Crosslinking Process Research Articles

Synthesis and characterization of chitosan-modified membrane for urea slow-release fertilizers

BackgroundUrea is a fertilizer widely used by farmers, especially vegetable farmers, due to its high nitrogen content, around 46 %. However, plants only use a small amount of nitrogen, a maximum of 35 %, while the remaining nitrogen is wasted and released into the environment. Undeniably, it causes increases production costs and environmental problems. A slow-release urea fertilizer (SRF) has been formulated to resolve these issues. MethodsIn this study, the membrane was made of chitosan with several crosslinking agents such as Tripolyphosphate (TPP). In addition, calcium ion bonds are expected to increase the interaction with urea fertilizer through the encapsulation process. The resultsOur data showed that urea slow-release fertilizer (SRF) with the chitosan/TPP/Ca membrane, was successfully synthesized. This membrane has the characteristics of a thin white layer that is transparent. The physical and chemical characterization of SRF membranes with various coating membrane variations showed that the chitosan/TPP/Ca-urea membrane has Young's modulus of 7.75–22.05 N/mm2, swelling of 109.52–132.62 % and porosity of 0.756–1.06 %. Functional group analysis shows that several spectral changes indicate the presence of crosslinking process between the chitosan functional groups and TPP. The urea release results show that the membrane is released through a diffusion mechanism. Furthermore, SEM results show that these membranes have pores with various shapes and sizes. ConclusionBased on the result, it can be concluded that chitosan membrane modification with the addition of TPP and calcium oxide provides improved membrane characteristic cs including degree of development, hydrophobicity, membrane stress, and nitrogen release on the membrane. This membrane shows is indicating suitability as a slow-release fertilizer.

Development of hyaluronic acid hydrogel containing prednisolone-encapsulated nonphospholipid liposomes for the treatment of rheumatoid arthritis.

Rheumatoid arthritis (RA) requires therapeutic approaches that alleviate symptoms and inhibit the progression of joint damage. Glucocorticoids (GCs) have been a cornerstone of RA treatment, yet their use is often limited by side effects. Recent advancements suggest that liposome-based delivery systems can improve GC biodistribution, minimizing toxicity. This study introduces an innovative tool for RA treatment using prednisone-encapsulated nonphospholipid liposomes (NPLs) in combination with a hyaluronic acid (HA) hydrogel. Our methodology involved incorporating prednisone (PR) with palmitic acid and cholesterol to formulate stable NPLs using a thin-film hydration technique. The synthesized PR-NPLs, characterized by a mean size of 150 nm, demonstrated uniform distribution and higher drug encapsulation in comparison with conventional phospholipid liposomes. In vitro assays revealed that PR-NPL markedly reduced inflammatory responses in macrophages. Additionally, we successfully incorporated PR-NPL into an HA hydrogel, employing a photoinitiated cross-linking process. This novel composite offered modulable PR release, governed by the degree of hydrogel cross-linking. The developed system presents a promising advancement in RA management, especially suited for intraarticular injections. It potentially enables targeted, controlled drug release with a reduced risk of side effects, signifying a significant improvement over existing RA therapies.

Why Single-Chain Nanoparticles from Weak Polyelectrolytes Can Be Synthesized at Large Scale in Concentrated Solution?

Here, the unresolved question of why single-chain nanoparticles (SCNPs) prepared from a weak polyelectrolyte (PE) precursor can be synthesized on a large is addresses, unlike SCNPs obtained from an equivalent neutral (nonamphiphilic) polymer precursor. The combination of the standard elastic single-chain nanoparticles (ESN) model -developed for neutral chains- with the classical scaling theory of PE solutions provides the key. Essentially, the long-range repulsion between electrostatic blobs in a weak PE precursor restricts the cross-linking process during SCNPs formation to the interior of each blob. Consequently, the maximum concentration at which PE-SCNPs can be prepared without interchain cross-linking is not determined by the full size of the PE precursor but, instead, by the smaller size of its electrostatic blobs. Therefore, PE-SCNPs can be synthesized up to a critical concentration where electrostatic blobs from different chains touch each other. This concentration can be 30 times higher than that for non-PE polymer precursors. Upon progressive dilution, the size of PE-SCNPs synthesized in concentrated solution increases until it reaches the bigger size of PE-SCNPs prepared under highly diluted conditions. PE-SCNPs do not adopt a globular conformation either in concentrated or in diluted solution. It shows that the main model predictions agree with experimental results.

Curing and Cross-Linking Processes in the Poly(3,3-bis-azidomethyl oxetane)-tetrahydrofuran/Toluene Diisocyanate/Trimethylolpropane System: A Density Functional Theory and Accelerated ReaxFF Molecular Dynamics Investigation.

The physical and chemical properties of solid propellant are influenced by the composition and structure of the binder, with its network structure being formed through curing and cross-linking reactions. Therefore, understanding the mechanisms of these reactions is crucial. In this study, we investigated the curing and cross-linking mechanisms of poly(3,3-bis-azidomethyl oxetane)-tetrahydrofuran (PBT), toluene diisocyanate (TDI), and trimethylolpropane (TMP) using a combination of density functional theory (DFT) calculations and accelerated ReaxFF molecular dynamics (MD) simulations. DFT calculations revealed that the steric effect of the -CH3 group in TDI exerts a significant influence on the curing reaction between TDI and PBT. Additionally, in the cross-linking process, the energy barrier for TDI reacting with TMP was found to be much lower than that for TDI reacting with the PBT-TDI intermediate. Subsequently, we conducted competing reaction processes of TMP/TDI-PBT-TDI cross-linking and TDI-PBT-TDI self-cross-linking using accelerated MD simulations within the fitted ReaxFF framework. The results showed that the successful frequency of TMP/TDI-PBT-TDI cross-linking was substantially higher than that of TDI-PBT-TDI self-cross-linking, consistent with the energy barrier results from DFT calculations. These findings deepen our understanding of the curing and cross-linking mechanisms of the PBT system, providing valuable insights for the optimization and design of solid propellants.

Multi-Layer PVA-PANI Conductive Hydrogel for Symmetrical Supercapacitors: Preparation and Characterization.

This work describes a simple, inexpensive, and robust method to prepare a flexible "all in one" integrated hydrogel supercapacitors (HySCs). Preparing smart hydrogels with high electrical conductivity, ability to stretch significantly, and excellent mechanical properties is the last challenge for tailored wearable devices. In this paper, we employed a physical crosslinking process that involves consecutive freezing and thawing cycles to prepare a polyvinyl alcohol (PVA)-based hydrogel. Exploiting the self-healing properties of these materials, the assembly of the different layers of the HySCs has been performed. The ionic conductivity within the electrolyte layer arises from the inclusion of an H2SO4 solution in the hydrogel network. Instead, the electronic conductivity is facilitated by the addition of the conductive polymer PANI-PAMPSA into the hydrogel layers. Electrochemical measures have highlighted newsworthy properties related to our HySCs, opening their use in wearable electronic applications.

Ultra-hydrophobic Eucommia gum coating with temperature-responsive and shape-memory performance

The intelligent and multifunctional composites offer important applications in many fields. However, the fabrication of intelligent and multifunctional composites still faces limitations due to complicated processes, high costs, and restricted area coverage. Here, we present a new approach for creating a micro/nano-hybrid hierarchical Eucommia ulmoides gum (EUG) coating with outstanding superhydrophobic, temperature-responsive and shape-memory characteristics. The intelligent EUG coating prepared in this study can regulate the change and recovery of the microstructure of the coating surface by altering temperature and external force, thereby achieving control of the surface properties and memory performance of the coating. These EUG hydrophobic shape-memory coatings are obtained through the preparation of superhydrophobic sepiolite particles, spin coating, and chemical cross-linking processes. In addition to its performance advantages, the outstanding advantage of these composites is the simple and easy preparation process, regardless of the substrate surface topography. These novel superhydrophobic and temperature-responsive shape-memory EUG composites can achieve contact angle and thickness regulation. These superhydrophobic and temperature-responsive shape-memory EUG composites are highly expected to be applied in medical devices and intelligent textiles fields.

Poly[2]catenane Gels Based on Sequential Assembly of Small Molecules†

Comprehensive SummaryPolycatenane gels have attracted extensive attention due to their high degree of freedom and mobility. However, the syntheses of poly[2]catenane gels reported to date all rely on the polymer as the backbone. Herein, we prepared poly[2]catenane gels based on entirely sequential assembly of small molecules. Monomer M1 with two unclosed rings was first prepared, which self‐assembled to form supramolecular polymers (SPs) via hydrogen bonding and π‐π interactions. Upon adding small molecule monomers M2 and M3 with aldehyde groups, ring closing of SPs occurred because the amino groups in the SPs reacted with M2 to form imine bonds. In addition, M3, which had twice the number of aldehyde groups as M2, enabled SPs to ring‐close, causing the proceeding of crosslinking process at the same time. Thus linear SPs were transformed into poly[2]catenane gel networks. Due to the presence of hydrogen bonds in the poly[2]catenane gel, the gel also possessed stimulus responsiveness and self‐healing properties.

Preparation of cellulose derived carbon/reduced graphene oxide composite aerogels for broadband and efficient microwave dissipation

The development of cellulose derived carbon-based composite aerogels with light weight, broad bandwidth and strong absorption remains a challenging task. In this work, the cellulose derived carbon/reduced graphene oxide composite aerogels were prepared by a two-stage process of chemical crosslinking and high-temperature carbonization. The results revealed that the as-fabricated binary composite aerogels had a unique lightweight characteristic and three-dimensional porous network structure, which was chemically crosslinked by epichlorohydrin. Furthermore, the weight concentration of graphene oxide (GO) had a notable influence on the electromagnetic parameters and microwave absorption properties of the composite aerogels. The obtained binary composite aerogel possessed the optimal microwave dissipation capability when the concentration of GO was 1.5 mg/mL. Remarkably, the minimum reflection loss reached −50.42 dB at a thickness of 2.47 mm and a filling ratio of 17.5 wt%. Concurrently, the composite aerogel with a comparable thickness of 2.73 mm showed a wide effective absorption bandwidth of 7.28 GHz, spanning the total Ku-band and extending into a portion of the X-band. The radar cross section contribution of binary composite aerogels in the far-field was also simulated by computer simulation technique. In addition, the potential microwave attenuation mechanism was proposed. It was believed that the results of this paper would offer a reference for the preparation of cellulose derived carbon-based composite aerogels as efficient and broadband microwave absorbers.

Enhanced UV Penetration and Cross-Linking of Isoporous Block Copolymer and Commercial Ultrafiltration Membranes using Isorefractive Solvent.

Amphiphilic block copolymers are promising candidates for the fabrication of ultrafiltration membranes with an isoporous integral asymmetric structure. The membranes are typically fabricated by the combination of block copolymer self-assembly and the non-solvent-induced phase separation (SNIPS) process resulting in isoporous integral asymmetric membranes. Certainly, all these membranes lack thermal and chemical stability limiting the usage of such materials. Within this study, the fabrication of completely cross-linked isoporous integral asymmetric block copolymer membranes is demonstrated by UV cross-linking resulting in chemical and thermal stable ultrafiltration membranes. The UV cross-linking process of PVBCB-b-P4VP (poly(4-vinylbenzocyclobutene)-b-poly(4vinylpyridine)) block copolymer membranes in dependency of irradiation time, intensity, distance between membrane and UV source and the wavelength is investigated. Furthermore, it is shown that the penetration depths can be increased by soaking the membranes in wave-guiding solutions before UV cross-linking is carried out. Moreover, a completely new and easy cross-linking strategy is developed based on isorefractive solvents resulting in thermal and chemically stable membranes that are cross-linked through the whole membrane thickness. Finally, the new cross-linking strategy in isorefractive solutions is transferred to commercial PVDF and PAN-co-PVC polymer membranes paving the way for more stable and sustainable ultrafiltration membranes.

Effect of Crosslinking Agents on Chitosan Hydrogel Carriers for Drug Loading and Release for Targeted Drug Delivery.

Numerous studies report on chitosan hydrogels in different forms, such as films, porous structures, nanoparticles, and microspheres, for biomedical applications; however, this study concentrates on their modifications with different crosslinking agents and observes their effects on drug loading and releasing capacities. Linear chitosan, along with chitosans crosslinked with two major crosslinkers, i.e., genipin and disulfide, are used to formulate three different hydrogel systems. The crosslinking process is heavily impacted by temperature and pH conditions. Three different drugs, i.e., thymoquinone, gefitinib, and erlotinib, are loaded to the hydrogels in de-ionized water solutions and released in phosphate-buffered solutions; thus, a total of nine combinations are studied and analyzed for their drug loading and releasing capabilities with ultraviolet-visible (UV-Vis) spectroscopy. This study finds that thymoquinone shows the lowest loading efficacy compared to the two other drugs in all three systems. Gefitinib shows stable loading and releasing regardless of crosslinking system, and the genipin-crosslinked system shows stable loading and releasing with all three drug molecules. These experimental results agree well with the findings of our previously published results conducted with molecular dynamics simulations.

Designing Advanced Cross-Linked Proton Exchange Membranes with Enhanced Structural Homogeneity and Proton Conductivity via Radiation-Induced RAFT Polymerization.

This study introduces an innovative approach to fabricate well-defined cross-linked proton exchange membranes (PEMs) using radiation-induced reversible addition-fragmentation chain transfer (RAFT)-mediated polymerization on cost-effective ethylene tetrafluoroethylene (ETFE) films. The incorporation of the RAFT mechanism into the cross-linking process significantly enhanced structural homogeneity, providing uninterrupted proton conductivity. Thorough characterizations confirmed the successful grafting of polystyrene (PS) chains onto ETFE films and subsequent sulfonation. Despite a reduction in proton conductivity attributed to restricted chain movements, a notable improvement in chemical stability was observed after cross-linking reactions. Chemical stability of the cross-linked membranes increased approximately 4-fold compared to those synthesized without a cross-linker. The synthesized PEMs with degrees of grafting at 45% and 67% demonstrated superior proton conductivity, outperforming various alternatives, including commercial Nafion samples. Specifically, these cross-linked membranes exhibited promising proton conductivity values of 93.7 and 139.1 mS cm-1, respectively. This work highlights the potential of radiation-induced RAFT-mediated polymerization in carrying out cross-linking reactions as an efficient pathway for designing well-defined high-performance PEMs, offering enhanced homogeneity and conductivity compared to existing literature counterparts.

A novel strategy and characteristics of PVA/citric acid cross-linked hydrophilic elastic sponge of cellulose based on medicinal herb residue

A new ultra-hydrophilic elastic sponge composite has been proposed. Medicinal herbs, commonly used in herbal medicine and subsequently discarded, are rich in natural polymer substances, making them promising candidates for various material industries. TEMPO-oxidized cellulose was extracted from medicinal herb residue, and the physicochemical properties of an ultra-hydrophilic elastic sponge, prepared through a PVA and CA impregnate cross-linking process, were investigated. The fabricated composite sponge exhibited an increase in compressive stress-strain proportional to the PVA cross-linking concentration, and its water retention capability was assessed through retention tests. Swelling tests for various solvents were conducted to evaluate the potential use of the sponge in diverse industries, revealing the highest swelling ratio in water. Pressure distribution measurements using prescale film indicated that the sponge's shock absorption capacity was enhanced by PVA cross-linking, leading to improved pressure dispersion.

Alternative Polysaccharide Wound Dressing from Heat-Moisture Starch/Basil Seed (O. Basilicum L.) Mucilage with Incorporated Glycolic Acid Antimicrobial Agent

In order to improve the behavior in water and the mechanical properties of heat-moisture treated starch, natural basil seed mucilage with high hydrophilicity and crystallinity was incorporated for wound dressing application. In addition, succinic acid cross-linking was used to enhance the durability of the material in water and glycolic acid was utilized as an antimicrobial agent. The effectiveness of the cross-linking process could be observed from the significant increase in dimensional stability from higher gel fraction value and increment of mechanical properties. Furthermore, the incorporation of glycolic acid into the wound dressing films demonstrated antibacterial efficacy, resulting in 100% bacterial reduction against S. aureus and E. coli strains. These films exhibited low cytotoxicity toward human epidermal keratinocytes (HaCaT) cells, indicating their potential for biomedical applications. Moreover, functional group analysis, crystallinity, morphology, thermal properties, gel fraction, water vapor transmission rate, free swell absorption, and mechanical properties were also examined.

Chitosan aerogel loaded with biogenic palladium nanoparticles CH/Pd NPs exert antibacterial activity and wound addressing application in vitro and in vivo against bacterial skin infections

Bacterial skin infections that infect wounds and burns are considered one of the most serious medical problems that lead to delay wound healing, toxicity and even death. Therefore, there is an urgent need to develop an effective pharmaceutical material that promotes the treating of skin bacterial infections. Within this, we aimed in this study to synthesis and assess the effectiveness of novel chitosan/palladium nanoparticles (CH/Pd NPs) aerogel composites in treating bacterial skin infections and wound healing. Green method was employed for synthesis of Pd NPs using Allium sativum (A. sativum) extract, while crosslinking process and freeze-drying cycle were utilized for preparation of CH/Pd NPs aerogel composites. The prepared Pd NPs and CH/Pd NPs aerogel composite were thoroughly characterized using UV–vis, FTIR, XRD and SEM. The GC–MS analysis revealed that the main components in the A. sativum were diallyl disulfide (55.88 %) and diallyl trisulfide (24.34 %) which were among the four identified components. Additionally, the total phenols and flavonoids contents were 61.3 mg GAE/100 g and 18.8 mg QE/100 g, respectively. The swelling capacity of CH/Pd NPs aerogel microspheres reach 400 % with blood compatibility and slightly hemolysis ratio about 0.4 %. In vitro, the antibacterial studies demonstrated that loading Pd NPs with CH aerogel microspheres enhanced their effectiveness against MDR bacteria with complete inhibition for all bacterial strains growth. The CH/Pd NPs aerogel microspheres exhibited a significant inhibitory effect on biofilm formation. The biofilm inhibition percentage was found to be 87 % against the biofilm of S. aureus and 80 % against the biofilm of P. aeruginosa. In vivo infection model in rats, CH and CH/Pd NPs aerogel films stimulated skin tissue formation and healing wounds completely in 6 days with highly reduced in MDR and biofilm producing bacterial count. Finally, CH/Pd NPs aerogel composites represent a promising therapeutic strategy for the effective and enhanced healing of infected wounds.

Thermal curing mechanisms and cross-linking network structure of a novel silicon-containing arylacetylene resin with 2,7-diethynylnaphthalene unit

Silicon-containing arylacetylene resin and its composites have attracted great interest as emerging heat-resistant materials, but their curing mechanisms and products are still elusive. In this work, the influences of the terminal and inner acetylenes on the curing mechanisms of silicon-containing arylacetylene resin with 2,7-diethynylnaphthalene were first identified by density functional theory. Two reaction pathways were proposed and their products include polyenes, anthracene dimers, and benzene trimers. To gain a distinct observation of the cross-linking process, molecular dynamics simulations were used to construct a cross-linking polymerization model. The effects of the temperature on the cured structure were investigated by analyzing the characteristics of the cross-linked network. As expected, higher curing temperature will make the larger proportion of polyene chain and aromatic ring in the terminal alkyne−terminal alkyne route, meanwhile, for the inner alkyne−inner alkyne route, the short chains and a small amount of aromatic rings are major productions. Overall, our cross-linking method may provide an unique guidance for studying the cured structure of other thermosetting resins.

Nondestructive Direct Patterning of Both Hole Transport and Emissive Layers for Pixelated Quantum-Dot Light-Emitting Diodes.

Considering the increasing demand for high-resolution light-emitting diodes (LEDs), it is important that direct fine patterning technologies for LEDs be developed, especially for quantum-dot LEDs (QLEDs). Traditionally, the patterning of QLEDs relies on resin-based photolithography techniques, requiring multiple steps and causing performance deterioration. Nondestructive direct patterning may provide an easy and stepwise method to achieve fine-pixelated units in QLEDs. In this study, two isomeric tridentate cross-linkers (X8/X9) are presented and can be blended into the hole transport layer (HTL) and the emissive layer (EML) of QLEDs. Because of their photosensitivity, the in situ cross-linking process can be efficiently triggered by ultraviolet irradiation, affording high solvent resistance and nondestructive direct patterning of the layers. Red QLEDs using the cross-linked HTL demonstrate an impressive external quantum efficiency of up to 22.45%. Through lithographic patterning enabled by X9, line patterns of HTL and EML films exhibit widths as narrow as 2 and 4 μm, respectively. Leveraging the patterned HTL and EML, we show the successful fabrication of pixelated QLED devices with an area size of 3 × 3 mm2, alongside the successful production of dual-color pixelated QLED devices. These findings showcase the promising potential of direct patterning facilitated by engineered cross-linkers for the cost-effective fabrication of pixelated QLED displays.

Dicyanamide ionic liquid mixtures for curing and modifying flax-fiber reinforced epoxy resin composites

Epoxy composites reinforced with natural fibers are a research area that has been growing tremendously in recent years, with increasing reports providing a better understanding of the interactions within such structures, resulting in newer and more specialized applications. This article presents a comprehensive study on the design and application of ionic liquids (ILs) in the development of flax fiber-reinforced epoxy composites with tailored mechanical properties. Three distinct ILs, namely 1-hexyl-3-methylimidazolium dicyanamide [HMIM][DCA], 1-hexyl-1,4-diazabicyclo[2.2.2]octan-1-ium dicyanamide [DABCO-C6][DCA], and trimethyloctadecylammonium dicyanamide [N11118][DCA], were strategically engineered to incorporate longer carbon chains, with the primary objective of influencing the mechanical parameters of the resulting composites, specifically aiming for enhanced flexibility and resistance to bending and stretching. Using these designed ILs, two mixtures were developed and crafted to facilitate the effective curing of epoxy resin, which was examined using Differential Scanning Calorimetry (DSC). Investigation of the resin crosslinking process revealed that the mixtures of ILs exhibited a lower total enthalpy of thermal conversion than single-IL systems. Moreover, shifts in the polymerization onset temperatures were observed for the mixtures, with some systems displaying dual temperature peaks during crosslinking, indicative of potential parallel polymerization reactions.

Thermal-oxidative stability of PVC compositions modified with a bromine-containing plasticizer-flame retardant

The possibility of creating polymer compositions based on polyvinyl chloride plasticized with a bromine-containing flameretarding plasticizer has been investigated. Their thermostability at introduction of plasticizer with different bromine content was evaluated. The optimal concentrations of bromine in the flame-retarding plasticizer to increase the thermal stability of the polymer composition have been established. It is noted that increasing the concentration of bromine in the flame-retarding plasticizer increases the rate of elimination of hydrogen bromide and slows down the thermal destruction of the polymer matrix. It is shown that during thermo-oxidative degradation of plasticized PVC composite, hydrogen bromide is first eliminated from flame-retarding plasticizer, which accelerates the process of polyene formation and additional cross-linking of polymer macromolecules. An increase in the tensile strength of plasticized compositions at the introduction of optimal dosages of flame-retarding plasticizer was observed.

Retentive bio-based chemical gel for removing glues from water-sensitive wooden artworks

Aged animal glues degrade and weaken over time, resulting in flakes and cracks on the material employed by wooden manufacturers and luthiers. Because of this deterioration, conservators and restorers remove aged water-soluble glues with a water swab, smoothing enough to clean them mechanically and putting on new reversible glues. However, it raises the question of whether a water swab can control moisture delivery while removing glue from wood, a hygroscopic and water-sensitive material.This study formulated a chemically crosslinked film-forming hydrogel based on sodium alginate (SA) with (3-Glycidoxypropyl)trimethoxysilane (GPTMS) and calcium chloride, named as CA-GPTMS to construct a retentive gel. Synthesized gel materials were characterized using several methods: liquid state NMR, FTIR-ATR, and SEM-EDS analyses were involved in examining the cross-linking process, while moisture and mechanical properties were examined to understand its suitability for the cleaning application process. The strategies for applying the CA-GPTMS gel on wood surface were to selectively soften the glue and to remove it as well as leave no residues on the wood surface. The cleaning process was investigated by using different techniques, i.e., stereomicroscopy, reflection-FTIR, and SEM-EDS. Compared to traditional rigid Agar gel, the CA-GPTMS gel appeared successfully resistant to destruction and was suitable for application on highly water-sensitive surfaces.

Surface Modification of Polyimide Aerogel by Thermoplastic Polyurethane for Enhanced Mechanical Strength and Thermal Insulation Performance.

Polyimide (PI) aerogel is a good thermal insulation material with the highest temperature resistance in practical application. But the mechanical strength of PI aerogels prepared by freeze-drying or thermoimide methods is weak. In this research, TPU was selected as an aging solution to solve the problem of the low mechanical strength of PI aerogel prepared by the freeze-drying method. Previous work has certified that the coupling of PI and thermoplastic polyurethane (TPU) can enhance the mechanical strength of PI aerogel to a certain extent due to the flexibility of TPU. But excessive TPU will change the PI structure in the cross-linking process and decrease the mechanical strength of the aerogel. Thus, a new kind of PI gel modification method was provided by using TPU as an aging solution, and the mechanical strength of PI aerogel is improved to 3.06 MPa. Furthermore, the shrinkage, specific surface area, waterproof angle, and thermal conductivity all show good performance, thus enabling PI aerogel to be used in many aspects. Specially, the method is simple and can be used to prepare some other high-strength aerogels.