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

Abstract

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

Dielectric Relaxation Spectroscopy of Gradient Copolymers and Block Copolymers: Comparison of Breadths in Relaxation Time for Systems with Increasing Interphase

“…The nBA block-related peaks all exhibited maxima at -48°C, while the styrene block response shifted from 104°C for the high molecular weight case (S-block-nBA23-364K) to 94°C for the moderate molecular weight case (S-block-nBA68-51K); the 51K copolymer response is also broader than that of the 364K copolymer. This reflects the reduced degree of phase segregation that is induced by the decreasing molecular weight of the system, with the 51K case being only moderately segregated ( χN = ∼16-40) while the 364K case is strongly segregating ( χN = ∼100-270) (using χ values reported in the literature 52,53 ). The relative magnitude of the two transitions in each block copolymer also changes to reflect the relative comonomer compositions, as expected.…”

Fabrication and characterization of PLA/PP/ABS ternary blend

“…Therefore, to avoid the complicated chemical reactions associated with compatibilizers, ABS can act efficiently to improve the mechanical properties as well as reduce the cost of PLA/PP polymer blends. To further understand the miscibility of polymer blends, Flory‐Huggins parameter was evaluated using the following equation where R is general gas constant, V r is molar volume, δ 1 and δ 2 are solubility parameters of the two polymers. The solubility parameter of polymer consists of dispersive (δ d ), polar (δ p ), and hydrogen‐bond component (δ h ) given by the following equation …”

“…Therefore, to avoid the complicated chemical reactions associated with compatibilizers, ABS can act efficiently to improve the mechanical properties as well as reduce the cost of PLA/PP polymer blends. To further understand the miscibility of polymer blends, Flory-Huggins parameter [30][31][32][33][34] was evaluated using the following equation…”

Potential of sodium alginate/titanium oxide biomembrane nanocomposite in DMFC application

“…The high homogeneity of membrane can be related to the high miscibility between SA polymer and TiO 2 nanofiller. 36 The solid membrane structure is a good feature for proton conductivity and reduces the rate of loss of methanol fuel. This polymer nanocomposite has a microstructure comprising interconnected SA biopolymer and TiO 2 inorganic nanofiller.…”