Phase separation and mechanical properties of polyketone/polyamide polymer alloys

Abstract

ABSTRACT:We have investigated polyketone (PK)/ polyamide 6 (PA) polymer alloys having enhanced Charpy impact energy greater than that of polycarbonate (PC) as a result of moisture absorption. From the results of differential scanning calorimetry (DSC), Raman spectroscopy, and transmission electron microscope (TEM) observation of the polymer alloys, it was found that PK-rich and PA-rich phases exist at the nanometer level in the polymer alloys; however, a microscopic interaction phase formed between the two phases. 3D-TEM observations, electron energy loss spectroscopy, and small-angle X-ray scattering measurements revealed that a co-continuous nanolayer formed from the PA-rich phase and lamella network of the PKrich phase. Moreover, the interaction and mobility of PK and PA molecular chains were investigated by using a 13 C cross polarization/magic angle sample spinning NMR technique. It was found that moisture absorption markedly enhances the mobility of PA molecular chains in PK/PA alloys. This suggests that the wet (moisture-absorbed) PA phase of PK/PA alloys allows quick deformation upon impact stimulation. On the other hand, the results of Charpy impact tests showed that the total impact energy (E total ) of the wet polymer alloy was much higher than that of the dry one. An examination of the load-displacement curves revealed that the wet samples showed a pronounced increase in displacement compared with the dry ones. From these results, it was concluded that the lamella network of the PK-rich phase sustains the maximum stress and that the large displacement of the PA-rich phase increases the impact energy.

Study of compatibility between aliphatic polyketone terpolymer and poly(styrene‐r‐acrylonitrile)

“…Figures and are the SEM photos of cryofractured surface of PK, SAN, and their blends at various compositions. The cryofractured surfaces of PK show ductile characteristics (i.e., deformed and rough surface) while fracture surfaces of SAN40 and SAN48 show brittle features (i.e., clean and smooth surface) (Figure ) …”

Progress in polyketone materials: blends and composites

“…Kato and co‐workers surprisingly found that the absorption of moisture markedly improved the impact strength of POK/PA6 blends. The water‐absorbing amorphous phase of PA6 played an important role in enabling POK/PA6 blends to exhibit high impact strength and toughness, which was over 150 kJ m −2 and even close to 200 kJ m −2 , whereas the value under a dry condition was less than 50 kJ m −2 . TEM results revealed that the POK/PA6 alloys show a characteristic microstructure consisting of the PA6‐rich phase and a lamellar network of the POK‐rich phase, as shown in Fig.…”

“…42,43 Elastomer-toughened polymer blends, while increasing toughness, generally lead to deterioration of tensile strength and stiffness. However, blending of POKs with PAs including amorphous PAs 44,45 and semi-crystalline ones [46][47][48] resulted in toughened POK materials with good structural strength and ductility.…”

The role of a polyester-based thermoplastic elastomer in the crystallization of an aliphatic polyketone terpolymer

“…Favorable properties such as high tensile strength, high wear resistance, low gas permeability and high chemical resistance give EPCO great potential as an engineering plastic and a barrier packaging material. [1][2][3][4][5][6][7][8][9] However, control of the temperature to below 240°C is recommended for the melt fabrication process of EPCO because thermal degradation occurs readily at a higher temperature. [10][11][12][13][14] This is a result of residual palladium, the polymerization catalyst, for EPCO, which frequently causes trouble in the melt processing of EPCO because of a very narrow processing window.…”