Miscibility and Crystalline Morphology in Blends of Poly (vinyl acetate) with a Homologous Series of Aliphatic Polyesters
| Autor: | Chao-Shun Chang, 張朝順 |
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| Rok vydání: | 2005 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 93 Miscibility and crystalline morphology in blends of poly (vinyl acetate) with a homologous series of aliphatic polyesters were exploring by differential scanning calorimeter(DSC)、polarized-light microscopy(PLM)、scanning electron microscopy(SEM) and Wide-angle X-ray Scattering Diffractometer(WAXS). These aliphatic polyesters includes poly(ethylene succinate)(PES,CH2/COO=2)、poly(ethylene adipate)(PEA,CH2/COO=3)、poly(1,3-propylene adipate) (PPA,CH2/COO=3.5)、poly(1,4-butylene adipate) (PBA,CH2/COO=4)、poly(ethylene azelate)(PEAz,CH2/COO=4.5)、poly(1,6-hexamethylene adipate)(PHA,CH2/COO=5) and poly(1,6-hexamethylene sebacate)(PHS,CH2/COO=7). PVAc is found to be miscible with PEA、PPA and PBA as shown by existence of single composition dependent glass transition temperature over the entire composition. However, blends containing PES exhibited only partial miscibility. The experiment’s result show that spherulite morphology of PEA and PPA do not change as blending with PVAc. Obviously, the spherulite morphology of blends are similar to that of neat PEA and PPA. However, the results of kinetic analysis evident that nucleation mechanisms of PEA and PPA should have some variation and their nucleation rates are decreased when blending with PVAc. The nucleation rates of PEA will acutely decrease as the amounts of PVAc up to 30%, but those of PPA reduce just as PVAc adding. Otherwise, in the PVAc/PBA blending composition with 10% PVAc, there is a relative lower nucleation rate of kinetic system. The phenomenon causes that δ parameter of coarseness increase and dendrite spherulites are formed. Among the competition of dendrite spherulites and ring-banded spherulites, the structures of dendrite spherulites are destroyed and then disappeared. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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