A synthesized semi‐aromatic copolyamaide through synergy of three different kinds of monomers: Toward high transparency, excellent heat resistance and melt flowing property

Abstract

To fabricate the low‐cost transparent polyamide with high heat resistance and good melt flowing property simultaneously is a huge challenge in many high‐end fields due to the contradiction between these two properties. In order to balance this contradiction, in this paper, by using isophthalic acid (IPA, aromatic monomer), 4,4′‐methylenebis(cyclohexylamine) (PACM, alicyclic monomer) as rigid stereoscopic monomers, 1,6‐hexanediamine (HMD, aliphatic monomer) as the flexible monomer, a series of transparent poly(hexamethylene isophthalamide/poly(m‐benzoyl4,4′‐methylenebis(cyclohexylamine)) (PA6I/PACMI) with rigid and stereoscopic structure (corresponding to the large distance between adjacent molecular chains) were successfully synthesized. The results indicated that the newly synthesized PA6I/PACMI copolymer has an intrinsically amorphous structure and high optical transparency, which could reach as high as 90%. Furthermore, the highest glass transition temperature (Tg) of the copolymer is over 153.9°C, at the same time, the copolymer also possesses excellent melt flowing property, which can be melt processed easily. Therefore, the newly synthesized copolymer has great advantages in many fields, and it can also shed light on the design and fabrication of high‐performance materials.

Effect of intermolecular hydrogen bonding strength on the dynamic fragility of amorphous polyamides

“…Co-Polyamides were synthesized in a 5 L autoclave equipped with a magnetic stirrer in accordance with reference. 26 DDCA and DCA in different relative ratios, MACM, SHP (catalyst), acetic acid, and deionized water were successively added into the autoclave. Here, acetic acid was introduced to prevent postcondensation and further increase of T g , whereas deionized water was used to reduce the volatilization of amine.…”

“…[23][24][25] Monomers with rigid cyclic unit or other large pendant groups, such as 4,4'-methylenebis(2-methylcyclohexanamine) (MACM) and 4,4'methylenebis(cyclohexylamine) (PACM), were widely introduced to the backbone to destroy the regularity of molecular chains and therefore the amorphous structures were obtained. [26][27][28] It should be pointed out that these prominent properties of polyamides originate mainly from the strong inter-HB interactions, [29][30][31] which should play a crucial role on the dynamic fragilities. Moreover, the strength of inter-HB interactions of polyamides could be easily mediated by tuning the chain length of diamine or dicarboxylic acid, steric hindrance, and bulkiness, and therefore providing a good candidate to systematically investigate the effect of macromolecular-induced inter-HB strength on fragilities.…”

Research Progress of Semi-Aromatic Copolyamides: Structure-Property Relationship

“…The terephthalic acid units in the chain segment will reduce the processing performance of the copolyamides. Adding asymmetric isophthalic acid units to the chain segment can obtain amorphous segments and improve the melt flow performance of the copolyamides [13].…”

An Intrinsically Transparent Polyamide Film with Superior Toughness and Great Optical Performance

“…On the other hand, a series of transparent poly(hexamethylene isophthalamide/poly(m-benzoyl4,4′-methylenebis(cyclohexylamine)) (PA6I/PACMI) have also been successfully synthesized, which exhibited an essentially amorphous structure and high optical transparency with transmittance reaching up to 90% [ 22 ]. Moreover, a novel transparent engineering polyamide, which was PA 10I/10T (synthesized from poly(decamethylene isophthalamide) (PA10I), isophthalic acid (IPA), and DA10), has also been obtained with the transmittance ranging between 85.0% and 90.0% [ 23 ].…”