Compression and Thermal Expansion Behaviors of Highly Crystalline Polyimide Particles Prepared from Poly(amic acid) and Monomer Salts,Macromolecules

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Compression and Thermal Expansion Behaviors of Highly Crystalline Polyimide Particles Prepared from Poly(amic acid) and Monomer Salts
Macromolecules ( IF 5.1 ) Pub Date : 2021-09-14 , DOI: 10.1021/acs.macromol.1c00779
Eisuke Fujiwara ₁ , Ryohei Ishige ₁ , Daniel Alonso Cerrón-Infantes _{2,

3,

4} , Michael Josef Taublaender _{2,

3} , Miriam M. Unterlass _{2,

3,

4,

5} , Shinji Ando ₁

Affiliation

This study discusses the lattice deformation with an increase in the pressure or temperature of a rigid-rod aromatic polyimide (PI), poly(p-phenylene pyromellitimide), which was enhanced with an increase in the weight density of the lattice. This unique behavior is caused by the suppression of lattice deformation, by means of “misfit strain”, which is induced by the mismatch of the interchain distances between the crystalline and noncrystalline domains. For lattice compression under hydrostatic pressure, the interchain compression was suppressed with a decrease in the crystallinity and/or an increase in the number of PI chains penetrating the interfaces between the crystalline and noncrystalline domains, which is caused by an enhancement of the misfit strain in the crystalline lattice. In contrast, the lattice strain along the main-chain direction (c axis) increased with an increase in the volume fraction of the compressible space near the PI chain ends included in the crystalline domain. Moreover, the thermal expansion of the crystalline lattice was inversely related to the lattice compression, and the coefficient of volumetric expansion increased with an increase in the volumetric compressibility. Accordingly, these results show that the compression and thermal expansion behaviors of the crystalline lattice of the PI are mainly determined by the higher-order structures at the mesoscopic scales, such as the crystallinity and segregated structures between the crystalline and noncrystalline domains, rather than by the crystalline lattice density.

中文翻译：

由聚酰胺酸和单体盐制备的高结晶聚酰亚胺颗粒的压缩和热膨胀行为

本研究讨论了刚性棒芳族聚酰亚胺 (PI)、聚 ( p-亚苯基均苯四甲酰亚胺），随着晶格重量密度的增加而增强。这种独特的行为是通过“错配应变”抑制晶格变形造成的，错配应变是由结晶域和非结晶域之间的链间距离不匹配引起的。对于静水压力下的晶格压缩，由于结晶度的降低和/或穿透结晶域和非晶域之间界面的 PI 链数量的增加，链间压缩受到抑制，这是由错配应变的增强引起的。晶格。相反，沿主链方向的晶格应变 ( c轴）随着包含在结晶域中的 PI 链末端附近的可压缩空间的体积分数的增加而增加。此外，晶格的热膨胀与晶格压缩成反比，体积膨胀系数随着体积压缩率的增加而增加。因此，这些结果表明，PI 晶格的压缩和热膨胀行为主要由细观尺度的高阶结构决定，例如结晶和非晶域之间的结晶度和分离结构，而不是由晶格密度。

更新日期：2021-09-28

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