Amos Golovoy

Polysulphone and poly(phenylene sulphide) blends: 1. Thermal characterization and phase morphology

Abstract The phase behaviour and morphology of injection moulded specimens of polysulphone (PSF) and poly(phenylene sulphide) (PPS) blends were studied by differential scanning calorimetry (d.s.c.), dynamical mechanical thermal analysis (d.m.t.a.) and transmission electron microscopy (TEM). The blends are phase separated regardless of the blend composition as revealed by d.s.c., d.m.t.a. and TEM. Upon annealing at 160°C for 2 h, d.m.t.a. results indicate that the PPS phase remains in the amorphous state at compositions

Polysulphone and poly(phenylene sulphide) blends: 2. Mechanical behaviour

Abstract This paper reports the mechanical behaviour of injection moulded blends of polysulphone (PSF) and poly(phenylene sulphide) (PPS). The blends prepared by melt-extrusion and subsequent injection moulding are phase separated. Depending on moulding conditions, thermal history, and composition, tensile behaviour ranged from brittle to ductile, with or without cold drawing. Cold drawing was observed in compositions as-moulded with up to 50% by weight PPS. Upon annealing for 2h at 160°C, ductile failure was maintained for blends containing up to 35% by weight PPS. All other compositions failed in brittle fashion. Flexural strength and modulus, before and after annealing, exhibited negative deviation from the rule of mixtures. All the blends were found to be notch sensitive.

Polysulfone and poly(phenylene sulfide) blends: 3. Rubber toughening

Abstract Melt-blended polysulfone (PSF) and poly(phenylene sulfide) (PPS) are notch sensitive. A significant improvement in the notched Izod impact toughness occurs when at least 10 wt% of a shell-core rubber modifier is incorporated into the blend. At rubber modifier levels above 15 wt%, the notched Izod impact strength was essentially retained upon annealing at 160°C for 2 h, while below 15 wt% of rubber modifier, the notched Izod impact strength decreases after annealing under the same conditions. Izod impact fracture surface morphology was studied using scanning electron microscopy (SEM). Fracture surfaces without a rubber modifier exhibit cavitation around the dispersed phase, i.e. PPS. On the other hand, fracture surface morphology of the rubber toughened blends with the same PSF/PPS composition show no cavitation surrounding the dispersed phase. Blend morphology was also studied using transmission electron microscopy (TEM).

The Impact Behavior of Glass and Carbon Fiber Composites

Abstract Impact behavior of glass and carbon fiber composites has been studied in some detail both with respect to methodology of testing and to interpretation of the influence of fiber orientation and viscoelastic resin properties on the measured fracture energies [14]. Most authors use some variation of the Charpy drop- weight test in which the impacted beam specimen is placed between two anvils. It is known that when the ratio of the span between the anvils to specimen thickness is small, e.g., less than 10, shear effects are very important. Most authors, therefore, test specimens at a larger span-to-thickness ratio, usually 16 and above. At these ratios the failure induced will be essentially a tensile fail- ure, dominated by fiber orientation and volume.

On-Board Storage and Home Refueling Options for Natural Gas Vehicles

In this paper options for on-board storage and home refueling of natural gas vehicles are presented and discussed. The on-board natural gas storage options considered are: storage at 2.2 MPa (300 psig) in activated carbon-filled cylinders, and 7.0 MPa (1000 psig) and 16.7 MPa (2400 psig) in hollow cylinders. Information is presented on small home refueling compressors designed to compress the natural gas to the above mentioned storage pressures. Also shown are data on the density and energy density of natural gas at pressures up to 21 MPa (3000 psig). It is found that to achieve a range of 160 km (100 miles), a 12.7 km/L (30 mpg) vehicle requires 232, 170 and 62 liters (8.2, 6.0 and 2.2 cu ft), respectively, of natural gas storage volume at the three pressures considered. A preliminary comparison of the three storage options suggests that storage above 7.0 MPa is preferred.

Hydrolytic Stability of Polyphenylene Sulfide/Polyarylate Blends

Abstract In the immiscible blends of poly(phenylene sulfide) (PPS) and polyarylate (PAR), absorbed moisture partitioned into each phase according to the equilibrium value of the homopolymers. The water diffusivity was observed to decrease with increasing PPS concentration and at >45%, when PPS became the major component in the skin region, the diffusivity was equal to that of neat PPS. The molecular weight of the PAR fraction was found to degrade linearly with time due to hydrolysis.