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

Physical Characterization of Photosensitive Polyimide

1997 ◽  
Vol 476 ◽  
Author(s):  
Y.L. Zou ◽  
T.L. Alford ◽  
J.W. Mayer
Keyword(s):  
Coefficient Of Thermal Expansion ◽  
Polyimide Film ◽  
Decomposition Temperature ◽  
Film Plane ◽  
Polymer Chains ◽  
Dielectric Anisotropy ◽  
Polyimide Films ◽  
Design And Optimization

AbstractPolyimides prepared from oxydiphthalic anhydride and diamine precursors can be photosensitive. The thermal, mechanical, and dielectric properties of the polyimide films have been characterized with various techniques. The thermal decomposition temperature of the cured film is 520 °C, and the coefficient of thermal expansion is 20 × 10−6/°C. The polymer chemistry and processing conditions result in a low stress (<26 MPa) in the polyimide film as measured in situ during the curing and cooling cycles. Pads of 6 μm were patterned through the photosensitive polyimide at a sensitivity of 110 mJ/cm2 to i-line wavelength. The polyimide films exhibit anisotropy with an in-plane refractive index of 1.74 and an oul-of-plane index of 1.62 measured at 632.8 nm wavelength. This indicates a preferred orientation of polymer chains in the film plane. The estimated dielectric anisotropy should be considered a major factor for device design and optimization.

Catecholated graphene-filled polyimide with enhanced mechanical, thermal, and tribological properties

2020 ◽  
pp. 095400832094035
Author(s):  
Xing Wu ◽  
Zhengyu Jin ◽  
Yuejin Zhu ◽  
Haichao Zhao
Keyword(s):  
Friction And Wear ◽  
In Situ Polymerization ◽  
Cycloaddition Reaction ◽  
Mechanical Analysis ◽  
Dipolar Cycloaddition ◽  
Wear Properties ◽  
Comprehensive Properties ◽  
Transmission Electron ◽  
Friction And Wear Tests

In order to achieve good dispersion of graphene in polyimide (PI), catecholated graphene (G-Cat) was prepared by 1,3-dipolar cycloaddition reaction of N-methylglycine and 3,4-dihydroxybenzaldehyde with graphene sheets. G-Cat/PI composites were prepared by in situ polymerization with pyromellitic dianhydride and 4,4-oxydianiline in the presence of G-Cat. The successful modification of graphene was proved by infrared spectroscopy, Raman spectroscopy, and transmission electron microscopy. The comprehensive properties of G-Cat/PI composites were studied by tensile, dynamic mechanical analysis, thermogravimetric analysis, and friction and wear tests. By observing the morphology of wear marks, the friction and wear properties of the composites were emphatically analyzed. Therefore, graphene/PI composites were expected to have broad application prospects in lubrication and wear resistance.

Research on Friction and Wear Properties of MC Nylon/ Carbon Nanotubes Composites

2013 ◽  
Vol 662 ◽  
pp. 40-43
Author(s):  
Tie Jun Ge ◽  
Jing Wang ◽  
Wei He
Keyword(s):  
Friction And Wear ◽  
Adhesive Wear ◽  
In Situ Polymerization ◽  
Weight Percent ◽  
Wear Properties ◽  
Mechanics Performance ◽  
Long Time ◽  
Carbon Nano Tubes ◽  
Friction And Wear Properties ◽  
Short Time

In this article, MC nylon/carbon nano tubes (CNTs) composites were prepared by in-situ polymerization method. The friction and wear properties were determined. The sample wear surface morphology carried out by scanning electron microscope (SEM) and the wear mechanism was investigated. It was found that the friction coefficient of composites has decreased with the amount of CNTs increasing in the composites. Addition amount of CNTs is up to 0.3% (weight percent), abrasion index decreased to minimum. The abrasion index of the sample of wearing a long time is smaller than that of the sample of wearing a short time. The sample with wearing less time mainly take place adhesive wear, however, mainly happen abrasive wear and adhesive wear for wearing time is longer. Further more, carbon nano tubes (CNTs) are not only improve the wear resistance of composites but also improve the mechanics performance.

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.

Preparation of Fluorinated Graphene Oxide/Polyimide Composites with Low Dielectric Constant and Moisture Resistance

NANO ◽  
2018 ◽  
Vol 13 (08) ◽  
pp. 1850098
Author(s):  
Dongqing He ◽  
Zhiguo Wang ◽  
Jiapeng Long ◽  
Bing Liang
Keyword(s):  
Dielectric Constant ◽  
Graphene Oxide ◽  
In Situ Polymerization ◽  
Composite Films ◽  
Decomposition Temperature ◽  
Low Dielectric ◽  
Strong Interfacial Interaction ◽  
Fluorinated Graphene ◽  
Different Content ◽  
Fluorinated Graphene Oxide

Fluorinated graphene oxide (FGO) was successfully prepared in this paper, and the chemical structure of FGO was characterized. A series of polyimide (PI) composite films with different content of FGO was prepared by in situ polymerization. Because of the homogeneous dispersion of FGO and the strong interfacial interaction between FGO and the PI matrix, the resulting composite films that contained FGO exhibited effects of mechanical properties, thermal properties and dielectric properties that were even better than the pure PI. Furthermore, due to the hydrophobic properties of FGO, the water absorption of the composite films were reduced. The result showed when the 0.6[Formula: see text]wt.% FGO was filled into the PI, the tensile strength was increased about 66.3%, the decomposition temperature was increased from 540∘C to 570∘C, and the dielectric constant (Dk) decreased with the increasing content of FGO, and a Dk value of 2.28 was achieved when the content of FGO was 1.0[Formula: see text]wt.%.

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 AC CONDUCTIVITY AND DIELECTRIC STUDIES OF POLYPYRROLE-PAPAIN COMPOSITE

2019 ◽  
Vol 7 (8) ◽  
pp. 332-338
Author(s):  
Pandey Munish ◽  
Badlani Richa
Keyword(s):  
Dielectric Constant ◽  
Room Temperature ◽  
In Situ Polymerization ◽  
Weight Percent ◽  
Oxidizing Agent ◽  
Dielectric Studies ◽  
Dielectric Constant And Loss ◽  
Lcr Meter ◽  
Room Temperature Dielectric Constant

Enzyme doped polypyrrole polymer were synthesized by in situ polymerization where ferric chloride works as an oxidizing agent. The different weight percent of papain was added at the time of polymerization. The polypyrrole-papain composite of various composition was analyzed for its dielectric and a. c. conductivity by using LCR meter at room temperature. Dielectric constant and loss decreases, with escalation in frequency. The variation in dielectric constant and dielectric loss was also noted with change in papain percentage in pyrrole.

A Mechanism Design of Friction and Wear Test Based on Liquid Medium

2013 ◽  
Vol 703 ◽  
pp. 212-216
Author(s):  
Wei Wu Zhao ◽  
Xiang Yu ◽  
Zhi Hang Luo ◽  
Jie Ai ◽  
Xi An Zhao
Keyword(s):  
Liquid Medium ◽  
Friction And Wear ◽  
Wear Behavior ◽  
Wear Test ◽  
In Situ Observation ◽  
Wear Properties ◽  
Properties Of Materials ◽  
Friction And Wear Properties ◽  
Ball On Disc

Friction and wear tester is an important device for detecting friction and wear properties of materials. There is inadequacy of research on friction and wear behavior of geological drilling mechanisms serving under complicated liquid circumstances like water, oil and mortar. This article describes an accessory mechanism for commonly used ball-on-disc tribometer which can be applicable in liquid medium. A new oil cup is designed and composed of oil cup sleeve, oil cup lid, transition station, worktable and etc. Interference connection is adopted between oil cup and rotary test bench of tester. Materials are chosen so as to meet requirement from actual working conditions and to simulate the friction and wear test in liquid medium. The mechanism designed share characters of convenient operation, in-situ observation and friendly environment.

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