Skip to main content
White Papers

Nylon Structure vs. Water Absorption

Nylon, also known as polyamide (PA), resins are a diverse group of materials. The versatility of polyamides make this family of polymers one of the most widely used thermoplastics. Could Wallace Carothers ever have anticipated the significance of his material invention?

The molecular architecture, and especially the ratio of carbon atoms to amide functionality, is what gives each different type of polyamide structure is unique property characteristics.

Nylon (polyamide) molecular structure showing amide and methylene functionalities

This structural relationship affects all the properties of the material, including:

  • Mechanical properties
  • Thermal characteristics
  • Degradation resistance
  • Water absorption

Water absorption is an extremely important metric for polyamide materials, since the fundamental properties, such as tensile strength, modulus, impact resistance, and the glass transition temperature, of these materials are different at varying levels of water absorption. The level of water absorption within aliphatic polyamides is directly related to the ratio of paraffinic (methylene) content to amide functionality. The higher the relative proportion of paraffinic structure, the less the water absorption, which in turn results in a lower level of property alteration.

Once again, the properties of plastic materials are directly related to the molecular structure of the polymer.

Water absorption of nylon, polyamide, resin is related to the molecular structure

Jeffrey A. Jansen

Jeffrey A. Jansen is the Engineering Manager and a Partner at The Madison Group. He was elected as a Fellow of the Society by the Society of Plastics Engineers. Jeff is a proven plastic professional with more than 30 years of experience solving problems and addressing opportunities related to polymeric materials. He specializes in failure analysis, material identification and selection, as well as compatibility, aging, and lifetime prediction studies for thermoplastic materials. Jeff has performed over 5,000 investigations, both for industrial clients and as a part of litigation. He regularly presents seminars and webinars, covering a wide range of topics related to plastics failure, material performance, testing, and polymer technology. Jeff is a graduate of Carroll College and the Milwaukee School of Engineering.