title: Crystalline transition and morphology variation of polyamide 6/CaCl2 composite during the decomplexation process.
abstract: In this work, we developed a new method to prepare porous PA6 with different morphologic feature and crystalline forms via the decomplexation of PA6/CaCl2 composite. The structures and morphology of thus obtained materials were characterized by vibrational spectroscopy (FT-IR and Raman) and scanning electron microscope (SEM) method. When amorphous PA6/CaCl2 composite films were treated in water at room temperature, PA6 re-arranges into γ form. However, decomplexation of the PA6/CaCl2 composite in boiling water produces PA6 in α crystalline form. If the PA6/CaCl2 composite is soaked in methanol, part of PA6 is dissolved or swollen in methanol/metal salt solutions. As a result, a dissolve/precipitation process occurred during the decomplexation process, which led to the formation of PA6 in α crystalline form. Further investigation demonstrates that the morphologies of the porous PA6 could be adjusted by using different solvents and/or different decomplexation conditions.
authors.affiliation: Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, PR China.
authors.forename: Shaoxuan
authors.initials: S
authors.lastname: Liu
authors.forename: Chengfeng
authors.initials: C
authors.lastname: Zhang
authors.forename: Edyta
authors.initials: E
authors.lastname: Proniewicz
authors.forename: Leonard M
authors.initials: LM
authors.lastname: Proniewicz
authors.forename: Younkyoo
authors.initials: Y
authors.lastname: Kim
authors.forename: Jun
authors.initials: J
authors.lastname: Liu
authors.forename: Ying
authors.initials: Y
authors.lastname: Zhao
authors.forename: Yizhuang
authors.initials: Y
authors.lastname: Xu
authors.forename: Jinguang
authors.initials: J
authors.lastname: Wu
mesh_terms: D002122:Calcium Chloride / Q000737:chemistry*; D002209:Caprolactam / Q000031:analogs & derivatives* / Q000737:chemistry; D003460:Crystallization; D008855:Microscopy, Electron, Scanning; D044367:Phase Transition; D011108:Polymers / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D013059:Spectrum Analysis, Raman
chemical_list: D011108:Polymers; C009916:nylon 6; D002209:Caprolactam; D002122:Calcium Chloride
keywords: Crystalline transition; Polyamide 6; Polyamide 6/CaCl(2) composites; Porous films