Correlations between thermal and tensile behavior with friction coefficient in copolyamides 6/12

• Published in: Wear 2017-02, Vol.372-373, p.76-80
• Main Authors: Álvarez-Láinez, Mónica Lucía, Jairo, A Palacio R
• Format: Article
• Language: English
• Subjects: Coefficient of friction; Copolymerization; Copolymers; Crystal structure; Crystallinity; Crystallization; Elongation; Formulations; Friction; Friction coefficient; Gas absorption; Hydrogen bonds; Impact strength; Lubricants; Mechanical properties; Modulus of elasticity; Polyamide resins; Polymerization; Properties relationship; Tensile properties; Tensile strength; Thermal behavior, copolyamide 6/12; Water absorption
• ISSN: 0043-1648; 1873-2577
• DOI: 10.1016/j.wear.2016.11.018

Although polyamide 6 (PA6) obtained from ε-caprolactame (CL) is an engineering polymer with outstanding properties used in sliding applications, it exhibits low impact strength and high water absorption. Those are some of the reasons why copolymerization between CL and laurolactame (LL) is desired. In this work, copolymers from 0–100wt% LL are prepared to evaluate crystallinity, melting behavior, tensile properties and those properties are correlated with coefficient of friction. Experimental results show that PA6 (0wt%) crystallinity and elasticity modulus are higher than those obtained from 100wt%LL (PA12), but friction coefficient in PA6 is lower than that of PA12. While with 60wt% LL crystallinity and elastic modulus reach a minimum value, with 350% elongation and coefficient of friction they register a maximum value. Our results suggest that crystallinity and elastic modulus are opposed to coefficient of friction. The absence of hydrogen bonds produces irregularities in the chain, reducing the crystal formation; such behavior is a consequence of copolymerization. Our findings will help to customize copolyamide, modulate the response between mechanical properties and friction behavior, as well as evaluate when it is necessary to add lubricants in the copolymer formulations. •Copolimerization reduces amide groups line up and crystallinity.•The Friction coefficients of copolyamide 6/12 were measured•The Friction coefficients of copolyamides are higher than in homopolyamides•Crystallinity and elastic modulus are opposed to friction coefficient.