Stamping tensile strength

The tensile strength of a cellular material is determined by measuring the uniformly applied force required to break the sample. The test piece is usually dumbbell-shaped (Fig. 13) and is cut or stamped (clicked) out of a sheet of foam with a test piece cutter. The rectangular cross section specimen should be prepared with care, since any snags or imperfections may cause premature fracture of the material under test. The cutting out of the material may also be useful in obtaining an indication of the clickability" of the foam. 

As the proportion of reclaimed fibres rises, stamping force (static puncture strength, CBR test) declines. The reason is the same as with maximum tensile strength. 

From 20% upwards of reclaimed fibres blended in, the loss of maximum tensile strength and stamping force becomes too high (Fig. 9.1). 

Decline in maximum tensile strength (%) ( ) and in stamping force ( ) as depending on proportions in PP reclaimed fibres. 

However, they can also be transfer or compression molded, solid state formed or thermoformed. PC is the matrix phase in most of these blends. The impact modifier can be PE, ABS or acrylic copolymer, e.g., MBS. The blends show good processability, heat resistance, ductility, HDT, high modulus, impact, tensile and flexural strength over a wide temperature range, good adhesion, solvent, chemical, and UV resistance. They can be painted, hot stamped, metallized and plated. Some blends (containing PB as impact modifier) may have poor weatherability. The blends are mainly used in the automotive industry. 

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