Miscibility and phase behavior of poly(D,L-lactide)/poly(p-vinylphenol) blends

Abstract

ABSTRACT:The miscibility of poly(D,L-lactide) (PDLLA) and poly(p-vinylphenol) (PVPh) blends has been studied by differential scanning calorimetry and Fourier transform infrared spectroscopy (FTIR). Phase separation was observed in blends over a wide composition range. A PDLLA-rich phase was found to coexist with an almost pure PVPh phase. The quenched blend samples showed two glass transitions (T g s), except for a blend with a low PVPh content. However, the T g value of the PDLLA-rich phase showed a gradual increase with increasing PVPh content. No evidence of interassociation (hydrogen bond formation) between PDLLA and PVPh was found by FTIR. The phase behavior of the blends was simulated using an association model. The results suggested that the equilibrium constant of interassociation between PDLLA and PVPh was small. The phase compositions of the two separated phases were calculated using Fox, Gordon-Taylor, and Couchman equations. The amount of PVPh in the PDLLA-rich phase increased with increasing PVPh content in the blend.

Poly(para‐dioxanone)/poly(D,L‐lactide) blends compatibilized with poly(D,L‐lactide‐co‐para‐dioxanone)

“…In our earlier work, we have investigated the blend system of PPDO with more hydrophobic poly( D , L ‐lactide) (PDLLA), and it is also seen that this blend system is immiscible 6. As we know, the compatibility of components in blends usually plays an important role in determination of the properties of the polymer blends 7–9. Usually, the conventional method for compatibilizing two incompatible polymers is by introducing a third component as a compatibilizer, and the addition of a random copolymer has been considered to be an effective approach 10, 11.…”

“…6 As we know, the compatibility of components in blends usually plays an important role in determination of the properties of the polymer blends. [7][8][9] Usually, the conventional method for compatibilizing two incompatible polymers is by introducing a third component as a compatibilizer, and the addition of a random copolymer has been considered to be an effective approach. 10,11 In the case of a random copolymer, a single polymer chain may make multiple crossings at the interface.…”

Poly(Lactic Acid) Blends

“…Solution blends of amorphous/amorphous polymers, PVPh/PDLLA, from methyl ethyl ketone (MEK) were immiscible, whereas solution blends from THF exhibited phase separation with PVPh content not less than 40 or 60 wt% [52,53]. The spinodal phase diagrams (phase separation) of PVPh/PDLLA blends from THF can be simulated using an association model with small values of the interassociation constant (k A < 5) [52].…”

“…The spinodal phase diagrams (phase separation) of PVPh/PDLLA blends from THF can be simulated using an association model with small values of the interassociation constant (k A < 5) [52]. Solution blends prepared from solution/precipitation with THF/hexane were miscible with q of À87 and evidence of hydrogen bonding determined from FTIR [53,54].…”

Exothermal Process in Miscible Polylactide/Poly(vinyl phenol) Blends: Mixing Enthalpy or Chemical Reaction?

“…However, initial studies on PLLA/PVPh blends [3] and PDLLA/PVPh [4] blends carried out on samples prepared by solvent casting showed phase separation. In a series of recent papers [2,5] , we re-examined the phase behavior of these systems and found miscibility for samples obtained by solution/precipitation; hence, phase separation results reported for the solution cast blends were attributed to the Dx effect.…”