• Journal of Adhesion and Interface
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• v.10 no.2
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• pp.98-105
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• 2009

Poly(amic acid) was synthesized from the reaction of p-PDA/ODA and PMDA/BPDA and silane oligomer containing epoxy group was also synthesized from the reaction of tetramethylorthosilicate (TMOS) and glycidol. After hybridizing poly (amic acid) and silane oligomer, they were effectively converted into polyimide/silica hybrid films by thermal imidization process. As the silica contents in hybrid films increased, CTE values decreased from 17 ppm/K to 10 ppm/K and the tensile modulus increased, in spite of decreasing tensile strength. In addition, the peel test showed that the adhesion strength of hybrid film was enhanced from $0.43kg_f/cm$ to $1.02kg_f/cm$. Therefore, it could be concluded that the polyimide/silica hybrid film is effective to enhance adhesion strength for FCCL films.

• Applied Chemistry for Engineering
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• v.10 no.7
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• pp.979-984
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• 1999

Aromatic soluble polyimides were synthesized from 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane and various dianhydrides such as pyromelltic dianhydride(PMDA), 3,3',4,4'-benzophenone tetracarboxylic dianhydride(BTDA), and 4,4'-(hexafluoroisopropylidene)-bis(phthalic anhydride)(6FDA). Polyimides prepared by thermal imidization were insoluble in common organic solvents (acetone, MNP, DMAc, DMSO, THF, and DMF) but those prepared by chemical imidization were soluble. The difference of solubility was explained by esterification between hydroxyl group and $CH_3COO^-$ from acetic anhydride used as a dehydration agent in chemical imidization. Glass transition temperatures of polyimides by thermal method were higher than those by chemical method. All of the polyimides are stable up to $300^{\circ}C$ regardless of the sample preparation. The x-ray diffraction patterns showed that all polyimides were amorphrous.

• Applied Chemistry for Engineering
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• v.9 no.1
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• pp.58-65
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• 1998

Substituted dicyandiamide(Sub-DICY), Accelerated dicyandiamide(Acc-DICY), Trimellitic anhydride(TMA), Pyromellitic dianhydride(PMDA) and Phenolic curing agent(Ph.C.A.) are mainly used for epoxy powder coating curing agent. Various characteristics of epoxy films fully cured by optimum condition such as mechanical properties like $T_g$, tensile strength, elongation at break hardness, abrasion resistance and chemical properties like water absorption, acid resistance, alkali resistance and electrical properties, corrosion resistance are determined by various measuring devices and analyses devices. In conclusion, phenolic curing agent was shown excellent thoughness but severe color change as temperature increased. Acid anhydride has excellent insulation properties and color stability at elevated temperature but lower thoughness and adhesion to substrate. DICY curing agent was shown high water absorption and severe color chance as temperature increased.

• Journal of the Korean Institute of Telematics and Electronics T
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• v.36T no.2
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• pp.1-7
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• 1999

The polymide thin films were fabricated by vapor deposition polymerized method of dry processes and studied the electric breakdown characteristics by self healing method. Polyamic-acid(PAA) thin films prepared by vapor deposition-polymerization (VDP) from PMDA(Pyromellitic dianhydride) and DDE(4,4'-diaminodiphenyl ether) were changed to PI thin films by thermal curing. In the same sample, electric breakdown fields increase with increasing test number, and then saturated over test number of the 25th. When the curing temperatures were 200$^{\circ}C$, 250$^{\circ}C$, 300$^{\circ}C$ and 350$^{\circ}C$, the electric breakdown strengths of PI were 1.21MV/cm, 3.94MV/cm, 4.61MV/cm and 4.55MV/cm at the test number of 40th.

• Membrane Journal
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• v.11 no.3
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• pp.116-123
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• 2001

Polyimide-silica hybrid membranes were prepared and the effect of silica content on the structural properties and the gas transport properties was studied. The hybrid membranes were obtained by the sol-gel process starting from 1,2,4,5-benzenetetracarboxylic dianhydride(PMDA), 4,4`-diamino- diphenyl oxide(ODA) and tetraethoxysilane(TEOS) in N,N` dimethylacetatmide (DMAc) solvent. The structural characterizations of the membrane were performed by FT-IR, EDX, TGA and SEM. The gas permeation experiments with ${N_2}, {O_2}, {H_2}, {CO_2}and ${CH_4}$ were carried out at the temperature of $25^{\circ}C$ and in the range of pressure from 3atm to 7atm. the hybrid membranes showed higher thermal stability than PI membranes. The silica patricles were uniformly embedded in the polyimide matrix and the size of silica particles increased with increasing silica content. The permeability coefficients of ${N_2}, {O_2}, {H_2}, {CO_2}and ${CH_4}$ increased with increasing silica content but the diffusion coefficients might appear to be a result of a solubility enhancement. In spite of the permeability enhancement, an increase in the selectivities of ${H_2}/{N_2}, ${H_2}/{O_2} and ${H_2}/{CO_2} was observed.

• Polymer(Korea)
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• v.31 no.2
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• pp.130-135
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• 2007

To enhance the thermo-mechanical properties of polyimide films which have potential application for the FCCL, we have synthesized the poly (amic acid) s composed of 4-components PMDA/BTDA and PDA/ODA as monomer system, u4 then they were effectively converted into 4-component polyimide films by thermal imidization process. It has been found that CTE values in the range of $100\sim200^{\circ}C$ decreased with the amount of PDA, which also caused 36% and 59% increases in tensile modulus and strength respectively. And also, peel test results on 3-layered copper clad laminate using 4-component polyimide films showed excellent adhesion strength above 1.8 kgf/cm. On the basis of obtained results it can be concluded that 4-component polyimide films may be applied for the high performance FCCL base films.

• Journal of Adhesion and Interface
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• v.1 no.1
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• pp.38-46
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• 2000

A novel diamine monomer, containing fluorine and phosphine oxide, bis(3-aminophenyl) 3,5-bis(trifluoromethyl) phenyl phosphine oxide (mDA6FPPO), was prepared via Grignard reaction, and utilized to prepare polyimides with dianhydrides such as PMDA, 6FDA, BTDA or ODPA, by the conventional two-step route; preparation of poly(amic acid), followed by solution imidization. The polyimides were characterized by FT-lR, NMR, DSC and DMA, with intrinsic viscosity, and adhesive properties were also evaluated. A phosphine oxide containing monomer, bis(3-aminophenyl) phenyl phosphine oxide (mDAPPO) a nd a commercial 3,3'-diamino diphenyl sulfone (mDDS) were also used for comparison. The polyimides with mDA6FPPO exhibited high $T_g$, excellent solubility, and good adhesive properties.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2001.10a
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• pp.137-140
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• 2001

Oragnic/inorganic hybrid materials prepared by sol-gel method have rapidly become a fasci nating research field in materials science. In this study, Polyimide/$\textrm{TiO}_2$ composites were synthesized from nano-sized anatase $\textrm{TiO}_2$ and two types of Polyimide (BTDA-PPD, PMDA-ODA) by Sol-gel method. Nano-sized $\textrm{TiO}_2$ particles were prepared from $\textrm{TiOEt}_4$ solution. The composites were charcaterized by using XRD, TGA, IR, TEM, and Atomic Force Microscope(AFM). $\textrm{TiO}_2$ nano particles were dispersed well in polyimide matrix and the thermal stability of polyimide was improved with $\textrm{TiO}_2$ nano-sized particles.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1997.04a
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• pp.293-296
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• 1997

The experimental system used for vapor deposition polymerization (VDP) from PMDA (Pyromellitic dianhydride) and DDE (4, 4-diaminodiphenyl ether) were changed to PI (polyimide) thin films by thermal curing. The curing temperatures were 20$0^{\circ}C$, 25$0^{\circ}C$, 30$0^{\circ}C$, 35$0^{\circ}C$. When test number was 40, the electric breakdown strengths of PI were 1.21MV/cm, 3.94MV/cm, 4.61MV/cm, 4.55MV/cm according to curing temperatures.

• Korean Journal of Materials Research
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• v.26 no.9
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• pp.478-485
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• 2016

An amide group was introduced to restrain the cohesion of silica nano-particles and copolymerized with polyamic acid. Amide block copolymers were prepared using silica and (3-mercaptopropyl) trimethoxysilane (MPTMS) with a siloxane group, using 2, 6-Lutidine as a catalyst. Amide block polymers and copolymers were synthesized via ATRP after brominating pyromellitic dianhydride (PMDA) and polyamic acid of methylene diphenyl diamine (MDA) using ${\alpha}$-bromo isobutyryl bromide. Characteristic peaks of copolymer with amide and imide groups and patterns of amorphous polymers were studied using FT-IR and XRD analyses; an analysis of the surface characteristic groups was conducted via XPS. Changes in the thermal properties were examined through DSC and TGA; solubility for solvents was also studied.