ISSN:
0193-7197
Keywords:
Chemistry
;
Chemical Engineering
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
,
Process Engineering, Biotechnology, Nutrition Technology
Notes:
In this study, natural, delaminated and silane-treated micas were screened to give fractions passing 60 to 325 screen mesh sizes. The micas were used as fillers (to 80 wt. percent) in plasticized PVC compounds, their dispersion behavior and their effects on mechanical properties of compounds being noted, and compared with the performance of similarly compounded PVC with CaCO3 fillers. The fusion and dispersion performance of these solids was contrasted strongly. While fusion time and maximum torque in Brabender mixing responded only weakly to the presence of CaCO3, in the presence of ≳40 wt. percent mica both of these parameters increased sharply. The elastic modulus of filled compounds indicated little reinforcement by CaCO3, while mica raised the modulus as much as 150 percent, suggesting significant bonding at the filler-matrix interface. This bonding appeared unable to withstand shear strain, elongations at rupture of mica-filled compounds falling catastrophically when compared with CaCO3-filled controls. The tested micas appear of questionable value as substitutes for inexpensive commodity fillers. As expected, at given loading, finer-particle micas gave increased values of the elastic modulus, but particle size did not strongly affect ultimate mechanical properties. Torque maxima and equilibria in mixing correlated well with particle size. Silane-treated micas produced compounds with properties only mildly different from those using untreated versions. Thus, in PVC (and possibly in other chloride-group containing polymers) interfacial conditions seem only mildly influenced by conventional coupling technology.
Additional Material:
5 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/vnl.730060405
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