scholarly journals Enhanced Thermal Stability of Thermoplastic Polymer Nanostructures for Nanoimprint Lithography

Materials ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 545 ◽  
Author(s):  
Youwei Jiang ◽  
Bingqing Luo ◽  
Xing Cheng
Keyword(s):  
Thermal Stability ◽  
Glass Transition ◽  
Nanoimprint Lithography ◽  
Polymer Melt ◽  
Thermoplastic Polymer ◽  
Precise Control ◽  
Polymer Nanostructures ◽  
Thin Polymer ◽  
The Time Domain ◽  
Thermal Stability Of

Thermoplastic polymer micro- and nanostructures suffer pattern decay when heated to a temperature close to or above the polymer’s glass transition temperature. In this work, we report enhanced thermal stability of polycarbonate nanostructures at temperatures well above their glass transition temperatures. Based on this observation, we develop a unique technique for high-resolution polymer patterning by polymer reflows. This technique is characterized as the precise control of polymer reflows regardless of the annealing time, which avoids the time-domain nonlinear reflow of the polymer melt. We also implement thermal nanoimprinting in a step-and-repeat fashion, which dramatically increases the throughput of the thermal nanoimprint. The enhanced pattern stability against thermal reflow also allows for multiple imprinting at the same location to generate complex resist patterns from a simple mold structure. Since modern lithography often uses thin resist films (sub-100 nm) due to the restraint from the pattern aspect ratio, the unusual annealing behavior of thin polymer films is highly relevant in sub-100 nm lithographic processing.

The effect of methyl and methoxy substituents on dianilines for a thermosetting polyimide system

2020 ◽  
Vol 32 (7) ◽  
pp. 801-822 ◽  
Author(s):  
John J La Scala ◽  
Greg Yandek ◽  
Jason Lamb ◽  
Craig M Paquette ◽  
William S Eck ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Molecular Weight ◽  
Glass Transition ◽  
Elevated Temperature ◽  
Methyl Substituent ◽  
Glass Transition Temperatures ◽  
High Performing ◽  
Methoxy Substituent ◽  
Acidic Conditions ◽  
Thermal Stability Of

4,4′-Methylenedianiline (MDA) is widely used in high-temperature polyimide resins, including polymerization of monomer reactants-15. The toxicity of MDA significantly limits the manufacturability using this resin. Modifying the substitution and electronics of MDA could allow for the reduction of toxicity while maintaining the high-performing properties of the materials derived from the modified MDA. The addition of a single methyl substituent, methoxy substituent, location of these substituents, and location of the amine relative to the phenolic bridge were modified as were other non-aniline diamines. Various anilines were condensed with paraformaldehyde under acidic conditions to yield dianilines. These dianilines and diamines were reacted with nadic anhydride and 3,3′,4,4′-benzophenonetetracarboxylic dianhydride in methanol to form the polyamic acid oligomers and heated at elevated temperature to form polyimide oligomers. It was found that the molecular weight of the oligomers derived from MDA alternatives was generally lower than that of MDA oligomers resulting in lower glass transition temperatures ( T gs) and degradation temperatures. Additionally, methoxy substituents further reduce the T g of the polymers versus methyl substituents and reduce the thermal stability of the resin. Methyl-substituted alternatives produced polyimides with similar T gs and degradation temperatures. The toxicity of the MDA alternatives was examined. Although a few were identified with reduced toxicities, the alternatives with properties similar to that of MDA also had high toxicities.

Nanocomposite Epoxy Resin for SiC Module

2011 ◽  
Vol 2011 (HITEN) ◽  
pp. 000196-000200 ◽  
Author(s):  
Kenji Okamoto ◽  
Yuji Takematsu ◽  
Miyako Hitomi ◽  
Yoshinari Ikeda ◽  
Yoshikazu Takahashi
Keyword(s):  
Thermal Stability ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Epoxy Resin ◽  
Molecular Motion ◽  
Experimental Results ◽  
Power Module ◽  
Operation Temperature ◽  
Thermal Stability Of

There is a demand to improve the thermal stability of epoxy molding resins used in the power module of SiC power chips operating at temperatures of 200°C or more. This paper describes a technique for increasing the thermal stability of the resin by decreasing molecular motion through the addition of nanofiller. The experimental results showed that the glass transition temperature (Tg) of the epoxy resin increased by approximately 30°C when the silica nanofiller was added. The epoxy resin added nanofiller was investigated in order to achieve the operation temperature 200°C of power module.

Thermal Stability of Bulk Metallic Glasses. Influence on Mechanical Properties

1998 ◽  
Vol 554 ◽  
Author(s):  
J. M. Pelletier ◽  
Y. Jacquemard ◽  
J. Perez ◽  
R. Perrier de la Bathie
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Glass Transition ◽  
Metallic Glasses ◽  
Bulk Metallic Glasses ◽  
Atomic Mobility ◽  
Heating Rates ◽  
Characteristic Temperatures ◽  
Shear Elastic Modulus ◽  
Thermal Stability Of

AbstractTwo Zr-base bulk metallic glasses were investigated in the present work. DSC experiments were performed at different heating rates (dT/dt). Evolution of the characteristic temperatures, glass transition and onset of crystallisation, were determined as a function of dT/dt. Evolution of shear elastic modulus and internal friction are measured as a function of temperature and resulting microstructural evolution; these evolutions are related to variation of the atomic mobility.

scholarly journals Synthesis and Properties of Bulk Metallic Glasses in Pd-Ni-P and Pd-Cu-P Alloys

1996 ◽  
Vol 455 ◽  
Author(s):  
Y. He ◽  
R. B. Schwarz
Keyword(s):  
Thermal Stability ◽  
Glass Transition ◽  
Metallic Glasses ◽  
Amorphous Alloys ◽  
Composition Range ◽  
Wide Composition Range ◽  
Upper Limit ◽  
Ternary Alloy Systems ◽  
The Difference ◽  
Thermal Stability Of

ABSTRACTBulk amorphous Pd-Ni-P and Pd-Cu-P alloy rods with diameters ranging from 7 to 25 mm have been synthesized over a wide composition range using a fluxing technique. For most bulk amorphous Pd-Ni-P alloys, the difference ΔT = Tx - Tg between the crystallization temperature Tx and the glass transition temperature Tg is larger than 90 K, while for bulk amorphous Pd-Cu-P alloys, ΔT varies from 27 to 73 K. Pd40Ni40P20 has the highest glass formability, and 300-gram bulk amorphous cylinders, 25 mm in diameter and 50 mm in length, can be easily produced. This size, however, is not an upper limit. The paper presents the glass formation ranges for both ternary alloy systems and data on the thermal stability of the amorphous alloys, as well as their specific heat, density, and elastic properties.

Application of ionic liquid [bmim]PF6 as green plasticizer for poly(L-lactide)

e-Polymers ◽  
2008 ◽  
Vol 8 (1) ◽  
Author(s):  
Puyu Zhang ◽  
Lichao Peng ◽  
Wenbin Li
Keyword(s):  
Thermal Stability ◽  
Differential Scanning Calorimetry ◽  
Ionic Liquid ◽  
Glass Transition ◽  
Transition Temperature ◽  
Poly Ethylene Glycol ◽  
Scanning Calorimetry ◽  
Poly Ethylene ◽  
Thermal Stability Of ◽  
Better Than

AbstractIonic liquid [bmim]PF6 (1-butyl-3-methylimidazolium hexafluoro phosphate) was synthesized and characterized. It was used as the plasticizer for poly(L-lactide) (PLLA). The glass transition temperature (Tg) and the thermal stability of the plasticized PLLA samples were measured by thermogravimetry (TG) and differential scanning calorimetry (DSC). Compared with poly(ethylene glycol) having Mw of 300 g/mol (PEG300), TG results showed that the thermal stability of PLLA plasticized with ionic liquid was better than that of PLLA plasticized with PEG300. The Tg of plasticized PLLA decrease with increasing the content of ionic liquid [bmim]PF6 from 2 wt.% to 10 wt.%. The Tg of PLLA can be reduced to 40°C when the content of ionic liquid [bmim]PF6 was 10 wt.%. The materials of PLLA with plasticizer were also investigated using polarizing microscope (POM), the results of which indicate that the movements of PLLA chains were improved when ionic liquid plasticizer was used.

scholarly journals Enhancing the Thermal Stability of Ionogels: Synthesis and Properties of Triple Ionic Liquid/Halloysite/MCC Ionogels

Molecules ◽  
2021 ◽  
Vol 26 (20) ◽  
pp. 6198
Author(s):  
Olga V. Alekseeva ◽  
Valeriya D. Shibaeva ◽  
Andrew V. Noskov ◽  
Vladimir K. Ivanov ◽  
Alexander V. Agafonov
Keyword(s):  
Thermal Stability ◽  
Ionic Liquid ◽  
Glass Transition ◽  
Mechanical Characteristics ◽  
Interlayer Space ◽  
Xrd Analysis ◽  
Mechanical Tests ◽  
Water Molecules ◽  
Residual Water ◽  
Thermal Stability Of

In this study, an ionic liquid (IL), 1-butyl-3-methylimidazolium acetate, was used to prepare ionogels with microcrystalline cellulose (MCC) and halloysite (Hal). SEM, XRD, TG, DSC, FTIR spectroscopy, conductometry and mechanical tests were used to study the morphology, structure, thermal behaviour and electrophysical and mechanical characteristics of synthesised ionogels. XRD analysis showed a slight decrease in the interlayer space of halloysite in ionogels containing MCC, which may have been associated with the removal of residual water molecules resulting from hydrophilic IL anions and polymer macromolecules. A change in conductivity and glass-transition temperature of the ionic liquid was revealed due to intercalation into halloysite (a confinement effect) and modification with cellulose. For triple IL/Hal/MCC ionogels, the characteristic thermal degradation temperatures were higher than the corresponding values for IL/Hal composites. This indicates that the synthesised IL/Hal/MCC ionogels are characterised by a greater thermal stability than those of IL/Hal systems.

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