Highly solvent-stable polyimide ultrafine fibrous membranes fabricated by a novel ultraviolet-assisted electrospinning technique via organo-soluble intrinsically negative photosensitive varnishes

Qi, Lin; Guo, Chenyu; Huangfu, Meng‐ge; Zhang, Y.; Wu, Lin; Zhi, Xin‐xin; Liu, J. G.; Zhang, X. M.

doi:10.3144/expresspolymlett.2021.8

Cited by 5 publications

(3 citation statements)

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“…In the current work, a series of electrospinning PI NFMs designed for high-temperature adhesion applications have been prepared and characterized as part of our ongoing efforts to develop high-performance PI NFMs for high-tech applications [24][25][26][27][28]. First, the flexible ether linkages were introduced into the molecular structure of the PIs via the ether-containing dianhydride and diamine monomers in order to afford good adhesion to metal substrates, which has been widely adopted for the development of PI adhesives.…”

Section: Introductionmentioning

confidence: 99%

Preparation and Properties of Electrospun Phenylethynyl—Terminated Polyimide Nano-Fibrous Membranes with Potential Applications as Solvent-Free and High-Temperature Resistant Adhesives for Harsh Environments

Shen

Jia

et al. 2021

Nanomaterials

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High-temperature-resistant polymeric adhesives with high servicing temperatures and high adhesion strengths are highly desired in aerospace, aviation, microelectronic and other high-tech areas. The currently used high-temperature resistant polymeric adhesives, such as polyamic acid (PAA), are usually made from the high contents of solvents in the composition, which might cause adhesion failure due to the undesirable voids caused by the evaporation of the solvents. In the current work, electrospun preimidized polyimide (PI) nano-fibrous membranes (NFMs) were proposed to be used as solvent-free or solvent-less adhesives for stainless steel adhesion. In order to enhance the adhesion reliability of the PI NFMs, thermally crosslinkable phenylethynyl end-cappers were incorporated into the PIs derived from 3,3’,4,4’-oxydiphthalic anhydride (ODPA) and 3,3-bis[4-(4-aminophenoxy)phenyl]phthalide (BAPPT). The derived phenylethynyl-terminated PETI-10K and PETI-20K with the controlled molecular weights of 10,000 g mol−1 and 20,000 g mol−1, respectively, showed good solubility in polar aprotic solvents, such as N-methyl-2-pyrrolidinone (NMP) and N,N-dimethylacetamide (DMAc). The PI NFMs were successfully fabricated by electrospinning with the PETI/DMAc solutions. The ultrafine PETI NFMs showed the average fiber diameters (dav) of 627 nm for PETI-10K 695 nm for PETI-20K, respectively. The PETI NFMs showed good thermal resistance, which is reflected in the glass transition temperatures (Tgs) above 270 °C. The PETI NFMs exhibited excellent thermoplasticity at elevated temperatures. The stainless steel adherends were successfully adhered using the PETI NFMs as the adhesives. The PI NFMs provided good adhesion to the stainless steels with the single lap shear strengths (LSS) higher than 20.0 MPa either at room temperature (25 °C) or at an elevated temperature (200 °C).

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Section: Introductionmentioning

confidence: 99%

Preparation and Properties of Electrospun Phenylethynyl—Terminated Polyimide Nano-Fibrous Membranes with Potential Applications as Solvent-Free and High-Temperature Resistant Adhesives for Harsh Environments

Shen

Jia

et al. 2021

Nanomaterials

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“…PI nanofibrous membranes (NFMs) prepared by an electrospinning procedure have been widely used in various fields due to their excellent combined properties [ 20 ]. Based on our previous research on the research and development of high-performance PI NFMs [ 21 , 22 , 23 , 24 , 25 ], it can be found that the solvent-free characteristics, good flexibility, highly entangled microstructure, and good processability of the PI NFMs make them good candidates for high-performance adhesives. Thus, it could be anticipated that electrospun PI NFMs might find wide applications as high-temperature-resistant adhesives.…”

Section: Introductionmentioning

confidence: 99%

Methylethynyl-Terminated Polyimide Nanofibrous Membranes: High-Temperature-Resistant Adhesives with Low-Temperature Processability

Qi¹,

Ren²,

Liu³

et al. 2022

Polymers

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As an alternative to traditional riveting and welding materials, high-temperature-resistant adhesives, with their unique advantages, have been widely used in aviation, aerospace, and other fields. Among them, polyimide (PI) adhesives have been one of the most studied species both from basic and practical application aspects. However, in the main applications of solvent-type PI adhesives, pinholes or bubbles often exist in the cured PI adhesive layers due to the solvent volatilization and dehydration reaction, which directly affect the adhesive performance. To address this issue, electrospun PI nanofibrous membranes (NFMs) were employed as solvent-free or solvent-less adhesives for stainless steel in the current work. To enhance the adhesion of PI adhesives to the metal substrates, phenolphthalein groups and flexible ether bonds were introduced into the main chain of PIs via the monomers of 4,4′-oxydiphthalic anhydride (ODPA) and 3,3-bis[4-(4-aminophenoxy)phenyl] phthalide (BAPPT). At the same time, the methylethynyl group was used as the end-capping component, and the crosslinking reaction of the alkynyl group at high temperature further increased the adhesive strength of the PI adhesives. Three kinds of methylethynyl-terminated PI (METI) NFMs with the set molecular weights of 5000, 10,000, and 20,000 g/mol were first prepared via the one-step high-temperature polycondensation procedure. Then, the PI NFMs were fabricated via the standard electrospinning procedure from the soluble METI solutions. The afforded METI NFMs showed excellent melt-flowing behaviors at high temperature. Incorporation of the methylethynyl end-capping achieved a crosslinking reaction at 280−310 °C for the NFMs, which was about 70 °C lower than those of the phenylacetylene end-capping counterparts. Using the METI NFMs as adhesive, stainless steel adherends were successfully bonded, and the single-lap shear strength (LSS) was higher than 20.0 MPa at both room temperature (25 °C) and high temperature (200 °C).

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“…The developed polymers could potentially be used for data recording/erasing applications. In our previous work, a new procedure, the "ultraviolet-assisted electrospinning or electrospraying (UVAES)" technique, as shown in Figure 1a, was developed and adopted to fabricate the polyimide (PI) NFMs by using the organo-soluble and preimidized negative photosensitive polyimides (PSPIs) containing benzophenone units as the starting electrospinning solutions [17][18][19][20][21]. During the fabrication, photocrosslinking reactions induced by the photosensitive benzophenone units [22,23] in-situ occurred in the molecular structures of the ultrafine PI fibers with the UV exposure; thus, high-temperature and solvent-resistant polyimide (PI) NFMs were successfully obtained in one step.…”

Section: Introductionmentioning

confidence: 99%

Formation of Nano-Fibrous Patterns on Aluminum Substrates via Photolithographic Fabrication of Electrospun Photosensitive Polyimide Fibrous Membranes

Gao

Ren

et al. 2022

Nanomaterials

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The formation of polymeric micro-patterns on various substrates via a photolithography procedure has been widely used in semiconductor fabrication. Standard polymer patterns are usually fabricated via photosensitive polymer varnishes, in which large amounts of potentially harmful solvents with weight ratios over 50 wt% have to be removed. In the current work, a novel pattern-formation methodology via solvent-free electrospun photosensitive polymeric fibrous membranes (NFMs) instead of the conventional photosensitive solutions as the starting photoresists was proposed and practiced. For this purpose, a series of preimidized negative auto-photosensitive polyimide (PSPI) resins were first prepared via the two-step chemical imidization procedure from the copolymerization reactions of 3,3′,4,4′-benzophenonetetracarboxylic- dianhydride (BTDA) and two ortho-methyl-substituted aromatic diamines, including 3,3′,5,5′-tetramethyl-4,4′-diaminodiphenylmethane (TMMDA) and 3,7-diamino-2,8-dimethyl- dibenzothiophene sulfone (TSN). The derived homopolymer PI-1 (BTDA-TMMDA) and the copolymers, including SPI-2~SPI-6, with the molar ratio of 5~25% for TSN in the diamine units, showed good solubility in polar solvents. Then, a series of PSPI NFMs were fabricated via standard electrospinning procedure with the developed PSPI solutions in N,N-dimethylacetamide (DMAc) with a solid content of 25 wt% as the starting materials. The derived PSPI NFMs showed good thermal stability with 5% weight loss temperatures higher than 500 °C in nitrogen. Meanwhile, the derived PSPIs showed good photosensitivity to the ultraviolet (UV) emitting wavelengths of i-line (365 nm), g-line (405 nm) and h-line (436 nm) of the high-pressure mercury lamps in both forms of transparent films and opaque NFMs. Fine micro-patterns with a line width of around 100 μm were directly obtained from the representative SPI-4 NFM via standard photolithography procedure.

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Highly solvent-stable polyimide ultrafine fibrous membranes fabricated by a novel ultraviolet-assisted electrospinning technique via organo-soluble intrinsically negative photosensitive varnishes

Cited by 5 publications

References 0 publications

Preparation and Properties of Electrospun Phenylethynyl—Terminated Polyimide Nano-Fibrous Membranes with Potential Applications as Solvent-Free and High-Temperature Resistant Adhesives for Harsh Environments

Preparation and Properties of Electrospun Phenylethynyl—Terminated Polyimide Nano-Fibrous Membranes with Potential Applications as Solvent-Free and High-Temperature Resistant Adhesives for Harsh Environments

Methylethynyl-Terminated Polyimide Nanofibrous Membranes: High-Temperature-Resistant Adhesives with Low-Temperature Processability

Formation of Nano-Fibrous Patterns on Aluminum Substrates via Photolithographic Fabrication of Electrospun Photosensitive Polyimide Fibrous Membranes

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