Preparation, melting, glass relaxation and nonisothermal crystallization kinetics of a novel dendritic nylon-11

• Published in: Thermochimica acta 2011-09, Vol.524 (1), p.117-127
• Main Authors: Wan, Jintao, Bu, Zhi-Yang, Li, Cheng, Fan, Hong, Li, Bo-Geng
• Format: Article
• Language: English
• Subjects: activation energy; Advanced isoconversional method; ambient temperature; Applied sciences; crystal structure; Crystallinity; Crystallization; Crystals; Dendritic nylon-11; Differential scanning calorimetry; Exact sciences and technology; Extended Hoffman–Lauritzen method; Fourier transform infrared spectroscopy; glass; Glass transition; heat; Heating; Melting; melting point; Nonisothermal crystallization; Organic polymers; Physicochemistry of polymers; Properties and characterization; thermal stability; Transition temperature
• ISSN: 0040-6031; 1872-762X
• DOI: 10.1016/j.tca.2011.07.002

[Display omitted] ► A novel dendritic nylon-11 (DPA-11) is prepared and characterized using FTIR, TGA, WXRD, and DSC. ► The melting, glass relaxation and nonisothermal crystallization kinetics of DPA-11 is systematically studied by comparing with linear nylon-11. ►The isothermal crystallization kinetics of DPA-11 is analyzed using a number of classic methods (JMA, Ozawa, Mo and Vyazovkin). ► The equilibrium melting point of DPA-11 is determined from the Hoffman–Weeks method. ►The spherulitic growth of DPA-11 is examined using the extended Hoffman-Lauritzen method. A novel dendritic nylon-11, DPA-11, is prepared from the melting copolycondensation of 11-aminoundecanoic acid and the 2nd generation poly(propyleneimine) dendrimer as the dendritic unit, with its melting, glass-transition and nonisothermal crystallization behaviors highlighted. DPA-11 is characterized using FTIR, TGA, WXRD and DSC. The results show that PDA-11 has excellent thermal stability, at room temperature its δ′-form crystal is predominant, and the dual melting processes and glass transition occur during the heating. The subsequent crystallization kinetic analysis with JMA, Ozawa and Mo methods demonstrates the mechanisms and crystallizability changing with the relative crystallinity, α, especially, during the primary and secondary crystallization stages. Moreover, applying the Vyazovkin method yields the dependence of the effective activation energy on crystallinity, from which the crystallization mechanisms are discussed in detail. Then the equilibrium melting temperature is determined, being 200.9 °C. Furthermore, the spherulitic growth analysis with the extended Hoffman–Lauritzen method produces the Regime I/II transition temperature of 158° C.