The aim of this work was to develop a talc-like inorganic coating on the surface of the multiwalled carbon nanotubes (MWCNTs) to facilitate their mixing into the polypropylene and polyethylene matrix. Precursor compounds such as MgCl 2 Á 6H 2 O, Mg(NO 3 ) 2 Á 6H 2 O, MgO 2 C 4 H 10 and tetraethyl-orthosilicate (TEOS) were used to cover the surface of the MWCNTs. As prepared, coverages and polymer composites were characterized by transmission electron microscopy and X-ray diffraction techniques.

No abstract

The latest development in injection moulding technology is the introduction of pressure sensors in the cavity. The measured pressure value controls the machine, therefore the technology becomes more reliable. In this paper a cavity pressure measuring system is shown. It was developed for a falling dart test piece producing mould. The injection moulding machine, the mould and technology are shown in this paper.

The molten polymers are non-Newtonian materials because their viscosity apart from the temperature depends on the shear rate, pressure, the molecular weight, molecular weight distribution, flow geometry. The properties of the injection moulded part depend on the filling process. The goal of our research is to study the filling of the injection moulds. An instrumented injection mould was designed for the measurements. As against a standard injection mould, it has an open cavity so the material can flow out from the mould. Due to the technique, the filling time can be extended up to some seconds. The flow rate, in this manner the deformation rate, material and mould temperature was changed during the measurements. Due to the new technique, the cavity filling was studied and the pressure gradient was determined as function of process parameters. The flow properties were determined in wide shear rate range of the polyethylene (Tipolen FA 2210) material.

Many interdependent parameters must be controlled during injection mounding process to produce the proper quality product. Any external action can cause the quality changing of injected products (e.g. mechanical properties, color, dimensional accuracy). Quality checking can recognize those defective products after injection. Our goal is to set a measuring system for finding correlation between the parameters of technology and the cavity pressure. We were able to measure the pressure inside of the cavity. Stability of set up was investigated. The most important parameters were changed and the resulted cavity pressure was measured. During the resulted data, a special rheometer has been developing ÖsszefoglalásA fröccsöntés során igen sok egymástó függő technológiai paramétert kell kézben tartani, a megfelelő minőségű termék gyártásához. Bármilyen külső hatás a termék minőségének változását eredményezheti (mechanikai tulajdonságok, szín, méretpontosság, stb.). Minőségellenőrző módszerekkel ezek a hibák csak utólag vehetők észre, és selejtgyártás jöhet létre. Célunk egy olyan mérőrendszer kialakítása és üzemeltetése volt, amivel a technológiai paraméterek és a formaüregben lejátszódó folyamatok között tudunk kapcsolatot teremteni. Sikeres nyomásméréseket hajtottunk végre a szerszám formaüregébe. Megvizsgáltuk az egyes beállítások stabilitását. Változtattuk a legfontosabb paramétereket a gépen és mértük ezeknek a hatását az üregnyomásra. Folyamatban van egy reométer fejlesztése amely nagysebességű reológiai mérésekre lesz alkalmas.