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Effect of melt temperature and skin‐core morphology on the mechanical performance of nylon 6
Author(s) -
Murthy N. Sanjeeva,
Kagan Val A.,
Bray Robert G.
Publication year - 2002
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.11003
Subject(s) - materials science , crystallinity , ultimate tensile strength , composite material , elongation , core (optical fiber) , flexural strength , nylon 6 , microstructure , morphology (biology) , texture (cosmology) , quenching (fluorescence) , polymer , optics , image (mathematics) , physics , artificial intelligence , biology , computer science , fluorescence , genetics
Abstract The crystalline texture and mechanical (tensile and flexural) properties of injection molded nylon 6 were evaluated to understand the influence of the melt temperature ( T mlt ), one of the key‐processing variables. The mechanical properties are found to be sensitive to T mlt only below ∼ 250°C. Rapid quenching of the surface produces a skin with lower crystallinity than the core, which cools more slowly; because of this difference in the rate of cooling, the crystalline component in the skin is rich in γ and that in the core is rich in α. The thickness of this skin decreases from about 1.25 mm to 0.75 mm as T mlt increases from 225°C to 310°C. Higher tensile strength at yield, lower elongation at break and higher flexural strength were observed in specimens molded at lower T mlt . These characteristics are associated with thicker and less ordered skin, and a lower crystallinity core. The role of the T mlt , on microstructure and mechanical properties of injection molded nylon 6, the development of skin‐core morphology, and the role of the residual stresses in the core are discussed.