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:
Differential Scanning Calorimetry (DSC) measurements were performed on a series of ethylene-vinyl chloride copolymers (E-V) prepared via reductive dechlorination of poly(vinyl chloride) with tributyltin hydride. The copolymers were identical in chain length and branching distribution; differing only in comonomer content, sequence distribution, and stereoregularity of adjacent - V - units. Extrapolation of glass transition temperatures, Tg, measured for our E-V copolymers to pure polyethylene (PE) predicted a Tg = -85 ± 10°C for amorphous PE. E-V copolymers with greater than 60 mol percent - E - units exhibited melting endotherms from 20 to 128°C and degrees of crystallinity from 12 to 63 percent. The melting point depressions observed for our E-V copolymers were in agreement with Flory's theory, if the —CH2—CH2 moiety is considered to be the crystallizable unit and the moiety is assumed to prevent the —CH2—CH2— units attached on either side from being incorporated into the crystal. In general, the E-V copolymer blends with PE were incompatible, while those with PVC were compatible only for E-V copolymers with high V contents (〉80 mol percent). Blends of the amorphous E-V copolymers were found compatible if their V contents differed by less than 15 mol percent, while blends where one or both E-V copolymers are crystalline were found to be incompatible. The properties of these copolymers will be discussed in terms of their microstructure.
Additional Material:
3 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/vnl.730080303
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