ポリマーの結晶/非晶界面における分子鎖変形挙動の分子動力学解析

概要

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Two molecular dynamics simulations are conducted on the deformation behavior of the crystal/amorphous interface of polyehylene under tension. One, Model 0°, has the crystal of which chain direction is parallel to the tensile axis. The other, Model 45°, has the chain direction rotated 45° against the tensile direction. Detail observation of the chain structure at the interface in the equilibrium state unloaded, reveals that the interface in Model 45° is serrated by the recrystallization of amorphous chains while Model 0° has no remarkable change in the morphology of the interface. It is also observed in both Model 0° and Model 45° that the comformational defects propagate in the chain direction and make disorders in the crystalline phase. Then the tensile strain is applied on the models, leading the following results: (a) Model 0° shows the yielding and strain hardening, as observed in the nanoscopic specimen without crystalline phase reported in our previous work. The same mechanism of chain orientation and elongation take place in the amorphous phase at the interface. (b) Model 45° exhibits linear stress increase from the begining of the straining without remarkable yielding. It is because the molecular chains in the crystalline phase is also subjected to the force normal to the chain direction, so that the crystal deforms in the non-bonded direction and shows stress increase.
一般社団法人日本機械学会の論文
2004-05-25