Foam Production Research Articles

Evaluation of critical process parameter on the production of sustainable bead foams based on polylactic acid

A commercial grade of polylactic acid (PLA) was foamed without using modifiers to obtain expanded polylactic acid bead foams (EPLA). Typically, the foaming process is influenced by both melt properties and crystallization behavior. While factors like water temperature, die structure, and die temperature are known to have effects on bead foam processing, these aspects have not been thoroughly explored in the context of PLA bead foam production. To address this gap, a comprehensive investigation was undertaken, varying water temperature, die structure, and die temperature to discern their impact on PLA processing behavior. Results revealed that water temperature significantly influenced foaming behavior, particularly at elevated temperatures near the glass transition of PLA. Additionally, the study demonstrated that die size wielded a notable influence on all foam properties, dictating process limits. With the selection of an appropriate die size, the die temperature could be manipulated within the range of 190°C to 160°C, revealing a substantial impact on the overall process. Remarkably, the lowest densities achieved were 63 kg/m3 with an average cell size of 36 µm and a cell density of 1.1*107 cells per cm3.

Utilization of Neem Seed Oil as Surfactant in the Production of Flexible and Rigid Polyurethane Foam

Extraction and processing of polyether polyols derived from petrochemicals, commonly used as surfactants during polyurethane foam (PUF) production, contribute to carbon emissions and raises the issue of long-term sustainability given that petrochemicals are non-renewable resources. Here, 5 mg and 4 mg of neem seed oil are employed to form flexible and rigid PUF, classified purposefully based on their divergent usage. To find an environmentally friendly replacement, flexible PUF whose mass, volume, density, compression, tensile strength, cream time, foam rise and rising time are 0.0047 kg m3, 16.52 kg/m3, 8.10%, 39.28 kN/m2, 60s, 10s and 60s is formed by mixing 1.25 kg polyol, 5mg silicon oil and 10g calcium carbonate (CaCO3). Likewise, by mixing 1.2 kg polyol, 4mg silicon oil and 8g CaCO3, a rigid PUF with 0.005kg, m3, 16.2 kg/m3, 8.15%, 40.72 kN/m2, 50s, 15 cm and 58s key, physical and mechanical property as respectively listed under the flexible PUF formulation is produced. Both foams were produced using equal amounts of toluene diisocyanate, water, stannous octoate and methylene chloride, resulting in PUF that can be used in insulation, cushioning and construction support applications based on their characteristic height, density, tensile strength and compressive strength. As the surfactant, neem seed oil's potential in the synthesis of PUF cannot be overemphasized. The study of the kinetics of PUF production is limited and should trigger the adoption of biobased surfactants for industrial applications in the future.

Waste-to-resource: Employing lime mud as a foaming agent in glass foam manufacturing

The paper industry globally releases vast amounts of lime mud waste annually, raising environmental concerns. Composed mainly of calcium carbonate, lime mud has been utilized in various research works, including catalyst synthesis, cement production, and ceramic fabrication. This study investigates the use of lime mud as an eco-friendly foaming additive in the production of glass foam. Glass foams were prepared through a simple sintering method, utilizing glass cullet collected from households and incorporating different lime mud contents (0.5–2.0 wt%). The effects of lime mud concentration on the density, porosity, and pore size distribution of the glass foams were examined. Additionally, the thermal conductivity, compressive strength, and Weibull modulus were investigated in relation to the average porosity. The results revealed that the pore size distribution was dependent on the amount of lime mud, exhibiting three distinct distributions: a positively skewed distribution, a non-symmetric bimodal distribution, and a positively skewed distribution with a wide range. The Weibull modulus markedly decreased with increasing pore size. The compressive strength of the prepared glass foams ranged from 5.53±0.40–12.73±0.46 MPa, while the bulk density and porosity fell within the ranges of 0.41±0.02–0.70±0.04 g/cm3 and 72.12±1.45–85.38±0.98 %, respectively. The thermal conductivity could be as low as 0.07 W/m·K, approaching the upper limit for commercial glass foams used in thermal energy storage systems and meeting the requirements for Type I cellular glass thermal insulation classified by ASTM C552–16.

Environmental benefits of valorising food waste into bio-based polyols for the production of polyurethane rigid foams

Under the global pursuit of sustainable development, waste streams are being recognised as renewable feedstocks to produce value-added products. Given this, food waste (FW) was explored to synthesise bio-based polyols to further develop polyurethane rigid foams (PURF). However, relevant environmental aspects are yet to be examined to support this biorefinery scheme as a green and sustainable solution. In this work, we examined the environmental performance associated with the production of PURF using polyols derived from a FW biorefinery scheme by life cycle assessment (LCA). Analysis was first conducted at the polyol level. Different allocation and offset options were examined to configure the LCA model. Based on mass allocation, compared with fossil-based production, the production of FW-derived polyols achieved reductions of 24.30 % and 34.19 % in global warming potential (GWP) and cumulative energy demand (CED), respectively. At the midpoint level, FW-derived polyols had reduced impacts on human carcinogenic toxicity, freshwater eutrophication, and fossil resource scarcity but caused additional burdens on freshwater and marine ecotoxicity. Key environmental hotspots at this level included diethylene glycol, ion exchange resin (epoxidation catalyst), and hydrogen peroxide. The lipid content in FW also played a significant role. It was demonstrated that reducing the use of enzymes for FW hydrolysis to a cost-effective level remarkably mitigated the overall impacts of FW-derived polyol production. At the next level, we examined the production of FW-derived PURF using the obtained polyols. When 70 % of the polyols were replaced with bio-based products, the resultant PURF production achieved a GWP and CED of 5.67 kg CO2eq and 110.66 MJ/kg, respectively. In general, FW-derived PURF leads to environmental benefits compared to fossil-based ones. However, isocyanate used for foam formulation was the dominant contributor, causing almost two-thirds of the total impacts. The flame retardant also caused considerable impacts. Through the systematic examination of FW-derived polyols and PURF, this study demonstrated that FW-derived PURF could benefit the sustainable development of FW biorefineries and bio-based plastic industries, while the identified environmental hotspots need to be further studied and replaced with greener substitutes. AcronymsUnlabelled TableCEDCumulative energy demandDEGDiethylene glycolDALYDisability-adjusted life yearsFWFood wasteGWPGlobal warming potentialLCALife cycle assessmentLCILife cycle inventoryMDIMethylene diphenyl diisocyanateNIPUNon-isocyanate polyurethanespMDIPolymeric 4,4′-methylene diphenyl isocyanatePURFPolyurethane rigid foamsPUsPolyurethanesTPhPTriphenyl phosphateTCPPTris(1-chloro-2-propyl) phosphate

A statistical approach towards determining the governing parameters in volume expansion behavior of polypropylene foams

This study delves into the complex relationship between molecular structures and properties within polypropylene (PP) foams, with a particular focus on how various material parameters influence foamability. Multiple linear regression was adopted to efficiently assess the impact of eleven material parameters on foam expansion behavior. A primary finding is the significant role of branching index (g'vis) in shaping the expansion profile (i.e., the foaming window, maximum expansion ratio (Φmax), and optimum foaming temperature (Toptimum)). Additionally, Z-average molecular weight (Mz) is identified as crucial factor influencing the foaming window. Furthermore, the Winter-Chambon parameter n, indicator of the relaxation behavior of a resin in the terminal zone, is distinguished as a key parameter in determining Φmax. The crystallization temperature (Tc) also plays a pivotal role, particularly in its relationship with Toptimum. The research further highlights the significance of long-chain branching (LCB) and suggests strategies for cost reduction by minimizing the degree of LCB without compromising foaming performance, achievable through the adjustment of Mz and n. This strategy was exemplified through the comparison of two LCB PP resins, PP-12 and PP-22, demonstrating the feasibility of achieving similar foamability with adjustments in material parameters. The findings offer a detailed assessment of these parameters' influence on foamability, presenting valuable guidelines for optimizing PP foam production and customizing material properties for targeted applications.

Unlocking the potential of functionalized cottonseed oil for the production of biobased epoxy foams

Nowadays, polymer foams are present in various areas of modern life. Having valuable and versatile features, they are utilized for insulation, packaging, sound absorption, cushioning and many other applications. Most of the commercially available polymer foams, whether rigid or flexible, are made from petrochemicals. Among these porous polymers, polyurethanes derived from highly hazardous isocyanates are dominant. Replacement of such foams with more environmentally safe materials holds great significance in the context of sustainability policy. Therefore, the utilization of molecules derived from biomass for the production of porous polymer foams is of considerable importance. This work focuses on the development of thermoset flexible foams based on plant oil, namely cottonseed oil. The polymeric matrix of the foams was prepared by the reaction of epoxidized cottonseed oil (ECO) with a cyclic anhydride in the presence of a catalyst, whereas the gaseous phase was generated by the addition of a chemical blowing agent. The morphology of the prepared foams was characterized using Scanning Electron Microscopy, while the internal structure of the foams was studied via Micro-Computed Tomography. The thermomechanical properties of foams were evaluated by Thermogravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC) and Dynamic Mechanical Analysis (DMA). Possessing flexibility, softness, high porosity and shape memory ability, the prepared foams can be considered as potential cost-effective and eco-friendly options for flexible foams market: furniture, carper underlay, bedding.

Waste-to-energy: Repurposing flexible polyurethane waste for triboelectric nanogenerator applications

Triboelectric Nanogenerators (TENG) is a promising approach for clean energy harvesting. Light weight, flexible, cheap and environmentally-friendly materials are being explored as potential components in the TENG device in order to increase its efficiency. This paper reports the first effort to successfully utilize rebonded flexible polyurethane (RFPU) waste as a tribopositive material in a TENG device. A batch moulding technique was used to create two different densities (60 and 70 kg/m3) of flexible polyurethane (FPU) scraps, including customer waste and slabstock foam production waste. The current study investigates the effect of density on the compression strengths of the RFPU materials, as well as the impact on the output voltage of the TENG. Additionally, the effect of various RFPU sheet thicknesses (2, 4, 6, and 8 mm) as well as the effect of different applied forces and frequencies on the TENG's output voltage were investigated. The findings showed that the compressive strength increases with higher RFPU density. The output voltage values of the TENG device were recorded both with and without pre-charging. The results, without pre-charging, revealed that the highest output voltage of the TENG was obtained using an RFPU sheet with a density of 60 kg/m3. Furthermore, output voltage was shown to decrease with increasing RFPU sheet thickness and to increase with applied frequency. Pre-charging showed a similar trend, but yielded better results compared to the RFPU samples that were not pre-charged. The power density peaked at 0.085 mW/cm2, at a load resistance of 5 MΩ and a force of 4.7 N. The RFPU-based TENG successfully powered four white LEDs connected in series. Analysis of the embodied energy associated with using PU foam waste instead of virgin PU foam was conducted and demonstrated that utilizing PU foam waste provides environmental benefits due to the significant contribution of raw materials to the overall embodied energy in PU foam that is saved when reusing foam waste. Additionally, assessing the embodied energy of the components of the TENG device was also conducted and shows that the generated energy can partially offset the embodied energy of the TENG device. As a result, the prepared RFPU material not only helps to safeguard the environment but also shows great promise for use in developing more efficient and affordable TENGs in the future.

Fundamental mechanical relations of open-cell metal foam composite materials with reticular porous structure

The compressive behavior is one of the most fundamental mechanical properties for engineering materials. In this paper, the octahedral structure model of porous materials is used to evolve the mechanical analysis model under compressive loading for the porous composite materials, which are resulted from reticular metal foams with pore struts presenting multilayered structure. Starting from this analysis model, some fundamental mechanical relationships, including those of the safe load-bearing and overall strength, have been deduced for these porous composite materials. The compressive strength has been characterized for the porous composite body, corresponding to the overall failure caused by the prior breakage of the strut core and by the prior breakage of the strut shell, respectively. The nickel foam products manufactured on the production line of enterprise were used to make porous composite materials by coating the pore struts with epoxy resin, and the metal foam composite material was obtained with the composite pore-struts of metal/resin multilayered structure. Using this porous composite material for compression experiments, it is found that the experimental data match well with the mathematical relationship from the present theoretical model. The results verify the feasibility of this analysis model and the practicality of the relevant mathematical relationship.

Plant Design for the Production of Propylene Oxide by Isopropylbenzene 2-phenylpropane, or (1-Methylethyl) Benzene (Cumene)

Cumene is a colorless, volatile liquid with a gasoline-like odor. It’s also known as isopropylbenzene, 2-phenylpropane, or (1-methylethyl) benzene. It’s a natural component of coal tar and crude oil, and it can also be employed in gasoline as a blending component. Cumene hydroperoxide is produced by oxidizing cumene with benzene and propylene in the presence of air. As a result, the cumene hydroperoxide is changed to cumyl alcohol, which is then transformed to propylene without the use of oxygen. Propylene oxide is an organic compound produced through various methods such as the cumene process and the hydroperoxide process. The cumene method is preferred due to its low by-product production and high market value of co-products. The reactive distillation process is a feasible method for producing propylene oxide with high purity and reduced costs. Future work includes optimizing processes, developing new catalysts, and improving efficiency. Propylene oxide has practical applications in the production of polyurethane foams, coatings, adhesives, polyether polyols, and propylene glycols.

Environmentally Friendly Biocomposites for The Adsorption of Mancozeb Pesticide from Water

Objective: Developing polyurethane foams and composites incorporating petroleum catalyst residue (RC) and rice husk ash (RHA) to adsorb the pesticide mancozeb from water. Theoretical Framework: The annual global consumption of pesticides reaches 2.6 million tons, resulting in significant environmental impacts. Not only does this excess increase health risks, but the persistence of pesticides in water bodies emphasizes the need for effective alternatives for their removal, such as adsorption using polyurethane foams. Method: The polyurethane composites were synthesized with the incorporation of 20% and 50% of RC and RHA waste, respectively, in relation to the total mass of polyols. Characterization analyses were carried out using thermogravimetry, Fourier Transform Infrared Spectroscopy and X-ray diffraction. The composites were immersed in aqueous solutions of mancozeb at a concentration of 500 ppm, stirred for 24 hours at 150 rpm and the solution analyzed by UV-Vis. Results and Discussion: The foams showed chemical and dimensional stability. The composites synthesized with a high amount of waste incorporated achieved greater adsorption capacity. Research Implications: Este trabalho promove a economia circular ao desenvolver compósitos de poliuretano que incorporam resíduos para a remoção eficiente de pesticidas da água. Originality/Value: The results are promising for the use of waste in the production of sustainable polyurethane foams that can be applied in the water purification process.

Vanillic acid-based pro-coagulant hemostatic shape memory polymer foams with antimicrobial properties against drug-resistant bacteria

Uncontrolled bleeding is the primary cause of trauma-related death. For patients that are brought to the hospital in time to receive treatment, there is a great risk of contracting drug-resistant bacterial wound infections. Therefore, low-cost hemostatic agents with procoagulant and antibacterial properties are essential to reduce morbidity and mortality in patients with traumatic wounds. To that end, we introduced vanillic acid (VA) into shape memory polymer (SMP) foams through a dual incorporation mechanism to make dual vanillic acid (DVA) foams. The dual mechanism increases VA loading while allowing burst and sustained delivery of VA from foams. DVA foams exhibit antimicrobial and antibiofilm properties against native and drug-resistant Staphylococcus aureus (S. aureus) and Staphylococcus epidermidis. Also, DVA foams inhibit the growth rate of both methicillin-sensitive and -resistant S. aureus colonies to limit their size and promote small colony variants. DVA SMP foams induced primary and secondary hemostasis in in vitro blood interaction studies. As a proof of concept, we demonstrated easy delivery and rapid clotting in a porcine liver injury model, indicating DVA foam feasibility for use as a hemostatic dressing. Thus, the inexpensive production of DVA SMP foams could enable a cost-effective procoagulant hemostatic dressing that is resistant to bacterial colonization to improve short- and long-term outcomes for hemorrhage control in traumatically injured patients. Statement of significanceUncontrolled bleeding is the primary cause of preventable death on the battlefield. Of patients that survive, ∼40 % develop polymicrobial infections within 5 days of injury. Drug-resistant infections are anticipated to cause more deaths than all cancers combined by 2050. Therefore, novel non-drug-based biomaterials strategies for infection control in wound care are increasingly important. To that end, we developed hemostatic polyurethane foams that include antimicrobial and pro-coagulant vanillic acid, a plant-based antimicrobial species. These foams provide excellent protection against native and drug-resistant bacteria and enhanced coagulation while remaining cytocompatible. In a pilot porcine liver injury model, vanillic acid-containing foams stabilized a bleed within <5 min. These biomaterials provide a promising solution for both hemorrhage and infection control in wound care.

Application of Technological Procedure Automated Guided Vehicles in the Production Hall of a Company Due to Increasing the Automation—Case Study

This paper discusses the possibility of deploying automated guided vehicle (AGV) technology in a company’s production hall. Chronometric measurements of material handling and people handling were performed. The handling processes were divided into five sub-processes, which were analysed in terms of production line operation, distance, and carrying capacity of the automated guided vehicles. Based on the measurements, we found that it was necessary to use four vehicles for handling in the foam production hall. The company is applying this automation project to foams, and after successful testing, plans to continue with automation for leather upholstery. To ensure the correct chronometric results, we measured the distances between each workstation on the production floor at the company. Based on an analysis of material handling on the production lines, we evaluated that there is a possibility of applying AGVs on the entire production floor. We analysed the volumes of material transfer and the possibilities of interconnection within the existing material handling in the enterprise. Complications arise when deploying AGVs in the plant because the handling to the production lines is not only provided by the parent company, but also by the component suppliers themselves. Based on this observation, we have identified potential collision points within the operation between automated guided vehicles and other material handling equipment or people. For this reason, we deployed one more AGV on the handling routes to prevent unwanted collisions. This means that a human would be able to perform even more processes than a machine and can circulate 80 times, where a machine under the same conditions would only perform the entire circulation 57 times. There is room here to use humans for other processes and to automate the handling of goods, although it introduces delays that can be eliminated by deploying additional automated guided vehicles. This opens room for further research questions on how these vehicles can be deployed, even in a small space, and how existing material handling can be automated.

High-strength, impact-resistant PP/PTFE composite foam with enhanced surface appearance achieved through mold-opening microcellular injection molding

Poor surface appearance and decreased mechanical performance are critical factors limiting the broad application of Microcellular injection molding (MIM) in foamed polymer products. Herein, in-situ polytetrafluoroethylene (PTFE) nanofibrils reinforced polypropylene (PP) foams with high strength, impact resistance, and enhanced surface quality were prepared by mold opening microcellular injection molding (MOMIM). PTFE nanofibers with different diameters were introduced into the PP matrix via twin screw extrusion and significantly enhanced the crystallinity and viscoelasticity of the PP matrix with the enhancement being more pronounced for the finer PTFE fibers. High-density oriented cellular structures were formed in the MOMIM PP/PTFE foams owing to the heterogeneous nucleation of PTFE and the stretching effect of the mold opening process. The optimum MOMIM PP/PTFE foam fabricated possesses a high cell orientation angle close to 90° and a large cell aspect ratio of 5.3, which reached a 34.37 % increase in tensile strength and a 73.08 % increase in impact strength owing to the synergetic effects of the PTFE network and the highly oriented fine cell structure, which effectively dissipated the tensile stress and impact stress by cell wall twisting and folding deformation. Furthermore, the MOMIM PP/PTFE foam showed a significantly enhanced surface quality compared to the MIM foam due to the reduced dragging flow in MOMIM, which greatly hindered cell rupture on the foam surface. Therefore, this work provides insights into the MOMIM of polymer composites containing fibrous fillers and the enhancement of tensile properties, impact resistance, and surface quality of foam products.

Liquefaction optimization of grape pulp using response surface methodology for biopolyol production and bio-based polyurethane foam synthesis.

Both environmental and economic disadvantages of using petroleum-based products have been forcing researchers to work on environmentally friendly, sustainable, and economical alternatives. The purpose of this study is to optimize the solvothermal liquefaction process of grape pomace using response surface methodology coupled with a central composite design. After investigating the physicochemical properties of the liquified products (biopolyol) in detail, a bio-based rigid polyurethane foam (RPUF) was synthesized and characterized. The hydroxyl and acid numbers and viscosity values of all the biopolyols were analyzed. According to variance analysis results (%95 confidence range), both the reaction temperature and catalyst loading were determined as significant parameters on the liquefaction yield (LY). The model was validated experimentally in the following reaction conditions: 4.25% catalyst loading, 50 min reaction time, and 165 °C reaction temperature, which yields an LY of 81.3%. The biopolyols produced by the validation experiment display similar characteristics (hydroxyl number: 470.5 mg KOH/g; acid number: 2.31 mg KOH/g; viscosity: 1785 cP at 25 °C) to those of commercial polyols widely preferred in the production of polyurethane foam. The physicochemical properties of bio-based foam obtained from the biopolyol were determined and the thermal conductivity, closed-cell content, apparent density, and compressive strength values of bio-based RPUF were 31.3 mW/m·K, 71.1%, 33.4 kg/m3, and 105.3 kPa, respectively.

Growth performance, biochemical outcomes, and testicular histological features in male Japanese quails supplemented with milk thistle seeds

BackgroundDue to its rich content of active phytochemicals, milk thistle is regarded as a promising nutritional supplement for quails, particularly in regions with limited financial resources. Thus, our study aimed to evaluate the possible beneficial impact of aqueous extract of milk thistle seeds (MTS) at two graded concentrations (10 and 20 ml/L of drinking water) on male Japanese quails during their reproductive period.ResultsThe phytochemical analysis revealed the presence of 29 active compounds, including nine flavonoids and ten phenolic compounds. The supplemented groups showed significant improvements in body weight gain. MTS1 group exhibited a notable decrease in daily feed consumption, while MTS2 group showed a significant increase in daily water consumption. There was a dose-dependent increase in cecum length. The total count of intestinal bacteria decreased in a dose-dependent manner. Incorporating aqueous extract of MTS at concentration of 10 ml /L resulted in a significant increase in total protein and packed cell volume. Similar increases in globulin and decreases in the albumin/globulin ratio and aspartate aminotransferase (AST) were observed with both doses of supplementation. A significant decrease in total cholesterol and AST was observed in the high-dose group. Significantly higher plasma testosterone and triiodothyronine levels were observed only in the high-dose group, while plasma thyroxine levels were similarly increased in both supplemented groups. Intervention with MTS resulted in dose-dependent increases in cloacal gland index and cloacal foam production. Both supplemented groups showed significant increases in the diameter of seminiferous tubules and the number of Sertoli cells.ConclusionMarked growth-promoting, antibacterial, and reproductive-enhancing effects were observed when incorporating aqueous extract of MTS into the quails’ drinking water, particularly at a dosage of 20 ml/L.

Innovative reinforcement method for metal foam cell wall using CNTs

Carbon nanotubes (CNTs) and their composites are gaining popularity due to their exceptional strength qualities. It is well known that adding CNTs to metal foam composites boosts compressive strength. On the other hand CNT addition is still a costly process due to high cost of the CNTs. This study presents a novel and cost-effective solution by selectively adding CNTs to the structurally weakest regions of aluminum foam materials produced via powder metallurgy, employing a newly developed focused multi-step additive method. The cell borders of aluminum foam are strengthened with multiple spherical layers of CNTs, using a transfer method by initially coating the space holders used at the foaming process. The strength increase effect of this CNT addition method was compared with the widely known aluminum foam production parameters via a 4-parameter design of experiment (DOE) study. Compressive strength values of the samples were evaluated using a constant speed compression test acc. to ISO13314. The compacting pressure, CNT concentration, sintering temperature, and sintering period were chosen as DOE parameters, and 78% of the interactions effecting on final compressive strength could be explained with the model. As a result, it was established that, compared to the other parameters, sintering duration had the highest influence on compressive strength. But besides It has also been shown that adding 0.53% CNT by weight only to the cell border regions increases overall strength by 9%. This weight-strength increase ratio is compared with similar studies in the literature and found to be providing a production cost advantage due to the lower amount of CNT addition requirement for the comparable weight relative strength increase. Focused strength increase method has potential to enable controlled failure of foam materials by selectively strengthening strength critical areas of a component.

Foam fractionation studies of recombinant human apolipoprotein A-I

Apolipoprotein A-I (apoA-I), the primary protein component of plasma high-density lipoproteins (HDL), is comprised of two structural regions, an N-terminal amphipathic α-helix bundle domain (residues 1–184) and a hydrophobic C-terminal domain (residues 185–243). When a recombinant fusion protein construct [bacterial pelB leader sequence – human apoA-I (1–243)] was expressed in Escherichia coli shaker flask cultures, apoA-I was recovered in the cell lysate. By contrast, when the C-terminal domain was deleted from the construct, large amounts of the truncated protein, apoA-I (1–184), were recovered in the culture medium. Consequently, following pelB leader sequence cleavage in the E. coli periplasmic space, apoA-I (1–184) was secreted from the bacteria. When the pelB-apoA-I (1–184) fusion construct was expressed in a 5 L bioreactor, substantial foam production (~30 L) occurred. Upon foam collection and collapse into a liquid foamate, SDS-PAGE revealed that apoA-I (1–184) was the sole major protein present. Incubation of apoA-I (1–184) with phospholipid vesicles yielded reconstituted HDL (rHDL) particles that were similar in size and cholesterol efflux capacity to those generated with full-length apoA-I. Mass spectrometry analysis confirmed that pelB leader sequence cleavage occurred and that foam fractionation did not result in unwanted protein modifications. The facile nature and scalability of bioreactor-based apolipoprotein foam fractionation provide a novel means to generate a versatile rHDL scaffold protein.

Advances in Inorganic Foam Materials Fabricated Via Blowing Strategy: A Comprehensive Review.

Two-dimensional (2D) materials with excellent properties and widespread applications have been explosively investigated. However, their conventional synthetic methods exhibit concerns of limited scalability, complex purification process, and incompetence of prohibiting their restacking. The blowing strategy, characterized by gas-template, low-cost, and high-efficiency, presents a valuable avenue for the synthesis of 2D-based foam materials and thereby addresses these constraints. Whereas, its comprehensive introduction has been rarely outlined so far. This review commences with a synopsis of the blowing strategy, elucidating its development history, the statics and kinetics of the blowing process, and the choice of precursor and foaming agents. Thereafter, we dwell at length on across-the-board foams enabled by the blowing route, like BxCyNz foams, carbon foams, and diverse composite foams consisting of carbon and metal compounds. Following that, a wide-ranging evaluation of the functionality of the foam products in fields such as energy storage, electrocatalysis, adsorption, etc. is discussed, revealing their distinctive strength originated from the foam structure. Finally, after concluding the current progress, we provide some personal discussions on the existing challenges and future research priorities in this rapidly developing method.

Eco-conscious upcycling of sugarcane bagasse into flexible polyurethane foam for mechanical & acoustic relevance.

This study explores the use of sugarcane bagasse (SCB), a byproduct of sugarcane processing, as a bio-filler in the production of flexible polyurethane foam (FPU), focusing on its benefits for both the environment and the economy. By varying the inclusion of SCB waste from 1 to 6 wt%, the research aims to enhance the FPU's mechanical and acoustic characteristics. Techniques such as Fourier transform infrared (FTIR) spectroscopy and field emission scanning electron microscopy (FESEM) were utilized to analyze the chemical structure and surface characteristics of both SCB and the FPU/SCB composites. Additionally, tests on gel fraction, density, and mechanical properties were conducted. The results indicate that adding 4 wt% SCB to FPU considerably improved the foam's properties. This modification resulted in a 148.63% increase in apparent density, a 228.47% rise in compressive strength, and a 116.24% boost in tensile strength. Furthermore, sound absorption across various frequency ranges was enhanced compared to the control foam. Additionally, the findings show that SCB effectively shifts sound absorption characteristics to lower frequencies. Specifically, at a low frequency of 500 Hz, the sound absorption coefficient increased to 0.4 with a foam thickness of 20 mm. This demonstrates that SCB can significantly improve FPU's performance, making it an attractive option for applications requiring noise mitigation, such as in the automotive and construction industries, thereby offering a sustainable solution to waste management and materials innovation.

Selection of indigenous Saccharomyces cerevisiae strains with good oenological and aroma characteristics for winemaking in Ningxia China

Ningxia is one of the well-known wine producing regions in China. However, the oenological and aroma characteristics of indigenous yeasts remains hidden. The fermentative and oenological properties including stress resistance, hydrogen sulfide, foam production levels; killer phenotype, and flocculation of 89 Ningxia indigenous Saccharomyces cerevisiae isolates and ten commercial yeasts were evaluated. The fermentative and oenological properties of the tested strains varied significantly. They could resist 500 g/L glucose, 300 mg/L SO2, 14% (v/v) ethanol and pH 2.8, and produce more esters. They also produce low levels of ethanol and could conduct fermentations vigorously and at a high rate. Cabernet Sauvignon wines made with NXU 21–24 showed the high intensity of tropical fruit, dry fruit, temperate fruit, and spicy flavor. The floral flavor in NXU 21–102 fermented wine is very intense. The indigenous S. cerevisiae strains of NXU 21–102 and NXU 21–24 exhibited potential use as starter cultures in wine production.