofibers for transdermal delivery of diclofenac diethylamine

Non-steroidal anti-inflammatory drugs (NSAIDs) are the most prominent painkiller and anti-inflammatory drugs with gastrointestinal (GI) adverse effects. Transdermal drug delivery systems (TDDS) could overcome GI adverse effects associated with oral ingestion of NSAIDs as well as maintaining a prolonged release of the drug. The main aim of this study was to prepare and investigate diclofenac diethylamine (DDA) loaded nanofibers made of ethyl cellulose (EC) and polyvinyl pyrrolidone K90 (PVP) using electrospinning. The impact of penetration enhancers such as nerolidol and farnesol on release profiles through cellophane membranes and other characteristics of nanofibers were also investigated. Based on release studies, some formulations were selected for release examination through rate skin using Franz diffusion cells. To gain insight about potential interactions between drug and polymers FTIR, DSC, and XRD analyses were performed. Morphology examination was also conducted using scanning electron microscopy (SEM). Morphology studies showed that nanofibers made of EC only are greater in the mean diameter than other nanofibers while other formulations were not significantly different from each other regardless of the presence of penetration enhancers. EC nanofibers had the lowest elastic modulus and tensile strength and most elongation at break which makes them the least tough and most flexible nanofibers among all the formulations. The addition of PVP increased the toughness and decreased the flexibility of nanofibers. The addition of nerolidol did not alter the mechanical properties of nanofibers significantly, while the addition of farnesol increased elastic modulus, tensile strength, and elongation at break significantly in a concentration-dependent manner. EC nanofibers had the lowest release rate and lowest total cumulative release content while the addition of PVP significantly improved both of these features. In release studies through cellophane membrane, the addition of 5 % of penetration enhancer slightly increased the release rate while did not significantly alter cumulative release while the addition of 10 % farnesol notably increased the release rate and total cumulative released content. Release studies through rat skin were in accordance with cellophane membrane studies and the formulation with 10 % farnesol had the most release rate and total cumulative release and these findings confirm the positive effect of penetration enhancers. DSC thermogram showed an amorphous state of the drug in fibres and this was supported by XRD results. The FTIR results confirmed that no chemical interaction between the drug and other formulation components has occurred and no new compounds have been formed. Based on these results, the utilization of DDA-loaded PVP and EC nanofibers in conjunction with a penetration enhancer showed significant potential for application in transdermal patches.

Current and Future Effects of Climate Change on Airborne Allergens.

Delineation of the impact of elevated carbon dioxide and concomitant global warming on airborne allergens is performed. European tree pollen trends in general showed earlier start and end dates and increased total pollen release, with some differences both in locale and among species. Earlier flowering was also seen with grasses and weeds. In the case of some boreal trees, flowering was delayed due to a pre-seasonal requirement for necessary accumulated chilling temperature to achieve bud-set. Anthropogenic climate change induced rise in temperature and CO2 levels has resulted in demonstrable increases in aeroallergens. This has been most dramatic in tree pollen annual load, but also seen with grasses and weeds. Collected data is greatest for the Northern Hemisphere, especially the European continent, with supporting data from North America and Australia.

Variation in Soil CO2 Fluxes across Land Cover Mosaic in Typical Tundra of the Taimyr Peninsula, Siberia

Increased warming in the Arctic is of great concern. This is particularly due to permafrost degradation, which is expected to accelerate microbial breakdown of soil organic carbon, with its further release into the atmosphere as carbon dioxide (CO2). The fine-scale variability of CO2 fluxes across highly mosaic Arctic tundra landscapes can provide us with insights into the diverse responses of individual plant communities to environmental change. In the paper, we contribute to filling existing gaps by investigating the variability of CO2 flux rates within different landscape units for dominant vegetation communities and plant species across typical tundra of the southern part of the Taimyr Peninsula, Siberia. In general, the variability of soil CO2 flux illustrates a four-fold increase from non-vascular vegetation, mainly lichens and mosses (1.05 ± 0.36 µmol m−2 s−1), towards vascular plants (3.59 ± 0.51 µmol m−2 s−1). Barren ground (“frost boils”) shows the lowest value of 0.79 ± 0.21 µmol m−2 s−1, while considering the Arctic “browning” phenomenon, a further substantial increase of CO2 flux can be expected with shrub expansion. Given the high correlation with top soil temperature, well-drained and relatively dry habitats such as barren ground and non-vascular vegetation are expected to be the most sensitive to the observed and projected temperature growth in the Arctic. For mixed vegetation and vascular species that favor wetter conditions, soil moisture appears to play a greater role. Based on the modeled seasonal pattern of soil CO2 flux and precipitation records, and applying the rainfall simulations in situ we outlined the role of precipitation across enhanced CO2 emissions (i.e., the “Birch” effect). We found that a pulse-like growth of soil CO2 fluxes, observed within the first few minutes after rainfall on vegetated plots, reaches 0.99 ± 0.48 µmol m−2 s−1 per each 1 mm of precipitation, while barren ground shows 55–70% inhibition of CO2 emission during the first several hours. An average additive effect of precipitation on soil CO2 flux may achieve 7–12% over the entire growing season, while the projected increased precipitation regime in the Arctic may strengthen the total CO2 release from the soil surface to the atmosphere during the growing season.

Modelling the controlled drug release of push-pull osmotic pump tablets using DEM

The push-pull osmotic pump tablet is a promising drug delivery approach, offering advantages over traditional dosage forms in achieving consistent and predictable drug release rates. In the current study, the drug release process of push-pull osmotic pump tablets is modelled for the first time using the discrete element method (DEM) incorporated with a microscopic diffusion-induced swelling model. The effects of dosage and formulation design, such as delivery orifice size, drug-to-polymer ratio, tablet surface curvature, friction between particles and cohesion of polymer particles, on the drug release performance are systematically analysed. Numerical results reveal that an enlarged delivery orifice significantly increases both the total drug release and the drug release rate. Moreover, the larger the swellable particle component in the tablet, the higher the drug release rate. Furthermore, the tablet surface curvature is found to affect the drug release profile, i.e. the final drug release percentage increases with the increasing tablet surface curvature. It is also found that the drug release rate could be controlled by adjusting the inter-particle friction and the cohesion of polymer particles in the formulation. This DEM study offers valuable insights into the mechanisms governing drug release in push-pull osmotic pump tablets.

River floodplains as source or sink for fine sediment and total phosphorus export in an agricultural watershed

AbstractFloodplains constitute a vital and integrated component of the riverine network ensuring the connectivity and continuity of the river with the upland watershed areas. However, the sediment trapping efficiency of floodplains has not been well investigated. The purpose of this experimental study was to evaluate the functionality of floodplains to act as either sources or sinks for fine sediments and sediment‐bound nutrients (e.g., total phosphorus) during floods of various return periods. Thus, we hypothesized that (i) soil texture, in terms of topsoil erodibility and (ii) the magnitude of the incoming flood, in terms of the applied shear stress, are the two key parameters govern river floodplains' ability to store or release fine sediments and total phosphorus, during major flood conditions. Topsoil erodibility experiments were coupled with site‐specific flood inundation maps to estimate the eroded fine sediment mass and the total phosphorus release rates per unit area per unit time of each flood condition considered. Results suggested that the floodplain soils of the upstream reaches act as net sources, the floodplains of the midstream reaches have a dual functionality; during low magnitude flood events (up to 10‐year return periods), they act as net sinks, while during higher flood events, they act as sources; and the floodplains of the downstream reaches largely act as sinks. This study results are applicable for watershed managers to identify floodplain areas vulnerable to erosion and sources of nutrient pollution.

Utilizing the oxidation defects of black phosphorus to reduce and stabilize copper(I) molybdate to achieve flame retardancy and smoke suppression in polycarbonate composites

Promising phosphorus-based flame retardants reduce thermal hazards while increasing non-thermal hazards. This work utilizes the oxidative defects of black phosphorus, which can synchronously reduce and stabilize copper(I) molybdate while introducing surface modification with sodium alginate in an environmentally friendly ball milling process to enhance dispersibility. First, the T5% and Tmax of PC/BP@CM@SA (2 wt%) increase by 9.5 °C and 8 °C, respectively, under nitrogen. Second, UL-94 V0 was achieved, and the peak heat release rate, total heat release, and total smoke release decreased by 44.0 %, 22.1 %, and 17.0 %, respectively. Compared with that of the neat sample, the height of the char layer doubled, while its graphitization degree decreased from 2.38 to 2.14. In short, this is largely attributable to the catalytic action and physical barrier effect of BP@CM@SA. This study provides a way to balance the reduction in thermal hazards and increase in non-thermal hazards of phosphorus-based flame retardants such as black phosphorus.

A fully bio‐based epoxy resin with excellent mechanical properties combines flame retardancy and degradability

AbstractTraditional epoxy resins are made from non‐renewable fossil resources, which are difficult to reprocess and recycle, and their flammability makes them unsafe during use. In this experiment, an epoxy resin containing Schiff base (TA‐VAN‐EP) was synthesized successfully with biomass‐derived raw materials. This new material not only had favorable mechanical properties but also had good flame retardancy and degradation properties. The chemical structure of TA‐VAN‐EP was characterized by Fourier transform infrared (FTIR) spectroscopy and 1H nuclear magnetic resonance (NMR) spectroscopy. Its mechanical properties, thermal stability, flame‐retardant properties, and other properties were tested. The results showed that, compared with the pure epoxy resin (EP), the mechanical properties of TA‐VAN‐EP were significantly improved, and the glass transition temperature (Tg) was increased from 152°C to 190°C. Additionally, TA‐VAN‐EP reached a V‐1 rating during the UL‐94 test, and the limited oxygen index (LOI) value increased from 24.7% to 28.4%. Also, the total heat release (THR), smoke production rate (SPR), and total smoke release (TSR) decreased extremely. Moreover, TA‐VAN‐EP demonstrated good degradation performance under acidic conditions. In conclusion, this work provided a new idea for the production of bio‐based flame‐retardant epoxy resin with promising degradable abilities and mechanical properties.

Micro-encapsulation of garlic oil using esterified-wheat porous starch and whey protein isolate: Physicochemical properties, release behavior during in vitro digestion

The study aimed to inhibit the stimulating impact of garlic oil (GO) on the stomach and attain high release in the intestine during digestion. So, wheat porous starch (WPS) was modified with octenyl succinic acid (OSA) and malic acid (MA) to obtain esterified WPS, OWPS and MWPS, respectively. The differences in physicochemical, encapsulation, and digestive properties of two GO microcapsules, WPI/OWPS/GO and WPI/MWPS/GO microcapsules produced by using OWPS and MWPS as variant carrier materials and whey protein isolate (WPI) as the same coating agent, were compared. The results found that OWPS had greater amphiphilicity, while MWPS had better hydrophobicity and anti-digestive ability than WPS. Encapsulation efficiency of WPI/OWPS/GO (94.67 %) was significantly greater than WPI/MWPS/GO (91.44 %). The digestion inhibition and low GO release (approximately 23 %) of WPI/OWPS/GO and WPI/MWPS/GO microcapsules in the gastric phase resulted from the protective effect of WPI combined with the good adsorption and lipophilicity of OWPS and MWPS. Especially, WPI/OWPS/GO microcapsule was relatively stable in the gastric phase and had sufficient GO release (67.24 %) in the intestinal phase, which was significantly higher than WPI/MWPS/GO microcapsule (56.03 %), benefiting from the adsorption and digestive properties of OWPS, and resulting in a total cumulative GO release rate of 90.86 %.

Development of single layer osmotic controlled release tablet for low soluble drug: Single Core Osmotic Pump (SCOP)

A novel Single Core Osmotic Pump (SCOP) pill has been created to administer high doses of the low solubility medication Rifaximin using osmosis. The formulations were evaluated using six comparative parameters: Q24 (total release after 24 hours), Q12 (total release after 12 hours), TL (lag time), RSQzero12 (R square of the zero-order equation for drug release in 12 hours), RR12 (in vitro release rate for 12 hours), and T80% (time required to deliver 80% of the drug). The drug release profile from osmotic devices shows that the choice of polymer and its concentration in the core formulation can significantly impact the release of the drug. Augmenting the osmogent quantity to an optimal level resulted in a substantial enhancement of Q12 and a notable improvement in the zero-order release pattern of rifaximin. In order to improve the bioavailability of the core formulation, an additive called citric acid was included. Citric acid has several properties that contribute to this enhancement, such as increased solubility of the active ingredient, the creation of a difference in osmotic pressure, regulation of the flow of the active ingredient, and making the composition containing the active ingredient more water-loving. Consequently, TL and T80% experienced a decline, whereas Q12 and RR12 saw a rise. The concentration of PEG 4000 in the semipermeable membrane of the SCOP was found to have a significant impact on TL, T80%, Q12, Q24, and RR12. Specifically, increasing the concentration of PEG 4000 led to a decrease in TL and T80%, while increasing Q12, Q24, and RR12. The optimal aperture diameter for achieving a zero-order release pattern was found to be 850 μm. This study also demonstrated that optimizing the thickness of SPM is crucial for achieving zero order kinetics. The invented SCOP technology has the potential to create a single layer osmotic controlled release tablet of a water insoluble medication with a high dosage.

Release dynamics of nanodiamonds created by laser-driven shock-compression of polyethylene terephthalate

Laser-driven dynamic compression experiments of plastic materials have found surprisingly fast formation of nanodiamonds (ND) via X-ray probing. This mechanism is relevant for planetary models, but could also open efficient synthesis routes for tailored NDs. We investigate the release mechanics of compressed NDs by molecular dynamics simulation of the isotropic expansion of finite size diamond from different P-T states. Analysing the structural integrity along different release paths via molecular dynamic simulations, we found substantial disintegration rates upon shock release, increasing with the on-Hugnoiot shock temperature. We also find that recrystallization can occur after the expansion and hence during the release, depending on subsequent cooling mechanisms. Our study suggests higher ND recovery rates from off-Hugoniot states, e.g., via double-shocks, due to faster cooling. Laser-driven shock compression experiments of polyethylene terephthalate (PET) samples with in situ X-ray probing at the simulated conditions found diamond signal that persists up to 11 ns after breakout. In the diffraction pattern, we observed peak shifts, which we attribute to thermal expansion of the NDs and thus a total release of pressure, which indicates the stability of the released NDs.

The carbon release triggered by 1.32 Ga sill emplacement and its potential environmental implications

Magmatic activity is one of the important pathways for the delivery of deep Earth carbon to the surface. The massive carbon release in this process can have significant impacts on atmospheric-oceanic environment. Previous studies have done a lot of work on the relationship between Phanerozoic magmatic activity and carbon release, but there is relatively limited attention has been given to investigating the association between Precambrian magmatic activity and carbon release. The Yanliao Large Igneous Province at 1.32 Ga exhibits extensive development of sills, and the reaction between sills and surrounding rocks triggers the release of carbon. Simultaneously, the magmatic activity during this period is considered as the final response to the breakup of the Columbia supercontinent, coinciding with the occurrence of the Mesoproterozoic Oxygenation Event To explore the connection between this magmatic activity and global carbon cycling, environmental changes and planetary evolution, nine representative stratigraphic columns are selected from the Yanliao area. We use the SILLi 1.0 1D model by utilizing the one-dimensional finite element method (FEM) to simulate and estimate the amount of carbon release triggered by sill emplacement. The simulation results indicate that the emplacement of sills increased the surrounding rock temperature and vitrinite reflectance, leading to a decrease in the total organic carbon (TOC) content. A large amount of organic carbon and inorganic carbon was released, which was initiated by the reaction between sills and surrounding rocks, with a total carbon release up to 1.24 × 1013 tons. The estimated CO2 equivalent released during this magma activity episode is expected to be greater than 4.58 × 1013. In Mesoproterozoic strata, the emplacement of sills activates carbon within the lithosphere could have implications for the global environment. Further work needs to be done in other ancient cratons that possess Lower Riphean strata to find additional evidence of the impact of this magmatic event on the Earth system. From this study, it is evident that magmatic activity during the Precambrian period could promote the activation of carbon in crustal sediments and influence global environment, which can a reference for people to understand the planetary evolution process.

Interface engineering of multi-component core-shell flame retardant towards enhancing fire safety of thermoplastic polyurethane and mechanism investigation

Polymeric materials usually present substantial hazards to human health and the environment as a consequence of their flammability which leads to the emission of a great deal of heat and toxic fumes. To address this issue, it is imperative to urgently enhance the flame retardancy of polymer materials. This study focuses on the synthesis of a novel gel-silica/polydopamine double-layer microencapsulated cobalt ions (Co2+) modified ammonium polyphosphate (APP-Co@PDA@Si) and its utilization in thermoplastic polyurethane (TPU) composites. The resulting TPU composite, containing 10.0 wt% APP-Co@PDA@Si, exhibited excellent flame-retardant properties, i.e. achieving a limiting oxygen index of 30.0 % and the V-0 grade in the UL-94 test. Furthermore, peak heat release rate, total heat release, peak smoke production rate, and total smoke release of the TPU composite were decreased by 88.51 %, 66.06 %, 61.73 %, and 74.01 %, respectively, in comparison to those of pure TPU. The enhanced fire safety of the TPU composite was attributed to the synergistic effect among Co2+ catalytic carbonization, the free radicals capture effect of APP, and the flame-retardant functions of PDA and silane. This innovative strategy proposed in this work holds great promise for improving the fire-resistance of TPU.