Publisher Summary This chapter focusses on the solid-state transition behavior of blends. It discusses the criteria for miscibility and briefly reviews the widely used methods of glass transition temperature (Tg) measurement in polymer blends with respect to their advantages and limitations in the study of polymer compatibility. The methods by which Tg of polymers may be determined are differential thermal analysis (DTA), thermal optical analysis (TOA), probe penetration thermo-mechanical analysis (TMS), differential scanning calorimetry (DSC), dynamic mechanical and dielectric measurements, and dilatometry. DSC has been widely used in the study of blend compatibility and in the determination of crystallinity in crystalline-amorphous polymer blends. DSC thermograms are plots of heat capacity (Cp) versus temperature. Apart from rapidity of measurement, the principal advantages of DSC in the study of polymer blends are that only small (typically 5–30 mg) samples are required and the available rapid temperature scan permits the study of heat sensitive polymers such as PVC without the addition of stabilizers. Dynamic mechanical measurements are widely used in the study of polymer compatibility. With this technique, a dynamic modulus can be measured as a function of temperature over a range of frequencies. From traditional torsion pendulum measurements, the dynamic shear loss modulus (G") and the dynamic shear storage modulus (G') can be obtained as a function of temperature at a nominal frequency in the vicinity of 1 Hz. The chapter provides a detailed account of solid-state transition behavior of poly (2, 6-dimethylphenylene oxide)-polystyrene blends and PPO- poly-chloro-styrene blends.

Solid State Transition Behavior of Blends

Publisher Summary This chapter reports the experimental techniques and results obtained in the study of polymeric alloys. Polymeric alloys are formed when two polymers are thoroughly mixed in one body. The lattice model for liquid–polymer mixtures was extended to the mixture of two polymers. A thermodynamic theory, which considers the free energy change on mixing two infinitely long completely separated blocks without consideration of domain morphology, gives for the mean free energy of mixing per segment. It is found that during casting from solution, the presence of solvent at the point of polymer immobilization may influence the type of morphology that is thermodynamically favored. The presence of a solvent preferential for one of the blocks tends to produce the morphology according to the volume fraction of the solvated block. The use of the solubility parameter is restricted to polymer pairs whose interactions are determined solely by dispersion forces. It is observed that in the metastable region, between the binodal and spinodal, phase separation is expected to proceed by nucleation and growth.

16. Polymeric Alloys

New Transparent Impact-Resistant Polymer Blends from Resins and Rubbers Having Minimized Compositional Heterogeneities: II. Blends of Resins with Acrylic Copolymer Elastomers

L. Shepherd

Papers

New Transparent Impact-Resistant Polymer Blends from Resins and Rubbers Having Minimized Compositional Heterogeneities: II. Blends of Resins with Acrylic Copolymer Elastomers