ISSN:
0032-3888
Keywords:
Chemistry
;
Chemical Engineering
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
,
Physics
Notes:
Flashing in pure polyphenylene sulfide (PPS) and a blend containing PPS and liquid crystalline polymer (LCP) during injection molding was investigated by differential scanning calorimetry and scanning electron microscopy. The shape of the flash was observed by use of a projector. Flashing was detected in pure PPS and 90/10 PPS/LCP blend but was not found in other compositions, including pure LCP. The DSC thermograms of the flash revealed both exothermic and endothermic peaks at around 120° and 285°C. The first peak, known as crystallization temperature on heating, occurred as a result of early crystallization of PPS. The observed double peaks indicated that the degree of crystallinity was lower in the flash than in the molded part. The morphological studies revealed the presence of LCP fibrils in the skin region and droplets in the core region of 90/10 PPS blend. The absence of flash was attributed to the diameters of the fibrils and droplets, which were found to increase with increasing LCP component.
Additional Material:
12 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/pen.760350304
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