Advance application of Raman spectroscopy for quantitative analysis of noncrystalline components in thin films of poly(ε‐caprolactone)/poly(butadiene) blends

Abstract

A quantitative analysis method for the distribution of noncrystalline poly(butadiene) component in poly(ε-caprolactone)/poly(butadiene) (PCL/PB) binary blends have been analyzed by advance application of Raman spectroscopy, optical microscopy, and differential scanning calorimetry (DSC) techniques. Thin films of different compositions of PCL/PB binary blends were prepared from solution and isothermally crystallized at a certain temperature. After calibration with real data, quantitative analyses by Raman spectroscopy revealed the amorphous PB are trapped inside the PCL crystals. Polarized optical microscopy and real time atomic force microscopy were used to collect data for the crystal morphology and crystal growth rate. For pure PCL crystals, a morphology of truncated lozenge shape was observed, independent of crystallization temperature and regardless of the blends compositions. For the pure PCL and their blends, almost unique crystal growth rate was found. The miscibility behaviors using DSC were drawn through melting point depression method. The Hoffman-Weeks extrapolations of the blends were found to be linear and identical with those of the neat PCL. The interaction parameter for the blends indicating that the PCL and PB blends have no intermolecular interaction, confirming the blends are immiscible. Despite the immiscibility of the blend, the PCL crystals do not bend during the growth process and do not reduce the growth rate as they do for miscible blend systems.

Frustrated crystallization behavior under hierarchical confinement in electrospun fibers of poly(styrene)/poly(ethylene oxide)/poly(l‐lactide) ternary mixtures

“…[ 7–13 ] The interaction between components of a crystalline/crystalline polymer blend as well as the difference in the melting temperature between them are the crucial factors that determines the blend morphology and crystallization behavior. [ 14–29 ]…”

“…[7][8][9][10][11][12][13] The interaction between components of a crystalline/crystalline polymer blend as well as the difference in the melting temperature between them are the crucial factors that determines the blend morphology and crystallization behavior. [14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29] If the melting temperatures of the blend components (T m ) differ significantly, the component with the higher T m will crystallize first and form a template in which the other component will be spatially distributed. Such a distribution will depend on the interaction between the blend components, which results in fractionated crystallization by providing distinct environments (interspherulitic or intra-spherulitic) during crystallization of the blend component with low T m .…”

Detailed thermal analysis of crystallization kinetics and band morphology for future blending of absorbable poly(p‐dioxanone) monofilament surgical suture with poly(ε‐caprolactone)

“…[9][10][11] The degree of crystallinity for PDS is around 55% and the glass transition temperature is between −10 and 0°C, which can be treated as ideal for thermal analysis even at room temperature. We have studied a few poly(ε-caprolactone) poly(ε-caprolactone)/polymer blends [12][13][14][15] and our goal is to make a blend of PCL/PDS to improve several properties, e.g. mechanical properties for prolonging the healing period; we believe that PDS can be a good candidate for blends with PCL.…”