ISSN:
1436-2449
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
,
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
,
Physics
Notes:
Summary Two new lactone polymerization catalysts, tin(II)-bis(2,4-pentanedionato-O,O') (Zn(Acac)2) and zinc-bis(2,2-dimethyl-3,5-heptanedionato-O,O') (Zn(DMH)2), together with tin(II)-2-ethylhexanoate (Sn(Oct)2), were used to study the effect of the catalyst in the L-lactide polymerization on the nascent polymer structure. Using Zn(DMH)2 an ultra high crystalline polymer was obtained with a ΔHm of 100 J.g-1. Independent of the catalyst and the crystallinity the structure of the crystalline polymer was a pure α-structure as revealed by WAXS-measurements. SAXS-measurements showed a long period for both the Sn(Oct)2 and the Zn(DMH)2 polymer of about 33 nm., the latter revealing a more complex highly regular structure with up to fourth-order reflections. SEM micrographs showed a fibrillar like structure for the Zn(DMH)2 polymer.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00299350
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