USP Electronic Research Repository

Miscibility determination in poly(epsilon-caprolactone)/poly(vinyl formal) blend by equilibrium melting temperature and spherulite morphology

Rohindra, David (2009) Miscibility determination in poly(epsilon-caprolactone)/poly(vinyl formal) blend by equilibrium melting temperature and spherulite morphology. Journal of Macromolecular Science Part B: Physics, 48 (6). pp. 1103-1113. ISSN 0022-2348

Full text not available from this repository.

Abstract

Miscibility of poly(ε-caprolactone), (PCL), containing 1, 5, and 10 wt.% poly(vinyl formal) (PVF) blends was investigated by polarized optical microscopy (POM), atomic force microscopy (AFM), and differential scanning calorimetry (DSC) for spherulitic morphology and equilibrium melting temperature (T°m, via Hoffman-Weeks plot). The T°m of PCL in the blends was similar to that of pure PCL, indicating immiscibility. Isothermally, melt crystallized virgin PCL between 30°C and 50°C showed spherulitic morphology with negative birefringence, Maltese cross, and without extinction rings. The nucleation and growth rates of PCL spherulites were found to be dramatically reduced with the addition of PVF. Extinction rings and a change in the sign of the birefringence of the PCL spherulites were observed and were found to be dependent on blend composition and crystallization temperature. The presence of a ring pattern in spherulites was an indication of miscibility between the two polymers that had failed to be detected by thermal methods. The formation of a ring pattern is discussed in terms of lamella twisting originating from a change in the crystallization mechanism.

Item Type: Journal Article
Subjects: Q Science > QD Chemistry
Divisions: Faculty of Science, Technology and Environment (FSTE) > School of Biological and Chemical Sciences
Depositing User: Ms Neha Harakh
Date Deposited: 27 May 2009 14:43
Last Modified: 17 Jul 2012 21:28
URI: http://repository.usp.ac.fj/id/eprint/1499
UNSPECIFIED

Actions (login required)

View Item