Super-extrusion

Use super-extrusion (operating above the critical shear stress for melt fracture)... 

Super-extrusion is a technique whereby the shear stress in the die land is above the critical shear rate for melt fracture see Section 7.5.3.2. This is possible with polymers that exhibit a second stable region above the melt fracture region. Linear polymers such as HDPE, EEP, and PEA exhibit super-extrusion behavior. The melt fracture behavior can be determined on a capillary rheometer by running a polymer melt at different shear rates and observing the corresponding condition of the extru-date. A typical flow curve for a linear polymer is shown in Eig. 11.43. 

Flow curve of a linear polymer showing melt fracture and super-extrusion regions... 

SAF = super abrasion furnace ISAF = intermediate super abrasion furnace HAF = high abrasion furnace FEF = fast extrusion furnace ... 

Water intrusion-extrusion isotherms performed at room temperature on hydrophobic pure silica chabazite show that the water-Si-CHA system displays a real spring behavior. However, Pressure/Volume differences are observed between the first and the second cycle indicating that some water molecules interact with the inorganic framework after the first intrusion. 29Si and especially H solid state NMR and powder X-ray diffraction demonstrated the creation of new defect sites upon the intrusion-extrusion of water and the existence of two kinds of water molecules trapped in the super-cage of the Si-CHA a first layer of water strongly hydrogen bonded with the silanols of the framework and a subsequent layer of liquid-like physisorbed water molecules in interaction with the first water layer. 

A type of carbon black produced by burning natural gas or oil in a large furnace with a supply of air much lower than that required for complete combustion. The main types are super abrasion (SAF), intermediate super abrasion (TSAF), high abrasion (HAF), fast extrusion (FEF), general purpose (GPF), conductive (CF) and semireinforcing (SRF). 

Charge Air Cooling Duct on 2004 Ford Super Duty F-Series Truck is produced from soft and hard durometer Hytrel (TPEE) grades in sequential co-extrusion process. Three plastic pieces replace seven metal pieces. 

Two notable methods to produce microcellular foams include gas supersaturation in combination with an extrusion process developed by MIT/Trexel [84-86] and the continuous extrusion process by Dow [87,88]. Super-insulating materials are made by the encapsulation of a filler material inside a barrier film, aluminum foil, or metallized film. These materials exhibit 5-7 times the R-value of typical nonvacuum insulating materials depending on vacuum level and barrier and filler type. Uses for these VIPs (vacuum insulation panels) include refrigeration and controlled-temperature shipping containers. 

Figure 12.5 Rheological data (IS011403-2) for a super high-impact extrusion resin that has a volumetric flow rate (IS01133, 200°C/5.0kg) of 4...

Souto C, Rodriguez A, Parajes S, et al. A comparative study of the utility of two super-disintegrants in microcrystalline cellulose pellets prepared by extrusion/spheronization. Eur J Pharm Biopharm 2005 61 94-9. 

Hot isostatic pressing of near-net-shape parts from refractory or super-alloy metal powders is applied for jet engine parts. In contrast, common metals can readily be formed by conventional methods such as casting, rolling, forging, or extrusion. Therefore, only recently have metal fabricators begun to look more closely at the feasibility of isostatic pressing. 

Figure 5.30 Relation of reduction ratio and extrusion pressureJ i Note Extrusion aid used Super VM P Naphtha (Shell Extruder used Jennings extruder.

ST Injection molding, extrusion Super tough, high-viscosity resin, outstanding resistance against repetitive impact, even at very low temperature Fasteners and lock systems... 

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