Study of microindentation and differential scanning calorimetry of reinforced polyamide

摘要

Polyamides comprise the largest family of plastics engineering with a very wide range of applications in many fields of activities. Characteristically polyamides are resistant to wear and abrasion, have good mechanical properties even at elevated temperatures, low permeability to gases and good chemical resistance. Samples are obtained by monocomponent injection using Taguchi experimental plan with six input factors and two levels of variation for each of them. The considered parameters inside the experiment are mold temperature, melt temperature, injection pressure, injection speed, cooling time (in mold) and injection time. This study presents some aspects of microindentation and differential scanning calorimetry for polyamide with 30% fiberglass and microsphere reinforcement. For microindentation experimental study, UMT-2 universal equipment (CETR-Center of Trybology, INC. USA) is used. It was also used a sensor by 2 kg, a maximum force of 15 N and indenter radius Rockwell type with diamond peak is 200 μm. The software package used indicates microhardness values and indentation reduced modulus and Young's modulus and it generates experiment graphs. Concerning the differential scanning calorimetry the experiments were performed on differential scanning calorimeter (DSC) type F3 Maia (supplied by Netzsch) in argon protective atmosphere. The temperature difference between sample and reference is measured and recorded as heat flow. Temperature is measured using three thermocouples, one indicating the sample temperature, the temperature set point second and final furnace temperature. DSC thermograms evaluation will be done with PROTEUS software. To determine the critical points of transformation, transformation starting temperature (onset), temperature when 50% of the change occurred (peak) and finally the transformation temperature (end) and will use the tangent method. The amount of heat dissipated (in the case of endothermic transformation)/absorbed (in the case of exothermic transformation) will be determined using a sigmoidal baseline (ΔH area).