All-Aromatic (AB)_n-Multiblock Copolymers via Simple One-Step Melt Condensation Chemistry

Abstract

We have prepared (AB) n -multiblock copolymers based on N-(3′-hydroxyphenyl)­trimellitimide (IM), 4-hydroxybenzoic acid (HBA), and 6-hydroxy-2-naphthoic acid (HNA) via a simple one-pot melt condensation method. The blocky nature is the result of phase separation taking place in the early stages of the melt polymerization process. The liquid crystal HBA/HNA fraction phase separates from the isotropic HBA/IM fraction and this phase separation effectively shuts down transesterification reactions, preventing randomization of the polymer backbone. The (AB) n -multiblock copoly­(esterimide)­s exhibit two distinct glass transition temperatures (T gs). The first T g at ∼120 °C can be assigned to the HBA/HNA rich A-block and the second T g at ∼220 °C can be assigned to the HBA/IM rich B-block. When introducing imide-based phenylethynyl end-groups, these reactive functionalities end-up exclusively at the termini of the HBA/IM rich B-blocks, effectively forming a phenylethynyl-terminated B­(AB) n -reactive oligomer. Upon thermal treatment, cross-linking via the phenylethynyl end-groups results in a thermoset where the T g of the B-block increases by as much as ∼106 °C. The T g of the HBA/HNA A-block remains unchanged. Scanning electron microscopy experiments show a gradual change in morphology, from a typical fibrous LCP texture for the HBA/HNA rich polymers to a more consolidated morphology for the HBA/IM rich polymers. Atomic force microscopy images confirm the presence of two distinct domains when 44 mol % of HBA was replaced by IM. The “hard” imide rich B-blocks form domains of ∼100–200 nm that are embedded in the imide poor or “soft” A-blocks.

High‐performance soluble copolyarylate based on phenolphthalein: synthesis, characterization and properties

“…This finding was consistent with the DSC studies where PP0, PP10 and PP30 showed melting peaks (Fig. (a)) and with previous reports stating that these signals indicated a semi‐crystalline nature. Introducing PP into the PP0 backbone effectively reduced the intensity of the peaks.…”

The Thermal Properties and Degradability of Chiral Polyester-Imides Based on Several l/d-Amino Acids

“…Chiral PEIs (PEI3a–PEI3d′) were synthesized by direct polycondensation of diacid monomers (2a–2d′) with 4,4′-dihydroxydiphenyl ether under the reported method (see step 2 in Scheme 1 ) [ 25 , 26 , 27 ]. Yields and physical properties of PEIs are shown in Table 2 .…”

High-solubility aromatic polyesters with fluorene and phthalein groups: Synthesis and property

“…Apparently, the bulky fluorene and phthalein groups in the polymer backbone hinder the crystallization of the polymer, lowering the chain packing efficiency with a gain in free volume and thereby leading to amorphous aromatic polyester formation. 6,37 Notably, the amorphous structures of all the polymers were also reflected in their solubilities (Table 4).…”