scholarly journals The Potential Barrier and Thermal Stability Dependence on PI Thickness of Al/PI/c-Si Schottky Diode

2020 ◽  
pp. 3235-3241
Author(s):  
Hussein Kh. Rasheed ◽  
Aseel A. Kareem
Keyword(s):  
Thermal Stability ◽  
Thermal Decomposition ◽  
Interfacial Layer ◽  
Average Distance ◽  
Amic Acid ◽  
Complete Conversion ◽  
Polyimide Films ◽  
Ft Ir ◽  
Ir Analysis ◽  
Different Thickness

This research investigated the effectiveness of using different thickness values of polyimide (PI) interfacial layer in order to improve electrical and thermal properties of Al/ PI /c-Si capacitor. The PI spectra produced by poly(amic acid) (PAA) were characterized by using FT-IR analysis. After imidization of PAA, some absorption peaks vanished, whereas PI peaks appeared, due to the complete conversion of PAA to PI.     The results show that thermal decomposition resistance of polyimide films increases with the increase of polyimide thickness, because of the increase of the imide bond and the decrease of the average distance between amide groups.

Synthesis and properties of low coefficient of thermal expansion copolyimides derived from biphenyltetracarboxylic dianhydride with p-phenylenediamine and 4,4′-oxydialinine

e-Polymers ◽  
2016 ◽  
Vol 16 (4) ◽  
pp. 295-302 ◽  
Author(s):  
Yonglin Lei ◽  
Yuanjie Shu ◽  
Jinhua Peng ◽  
Yongjian Tang ◽  
Jichuan Huo
Keyword(s):  
Thermal Stability ◽  
Thermal Expansion ◽  
Coefficient Of Thermal Expansion ◽  
Thermomechanical Analysis ◽  
Amic Acid ◽  
Molar Ratio ◽  
Structure And Property ◽  
Property Relations ◽  
Ft Ir ◽  
Biphenyltetracarboxylic Dianhydride

AbstractA series of copolyimides were prepared by thermal imidization of poly(amic acid)s (PAAs) derived from 3,3′,4,4′-biphenyltetracarboxylic dianhydride (s-BPDA), 2,3′,3,4′-biphenyltetracarboxylic dianhydride (a-BPDA), p-phenylenediamine (PDA) and 4,4′-oxydialinine (4,4′-ODA) commonly used for the production of commercial polyimides. The flexible copolyimide films were obtained from that the molar ratio of s-BPDA, a-BPDA, PDA and 4,4′-ODA was 9:1:8:2 (Co-PIs-3), 8:2:9:1 (Co-PIs-5) and 8:2:8:2 (Co-PIs-6). These obtained copolyimide films were characterized by Fourier transform-infrared spectroscopy(FT-IR), wide angle X-ray (WAXD), Thermogravimetric (TG), dynamic mechanical thermal analysis (DMA), thermomechanical analysis (TMA), field-emission scanning electron microscopy (FE-SEM) and mechanical properties measurement. The results showed that three copolyimides remained semi-crystalline and exhibited high glass transition temperature (Tg), high thermal stability, great ultimate tensile strength and low coefficient of thermal expansion (CTE). The Co-PIs-5 had lower crystallinity, lower CTE, greater elongation at break, higher Tg and thermal stability and the greater dense extent, compared with Co-PIs-3 and Co-PIs-6. Structure and property relations of the prepared polyimides were also briefly discussed. The results revealed that the copolymerization of s-BPDA/PDA with a small number of 4,4′-ODA/a-BPDA was a useful means for enhancing flexibility without sacrificing low CTE.

Synthesis and properties of novel polyimides containing 2,6-benzobisoxazole units

e-Polymers ◽  
2009 ◽  
Vol 9 (1) ◽  
Author(s):  
Xiangli Meng ◽  
Yudong Huang ◽  
Zushun Lv ◽  
Hong Yu
Keyword(s):  
Thermal Stability ◽  
Weight Loss ◽  
Amic Acid ◽  
Aprotic Solvents ◽  
Polyimide Films ◽  
Excellent Thermal Stability ◽  
Glass Transition Temperatures ◽  
Aromatic Polyimides ◽  
H Nmr ◽  
Structures And Properties

AbstractThe diamine monomer, 2,6-bis(p-aminophenyl)-benzo-[1,2-d; 5,4-d’] bisoxazole was successfully synthesized. Three aromatic polyimides (PI) based on 2,6-bis(p-aminophenyl)-benzo-[1,2-d; 5,4-d’] bisoxazole were prepared via a conventional two-stage procedure with a variety of dianhydrides. Their structures and properties were characterized by FTIR, 1H NMR, TG, DSC and XRD. The intermediate poly(amic-acid)s (PAA) had inherent viscosities of 1.18-1.70 dL/g and could be thermally converted into lightly yellow polyimide films. The resulted polyimides showed excellent thermal stability, and the glass transition temperatures (Tg) of all polymers were above 280 oC, and the 5% weight loss temperatures of polymers were about 550 oC in N2. The solubility of these polyimides in various solvents was evaluated. They were all insoluble in conventional polar aprotic solvents.

scholarly journals Synthesis and characterization of polyimide thin films obtained by thermal evaporation and solid state reaction

2016 ◽  
Vol 34 (1) ◽  
pp. 132-136 ◽  
Author(s):  
Ikram Atta Al-Ajaj ◽  
Aseel A. Kareem
Keyword(s):  
Thin Films ◽  
Solid State ◽  
Solid State Reaction ◽  
Physical Vapor Deposition ◽  
Amic Acid ◽  
Surface Topology ◽  
Polyimide Films ◽  
Force Microscopy ◽  
Atomic Force ◽  
Ft Ir

AbstractIn this research polyimide films were prepared by physical vapor deposition (PVD), using solid state reaction of pyromellitic dianhydride (PMDA) and p-phenylene diamine (PDA) to form poly(amic acid) (PAA) films. The resultant films were converted to polyimide by thermal treatment, usually below 300 °C. For this study, a FT-IR spectrometer has been used to measure the effect of imidization temperature on the chemical structure of the vapor-deposited thin films of aromatic PI. When temperature increased, an increase in all absorption peaks was observed. This suggests that residual PAA monomers continued to be converted into PI. The surface topology of the PI films obtained at imidization temperatures of 150, 200, 250 °C for 1 hour was further examined by using AFM atomic force microscopy. It can be clearly seen that the surface became rougher with increasing imidization temperature. The thermal stability of polyimide was also studied by using thermogravimetric analysis (TGA).

Synthesis and Characterization of Polyimides Derived from 5-Amino-2(p-aminophenyl) Benzoxazole Monomer

2011 ◽  
Vol 415-417 ◽  
pp. 1789-1793
Author(s):  
Xiang Li Meng ◽  
Peng Wang ◽  
Ling Jiang
Keyword(s):  
Amic Acid ◽  
Synthesis And Characterization ◽  
Polyimide Films ◽  
Glass Transition Temperatures ◽  
Good Thermal Stability ◽  
Light Yellow ◽  
Structures And Properties ◽  
Ft Ir ◽  
Tetracarboxylic Dianhydride

Polyimides prepared from 5-amino-2(p-aminophenyl) benzoxazole (AAPB) with pyromellitic dianhydride(PMDA), 2,2’3,3’-biphenyl tetracarboxylic dianhydride(i-BPDA), 4,4’-oxdiphthalic anhydride(ODPA), 1,4-bis(3,4-dicarbosyphenoxy) benzene dianhydride(HQDPA) and 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride (6FDA) were synthesized successfully via a conventional two-stage method. Their structures and properties were characterized by FT-IR, DSC, TG and XRD. The intermediate poly(amic acid)s had inherent viscosity range of 0.86~2.18 dL/g and could be thermally converted into light yellow polyimide films. The polyimides showed excellent solvent resistance and good thermal stability. The glass transition temperatures (Tg) were found to be 336oC~369 oC .The decomposition started at a temperature above 530oC in N2 atmosphere.

Research on Some Aromatic Schiff Base Compounds and Metal Complexes with Different Substituted Groups

2011 ◽  
Vol 474-476 ◽  
pp. 1523-1528
Author(s):  
Ti Feng Jiao ◽  
Jian Liu ◽  
Li Hua Gao ◽  
Jing Xin Zhou ◽  
Yuan Yuan Xing
Keyword(s):  
Thermal Stability ◽  
Schiff Base ◽  
Metal Complexes ◽  
Metal Ion ◽  
Uv Spectra ◽  
Hydroxyl Group ◽  
Imino Group ◽  
Schiff Base Derivatives ◽  
Ft Ir ◽  
Ir Analysis

Two aromatic Schiff base derivatives and the corresponding metal complexes with different substituted groups were synthesized and characterized by many methods. The products were characterized by UV-Vis spectra, FT-IR spectra and thermal analysis, while the thermal stability was measured by TG-DTA instrument. FT-IR analysis indicated that the nitrogen atom in imino group and oxygen atom in phenolic hydroxyl group participated in coordinating with transition metal ion in different bridged mode. UV spectra also verified that different coordination modes can be performed between metal ions and ligands. In addition, the thermal stability of metal complexes had been obviously superior to that of the ligands. All results give a useful clue to obtain Schiff base derivatives with versatile property by regulating intramolecular substituted group and species of metal ion. The present results have showed potential application in fields of functional material and catalyst.

Thermal stability and FT-IR analysis of Phosphonium-based deep eutectic solvents with different hydrogen bond donors

2017 ◽  
Vol 242 ◽  
pp. 395-403 ◽  
Author(s):  
Hosein Ghaedi ◽  
Muhammad Ayoub ◽  
Suriati Sufian ◽  
Bhajan Lal ◽  
Yoshimitsu Uemura
Keyword(s):  
Thermal Stability ◽  
Hydrogen Bond ◽  
Deep Eutectic Solvents ◽  
Ft Ir ◽  
Ir Analysis ◽  
Hydrogen Bond Donors

Synthesis and Properties of Polyimides Containing Tert-Buty Group

2013 ◽  
Vol 275-277 ◽  
pp. 1636-1639
Author(s):  
Yun Hua Lu ◽  
Peng Pan ◽  
Bing Wang ◽  
Hong Bin Zhao ◽  
Zhi Zhi Hu
Keyword(s):  
Optical Properties ◽  
Fourier Transform ◽  
Amic Acid ◽  
Structure And Properties ◽  
Visible Spectroscopy ◽  
Polyimide Films ◽  
Solubility Test ◽  
Tert Butyl ◽  
Thermal Imidization ◽  
Ft Ir

Two diamine monomers 2-tert-butyl-1,4-bis(4-nitro-2-trifluoromethylphenoxy)benzene and 1,4-bis(4-amino-2-trifluoromethylphenoxy)benzene were reacted with the alicyclic dianhydride monomers 1,2,3,4-cyclobutanetetracarboxylic dianhydride to synthesize the poly(amic acid)s, and then obtain the corresponding polyimide films through thermal imidization. The structure and properties were characterized by fourier transform infrared spectroscopy (FT-IR), ultraviolet visible spectroscopy (UV-vis), thermogravimetic analysis (TGA), solubility test and so on. The effect of introduction of bulky tert-butyl and trifluoromethyl to the polyimide backbone on the properties of polyimide films was investigated. The experimental results showed that polyimides with tert-buty group exhibit excellent solubility, but their thermal and optical properties decreased slightly.

Polarized microbeam FT-IR analysis of single fibers

1996 ◽  
Vol 54 ◽  
pp. 206-207
Author(s):  
Liling Cho ◽  
David L. Wetzel
Keyword(s):  
Molecular Orientation ◽  
Transition Point ◽  
Polymer Fibers ◽  
Single Fiber ◽  
Wire Grid ◽  
Polyester Fibers ◽  
Ft Ir ◽  
Ir Analysis ◽  
The Relationship ◽  
Wire Grid Polarizer

Polarized infrared microscopy has been used for forensic purposes to differentiate among polymer fibers. Dichroism can be used to compare and discriminate between different polyester fibers, including those composed of polyethylene terephthalate that are frequently encountered during criminal casework. In the fiber manufacturering process, fibers are drawn to develop molecular orientation and crystallinity. Macromolecular chains are oriented with respect to the long axis of the fiber. It is desirable to determine the relationship between the molecular orientation and stretching properties. This is particularly useful on a single fiber basis. Polarized spectroscopic differences observed from a single fiber are proposed to reveal the extent of molecular orientation within that single fiber. In the work presented, we compared the dichroic ratio between unstretched and stretched polyester fibers, and the transition point between the two forms of the same fiber. These techniques were applied to different polyester fibers. A fiber stretching device was fabricated for use on the instrument (IRμs, Spectra-Tech) stage. Tension was applied with a micrometer screw until a “neck” was produced in the stretched fiber. Spectra were obtained from an area of 24×48 μm. A wire-grid polarizer was used between the source and the sample.

Synthesis and Evaluation of Levulinic Ester as Biodiesel Additives

2020 ◽  
Vol 71 (8) ◽  
pp. 21-26
Author(s):  
Elena-Emilia Oprescu ◽  
Cristina-Emanuela Enascuta ◽  
Elena Radu ◽  
Vasile Lavric
Keyword(s):  
Maximum Yield ◽  
Strength Distribution ◽  
Point Of View ◽  
Reaction Parameters ◽  
X Ray ◽  
Ethyl Levulinate ◽  
Ft Ir ◽  
Ir Analysis ◽  
Biodiesel Blend ◽  
Acid Strength Distribution

In this study, the SO42-/TiO2-La2O3-Fe2O3 catalyst was prepared and tested in the conversion of fructose to ethyl levulinate . The catalyst was characterized from the point of view of the textural analysis, FT-IR analysis, acid strength distribution, X-ray powder diffraction and pyridine adsorption IR spectra. The influence of the reaction parameters on the ethyl levulinate yield was study. The maximum yield of 37.95% in levulinate esters was obtained at 180 �C, 2 g catalyst and 4 h reaction time. The effect of ethyl levulinate addition to diesel-biodiesel blend in different rates, i.e, 0.5, 1, 2.5, 5 (w.t %) on density, kinematic viscosity and flash point was evaluated and compared with the European specification.

Formulation, Optimization,and Ex-Vivo Evaluation of Novel Lipid Carriers for Enhanced Transdermal Delivery of Hydroquinone

2020 ◽  
Vol 12 ◽  
Author(s):  
Shivani Verma ◽  
Sukhjinder Kaur ◽  
Lalit Kumar
Keyword(s):  
Ex Vivo ◽  
Skin Permeation ◽  
Topical Delivery ◽  
Gelling Agent ◽  
Minimum Size ◽  
Prolonged Release ◽  
Freeze Dried ◽  
Ft Ir ◽  
Ir Analysis ◽  
Skin Retention

Background: HQ is used for hyper-pigmentation treatment using conventional creams and gels. These formulations show various disadvantages like poor skin permeation, allergic reactions, and repeated use decreasing patient compliance. Objectives: The present work involved formulation, statistical optimization, and characterization of nanostructured lipid carriers (NLCs) for efficient topical delivery of hydroquinone (HQ) for hyperpigmentation treatment. Methods: The NLCs were optimized exploring Box–Behnken design (BBD) using three independent variables and two dependent variables. Formulation having the minimum size and maximum drug entrapment was considered as optimized formulation. Optimized formulation was evaluated for drug release followed by its freeze-drying. The freeze-dried formulation was subjected to differential scanning calorimetry (DSC) analysis, X-raydiffraction (XRD) analysis, and Fourier transform-infrared spectroscopy (FT-IR) analysis. Furthermore, NLCs based gel was prepared by using Carbopol 934 as a gelling agent. NLCs based gel was evaluated for skin permeation, skin retention, and skin distribution (through confocal microscopic analysis) using pig ear skin. Results: Optimized NLCs showed smaller particle size [(271.9 ± 9) nm], high drug entrapment [(66.4 ± 1.2) %], tolerable polydispersity index (PDI) (0.221 ± 0.012), and zeta potential [(-25.9± 1.2) mV]. The FT-IR analysis revealed excellent compatibility between HQ and other excipients. The Carbopol 934 gel containing NLCs showed high transdermal flux [(163 ± 16.2) μg/cm2/h], permeability coefficient (0.0326 ± 0.0016), and skin permeation enhancement ratio (3.7 ± 0.4) compared to marketed cream of HQ. The results of confocal microscopic (CLSM) analysis revealed the accumulation of optimized NLCs in the lower epidermal layers of skin. Conclusion: NLCs based gel was considered effective in the topical delivery of HQ to treat hyper-pigmentation due high skin permeation, skin retention, and prolonged release of HQ.

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