Intercalated montmorillonite by cyclotriphosphazene imidazole derivative and its thermal properties used in polyester

• Published in: Fire and materials 2017-06, Vol.41 (4), p.323-338
• Main Authors: Wang, Jiaoning, Chen, Guanyu, Su, Xingyong, Mao, Zhiping
• Format: Article
• Language: English
• Subjects: Ammonia; Burning; Chromatography; Combustion; Composite materials; Constraining; Dehydration; Flame retardants; Flammability; Gas chromatography; Gravimetric analysis; HCCP; Imidazole; intercalated; Intermediates; Mass spectrometry; Mass spectroscopy; Melt blending; MMT; Montmorillonite; NMR; Nuclear magnetic resonance; Oxygen; PET composites; Phosphorus; Polyethylene; Polyethylene terephthalate; Polymers; Pyrolysis; Scientific imaging; Spectroscopy; Thermal properties; Thermodynamic properties
• ISSN: 0308-0501; 1099-1018
• DOI: 10.1002/fam.2383

Summary Montmorillonite (MMT) and hexachlorocyclotriphosphazene (HCCP) are two focal materials to investigate in improving the thermal properties of polymer in recent years. They are used to improve the thermal performance of polymer from different aspects. MMT usually could play an important role in preventing or slowing down the penetration of heat and flame by layers of the mineral. However, making polymer dehydrate and carbonize and generating incombustible ammonia, which can dilute the concentration of combustible gas, are the major ways from HCCP. In this study, a novel intercalated MMT containing high content of phosphorus and nitrogen was synthesized by MMT and HCCP (HCCP‐in‐MMT). It was applied to improve the thermal performance of polyethylene terephthalate (PET) polymer. 1H NMR and 31P NMR technology were used to track the structures of a series of intermediates. The composites were prepared by melt‐blending neat PET with HCCP‐in‐MMT and named as PET/HCCP‐in‐MMT material. Three levels of HCCP‐in‐MMT (1, 3, and 5 wt%) were considered for the blends. The preliminary application in improving the thermal performance of PET was studied by thermo‐gravimetric (TG) analysis and pyrolysis–gas chromatography–mass spectrometry; pyrolysis–gas chromatography–mass spectrometry study showed that the introduction of HCCP‐in‐MMT would inhibit the pyrolysis of PET during heating or burning. The flame retardancy performance of PET composites was characterized by limiting oxygen index tests and UL‐94 test. The result showed that the composites could pass UL‐94 V‐1 and limiting oxygen index value 28.3% just only containing 5 wt% of HCCP‐in‐MMT. TEM showed that the inserted layer structure was formed between PET matrix and synthetic flame retardant HCCP‐in‐MMT. Copyright © 2016 John Wiley & Sons, Ltd.