Molecular Dynamics of ULTEM 9085 for 3D Manufacturing: Spectra, Thermodynamic Properties, and Shear Viscosity.

Luchinsky, Dmitry G ; Hafiychuk, Halina ; Hafiychuk, Vasyl ; Wheeler, Kevin R

关键词: AEROSPACE ENVIRONMENTS;    AMORPHOUS MATERIALS;    BULK MODULUS;    COEFFICIENTS;    INFRARED SPECTRA;    MOLECULAR DYNAMICS;    POLYMER BLENDS;    SPACE MANUFACTURING;    SPECIFIC HEAT;    THERMODYNAMIC PROPERTIES;    THREE DIMENSIONAL MODELS;    VISCOSITY;   

RP-ID  :  NASA/TM-2018-220213,L–12456,ARC-E-DAA-TN61894

美国|英语

来源: NASA Technical Reports Server

【 摘 要 】

We present results of a molecular dynamic analysis of welding at the polymer-polymer interface. The analysis is performed for polyetherimide/ polycarbonate polymer blends. The work is motivated by the applications to 3D manufacturing in space. In the first part of the report, we discuss bulk and spectral characteristics of the amorphous polymer blends. The vibrational and infra-red spectra obtained using auto-correlation functions calculations in molecular dynamics are compared with the experimental spectra. The mechanical and thermal properties of the samples including heat capacity, bulk modulus, and thermal expansion coefficients are estimated and compared with experimental values. In the second part of the report, we discuss the result of molecular dynamical modeling of shear viscosity in a fully atomistic model of amorphous polymer blends with flat interface. The key result of the research is the demonstration of shear thinning behavior of the shear viscosity as a function of shear rate which is in good agreement with experimental data.