Effect of thermal imidization and curing on fluorescence behavior of a phenylethynyl-terminated poly(amic acid)

2003 ◽  
Vol 11 (5) ◽  
pp. 297-302 ◽  
Author(s):  
Donghwan Cho ◽  
Gyeongmo Yang ◽  
Lawrence T. Drzal
Keyword(s):  
Amic Acid ◽  
Thermal Imidization

scholarly journals Colorless and Transparent Copolyimides and Their Nanocomposites: Thermo-Optical Properties, Morphologies, and Gas Permeabilities

Polymers ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 585 ◽  
Author(s):  
Hyeon Shin ◽  
Young-Je Kwark ◽  
Jin-Hae Chang
Keyword(s):  
Optical Properties ◽  
Coefficient Of Thermal Expansion ◽  
Amic Acid ◽  
Gas Permeation ◽  
Molar Ratio ◽  
Molar Ratios ◽  
Thermal Imidization ◽  
Organically Modified ◽  
Permeation Properties

A series of linear aromatic copolyimides (Co-PIs) were synthesized by reacting 4,4′-biphthalic anhydride (BPA) with various molar contents of 2,2′-bis(trifluoromethyl)benzidine (TFB) and p-xylylenediamine (p-XDA) in N,N′-dimethylacetamide (DMAc). Co-PI films were fabricated by solution casting and thermal imidization with poly(amic acid) (PAA) on glass plates. The thermo-optical properties and gas permeabilities of Co-PI films composed of various molar ratios of p-XDA (0.2–1.0 relative to BPA) were investigated. Thermal properties were observed to deteriorate with increasing p-XDA concentration. However, oxygen-transmission rates (O2TRs) and optical transparencies improved with increasing p-XDA concentration. Co-PI hybrids with a 1:0.2:0.8 molar ratio of BPA:TFB:p-XDA and organically modified hectorite (STN) were prepared by the in situ intercalation method. The morphologies and the thermo-optical and gas permeation properties of the hybrids were examined as functions of STN loading (5–50 wt %). XRD and TEM revealed substantial increases in clay particle agglomeration in the Co-PI hybrid films as the clay loading was increased from 5 to 50 wt %. The coefficient of thermal expansion (CTE) and the O2TR of a Co-PI hybrid film were observed to improve with increasing STN concentration; however, its optical transparency decreased gradually with increasing STN concentration.

Synthesis and characterization of new poly(diketone imide)s derived from 1,4-bis(3,4-dicarboxybenzoyl)benzene dianhydride and various diamines

2020 ◽  
Vol 32 (9) ◽  
pp. 1043-1051
Author(s):  
Lu Kuang ◽  
Wei-Hong Wei ◽  
Xiao-Yan Sang ◽  
Yang Pan ◽  
Cheng Song
Keyword(s):  
Mechanical Property ◽  
Tensile Strength ◽  
Ring Opening ◽  
Tensile Modulus ◽  
Amic Acid ◽  
Synthesis And Characterization ◽  
Aromatic Diamines ◽  
Thermal Imidization ◽  
Stage Process

1,4-Bis(3,4-dicarboxybenzoyl)benzene dianhydride, an aromatic bis(ketone anhydride) monomer, was synthesized by the Friedel–Crafts reaction of terephthaloyl dichloride and o-xylene, followed by the oxidation of the intermediate tetramethylated compound and cyclodehydration of the resulting tetraacid. A series of new poly(diketone imide)s (PDKIs) were prepared from this dianhydride with various aromatic diamines via a conventional two-stage process that included ring-opening polyaddition to form the poly(amic acid)s followed by thermal or chemical imidization. Most of the PDKIs through chemical imidization were soluble in aprotic amide solvents, such as N, N-dimethylacetamide, N-methyl-2-pyrrolidone, m-cresol, and so on. The resulting PDKIs had good thermal property with the glass transition temperature of 203–275°C, the temperature at 5% weight loss of 500–539°C, and the residue of 51–60% at 800°C in nitrogen. Additionally, strong and flexible PDKI films obtained by thermal imidization exhibited outstanding mechanical property with the tensile strength of 88.8–158.5 MPa, tensile modulus of 1.9–3.5 GPa, and elongation at breakage of 7–21%.

scholarly journals Reactivity of Poly(amic acid) Isomers in Thermal Imidization

1990 ◽  
Vol 22 (8) ◽  
pp. 725-732 ◽  
Author(s):  
Ning-Jo Chu ◽  
Jiann-Wen Huang
Keyword(s):  
Amic Acid ◽  
Thermal Imidization

An Electrospun Polyimide Ultrathin Fiber Membrane for Particle Filtration of Hot Gas

2014 ◽  
Vol 1048 ◽  
pp. 489-492 ◽  
Author(s):  
Jian Fei Xie
Keyword(s):  
High Temperature ◽  
High Performance ◽  
Amic Acid ◽  
Infrared Spectrometry ◽  
Fiber Membrane ◽  
Electrospun Membrane ◽  
Excellent Thermal Stability ◽  
High Performance Polymer ◽  
Thermal Imidization ◽  
Average Size

Electrospun membrane filters used to remove particles from hot gases were highly desired to meet the requirement of application in high temperature. Polyimide is a kind of high performance polymer, especially for excellent thermal stability and chemical resistance. In this paper, the polyimide precursor poly (amic acid) (PAA) was synthesized from 3,3’,4,4’-oxydiphthalic anhydride (ODPA) and 4,4’-methylenedianiline (MDA), the polyimide (PI) ultrathin fiber membrane was fabricated by electrospinning and followed by thermal imidization. Scanning electron microscope (SEM), infrared spectrometry (IR), and thermogravimetric analysis (TGA) were used for the characterizations of the polyimide ultrathin fiber Membrane, the tests show that the diameter of ultrathin fiber is uniform with an average size of around 400nm and the membrane is thermally stable at a high temperature of 500°C.

scholarly journals Enhancement of the Mechanical Properties of Polyimide Film by Microwave Irradiation

Polymers ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 477 ◽  
Author(s):  
Ju-Young Choi ◽  
Seung-Won Jin ◽  
Dong-Min Kim ◽  
In-Ho Song ◽  
Kyeong-Nam Nam ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Irradiation Time ◽  
Polyimide Film ◽  
Amic Acid ◽  
Polyimide Films ◽  
Inorganic Substance ◽  
Short Irradiation Time ◽  
Green Approach ◽  
Thermal Imidization ◽  
Mw Irradiation

Polyimide films have conventionally been prepared by thermal imidization of poly(amic acid)s (PAAs). Here we report that the improvement of tensile strength while increasing (or maintaining) film flexibility of polyimide films was accomplished by simple microwave (MW) irradiation of the PAAs. This improvement in mechanical properties can be attributed to the increase in molecular weight of the polyimides by MW irradiation. Our results show that the mechanical properties of polyimide films can be improved by MW irradiation, which is a green approach that requires relatively low MW power, very short irradiation time, and no incorporation of any additional inorganic substance.

Naphthalene Containing Polyimide Nanocomposites Hybrid with Organo-Modified Montmorillonite

2006 ◽  
Vol 111 ◽  
pp. 43-46
Author(s):  
B.K. Chen ◽  
S.Y. Tsay ◽  
C.P. Chen
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Dielectric Constant ◽  
Amic Acid ◽  
Aggregate Formation ◽  
Thermal And Mechanical Properties ◽  
Modified Montmorillonite ◽  
Thermal Imidization ◽  
Tetracarboxylic Dianhydride ◽  
Acid Precursor

To improve the thermal and mechanical properties of polyimides, a nanocomposite of naphthalene containing polyimide (PI) was hybridized with Montmorillonite (MMT). The PI was synthesized from a diamine, 2,7-bis (4-aminophenoxy) naphthalene and polymerized with a 3,3’,4,4’-benzophenone tetracarboxylic dianhydride via thermal imidization. PI-MMT nanocomposites were then prepared from a DMAc solution of poly(amic acid) precursor and a DMAc dispersion of MMT which were organo-modified with various amount of n-dodecylamine. Characterization results demonstrated that the introduction of a small amount of MMT (up to 5%) led to enhanced thermal stability and mechanical properties of PI. The 5% weight loss temperature in N2 was increased by 46oC in comparison to pristine PI with an organoclay content of 5%. The CTE and dielectric constant were decreased. However, at organoclay contents higher than 5% these properties were reduced because the organoclay was poorly dispersed and resulted in aggregate formation.

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