scholarly journals Low—Permittivity Copolymerized Polyimides with Fluorene Rigid Conjugated Structure

Materials ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6266
Author(s):  
Xiaodi Dong ◽  
Mingsheng Zheng ◽  
Baoquan Wan ◽  
Xuejie Liu ◽  
Haiping Xu ◽  
...  
Keyword(s):  
In Situ Polymerization ◽  
Signal Propagation ◽  
Dielectric Materials ◽  
Propagation Delay ◽  
Decomposition Temperature ◽  
Thermal Decomposition Temperature ◽  
Molecular Weights ◽  
Low Permittivity ◽  
Crosstalk Signal

As the miniaturization of electronic appliances and microprocessors progresses, low-permittivity interlayer materials are becoming increasingly important for their suppression of electronic crosstalk, signal propagation delay and loss, and so forth. Herein, a kind of copolyimide (CPI) film with a “fluorene” rigid conjugated structure was prepared successfully. By introducing 9,9-Bis(3-fluoro-4-aminophenyl) fluorene as the rigid conjugated structure monomer, a series of CPI films with different molecular weights were fabricated by in situ polymerization, which not only achieved the reduction of permittivity but also maintained excellent thermodynamic stability. Moreover, the hydrophobicity of the CPI film was also improved with the increasing conjugated structure fraction. The lowest permittivity reached 2.53 at 106 Hz, while the thermal decomposition temperature (Td5%) was up to 530 °C, and the tensile strength was ≥ 96 MPa. Thus, the CPI films are potential dielectric materials for microelectronic and insulation applications.

scholarly journals Investigation of Silicon Nanoparticle-Polystyrene Hybrids

2019 ◽  
Vol 2 (2) ◽  
pp. 49-50
Author(s):  
Madihah Khan ◽  
Alyxandra Thiessen ◽  
I Teng Cheong ◽  
Sarah Milliken ◽  
Jonathan G. C. Veinot
Keyword(s):  
Silicon Nanoparticles ◽  
In Situ Polymerization ◽  
Toxic Substance ◽  
Homogeneous Mixture ◽  
Silicon Nanoparticle ◽  
Molecular Weights ◽  
Abundant Element ◽  
The Stability ◽  
Led Lights

Current LED lights are created with quantum dots made of metals like selenium, tellurium, and cadmium which can be toxic. Silicon is used as a non-toxic substance and is the second most abundant element in the earth's crust. When silicon is prepared at a nanometer size, unique luminesce optical properties emerge that can be tuned using sized surface chemistry. Therefore, silicon nanoparticles can be used as an alternative emitter for LED lights. To produce hydride-terminated silicon nanoparticles we must synthesize the particles. Hydrogen silsesquioxane (HSQ) is processed at 1100 °C for one hour causing Si to cluster and form a SiO2 matrix, also known as the composite. The composite is then manually crushed in ethanol. The solution is further ground using glass beads, then filtered to get the composite powder. The final step is the HF etching. The hydride-terminated particles are then functionalized using three different methods to synthesize silicon nanoparticle-polystyrene hybrids, which determine the magnitude of luminosity and the quality of the hybrids. We spin coat each method and results were analyzed. Method 1 uses heat to functionalize hydride-terminated silicon nanoparticles with styrene. This process also causes styrene to attach to styrene to form a polystyrene chain. Method 1 gave a homogeneous mixture which yielded a consistent, bright and homogenous film. In method 2, dodecyl-terminated silicon nanoparticles are mixed with premade polystyrene. While this method gave better control of the amount of silicon nanoparticles inside the polymer hybrid, a homogeneous mixture was not created due to the different structures of polystyrene and dodecyl chains. Method 3 has dodecyl-terminated silicon with in-situ styrene polymerization. It generated a homogeneous mixture. The in-situ polymerization stabilizes the particles, allowing for brighter luminescence. Because of the stability and lower molecular weight, the mixture was easier to dissolve. We concluded that the different methods resulted in different polymer molecular weights and this created distinct properties between the polymer hybrids when spin-coating.    

scholarly journals PA6 and Halloysite Nanotubes Composites with Improved Hydrothermal Ageing Resistance: Role of Filler Physicochemical Properties, Functionalization and Dispersion Technique

Polymers ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 211 ◽  
Author(s):  
Valentina Sabatini ◽  
Tommaso Taroni ◽  
Riccardo Rampazzo ◽  
Marco Bompieri ◽  
Daniela Maggioni ◽  
...  
Keyword(s):  
Physicochemical Properties ◽  
Polymer Matrix ◽  
In Situ Polymerization ◽  
Cost Effective ◽  
Polyamide 6 ◽  
Halloysite Nanotubes ◽  
Amide Bonds ◽  
Molecular Weights ◽  
Dispersion Technique

Polyamide 6 (PA6) suffers from fast degradation in humid conditions due to hydrolysis of amide bonds, which limits its durability. The addition of nanotubular fillers represents a viable strategy for overcoming this issue, although the additive/polymer interface at high filler content can become privileged site for moisture accumulation. As a cost-effective and versatile material, halloysite nanotubes (HNT) were investigated to prepare PA6 nanocomposites with very low loadings (1–45% w/w). The roles of the physicochemical properties of two differently sourced HNT, of filler functionalization with (3-aminopropyl)triethoxysilane and of dispersion techniques (in situ polymerization vs. melt blending) were investigated. The aspect ratio (5 vs. 15) and surface charge (−31 vs. −59 mV) of the two HNT proved crucial in determining their distribution within the polymer matrix. In situ polymerization of functionalized HNT leads to enclosed and well-penetrated filler within the polymer matrix. PA6 nanocomposites crystal growth and nucleation type were studied according to Avrami theory, as well as the formation of different crystalline structures (α and γ forms). After 1680 h of ageing, functionalized HNT reduced the diffusion of water into polymer, lowering water uptake after 600 h up to 90%, increasing the materials durability also regarding molecular weights and rheological behavior.

Siloxane Polymers as Low Dielectric Materials for Microelectronics

1995 ◽  
Vol 390 ◽  
Author(s):  
C. P. Wong
Keyword(s):  
Dielectric Constant ◽  
Three Dimensional ◽  
Signal Propagation ◽  
Dielectric Materials ◽  
Propagation Delay ◽  
Dimensional Structure ◽  
Low Dielectric Constant ◽  
Interlayer Dielectric ◽  
Low Dielectric ◽  
High Dielectric

ABSTRACTA modem VLSI device is a complicated three-dimensional structure that consists of multilayer metallization conductor lines which are separated with interlayer-dielectrics as insulation. This VLSI technology drives the IC device into sub-micron feature size that operates at ultra-fast speed (in excess of > 100 MHz). Passivation and interlayer dielectric materials are critical to the device performance due to the conductor signal propagation delay of the high dielectric constant of the material. Low dielectric constant materials are the preferred choice of materials for this reasons. These materials, such as Teflon® and siloxanes (silicones), are desirable because of their low dielectric constant (∈1) = 2.0, 2.7, respectively. This paper describes the use of a low dielectric constant siloxane polymer (silicone) as IC devices passivation layer material, its chemistry, material processes and reliability testing.

scholarly journals Multi Self-Healable UV Shielding Polyurethane/CeO2 Protective Coating: The Effect of Low-Molecular-Weight Polyols

Polymers ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 1947
Author(s):  
Mohammad Mizanur Rahman ◽  
Rami Suleiman ◽  
Md. Hasan Zahir ◽  
Aasif Helal ◽  
A. Madhan Kumar ◽  
...  
Keyword(s):  
Molecular Weight ◽  
In Situ Polymerization ◽  
Outdoor Exposure ◽  
Low Molecular Weight ◽  
Self Healing ◽  
Polydimethyl Siloxane ◽  
Molecular Weights ◽  
Uv Shielding ◽  
Ceo2 Coating

We prepared a series of polyurethane (PU) coatings with defined contents using poly(tetramethylene oxide)glycol (PTMG) with two different molecular weights (i.e., Mn = 2000 and 650), as well as polydimethyl siloxane (PDMS) with a molecular weight of Mn 550. For every coating, maximum adhesive strength and excellent self-healing character (three times) were found using 6.775 mol% mixed with low-molecular-weight-based polyols (PU-11-3-3). Defined 1.0 wt% CeO2 was also used for the PU-11-3-3 coating (i.e., PU-11-3-3-CeO2) to obtain UV shielding properties. Both the in situ polymerization and blending processes were separately applied during the preparation of the PU-11-3-3-CeO2 coating dispersion. The in situ polymerization-based coating (i.e., PU-11-3-3-CeO2-P) showed similar self-healing properties. The PU-11-3-3-CeO2-P coating also showed excellent UV shielding in real outdoor exposure conditions.

scholarly journals The Use of Epoxy Silanes on Montmorillonite: An Effective Way to Improve Thermal and Rheological Properties of PLA/MMT Nanocomposites Obtained via “In Situ” Polymerization

2015 ◽  
Vol 2015 ◽  
pp. 1-16 ◽  
Author(s):  
Valentina Sabatini ◽  
Hermes Farina ◽  
Luca Basilissi ◽  
Giuseppe Di Silvestro ◽  
Marco A. Ortenzi
Keyword(s):  
Thermal Stability ◽  
Rheological Properties ◽  
In Situ Polymerization ◽  
Rheological Behaviour ◽  
Size Exclusion ◽  
Melt Crystallization ◽  
Scanning Calorimetry ◽  
Molecular Weights ◽  
Exclusion Chromatography

Polylactic acid (PLA) nanocomposites were prepared via “in situ” ring opening polymerization (ROP) of lactide using a montmorillonite, Cloisite 15A, employed after surface treatment with 3-Glycidoxypropyltrimethoxysilane. The dispersion of the nanoparticles was checked using Wide Angle X-Ray Scattering (WAXS) and Transmission Electron Microscopy (TEM); both the effects of different amounts of montmorillonite and silane were measured on molecular weights and on thermal and rheological properties, using Size Exclusion Chromatography (SEC), Differential Scanning Calorimetry (DSC), thermogravimetric analyses (TGA), and rheological analyses. It was found that even very low amounts (0.1% w/w) of nanoparticles greatly affect nanocomposites properties. Unmodified montmorillonite tends to decrease molecular weights, deactivating the catalytic system used for ROP of lactide, but when epoxy silane is present molecular weights increase. Melt crystallization temperatures increase with modified nanoparticles, which enhance crystallization process. TGA analyses show that when pure montmorillonite is present, nanocomposites have lower thermal stability with respect to standard PLA; when silane is used thermal stability can get much higher than standard PLA as silane content increases. The rheological behaviour of nanocomposites shows that melt viscosity is far higher than that of standard PLA at low shear rates and also a marked shear thinning behaviour can be achieved.

Characterization of Polystyrene (PS)/Organomodified Layered Double Hydroxide (OLDH) Nanocomposites Prepared by In Situ Polymerization

2011 ◽  
Vol 410 ◽  
pp. 164-167 ◽  
Author(s):  
Balakrushna Sahu ◽  
G. Pugazhenthi
Keyword(s):  
In Situ Polymerization ◽  
Sodium Dodecyl ◽  
Decomposition Temperature ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
Stretching Vibration ◽  
Xrd Patterns ◽  
Co Precipitation ◽  
Double Hydroxide

PS/LDH nanocomposites were synthesized via in-situ polymerization technique using styrene monomer with toluene as a solvent. A series of LDHs (Mg-Al, Co-Al, Ni-Al, Cu-Al, Cu-Fe and Cu-Cr LDHs) was first prepared from their nitrate salts by co-precipitation method. The above prepared, pristine LDHs were organically modified using sodium dodecyl sulfate (SDS) to obtain organomodified LDHs (OLDH). Then, PS nanocomposites containing 5 wt.% OLDHs were prepared by in-situ polymerization method. The structural and thermal properties of LDHs and corresponding nanocomposites were characterized by X-Ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA). The absence of OLDH peak (003) in the XRD patterns of PS/OLDH nanocomposite confirms the formation of exfoliated nanocomposites. The presence of sulfate groups in the modified LDHs is confirmed by FTIR analysis. The appearance of new peaks in the FTIR spectra in the region of 3400-3500 cm-1, 1670-1680 cm-1and 1200-1260 cm-1for O-H stretching, H-O-H vibration and stretching vibration of sulfate, respectively indicate the existence of LDHs in the PS/OLDH nanocomposites. The entire exfoliated PS/OLDH nanocomposites exhibit enhanced thermal stability relative to the pure PS. When 50% weight loss is selected as point of comparison, the decomposition temperature of nanocomposites is about 3-5oC higher than that of pure PS.

Exfoliated graphite nanoplatelets/poly(arylene ether nitrile) nanocomposites

2016 ◽  
Vol 29 (10) ◽  
pp. 1121-1129 ◽  
Author(s):  
Yingqing Zhan ◽  
Zhihang Long ◽  
Xinyi Wan ◽  
Yi He ◽  
Xiaobo Liu
Keyword(s):  
Electron Microscopy ◽  
Tensile Strength ◽  
In Situ Polymerization ◽  
Decomposition Temperature ◽  
Exfoliated Graphite ◽  
Graphite Nanoplatelets ◽  
Initial Decomposition Temperature ◽  
Arylene Ether ◽  
Exfoliated Graphite Nanoplatelets

In this work, we demonstrate a method for synthesis of exfoliated graphite nanoplatelets (xGnPs)/poly(arylene ether nitrile) (PEN) nanocomposites via an efficient in situ polymerization. The GnPs were treated by the ultrasonic bath to reduce the layers of the GnPs, where the PEN were intercalated subsequently. Therefore, the dispersion of xGnP in the PEN resin was enhanced through in situ polymerization, which was characterized and confirmed by scanning electron microscopy, transmission electron microscopy, and Fourier transform infrared spectroscopy. It was found that the tensile strength and modulus were greatly enhanced with the addition of xGnP. For 2.5 wt% of xGnP-reinforced PEN, the tensile strength and modulus were increased to 115 MPa and 3121 MPa, respectively. Owing to the well dispersion of xGnP, the low rheological percolation of 2.5 wt% for PEN nanocomposites was obtained. Besides, with 1 wt% of xGnP, the corresponding initial decomposition temperature ( Tin) increased from 451°C in pure PEN to 470°C. The addition of xGnP showed enhanced thermal stability of PEN nanocomposites, which demonstrated a promising method for preparing advanced polymer-based nanocomposites.

scholarly journals Dielectric, mechanical and thermal properties of all-organic PI/PSF composite films by in situ polymerization

e-Polymers ◽  
2020 ◽  
Vol 20 (1) ◽  
pp. 226-232 ◽  
Author(s):  
Peng Li ◽  
Jiajun Yu ◽  
Shaohua Jiang ◽  
Hong Fang ◽  
Kunming Liu ◽  
...  
Keyword(s):  
Thermal Properties ◽  
In Situ Polymerization ◽  
Composite Films ◽  
Dielectric Materials ◽  
Mechanical Analysis ◽  
Dielectric Measurement ◽  
Mechanical And Thermal Properties ◽  
High Dielectric Materials ◽  
High Dielectric

AbstractAll-organic high dielectric materials are highly required in the field of modern electronic industry and energy storage. In this work, all-organic polyimide/polysulfone composite films with different amounts of PSF (PI/PSF-X) were prepared by in situ polymerization followed by film casting and thermal treatment. The dielectric, mechanical and thermal properties of these PI/PSF-X composite films are characterized by dielectric measurement, tensile test, thermogravimetric analysis and dynamic mechanical analysis. The results suggest that the PI/PSF-X composite films have good dielectric properties, good mechanical properties and excellent thermal properties, which are suitable for applications in electronic devices in harsh environments, especially in high-temperature environments.

A Parametric Study and Characterization of Porous, Non-Permeable, and Conductive PEGDA-HEMA Hydrogels

2010 ◽  
Author(s):  
Christine Chan ◽  
Shannon Chang ◽  
Hani E. Naguib
Keyword(s):  
Electrical Properties ◽  
Water Content ◽  
Parametric Study ◽  
In Situ Polymerization ◽  
Decomposition Temperature ◽  
Mechanical And Electrical Properties ◽  
Conductive Hydrogels ◽  
Further Development

This study involved the development and characterization of novel porous, non-permeable, and conductive hydrogels. The hydrogels were fabricated with HEMA and crosslinked with PEGDA through a complete parametric study of the synthesis parameters which included water content and crosslinking content. The hydrogels were fabricated using UV photopolymerization and in situ polymerization of PPy, and characterization was conducted with respect to their physical, thermal, mechanical, and electrical properties. The physical properties were analyzed with respect to their swelling ratio and equilibrium water content. The thermal properties were analyzed based on the decomposition temperature and residue weight. The mechanical properties examined the elastic modulus of the hydrogels, and the electrical properties investigated the conductivity of the hydrogels. The relationships observed between the processing, structure, and resulting properties provide the basis for further development and application of these porous, non-permeable, and conductive hydrogels.

Properties of Porous Polyimide Films Based on Melamine Template

2019 ◽  
Vol 821 ◽  
pp. 160-166
Author(s):  
Qing Jun Ding ◽  
Hua Feng Li
Keyword(s):  
Dielectric Constant ◽  
In Situ Polymerization ◽  
Polyimide Film ◽  
Decomposition Temperature ◽  
Porous Films ◽  
Wear Properties ◽  
Polyimide Films ◽  
Oil Storage ◽  
Friction And Wear Properties

In this paper, melamine was used as porogen to prepare porous polyimide film by in-situ polymerization. The mechanical properties, thermal properties, dielectric properties, oil content and friction and wear properties of polyimide films with different porosity were investigated. The tensile strength of porous films decreases obviously with increase of melamine content. It shows the lower thermal decomposition temperature and the faster decomposition speed compared with the non-porous film, indicating higher heat exchange rate due to holes in porous films. As the porogen content increases, the dielectric constant decreases significantly, and the film with melamine content of 20 wt.% has the lowest dielectric constant of 2.43. The holes lead to good oil storage performance and the wear rate and the friction coefficient decrease with the increase of porosity. Keywords: polyimide; porous; melamine; dielectric; friction

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