Organic–Inorganic Hybrid Isocyanate-Based Polyimide Foams with Excellent Fire Resistance and Thermal Insulation Performance

Liu, Xinchao; Zhou, Peng; Zhang, Rubing

doi:10.1021/acsapm.2c01377

Cited by 10 publications

(4 citation statements)

References 44 publications

(86 reference statements)

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“…The pure phenolic sample, on the other hand, had the greatest TSP value, as shown in Figure 5d, indicating that less solid phase disintegrated as pyrolysis gas while a larger portion flowed as smoke and dust during the flaming process. 43 As a result, the mechanism of melamine-phenolic flame retardancy comprises gas elution in a fire scenario and dilution of the oxygen near the combustion source, which operates mostly in the gas phase by releasing nonflammable gases with a decrease in char formation.…”

Section: Thermal Stability Of Mpasmentioning

confidence: 99%

Lightweight Nitrogen-Doped Phenolic Aerogels with Flame-Retardant and Thermal-Insulation Properties

Cao,

Wang,

Cai

et al. 2023

ACS Appl. Polym. Mater.

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The inherent flammability of phenolic aerogels has imposed significant limitations on its utilization. In order to unlock the potential of phenolic aerogels as insulation and flame-retardant materials, we fabricate a series of melamine-phenolic aerogels (MPAs) based on a copolymerization reaction of melamine and phenolics in a sol−gel process. By varying the quantity of melamine, the microstructures and the corresponding thermal properties of MPAs are investigated. The results indicate that MPAs possess ultralow thermal conductivity of 0.036−0.038 W/(m•K) and a density of 0.34−0.40 g/cm 3 . In addition, melamine greatly increases the flame retardancy of phenolic aerogels. A modified phenolic aerogel containing 40 wt % melamine has a limiting oxygen index (LOI) value of 32.7%. The measured maximum heat release rate values of MPAs decrease with the increase of melamine portions in samples, ranging from 138 to 74 kW/m 2 in the cone calorimeter testing experiment. Furthermore, TG-MS-FTIR technology is used to analyze the gas emission during thermal decomposition, and the structure evolution of the solid phase is studied for a better understanding of the flame-retardant mechanism. This research is intended to present phenolic-based aerogel materials with outstanding overall performance and explore their potential for large-scale production in the future.

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Section: Thermal Stability Of Mpasmentioning

confidence: 99%

Lightweight Nitrogen-Doped Phenolic Aerogels with Flame-Retardant and Thermal-Insulation Properties

Cao,

Wang,

Cai

et al. 2023

ACS Appl. Polym. Mater.

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“…Most imides are introduced in polymer matrices via the reaction between amine and anhydride. , As isocyanates are used during PU synthesis, another more direct synthetic way to introduce imides is via the reaction between isocyanate and anhydride. Thus, the poly(urethane imide) (PUI) materials are typically prepared by the reaction of long-chain isocyanate-terminated prepolymers with dianhydrides. ,,,,− PUI materials are also reported to be prepared from the reaction of hydroxy-functionalized imide oligomers and diisocyanates , or the reaction of amine-functionalized isocyanate prepolymers with dianhydrides . However, a common feature of these preparations is the use of strong polar aprotic solvents, such as dimethylformamide, N -methyl-2-pyrrolidone, and dimethylacetamide that are hazardous and difficult to be removed, which limit the development of PUI materials in industrial scale production. , …”

Section: Introductionmentioning

confidence: 99%

Solvent-Free Preparation of Thermally Stable Poly(urethane-imide) Elastomers

Guo

Cristadoro²,

Kleemann³

et al. 2023

ACS Appl. Polym. Mater.

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Polyurethanes (PUs) are widely used in many applications due to their versatile chemical and physical properties. To meet the increasing demands on PU with respect to intrinsic mechanical and thermal properties, they can be modified with thermally stable aromatic imide structures to form poly(urethane imide) (PUI). However, the preparation of PUI materials has been limited by the need for strong polar solvents, which hinder their industrial scale development. In this work, we prepared imide-containing isocyanate-terminated prepolymers via the reaction of polymeric aromatic or aliphatic isocyanates and pyromellitic dianhydride in completely solvent-free conditions. The subsequent PUI elastomers made from these prepolymers exhibited enhanced char formation and stiffness in comparison to the reference elastomers without imide structures, among which the aromatic PUI elastomer shows improved flame retardancy according to the initial cone calorimetry measurement. This work demonstrates the potential use of imide prepolymers in other PU applications where high thermal stability and flame retardancy are required. The solvent-free synthesis also paves a way for the large-scale production of PUI materials.

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“…Xiang et al [ 23 ] prepared isocyanate-based polyimide flexible foams with different isocyanate index by one-step method, achieve high open porosity and low density. However, isocyanates with high chemical activity are prone to participate in a variety of side reactions to form a large number of urea groups and carbamate groups in the system [ 24 , 25 ], leading to a significant reduction in the heat resistance and flame retardancy of PIFs.…”

Section: Introductionmentioning

confidence: 99%

Preparation and Properties of High-Temperature-Resistant, Lightweight, Flexible Polyimide Foams with Different Diamine Structures

et al. 2023

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Polyimide foam (PIF) is a rising star in high-end applications such as aerospace thermal insulation and military sound absorption. However, the basic rule on molecular backbone design and uniform pore formation of PIF still need to be explored. In this work, polyester ammonium salt (PEAS) precursor powders are synthesized between alcoholysis ester of 3, 3′, 4, 4′-benzophenone tetracarboxylic dianhydride (BTDE) and aromatic diamines with different chain flexibility and conformation symmetry. Then, a standard “stepwise heating” thermo-foaming approach is used to prepare PIF with comprehensive properties. A rational thermo-foaming program is designed based on in situ observation of pore formation during heating. The fabricated PIFs have uniform pore structure, and PIFBTDA-PDA shows the smallest size (147 μm) and narrow distribution. Interestingly, PIFBTDA-PDA also presents a balanced strain recovery rate (SR = 91%) and mechanical robustness (0.051 MPa at 25% strain) and its pore structure maintains regularity after 10 compression–recovery cycles, mainly due to high rigidity of the chains. Furthermore, all the PIFs possess lightweight feature (15–20 kg∙m−3), good heat resistance (Tg at 270–340 °C), thermal stability (T5% at 480–530 °C), thermal insulation properties (λ = 0.046–0.053 W∙m−1K−1 at 20 °C, λ = 0.078–0.089 W∙m−1K−1 at 200 °C), and excellent flame retardancy (LOI > 40%). The reported monomer-mediated pore-structure control strategy can provide guidelines for the preparation of high-performance PIF and its industrial applications.

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Organic–Inorganic Hybrid Isocyanate-Based Polyimide Foams with Excellent Fire Resistance and Thermal Insulation Performance

Cited by 10 publications

References 44 publications

Lightweight Nitrogen-Doped Phenolic Aerogels with Flame-Retardant and Thermal-Insulation Properties

Lightweight Nitrogen-Doped Phenolic Aerogels with Flame-Retardant and Thermal-Insulation Properties

Solvent-Free Preparation of Thermally Stable Poly(urethane-imide) Elastomers

Preparation and Properties of High-Temperature-Resistant, Lightweight, Flexible Polyimide Foams with Different Diamine Structures

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