Controlling Cavitation of Semicrystalline Polymers during Tensile Drawing

A common belief is that liquids have no strength. An example is tap water. However, liquids devoid of dissolved gases and impurities exhibit strength. By analogy, it was expected that purification would reduce cavitation and would increase polymer strength. In contrast to expectation, purified polymers exhibited surprisingly more intense cavitation during tensile deformation than pristine ones. It was concluded that cavitation is initiated in amorphous phase from homogeneous nuclei that are fluctuations of free volume. It seems that introducing a liquid penetrant into interlamellar regions should lead to filling free volume pores and to a decrease of intensity of cavitation. Polyethylene, polypropylene, and polyamide were selected for experiments. Modification of amorphous phases of polymers was conducted by introduction chloroform and hexane for polyolefins and water for polyamide. Chosen liquids penetrate amorphous phase of polymers but do not influence their crystalline phase. Samples whose amorphous p...