Polymer/silicate interaction in nylon 6-clay hybrid studied by temperature programmed pyrolysis techniques

Abstract

Nylon 6-clay hybrid (NCH) was characterized by temperature-programmed pyrolysis (TPPy) techniques such as TPPy-mass spectrometry and TPPy-gas chromatography mainly focusing on the interaction between nylon 6 molecule and the surface of silicate monolayers in the NCH samples, which leads to the superior properties of the hybrid nanomateirals. Pyrolysis profile of nylon 6 matrix in the NCH samples was gradually shifted to lower temperature region with increase in the clay content. The yields of main pyrolysis products such as ε-caprolactam from the NCH samples decreased with increase in the clay content, whereas those of the nitrile compounds significantly increased. These results suggested that the clay surface accelerate cis-elimination reaction of nylon 6 matrix in the NCH samples to form the nitrile compounds rather than intramolecular amide exchange to ε-caprolactam. Based on the changes in pyrolysis behaviors of nylon 6 matrix in the NCH samples, the interaction between positively charged NH proton of nylon 6 molecules and negatively charged clay surface was proposed which would stabilize the six-membered transition state during pyrolysis.