Elastic modulus of the crystalline regions of polyimide derived from poly(amic acid)-biphtalic dianhydride andp-phenylene diamine

Nishino, Takashi; Miki, Norihiko; Mitsuoka, Yoshiaki; Nakamae, Katsuhiko; Saito, Takayuki; Kikuchi, Toru

doi:10.1002/(sici)1099-0488(19991201)37:23<3294::aid-polb4>3.0.co;2-j

Cited by 8 publications

(4 citation statements)

References 21 publications

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“…One of the most important mechanical properties of polymers is the elastic modulus of the crystalline regions (crystal modulus). The crystal modulus in the directions parallel ( E l ) and perpendicular ( E t ) to the chain axis have been measured by X-ray diffraction. − The E l value gives us information about the skeletal conformation, deformation mechanism, and maximum modulus for the specimen modulus of polymers. The E l values for polymers with fully extended planar zigzag conformation in the crystalline regions are 235 GPa for PE and 250 GPa for poly(vinyl alcohol) (PVA).…”

Section: Introductionmentioning

confidence: 99%

Crystal Modulus of Poly(glycolic acid) and Its Temperature Dependence

2017

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Elastic modulus of the crystalline regions (crystal modulus) of poly(glycolic acid) (PGA) in the directions parallel (E l ) and perpendicular (E t ) to the chain axis was measured by X-ray diffraction. The E l value of PGA was 104 GPa at room temperature. This relatively low E l value suggests that the PGA skeleton is not fully extended as reported before but contracted. The E t value of PGA was obtained as 7 GPa, which resembles that (7 GPa) of poly(vinyl alcohol) based on intermolecular hydrogen bonds. This reveals strong intermolecular interactions act between PGA molecules in the crystal lattice. Both low E l value and high E t value are considered to contribute to the extraordinarily high melting point (223 °C) of PGA among aliphatic polyesters. Temperature dependence (13–400 K) of both E l and E t of PGA was also investigated. Abrupt changes around 200 K for both directions were considered to be caused by molecular motion in the crystalline regions of PGA.

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Section: Introductionmentioning

confidence: 99%

Crystal Modulus of Poly(glycolic acid) and Its Temperature Dependence

2017

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“…There are three strategies commonly used to reduce the CTEs of PI films. The first approach is to subject the PAA or PI film to uniaxial or biaxial stretching at a high temperature (>150 °C) [26,27,28]. Upon stretching, the orientation of the molecular chains is improved along the stretching direction by promoting the aggregation of the PIs, and the regularity of the molecular chains is enhanced.…”

Section: Introductionmentioning

confidence: 99%

Mixed Rigid and Flexible Component Design for High-Performance Polyimide Films

Liang

Cao

et al. 2017

Polymers

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To develop the polyimide (PI) which is closely matched to the coefficient of the thermal expansion (CTE) of copper, a series of PIs are prepared from 5,4′-diamino-2-phenyl benzimidazole (DAPBI), 4,4′-diaminodiphenyl ether (ODA), and 3,3′,4,4′-benzophenonetetracarboxylic dianhydride (BTDA) using a sequential copolymerization, blade coating, and thermal imidization process. The physical properties of the PIs are effectively regulated and optimized by adjusting the ratio of the rigid DAPBI and flexible ODA components. By increasing the DAPBI content, thermal stability, dimensional stability, and mechanical properties, the resultant polymer is enhanced. PI-80 exhibits an excellent comprehensive performance, a glass transition temperature of 370 °C, and a tensile strength of 210 MPa. Furthermore, the CTE as calculated in the range 50–250 °C is ca. 19 ppm/K, which is equal to that of copper. A highly dimensionally stable, curl-free, and high T-style peel strength (6.4 N/cm) of copper/PI laminate was obtained by casting the polyamic acid onto copper foil (13 μm) and thermally curing at 360 °C, which indicates that it has the potential to be applied as an electronic film for flexible displays and flexible printed circuit boards. A structural rationalization for these remarkable properties is also presented.

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“…The Laue lattice factor cannot be neglected when (i) the number of subperiods in a unit cell (in the case of nylon 6 α‐form, this value corresponds to the number of methylene groups) is larger than the number of stacked unit cells in the crystallites, and (ii) the crystallite size is very small [19]. In these cases, higher‐order reflections give higher E l values and longer fiber identity periods.…”

Section: Resultsmentioning

confidence: 99%

“…The small E l value of PA9‐T can be attributed to these longer crankshaft arms (0.57 nm), where the moment of force acts during deformation. For PEEK, PEK, and PPS, the long force moment arm length of phenyl rings also lead to smaller E l values of 71, 57, and 28 GPa, respectively [19]. In the case of PE, which has an E l of 235 GPa, the arm length in the zig‐zag structure is as short as ca.…”

Section: Resultsmentioning

confidence: 99%

Crystal modulus of a new semiaromatic polyamide 9‐T

Uddin

Gotoh

Ohkoshi

et al. 2011

Polymer Engineering & Sci

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The elastic modulus (El) of crystalline regions in the direction parallel to the chain axis in a new semiaromatic polyamide 9‐T (PA9‐T) containing a long aliphatic chain unit was measured by X‐ray diffraction and the derived El value was discussed in terms of its molecular conformation and mechanical properties. For low and high molecular weight PA9‐Ts, the El value of 40 GPa was obtained. The low El value for PA9‐T is due to the presence of aromatic groups with long crankshaft arms, which result in a greater moment of force during deformation compared with those polymers with planner zigzag molecular conformation like polyethylene and nylon 6 α‐form. Another factor for the low El is due to the contraction of its molecular chains that is likely originated from the existence of a torsional conformation. The presence of contraction causes some internal rotation in the polymer chain during extensional deformation, which results in low El. POLYM. ENG. SCI., 2012. © 2011 Society of Plastics Engineers

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Elastic modulus of the crystalline regions of polyimide derived from poly(amic acid)-biphtalic dianhydride andp-phenylene diamine

Cited by 8 publications

References 21 publications

Crystal Modulus of Poly(glycolic acid) and Its Temperature Dependence

Crystal Modulus of Poly(glycolic acid) and Its Temperature Dependence

Mixed Rigid and Flexible Component Design for High-Performance Polyimide Films

Crystal modulus of a new semiaromatic polyamide 9‐T

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