ISSN:
0021-8995
Keywords:
Chemistry
;
Polymer and Materials Science
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:
Ease of processing suspension-polymerized polyvinyl chloride (PVC) is related to its ability to accept sufficient plasticizer, while remaining a dry, free-flowing powder. The successful incorporation of plasticizer, termed cold preblending or hot dryblending, depends upon basic physicochemical factors. Cold preblending corresponds to a purely geometrical filling of intraparticle pores and fissures, while hot dryblending depends additionally upon a time-dependent absorption. Quantitative laboratory tests for these two effects were developed and standardized. When applied to experimental and commercial lots of PVC and their fractions, the tests gave results which showed slight correlation with gross properties of the particles. However, intercorrelation between tests for cold preblending and hot dryblending was strong, indicating that the same factors may be responsible for both. The tests also provided good ratings of polymers for actual processing behavior. It is possible to control particle geometry via the process variables of suspension polymerization, and thence to regulate cold preblending behavior; the effects on hot dryblending are not as clear. Post-polymerization grinding markedly alters the PVC particle surfaces and can substantially improve hot dryblending capacity. Severe grinding is needed to change particle geometry enough for any large improvement of cold preblending.
Additional Material:
14 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/app.1964.070080315
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