Thermo-optical and differential scanning calorimetric observations of mobility transitions in polystyrene-poly(2,6-dimethyl-1,4-phenylene oxide) blends
TL;DR: In this article, the authors used TOA to monitor light transmission through birefringent scratches in a film during heating at constant rate in a microscope hot stage between crossed (90°) plane polarizers.
Abstract: Transition temperatures by thermo-optical analysis (TOA) and by DSC were measured on films of polystyrene (PS), poly(2,6-dimethyl-1,4-phenylene oxide) (PPO resin) and nine homogeneous blends of these polymers. The TOA procedure consists of automatically monitoring light transmission through birefringent scratches in a film during heating at constant rate in a microscope hot stage between crossed (90°) plane polarizers. The TTOA transition temperature, defined as the temperature of birefringence disappearance in the scratches, increased monotonically from 113°C for pure PS to 222°C for pure PPO resin at a 10°/min heating rate. The Tg (DSC) similarly ranged from 99°C to 212°C at a 20°/min heating rate. The TOA technique as described should be a useful addition to thermomechanical studies of transparent polymers and polymer blends.
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01 Jan 1980
492 citations
TL;DR: In this article, a general guide to polymer miscibility is presented, which is based on a simple balance between unfavourable physical forces, described in terms of non-hydrogen bonded solubility parameters, and favorable specific interactions.
272 citations
TL;DR: In this article, a calorimetric study was carried out on blends of poly(vinylidene fluoride) (PVF 2 ), and isotactic, atactic and syndiotactic poly(methyl methacrylate) (i-, a-, and s-PMMA).
200 citations
TL;DR: A brief overview of the important issues governing the behavior of polymer blends is presented in this paper, where the influence of melt processing conditions on the resulting properties and behavior of both miscible and immiscible blends is reviewed.
Abstract: A brief overview of the important issues governing the behavior of polymer blends is presented. Thermodynamic issues which determine the phase behavior of blends are reviewed and qualitatively related to physical interactions between blend components. The influence of melt processing conditions on the resulting properties and behavior of both miscible and immiscible blends is reviewed. The physical properties of blends are reviewed and illustrated by examples from recent work on miscible blends of polycarbonate with a copolyester and on the immiscible blends of polystyrene with high density polyethylene.
176 citations
TL;DR: In this paper, a planar relaxation of polystyrene was found in the first 1 and 10 nm from the free surface, whereas the dominant relaxation was normal to the surface.
Abstract: Near-edge X-ray absorption fine structure, NEXAFS, spectroscopy was used to investigate the relaxations of polystyrene, a typical amorphous polymer, near a free surface after the imposition of a small deformation. Using synchrotron radiation, the NEXAFS dichroic ratio was determined for both the Auger and total electron yield processes as a function of temperature to determine the orientation of the polymer in the first 1 and 10 nm from the free surface, respectively. Complete relaxation of the polymer was not seen for temperatures less than the bulk glass transition temperature. No evidence of enhanced mobility at the free surface was found. A planar relaxation of the polymer was found in the first nanometer from the free surface, whereas in the first 10 nm, the dominant relaxation was normal to the surface.
146 citations