A miscible homopolymer–copolymer pair viz., poly(ethyl methacrylate) (PEMA)–poly(styrene-co-butyl acrylate) (SBA) is reported. The miscibility has been studied using differential scanning calorimetry. While 1 : 1 (w/w) blends with SBA containing 23 and 34 wt % styrene (ST) become miscible only above 225 and 185 °C respectively indicating existence of UCST, those with SBA containing 63 wt % ST is miscible at the lowest mixing temperature (i.e., Tg's) but become immiscible when heated at ca 250 °C indicating the existence of LCST. Miscibility for blends with SBA of still higher ST content could not be determined by this method because of the closeness of the Tg's of the components. The miscibility window at 230 °C refers to the two copolymer compositions of which one with the lower ST content is near the UCST, while the other with the higher ST content is near the LCST. Using these compositions and the mean field theory binary interaction parameters between the monomer residues have been calculated. The values are χST-BA = 0.087 and χEMA-BA = 0.013 at 230 °C. © 2000 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 38: 369–375, 2000

https://onlinelibrary.wiley.com/doi/pdf/10.1002/%28SICI%291099-0488%2820000201%2938%3A3%3C369%3A%3AAID-POLB3%3E3.0.CO%3B2-W

Miscibility of poly(styrene-co-butyl acrylate) with poly(ethyl methacrylate): Existence of both UCST and LCST

Sorption and transport of CO2 and CH4 in chemically modified poly(phenylene oxide)

Polysulfone has been carboxylated, via a metalated intermediate, by reaction of a THF solution of polymer with n-butyllithium and then treatment with carbon dioxide. The polymer reactions with n-butyllithium were close to quantitative and did not require the use of a tertiary amine catalyst. A series of polymers ranging from 0.2 to 1.9 carboxyl groups per repeat unit was prepared by this method in the salt, acid and ester form. The structures of these polymer derivatives were characterized by 1H-NMR, 13C-NMR and IR. The glass transition temperatures and thermal stabilities were characterized by differential scanning calorimetry (DSC) and thermogravimetry (TG).

Synthesis and characterization of carboxylated polysulfones

The permeation behavior of water vapor, H-2, CO2, O-2, N-2, and CH4 gases in a series of novel poly(aryl ether sulfone)s has been examined over a temperature range of 30-100 degreesC. These polymers include four alkyl-substituted cardo poly(aryl ether sulfone)s and four intermolecular interaction enhanced poly(aryl ether sulfone)s. Their water vapor and gas transport properties were compared to the unmodified cardo poly(aryl ether sulfone) (PES-C). It was found that the bulky alkyl substituents on the phenylene rings were advantageous for gas permeability, while the intermolecular hydrogen bonds and ionic bonds resulted in a considerable increase in gas permselectivity. The causes of the trend were interpreted according to free volume, interchain distance, and glass transition temperature, together with the respective contribution of gas solubility and diffusivity to the overall permeability. Of interest was the observation that IMPES-L, which simultaneously bears bulky isopropyl substituent and pendant carboxylic groups, displayed 377% higher O-2 permeability and 5.3% higher O-2/N-2 permselectivity than PES-C. Furthermore, sodium salt form PES-Na+ and potassium salt form PES-K+ exhibited water vapor permeability twice as high as PES-C and H2O/N-2 selectivity in 10(5) order of magnitude.

Gas and Water Vapor Transport through a Series of Novel Poly(aryl ether sulfone) Membranes

The phase behavior of deuterated polystyrene-block-poly(n-pentyl methacrylate) copolymers (dPS−PnPMA) was investigated by using small-angle X-ray (SAXS) and neutron (SANS) scatterings and rheology. This block copolymer exhibited a closed-loop type of phase behavior as did hydrogenated PS−PnPMA copolymers. The closed loop consists of two transitions:  lower disorder-to-order transition (LDOT) and upper order-to-disorder transition (UODT) occurring at a lower and higher temperature, respectively. The segmental interaction parameter (χ) between dPS and PnPMA blocks at various temperatures was obtained by fitting the incompressible random phase approximation theory to SANS results using a low molecular weight of dPS−PnPMA exhibiting a disordered homogeneous state over the entire temperature range. We found that at higher temperatures χ increased initially with increasing temperature (T), achieved a maximum, and then decreased. Such behavior is in keeping with polymer blends or block copolymers that would exhi...

Phase Behavior of Deuterated Polystyrene-block-poly(n-pentyl methacrylate) Copolymers

Comportement de phase de melanges de polystyrene avec un copolymere statistique de poly(dimethyl-2,6 phenylene-1,4 oxyde) carboxyle, par calorimetrie differentielle et diffusion de la lumiere

/pdf/upper-and-lower-critical-solution-temperature-behavior-in-54k0zx6gvq.pdf

Upper and lower critical solution temperature behavior in thermoplastic polymer blends

Carboxylation avec le butyllithium dans le melange THF/toluene puis traitement avec CO 2 . Decarboxylation vers 350 o pour former l'acide

Guangmin Cong

Papers

Upper and lower critical solution temperature behavior in thermoplastic polymer blends

Synthesis and properties of carboxylate poly(2,6-dimethyl-1,4-phenylene oxide) and its ionomer