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Blends of Thermoplas™, a TPE based on blends of polypropylene and ethylene/α-olefin copolymers with various additives were prepared using a twin screw extruder. The mechanical, impact, rheological, thermal and chemical properties of the resultant blends and those of two commercially available TPE's (CTPE1 and CTPE2) used in fuel line covering applications were measured. Thermoplas™ had a percentage elongation at break of up to three times greater than both commercial materials, was more flexible, and had better impact strength at 25°C and -40°C. Thermoplas™ was less viscous than CTPE1 and CTPE2 in the shear rate range normally experienced during tube extrusion, when measured using capillary rheometry techniques. The lower viscosity of Thermoplas™ was also evident during cross-head extrusion trials, with line speeds for certain grades 50% greater than that achievable with CTPE1 and CTPE2. Thermoplas™ passed all heat aging and chemical conditioning tests to SAE J2027.

The diffusion of methanol, ethanol and toluene in a Nylon 12 and a poly(vinylidene) fluoride (PVDF) was measured using Fourier transform infrared-attenuated total reflectance (FTIR-ATR) spectroscopy, a technique which allows the quantification of the penetrant concentration diffusing in thin polymer films in situ. Furthermore, it is also possible to study multi-component diffusion using FTIR-ATR provided each component displays unique infrared absorbance peaks. Thin films of a Nylon 12 and PVDF were made by both solvent casting from either 1,1,1,3,3,3, hexafluoro-2-propanol or dimethylacetamide and by cast film extrusion. The films made by the cast film extrusion process had a more uniform thickness than those solvent cast. The diffusion coefficients of methanol, ethanol and toluene in Nylon 12 and PVDF were determined gravimetrically and by the FTIR-ATR technique. Both methods afforded comparable diffusion coefficients for similar solvent-polymer systems.