Synthesis and Properties of Cyclopentyl Cardo-Type Polyimides Based on Dicyclopentadiene

Abstract

A crucial polymer intermediate, 4-[1-(4-hydroxyphenyl)cyclopentyl]-phenol (bisphenol CP), was developed from dicyclopentadiene (DCPD), a key byproduct of the C5 fraction in petrochemicals. On the basis of bisphenol CP, a diamine, 4,4′-((cyclopentane-1,1-diylbis(4,1-phenylene))bis(oxy))-dianiline (cyclopentyl diamine; CPDA) was subsequently obtained through a nucleophilic substitution of bisphenol CP, followed by the hydrogenation process. By using the CPDA diamine, a series of polyimides with cyclopentyl (cardo) units on the backbone were prepared along with a reference polyimide (API-6F) based on 4,4′-(4,4′-(propane-2,2-diyl)bis(4,1-phenylene))bis(oxy)dianiline (BPAA), and 4,4′-(hexafluoroisopropylidene)-diphthalic anhydride (6FDA) for the exploration of structure-properties relationship. Thanks to the presence of cyclopentyl units, this type of cardo polyimides exhibited comparable tensile properties, especially a large elongation (25.4%). It is also worth noting that CPI-6F exhibited better solubility in organic solvents, such as NMP, DMAc, THF, and chloroform, than the other PIs. Gas separation properties were also evaluated for these cardo-type polyimides.

Synthesis and Characterization of Low-Melting-Point Polyamides with Trace Thermoreversible Cross-Linked Networks

“…In addition, according to the description of Bragg’s law, the interplanar spacings ( d ) of α 1 and α 2 are both significantly shifted, as listed in Table . With the increase of the 6F content, the d values of α 1 and α 2 decrease slightly, as aromatic ring increases the ability of π–π stacking between polymer chains, making the packing of the LMPA molecular chain more compact. − In contrast, with the introduction of the DA trace cross-linked networks in LMPA samples, the d values of α 1 and α 2 increased slightly as the polymer chain stacking possessed loose packing features and large void volumes caused by cross-linked networks …”

“…34−36 In contrast, with the introduction of the DA trace cross-linked networks in LMPA samples, the d values of α 1 and α 2 increased slightly as the polymer chain stacking possessed loose packing features and large void volumes caused by cross-linked networks. 37 Dynamic Mechanics of LMPAs with BMI Loading. Figure 6 shows the tan δ and storage modulus (G′) of LMPA-5 with various BMI loadings at 1 Hz.…”

Design, synthesis and characterization of novel fluorinated polyimide membranes with bulky pendant for gas transport

“…And the chemical structure modification of PI is usually achieved by changing the structure of dianhydride or diamine to adjust the FFV and gas transport performance 20 . Numerous studies have reported that the introduction of bulky side groups, 21, 22 flexible units, 23 non‐coplanar and asymmetric structures, 24–27 etc., into the polymer backbone is an effective method to decrease the regularity of polymer chains and weaken the accumulation of molecular chains, which greatly improve gas permeability of the polymer while maintaining moderate selectivity. In addition, the presence of fluorine in polymer chains improves the solubility, hydrophobicity, optical transparency and FFV, which is attributed to the unique physical and chemical properties of the fluorine atom, including low molar polarizability, small atomic radius and large electronegativity 28–31 .…”