Analogue calorimetry of polymer blends : poly(styrene-co-acrylonitrile) and poly(phenyl acrylate) or poly(vinyl benzoate)

Polylactide/graphene oxide nanosheets/clove essential oil composite films for potential food packaging applications.

Gradient copolymers with gradients in composition along the chain lengths are synthesized by controlled radical polymerization, and their damping behaviors are compared to those of random and block copolymers. The effect of comonomer incompatibility is studied by comparing behaviors of strongly segregating styrene/4-hydroxystyrene (S/HS) and moderately segregating styrene/n-butyl acrylate (S/nBA) copolymers. The effect of composition gradient steepness is studied by designing “constant” or “increasing” gradients via the comonomer addition rate during semibatch polymerization. Dynamic mechanical analysis (DMA) is used to compare the temperature dependences of the storage modulus (E′), loss modulus (E″), and tan δ of the materials. A glass transition breadth (ΔTg) is defined by a temperature range over which E′ decreases from 109 Pa to 108 Pa. The gradient copolymer ΔTgs are at least four times larger than the random copolymer ΔTgs. The S/nBA gradient copolymers show strong effects of gradient steepness on ΔTg, with ΔTg being much larger for the increasing gradient than for the constant gradient. DMA data are compared to predictions by Hashimoto et al. for tapered block copolymers in the limit where the taper extends across the entire chain. The shapes of their calculated temperature dependences of E′ and E″ correspond well to the gradient copolymers with large ΔTg values, providing strong support for symmetric gradient copolymers forming nanoscale, ordered domains with sinusoidal composition profiles. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 48–58, 2008

Gradient copolymers with broad glass transition temperature regions: Design of purely interphase compositions for damping applications

Facile fabrication of novel magnetic ZIF-67 MOF@aminated chitosan composite beads for the adsorptive removal of Cr(VI) from aqueous solutions.

Gradient copolymers are prepared from comonomer systems with a range of segregation strengths and homopolymer glass transition temperature (Tg) differences to explore the breadths that can be achie...

Glass transition breadths and composition profiles of weakly, moderately, and strongly segregating gradient copolymers: experimental results and calculations from self-consistent mean-field theory

Analogue calorimetry for blends of poly(vinyl ester)s and polyacrylates has been studied. Hydrogenated monomers were used as analogues of the corresponding polymers. It is found that isomeric esters differing only in the orientation of the COO group mix with only small heat change, which can be positive or negative. The values of the interaction energy density, B12 (in cal/cm3), are −0.045, 0.031, and −0.076, respectively, for the following binary mixtures; ethyl acetate + methyl propionate, n-propyl propionate + ethyl butyrate, and phenyl propionate + ethyl benzoate. The negative heat of mixing for the two pairs of very similar liquids, although unexpected, explains why the corresponding polymers are miscible. The small positive heat of mixing for the other pair is sufficient to predict demixing of the corresponding polymers, viz., poly(n-propyl acrylate) and poly(vinyl butyrate), which contradicts the observation of their homogeneous mixing. This suggests that hydrogenated monomers are not always the pr...

Analogue Calorimetric Studies of Blends of Poly(vinyl ester)s and Polyacrylates

Miscibility and phase diagrams of poly(phenyl acrylate) and poly(styrene-co-acrylonitrile) blends

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

Melting and crystallization behaviour of poly(vinylidene fluoride) samples in its blends with some polyacrylates, poly(vinyl esters) and poly(aryl ether ether ketone)

D. Rana

Papers

Analogue Calorimetric Studies of Blends of Poly(vinyl ester)s and Polyacrylates

Analogue calorimetry of polymer blends : poly(styrene-co-acrylonitrile) and poly(phenyl acrylate) or poly(vinyl benzoate)

Miscibility and phase diagrams of poly(phenyl acrylate) and poly(styrene-co-acrylonitrile) blends

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

Melting and crystallization behaviour of poly(vinylidene fluoride) samples in its blends with some polyacrylates, poly(vinyl esters) and poly(aryl ether ether ketone)