The deformation process of amorphous polymers and adhesive lap-shear joints formed thereof as studied by the emission of charged particles in high-vacuum technique

Abstract

The emission of charged particles in high vacuum (at a pressure of 10−5 Pa) has been investigated during the deformation process of the monolithic bulk samples of amorphous polystyrene (PS) and poly(2,6-dimethyl-p-phenylene ether) (PPE), and of homo- and hetero-adhesive single lap-shear joints PPE–PPE and PS–PPE, respectively. The adhesive joints were formed by holding in contact the two bulk samples of PPE or the samples of PS and PPE at a small contact pressure of 0.03 MPa at the self-healing temperatures well below (by 100 K or even lower) of the PPE bulk glass transition temperature. It has been shown that the mechanoemission of charged particles has occurred at the moment of fracture (time interval < 1 ms) both of the PS and PPE bulk samples and of the PPE–PPE and PS–PPE adhesive joints and continued after the adhesive joint fracture. It has been found that, upon the adhesive joints fracture, the emission of negative ions has not been observed while electrons have been emitted. The fracture mechanisms of the bulk samples and of adhesive joints have been discussed. An equation relating the concentration of the broken chemical bonds to the intensity of the charged particles has been proposed.