Synthesis and characterization of semi⁃aromatic polyamide containing piperazine ring

doi:10.19491/j.issn.1001-9278.2025.10.003

Abstract

Abstract:

Semi⁃aromatic polyamides combine the desirable properties of both aromatic and aliphatic polyamides. In this study， a novel difluorobenzamide monomer， N，N’⁃（1，4⁃Piperazinediyldi⁃3，1⁃propanediyl） bis（4⁃fluorobenzamide）（FDC⁃200）， was synthesized via a facile interfacial reaction between 1，4⁃bis（3⁃aminopropyl）piperazine and 4⁃fluorobenzoyl chloride. A series of polyamides incorporating piperazine rings were subsequently prepared from this monomer through nucleophilic substitution polymerization. The chemical structures of the monomer and polymers were confirmed by FTIR and ¹H⁃NMR spectroscopy. These novel polyamides exhibited outstanding thermal properties， with glass transition temperatures ranging from 149.0 to 171.4 ℃ and a 5 % weight loss temperature exceeding 385 ℃. The incorporation of a diphenyl sulfone moiety was found to significantly enhance multiple material properties. Specifically， it improved tensile strength （exceeding 60 MPa）， increased hydrophobicity （water absorption as low as 3.7 % for sample SPAS⁃50）， and enhanced solubility， thereby broadening processability. Furthermore， the diphenyl sulfone structure imparted excellent flame retardancy， with sample SPAS⁃50 achieving a UL 94 V⁃1 rating. This work demonstrates a promising strategy for developing high⁃performance semi⁃aromatic polyamides with a versatile property profile.

Key words: semi?aromatic polyamide, piperazine, nucleophilic substitution, processability

CLC Number:

TQ323.6

ZHENG Xinyuan, HUANG Xiao, YAN Guangming, ZHANG Gang, YANG Jie. Synthesis and characterization of semi⁃aromatic polyamide containing piperazine ring[J]. China Plastics, 2025, 39(10): 12-17.

Figures/Tables 13

Fig.1. The synthesis route of monomer FDC⁃200

Fig.2. The synthesis of semi⁃aromatic containing piperazine ring

样品	FDC⁃200含量/mol %	DCDPS含量/ mol %	拉伸强度/ MPa	拉伸模量/ GPa	断裂伸长率/%
SPA	100	0	60.0±3.4	2.44±0.25	13.6±4.95
SPAS⁃10	90	10	63.5±2.6	1.88±0.04	13.3±2.81
SPAS⁃30	70	30	66.2±3.2	2.19±0.02	19.7±3.29
SPAS⁃50	50	50	69.9±1.9	2.22±0.04	10.9±2.67

Tab.1. The formulation and mechanical properties of SPAs

Fig.3. The FTIR spectra and 1H⁃NMR spectra of FDC⁃200

Fig.4. FTIR spectra of SPAS

Fig.5. 1H⁃NMR spectra of SPAS

Fig.6. DSC curves of semi⁃aromatic polyamides SPAS

Fig.7. TG curves of semi⁃aromatic polyamides SPAS

Fig.8. Tensile strength of semi⁃aromatic polyamides SPAS

Fig.9. XRD curves of SPAS

Fig.10. The water absorption of SPAS films

Fig.11. The solubility of SPAS films in N⁃Methylpyrrolidone

Fig.12. Flame retardancy test results of SPAS

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