Nanofilled and/or toughened POM composites produced by water-mediated melt compounding: Structure and mechanical properties

Abstract

Abstract. Binary and ternary composites composed of polyoxymethylene (POM), polyurethane (PU) and synthetic boehmite alumina (AlO(OH)) were produced by water-mediated melt compounding technique. PU latex and/or aqueous alumina suspension were injected into the molten POM in a twin-screw extruder to prepare toughened and/or reinforced polymer composites. The dispersion of the alumina and PU was studied by transmission-and scanning electron microcopy techniques (TEM and SEM, respectively), and discussed. The crystallization of the POM-based systems was inspected by polarized optical microscopy (PLM). The mechanical and thermomechanical properties of the composites were determined in dynamic-mechanical thermal analysis (DMTA), short-time creep tests (performed at various temperatures), uniaxial static tensile and notched Charpy impact tests. Incorporation of alumina increased the stiffness and resistance to creep and reduced the tensile strength, elongation at break and impact toughness. The change in the above parameters was opposite for the POM/PU binary blends. Additional incorporation of alumina in the POM/PU blend enhanced the resistance to creep, elongation at break and maintained the impact toughness compared to the POM/PU blend.

Dielectric relaxations in polyoxymethylene and in related nanocomposites: Identification and molecular dynamics

“…It is rather suggested that the presence of the filler disturbs the amorphous-crystal interface in such a way that the nanofiller acts like a stretching agent for the chains located at the interface. Regarding that the crystallinity of the specimens, examined in the present work, is not affected by the inclusion of the filler [20], a similar interpretation can be adopted for the α-peak shift observed in our measurements.…”

“…Shift of the α-peak to higher temperatures, has been previously observed for POM following annealing, attributed to the increase of the crystallite size [6,22]. Nevertheless, previous morphological and thermal studies on POM/alumina systems, similar to the one studied in the present work, do not indicate any change in the crystalline structure of POM due to the incorporation of the alumina slurry [20]. As a result we cannot attribute the shift of α-peak to crystallinity changes.…”

“…The alumina and layered silicates contents, in the binary composites, were set at 3 wt%. The details of the preparation procedure can be found elsewhere [20][21][22].…”

Efficient one-step melt-compounding of copolyetheramide/pristine clay nanocomposites using water-injection as intercalating/exfoliating aid

“…A similar approach was proposed by Siengchin et al. to obtain toughened POM nanocomposites [29]. Besides, polyethers are reported to favor the untreated clay layers intercalation.…”

Nitrile rubber - based nanocomposites prepared by melt mixing: effect of the mixing parameters on mechanical, dynamic-mechanical and creep behavior

“…Short-time creep tests were carried out using the methodology described by Siengchin and Karger-Kocsis [43,44] , in a DMA Q800 apparatus (TA Instruments), using the tensile mode at 25 °C. The creep and recoverable compliance were determined as a function of time (t creep = 10 minutes and t recovery = 30 minutes) It was applied a tensile stress of 0.1 MPa.…”