Moldability tests

The low thermal stability of many poly(iminocarbonates) limits the use of melt fabrication techniques such as injection molding or extrusion. For example, among all six polymers tested, only poly-(Dat-Tyr-Hex) and poly(CTTH) had low enough softening points to be compression moldable without a significant degree of thermal decomposition. ... 

In the engineering development stage, a practical and workable design is developed. Prototype samples are produced on equipment located at the Technical Center that duplicates the production process to be used. A portion of the materials evaluation work is also performed at this time. Candidate materials are given performance tests and moldability is analyzed in detail. Cost and reliability factors are also considered at this time. 

Chemically modified cellulose in the form of cellulose nitrate or nitrocellulose was made and tested for commercial applications in Britain in the 1855-1860 period without much success. The discovery by Hyatt, in 1863, that cellulose nitrate could be plasticized with camphor to give moldability to the blend, made this material much more useful. By 1870, celluloid (plasticized cellulose nitrate) was being produced into a variety of commercial products such as billiard balls, decorative boxes, and combs. Nitrocellulose was also soluble in organic solvents, unlike cellulose, and so could be applied to surfaces in solution to form a coating, as in airplane dopes and automobile lacquers. It could also be solution spun into fibers (synthetic silk) and formed into photographic film, or used as a laminating layer in early auto safety glass. It was also used as an explosive. The hazard introduced to many of these uses of nitrocellulose by its extremely flammable nature resulted in an interest to discover other cellulose derivatives that could still be easily formed, like nitrocellulose, but without its extreme fire hazard. 

The moldability/1344 indicates the number of samples which, upon visual inspection, show flaws such as surface voids and rounded corners. Wire sweep and internal voids were determined by x-ray screening. These data may reflect a somewhat greater reactivity of the new molten resin. A further increase in resin viscosity may lead to wire sweep and other imperfections such as internal voids. A low resin bleed count supports this idea. (Resin bleed is resin material protruding onto leadframes beyond the rectangular shape of the resin mass). Linear devices were also molded over CuA leadframes at 175 and 150°C. The test yields were 98.0 and 98.8% respectively. These yields, as well as those obtained with A-42 leadframes (Table IV) are identical to the yeilds observed when commercial encapsulants are used. 

Rossi-Peakes tester n. An instrument for measuring the temperature at which a given amount of a molding powder will flow through a standard orifice in a prescribed period of time and pressure (ASTM Test D 569). The instrument tests a peculiar combination of properties of a thermoplastic molding compound that may relate to its moldability. 

Volatile control is crucial for the production of void-free phenolic-type laminates. A commercial vacuum-bag moldable phenolic prepreg system was used to test two types of vacuum-bag (VB) processes, namely single- (SVB) and double- (DVB) vacuum-bag processes. The DVB process enabled better control of volatiles, with the point of application of vacuum pressure selected to avoid excessive extravasation of resin to achieve the target resin content in the final consolidated laminate parts. Void-free quality parts have been produced using the DVB process, which exhibited improved mechanical properties compared to the parts produced by the SVB process (Hou et al., 2006). 

Freitag and Reinking reported on the property profile of Bayer s commercial polyarylate [31], They observed that polyarylate was less sensitive to specimen thickness than polycarbonate in the notched izod impact test. They stated that polyarylate is quite similar to polycarbonate in hydrolytic degradation by alkalis, dilute acids, and hot water. The injection moldability... 

Another PPS success story in the electrical/electronics industry concerns use of PPS in televisions.26 Here requirements included high temperature resistance, precision moldability, good arc tracking resistance, and good dimensional stability. Again, numerous materials were tested, but a fiberglass-reinforced PPS compound proved to be the material of choice for a series of pin cushion corrector coils used in color television sets. 

NatureWorks s injection moldable grade of Ingeo in the capillary rheometer test has shown a good fit into the Cross-WLF viscosity model (see Table 6.2). There are seven coefficients in the model and it is readily embedded into Moldflow software for injection molding simulation (Moldflow Plastic Labs 2007). Moldflow is computer software that is widely used across the plastic injection molding industry to predict and optimize the... 

Fig. 6 Influence of contaminants released from silicone gasket materials on the corrosion behavior of 316L. Ex situ immersion test H SO, pH 2, 500h, 100°C. LfMliquid injection moldable, SP screen printable...

Around April 1998, Monsanto sold the product line to Ormecon Chemie, a subsidiary of Zipperling Kessler, based in Ammersbek (near Hamburg), Germany. As of this writing, this firm continues to produce bulk Versicon. The PVC dispersion, called "Incoblend", is claimed to be injection-moldable. Neste Oy, Helsinki, Finland, and Hexcel Corp., also test marketed P(ANi) and P(3AT) powders for example one of the product lines of Neste Oy included poly(3-octyl thiophene) chemically polymerized using FeCla and with a weight-average MWt of ca. 89,000 [157]. 

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