Super Engineering Plastics and Forms

Shen, Yang; Hu, Aijun

doi:10.1016/b978-0-12-812640-0.00004-4

Cited by 6 publications

(7 citation statements)

References 56 publications

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“…The FT-IR spectra and TGA curves of T-PI powders demonstrate that post-heat treatment achieved complete imidization. In addition, the T-PI powders exhibited excellent thermal stability based on the rigid aromatic ring and imide structures. − …”

Section: Results and Discussionmentioning

confidence: 99%

“…The high thermal stability of PMDA-ODA PI limits its application to injection and extrusion molding. ,, The PMDA-ODA PI powder has therefore been used primarily as a compression-molding material. A compression molding method for fabrication of PMDA-ODA PI was developed by DuPont in the 1960s.…”

Section: Results and Discussionmentioning

confidence: 99%

“…A compression molding method for fabrication of PMDA-ODA PI was developed by DuPont in the 1960s. Shaped PI sheets or disks were first prepared by structuring of the PI powders followed by high-temperature sintering . These molded PI shapes can be ground, cut, and drilled to form a variety of shaped articles, including bushings, roller guides, gears, and bearings, which are useful over a wide temperature range.…”

Section: Results and Discussionmentioning

confidence: 99%

“…They are classified as high-performance polymers and used widely in aerospace, membranes, microelectronics, and optoelectronics due to their excellent thermal and mechanical properties and chemical resistance. − For example, a PI powder prepared from pyromellitic dianhydride (PMDA) and 4,4′-oxydianiline (ODA) is a lightweight and heat-resistant compression-molding material. A commercial example of PMDA-ODA PI, DuPont Corporation’s Vespel SP-1 product, is machined into bearings or sealing parts that are used under extremely harsh conditions. − The compression-molding process ensures that the PI particles coalesce tightly, in what is called a sintering process. , The molecular weight, degree of crystallinity, and specific surface area of the PI powder are known to influence the sintering behavior. − …”

Section: Introductionmentioning

confidence: 99%

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Preparation of Polyimide Powders via Hydrothermal Polymerization and Post-Heat Treatment for Application to Compression-Molding Materials

Jin

Choi

et al. 2022

ACS Sustainable Chem. Eng.

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Aromatic polyimides (PIs) are classified as highperformance polymers owing to their excellent thermal, mechanical, and chemical resistance, and they are used widely in aerospace, membranes, microelectronics, and optoelectronics industries. To synthesize aromatic PI powder in an environmentally friendly manner, a hydrothermal polymerization (HTP) method of heating dianhydride and diamine in distilled water in an autoclave has recently been suggested. However, the application of the hydrothermally synthesized PI powder has been very rare. In the present study, we first report the synthesis of hydrothermal PI powders and their application as compression-molding materials. A mixture of unreacted monomer salt (MS), oligoimide, and PI (MS/PI) powders was obtained in distilled water in an autoclave and thermally imidized to obtain a post-heat-treated polyimide (T-PI) powder with improved sintering behavior. The inherent viscosity, degree of crystallinity, and specific surface area of the T-PI powder were investigated for their suitability for compression molding. The mechanical properties of compression-molded specimens were observed to be affected by the properties of the T-PI powder. When the autoclave temperature was 140 or 160 °C, the T-PI powder showed effective sintering behavior. A tensile strength of 57.2−57.9 MPa, an elongation at break of 6.8−7.4%, and a density of 1.35−1.37 g/mL were achieved with the T-PI powder. Compression-molded specimens prepared with the T-PI powders showed excellent thermal properties and sufficient mechanical properties for use as thermally stable parts and shapes.

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Section: Results and Discussionmentioning

confidence: 99%

Section: Results and Discussionmentioning

confidence: 99%

Section: Results and Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Preparation of Polyimide Powders via Hydrothermal Polymerization and Post-Heat Treatment for Application to Compression-Molding Materials

Jin

Choi

et al. 2022

ACS Sustainable Chem. Eng.

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“…If after cleaning the substrate it still presents low wettability, surface pre-treatments may be needed. Such treatments include surface modification resorting to chemical modification, Inkjet Printing of Functional Inks for Smart Products DOI: http://dx.doi.org/10.5772/intechopen.104529 coating with hydrophilic moieties (such as PVP and PVA solutions) [97,98], plasma activation [98][99][100], mechanical abrasion, or superficial integration of nanoparticles or nanoclays [101], which increase surface roughness. Plasma activation is usually done by resorting to corona discharge plasma treatment and relies on the production of a high voltage electrical discharge that ionizes the molecules of the treated surface, positively changing its polarity (or oxidizing it) [99, 102, 103].…”

Section: Adhesion Between Inks and Substratesmentioning

confidence: 99%

Inkjet Printing of Functional Inks for Smart Products

Buga¹,

Viana²

2022

Production Engineering and Robust Control

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Inkjet printing is a recent promising technology for direct patterning of solution-based materials over different substrates. It is particularly interesting for applications in the flexible electronics field and smart products manufacturing, as it allows for rapid prototyping, design freedom, and is compatible with conductive, semiconductive, and dielectric inks that can be cured at low temperatures over several types of substrates. Moreover, the inkjet process allows for ink economization, since great electrical conductivity can be achieved despite the deposition of small volumes of ink. This chapter describes the overall process, the main inks and their features, the critical process variables, and its limitations. Applications related to inkjet printing of functional materials and smart products are highlighted. New technology advancements and trends are finally addressed.

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Direct Nanoimprint Lithography of Polyethersulfone Using Cellulose‐Based Mold

Takei

2020

Macro Materials & Eng

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and resist materials were investigated for the expanded nanoimprint lithography and application of biomass resources. [21][22][23][24][25] Herein, high-accuracy nanopatterning of PES using dimethylformamide as a dilution solvent was obtained by direct thermal nano imprint lithography using the newly modified solvent-permeable cellulosebased mold.In summary, the 900-nm line pattern failure of PES containing dimethylformamide as a dilution solvent was solved using the solvent-permeable cellulosebased mold. The direct nanoimprint lithography using the new solvent-permeable mold and solvent-mixed super-engineering plastics has realized the surface nanostructures of PES. Experimental SectionThe structures of a) hydroxypropyl cellulose with thermally cross-linked acryloyloxyalkyl groups in the solvent-permeable cellulose-based mold, b) 2-hydroxy-2-methylpropiophenone as an ultraviolet(UV) initiator, c) azobisisobutyronitrile as a thermal initiator, d) polyethersulfone, e) dimethylformamide as a dilution solvent with high solubility for increasing the fluidity of PES, f) novolac derivatives with hydroxyl groups to react with the cross-linker to improve adhesion to polyethersulfone during the imprinting process, g) 1,3,4,6-tetrakis(methoxymethyl) glycoluril as a cross-linker, and h) pyridinium p-toluenesulfonate as an initiator are shown in Figure 1.2-Methacryloyloxyalkyl isocyanate was reacted with hydroxypropyl cellulose to add thermally cross-linked acryloyloxyalkyl groups into the hydroxypropyl cellulose to prepare the solvent-permeable cellulose-based mold. The resulting chemical reaction between 2-methacryloyloxyalkyl isocyanates and hydroxypropyl cellulose was evaluated using attenuated total reflectance Fourier transform infrared spectroscopy. [26][27][28] Methyl ethyl ketone was blended with 2-methacryloyloxyalkyl isocyanates and hydroxypropyl cellulose. The content of 2-methacryloyloxyalkyl isocyanate and hydroxypropyl cellulose in the solution was 26 wt%. The solution was stirred under a nitrogen atmosphere at 63 °C for 2.5 h, after adding triethylamine with a concentration of 7.9 wt% to the solution. Gel-permeation chromatography (HLC-8320GPC, Tosoh) was used to obtain the molecular weight of solvent-permeable cellulosebased mold. The solvent-permeable cellulose-based mold with an average molecular weight of 53 000 relative to a polystyrene standard was developed. The solvent-permeable cellulose-based mold with thermally cross-linked acryloyloxyalkyl groups was formulated with the following concentrations: 95 wt% of cellulose derivative, 2.5 wt% of 2-hydroxy-2-methylpropiophenone, and 2.5 wt% of azobisisobutyronitrile as a thermal initiator.The adhesion underlayer material on substrates, such as stainless mesh plate and silicon wafer was prepared to provide an adhesion between the substrates and patterning materials, such as PES and solvent-permeable cellulose-based mold, thereby reducing the pattern Polyethersulfone (PES) with a glass transition temperature of 224 °C is a class of high-performance super engi...

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Super Engineering Plastics and Forms

Cited by 6 publications

References 56 publications

Preparation of Polyimide Powders via Hydrothermal Polymerization and Post-Heat Treatment for Application to Compression-Molding Materials

Preparation of Polyimide Powders via Hydrothermal Polymerization and Post-Heat Treatment for Application to Compression-Molding Materials

Inkjet Printing of Functional Inks for Smart Products

Direct Nanoimprint Lithography of Polyethersulfone Using Cellulose‐Based Mold

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