Crystallization of Nylon 11 under compressive high strain rates

Abstract

ABSTRACT:The mechanical behavior of semicrystalline Nylon 11 was studied at strain rates between 10 Ϫ3 and 8800 s Ϫ1. X-ray diffraction and DSC were employed to examine the crystal structure and the crystallinity content. The as-received material comprised a mixed structure of a predominately triclinic (␣) form. DSC revealed that the material gave rise to two melting peaks. The compressive flow stress of Nylon 11 experienced a large increase at 1200 s Ϫ1 and decreased at higher strain rates. The maximum level of the flow stress corresponded with a higher level of crystallinity and a structure mainly of a pseudohexagonal form. The subsequent drop in stress at higher rates was associated with a decrease in the crystallinity content and a mixed crystal structure, different from that observed in the as-received material. After compression, the low melting peak disappeared and the material melted over an increased temperature range.

Preparation and characterization of electrospun fibers of Nylon 11

“…The crystallinity of samples was calculated by dividing the heat of fusion of polymer samples to heat of fusion of 100% crystalline Nylon 11. The reported value of heat of fusion of 206 J/g for 100% crystalline Nylon 11 was used to calculate the % crystallinity [30]. ES10 and ES20 show higher crystallinity than MP and as received P samples.…”

Electrospinning of Nylon11: Effect of processing parameters on morphology and microstructure

“…The crystallinity of samples was calculated by dividing the heat of fusion of polymer samples by the heat of fusion of 100% crystalline Nylon11, which is 206 J/g [47]. Table 1 shows the results of DSC measurements for electrospun mats, solution cast films and melt pressed films.…”

In-Situ Reaction Influenced Polyamide 11 Crystallization in Polymer Blends

“…m is the heat fusion of 100% crystalline PA11 equal to 206 J g À1 [8,21] ; x is the weight fraction of PA11 in the blends.…”

“…PA11 is polycrystalline polymer. To date, at least five crystal forms have been reported by researchers [3][4][5][6][7][8] . Specifically, One triclinic a form, one monoclinic b form, and three hexagonal or pseudohexagonal forms, namely c, d, and d 0 , have been ascribed to PA11 [9] .…”

“…Moffatt et al [11] carried out a series of experiments of uniaxially deformed PA11 at a low strain rate and at a temperature of 80 C. They found a transition from a to c form, commencing at a draw ratio of $ 2 with an increasing fraction of the c phase as the draw ratio further increased. Fernandez et al [8] studied the effect of a high-rate compressive deformation on crystallographic and thermal properties of PA11. The results reveal that the maximum level of the flow stress corresponded with a higher level of crystallinity and a structure mainly of a pseudohexagonal form.…”