Miscibility of styrene/unsaturated polyester quasibinary systems: Unsaturated polyester chemical composition and molecular weight influence

Abstract

Unsaturated polyester prepolymers were synthesized with different chemical compositions and molecular weights. Cloud-point curves (CPC) were measured in St-UP quasibinary solutions, showing UCST behavior in all cases. The miscibility of the first UP samples series in St comonomer was enhanced when AA chemical comonomer concentration in UP prepolymer increased. In the second series, UP prepolymer miscibility increased with the molecular weight up to a maximum and, after that, the miscibility decreased. A thermodynamic analysis of experimental CPCs was performed using the Flory-Huggins (F-H) theory for polydisperse polymer solutions. A simple relationship between the interaction parameter and the temperature inverse could fit the measured CPCs in wide concentrations and molecular weight ranges. In the temperature interval where this fit took place, the positive enthalpic contribution to the interaction parameters determined the miscibility dependence with temperature in both UP sample series. The St-UP miscibility behavior was also correlated with UPs structural chemical parameters as: (a) the final HOÀ À and HOOCÀ À high polar groups concentration, (b) the chain backbone polar adipate and phthalate groups concentration, and (c) the UP size dependent mixing entropy. All these parameters are molecular weight dependent.

Morphology development and mechanical properties of unsaturated polyester resin containing nanodiamonds

“…This explanation is consistent with the literature that the hydroxyl and carboxyl termination groups of the polyester chain have an unfavorable effect on the miscibility of the polyester and styrene solution. 7,40 In fact, the ND-COOH particles are able to interact only with polyester molecules through the hydrogen bonding between the ester group and carboxyl group of ND-COOH.…”

Radiation and postirradiation crosslinking and structure of two unsaturated polyester resins

“…It is assumed that the radiation reaction conditions are isothermal, and because full conversion of all double bonds in UP resin cannot be achieved in such conditions despite constant initiation provided by irradiation, great part of double bonds remained unreacted, mostly buried inside microgels [18]. Low cure temperature [11] additionally reduced conversion. If a sample of such partially crosslinked resin is linearly heated in dynamic DSC experiment, ''residual heat'' DH R evolves from the reaction of those unreacted double bonds.…”

“…The reaction ends on vitrification, when glass transition temperature of the formed network becomes equal to the reaction temperature. This is one of the reasons why full conversion is impossible in isothermal conditions [11]. Although it is most often used, unpolar styrene is not a thermodynamically good solvent for relatively polar polyester [10,12,13], and so various saturated diacids or higher dialcohols are added in the preparation of polyesters to improve compatibility.…”

Tribological Properties of Vegetable Oils Modified by Reaction with Butanethiol

“…There are several reports where cloud point curves (CPC) are used to investigate the miscibility of binary and quasi-binary blends of polymers as a function temperature and composition (volume fractions of monomers or polymers with varying chemical structure, molecular weights, etc) [48][49][50][51][52][53]. The CPC separates the homogeneous phase (miscible composition) from the inhomogeneous phase (phase separated composition) of the blend.…”

“…Various experimental and computational methods have been applied to estimate the interaction parameter for use in prediction of CFC curves. Examples of blends used in such investigations are: styrene/unsaturated polyester [48], binary blends of star polymers [49], polystyrene/poly(Rmethylstyrene) and polystyrene/poly(vinyl methyl ether) [50], SBR/polybutadiene elastomer [51], polystyrene/ reactive epoxy monomers [52], linear poly(vinyl methyl ether)/four-armed star polystyrene [53].…”