Page 64 - 《橡塑技术与装备》英文版2026年3期

HINA R&P TECHNOLOGY AND EQUIPMENT

Research on analytical and identification methods for
nylon 6 and nylon 66 in rubber products

Liu Qingqing, Lv Shuangshuang, Zheng Ningjuan, Wang Xiaolei
(Aeolus Tyre Co. LTD., Jiaozuo 454003, Henan, China)
Abstract: Nylon 66 and nylon 6 enhance tire structural strength, durability and stability. As synthetic
fiber cords, they have excellent wear resistance, tensile strength and corrosion resistance, occupying an
important position in tire manufacturing. Different tires use different cords, so a simple method is needed for
rapid differentiation between nylon 6 and nylon 66. This paper compares methods including DSC melting
point, crystallinity, GCMS and TGA: crystallinity test results deviate significantly from theoretical values; TGA
weight loss analysis is easily affected by rubber adhering to cords; DSC melting point analysis is relatively fast
(≈30 minutes) but requires complete sample stripping from tire rubber, posing processing challenges; GCMS
structural analysis takes 50 minutes, is unaffected by surface rubber, and requires no sample processing. Thus,
GCMS is determined as the laboratory method for identifying nylon 6 and nylon 66.
Key words: nylon 6; nylon 66; DSC; TGA; GCMS; identification type
Classification number: TQ32 Article number: 1009-797X(2026)03-0018-04
Document code: B DOI:10.13520/j.cnki.rpte.2026.03.004

Nylon is a kind of polyamide thermoplastic resin, also different monomer raw materials of the two lead to significant
known as nylon. Among them, the two most commonly used differences in their structure and properties: nylon 6 has a
polyamides are nylon 6 and nylon 66, which account for about monoclinic crystal structure, while nylon 66 has a triclinic
98% of global production capacity and output. Its greatest crystal structure; the melting points of nylon 6 and nylon 66
characteristic is the presence of a considerable number of are 220 ℃ and 264 ℃ respectively; due to the higher density
amide groups in the molecular chain, and the formation of of hydrogen bonding in nylon 66 compared to nylon 6, the
hydrogen bonds between amide groups endows nylon materials crystallinity of nylon 66 is higher than that of nylon 6.
with good mechanical properties, fatigue resistance, and wear Currently, the application fields of nylon 6 and nylon 66
resistance. As a high-quality environmentally friendly fiber are becoming increasingly widespread, making it particularly
material, it is widely used in various fields such as clothing, important to accurately and rapidly identify the two types.
automotive, defense, aerospace, etc. At the same time, due Based on the differences in structure and performance
to its good mechanical properties, fatigue resistance, and between nylon 6 and nylon 66, this paper employs three
wear resistance, it is also widely used in harsh environments testing methods: differential scanning calorimetry (DSC),
such as garden tools, engine covers and intake manifolds in thermogravimetric analysis (TGA), and gas chromatography-
the automotive field, electronic component substrates and mass spectrometry (GCMS) for testing and analysis. The aim is
housings in the electronics field, and bearings and gears in to determine a precise and rapid method for identifying nylon
the mechanical field. Nylon 6 is formed by the ring-opening 6 and nylon 66 through melting point, crystallinity, thermal
polymerization of caprolactam monomers in a head-to-
tail manner, while nylon 66 is formed by the alternating Biography: Liu Qingqing (1990-), an engineer, primarily engages in
polymerization of hexamethylenediamine and adipic acid. The research and testing analysis related to rubber material technology.

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