Thermoplastics component quality

A comparatively new group of materials— thermoplastic elastomers or thermoplastic rubbers —combines the ease of processing of thermoplastics with qualities of traditional vulcanized rubbers, especially elasticity. Because of convenience in processing there is much interest too in blends of plastics with elastomers, which may be modified by the inclusion of filler or glass fibre. As an example, a rubber-like material that can be processed as a thermoplastic can be made by blending and melt-mixing an ethylene-propylene rubber with polypropylene. The use of such blends may be helpful when there are needs to reclaim and re-process material, and in order to obtain products with qualities intermediate between those of the main components of the blends. 

Winding process simulations for thermoplastic filaments are important for the component quality. Commercial simulation tools are not available yet. Research institutes are developing different process simulation programs to understand the influences of the material and the process on the component quality. Simulation programs from the CCM (University of Delaware, Center for Composite Materials, USA) and from the IVW (Institut fiir Verbundwerkstoffe GmbH, Germany) are presented hereafter. 

If the mobile phase is present in a significant concentration, as suggested by the results of solvent extraction studies (1,8), the practical meaning of the mobile phase to coal conversion processes may be profound. In coal liquefaction, two stage processes emphasizing the mobile phase and the macromolecular structure separately could well be most economical. In devolatilization kinetics, at least two sets of kinetic parameters are necessary to model the devolatilization phenomena associated with the mobile phase and the macromolecular structure respectively since the mobile phase components devolatilize at much lower temperatures than the macromolecular structure components 0. In addition, the mobile phase appears to have a significant influence on the thermoplastic properties of coal (0 and thereby on coke quality. 

Ecoflex is an essential component for the processing of renewable raw materials like starch and for producing high quality biodegradable and bio-based plastic films out of them. Ecoflex /thermoplastic starch compounds are used... 

As in injection molding of thermoplastics, the location of the sprue also influences the surface quality of injection-molded structural components made from phenolic resin molding compounds. 

These conditions lead to interesting extraction yields, but residence times in reactors have to be kept short in order to not degrade the biomass components substantially. In the following, lignin from lignocellulosic biomass was separated by subcritical water (<220 °C, <5 MPa) and was characterized by various analytical methods. Its efficient utilization as a matrix for thermoplastic materials could be proved. It is important in material manufacturing to have a simple method for quality control of the raw materials. One of them can be Near Infrared Spectroscopy (NIRS), for example [53-55]. 

The matched die method, which appears in Fig. 5.6, can produce the highest quality parts because precision machined dies act on both surfaces of a thermoplastic composite sheet. The reader should note that there is no requirement for both - or either - of the tool surfaces to be a precision shape. The designer has two surfaces available to control forming and can use them as needed to fabricate the component. 

As a true thermoplastic, FEP copolymer can be melt-processed by extrusion and compression, injection, and blow molding. Films can be heat-bonded and sealed, vacuum-formed, and laminated to various substrates. Chemical inertness and corrosion resistance make FEP highly suitable for chemical services its dielectric and insulating properties favor it for electrical and electronic services and its low frictional properties, mechanical toughness, thermal stability, and nonstick quality make it highly suitable for bearings and seals, high temperature components, and nonstick surfaces. 

Even in cases where one cannot unambiguously identify the components of a complex blend by its individual degradation pattern, it stiU may be possible to use the blend s TGA degradation curve as a quality control tool. For example, a commercial blend of an acrylonitrile-butadiene (ACN/BD) copolymer and a phenolic resin yields a tough thermoplastic/thermoset adhesive when cured that can hold brake linings in place and meet other demanding industrial applications. Isothermal cure of this adhesive was described in Section 3.4.3. 

Sintering and melting processes can process all the materials that behave as a thermoplastic and are available as a powder. They allow the production of internal cavities. The components do not require support structures. The processes are single-stage processes. The components are directly applicable after low rework, if the surface quality is accepted. The relatively rough surface is therefore one of the biggest disadvantages of the procedure. Especially for metal components, the rework becomes complex and also affects the accuracy. 

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