Miscibility

About: Miscibility is a research topic. Over the lifetime, 5521 publications have been published within this topic receiving 133547 citations. The topic is also known as: miscible.

Determination of structural and mechanical properties, diffractometry, and thermal analysis of chitosan and hydroxypropylmethylcellulose (HPMC) films plasticized with sorbitol

Abstract: In this work, the structural, mechanical, diffractometric, and thermal parameters of chitosan-hydroxypropylmethylcellulose (HPMC) films plasticized with sorbitol were studied. Solutions of HPMC (2% w/v) in water and chitosan (2% w/v) in 2% acetic acid solution were prepared. The concentration of sorbitol used was 10% (w/w) to both polymers. This solutions were mixed at different proportions (100/0; 70/30; 50/50; 30/70, and 0/100) of chitosan and HPMC, respectively, and 20 mL was cast in Petri dishes for further analysis of dried films. The miscibility of polymers was assessed by X-ray diffraction, scanning electronic microscopy (SEM), differential scanning calorimetry (DSC), and thermal gravimetric analysis (TGA). The results obtained indicate that the films are not fully miscible at a dry state despite the weak hydrogen bonding between the polymer functional groups.

Phase Behavior of Polystyrene and Poly(styrene-ran-styrenesulfonate) Blends

Abstract: The blend miscibilities of deuterated polystyrene (dPS) and sulfonated poly(styrene-ran- styrenesulfonate) (P(S-SS)) are examined by using forward recoil spectrometry (FRES) to probe the intermixing of bilayer films. This method directly determined the equilibrium coexistence compositions for dPS:P(S-SSx) blends where the degree of sulfonation (x) ranged from 0.2 to 2.6 mol %. In the temperature range 150-190 °C, FRES profiles reveal full miscibility for x e 0.2 mol % and complete immiscibility for x g 2.6 mol %. Partial miscibility exists in dPS:P(S-SSx) blends with x ) 0.7, 1.0, and 1.2 mol %, where between 150 and 190 °C the coexisting compositions show upper critical solution temperature (UCST) phase behavior. Blend interaction parameters, � blend, are calculated using the Flory-Huggins theory and the coexisting compositions of the partially miscible bilayers. The copolymer blend theory estimates the styrene-styrenesulfonate segmental interaction parameter to be extraordinarily large, � S/SS g 25. While the applicability of mean-field approaches is limited in this profoundly incompatible system, recent theories about random copolymers have established criteria for "self- demixing" due to their inherent compositional variations. Our estimate of the monomer-monomer interaction parameter suggests the potential for demixing in P(S-SSx) random copolymers that possess even a narrow distribution of compositions.

Miscibility Behavior and Specific Interaction of Phenolic Resin with Poly(acetoxystyrene) Blends

Abstract: Full Paper: The miscibility behavior and specific interaction of phenolic resin with poly(acetoxystyrene) (PAS) blends were examined using differential scanning calorimetry (DSC), fourier-transform infrared (FT-IR) spectroscopy and solid-state NMR. This phenolic/PAS blend is fully miscible, as indicated by a single glass-transition temperature, due to the formation of inter-hydrogen bonding between the hydroxyl group of the phenolic resin and the carbonyl group of PAS. The DSC study indicates that this phase-separation exothermic peak area is closely related to the interaction between the components. Furthermore, 13 C solid-state NMR and FT-IR spectroscopies were used to study the extent of specific interaction with various compositions and degrees of inter- and intramolecular hydrogen bonding. Moreover, the inter-association equilibrium constant and the related enthalpy of this phenolic/PAS blend were determined and used to predict the free energy and fraction of the hydrogen bonding according to the Painter‐Coleman association model.

Polymer-polymer miscibility determination via CP-MAS NMR in blends of deuteriated and protonated polymers

Abstract: Methode applicable lorsque le melange (PS/PUME, PMMA/PVC et PS/PMMA) contient meme entre 5 et 10% de l'un des polymeres