Vibration welding of alpha and beta isotactic polypropylenes: Mechanical properties and structure

Abstract

Abstract. Propylene homo-and copolymers (both random and block types) with and without beta nucleation were injection moulded and the related plaques joined by linear vibration welding. The melt flow index (MFI) of the polypropylenes was different. During vibration welding the pressure has been varied (0.5, 2 and 8 MPa). The properties of the welded plaques were determined under both static (tensile) and dynamic conditions (Charpy impact). It was found that the mechanical performance of the welds could strongly be improved when beta nucleated PP plaques were combined with each other. In other combinations the 'weaker' alpha modification controls the mechanical response. The supermolecular structure of the weld was assessed by polarised light microscopy using thin microtomed sections. Formations of the weld morphology along with its effects on the mechanical performance were discussed.

The effect of molecular mass on the polymorphism and crystalline structure of isotactic polypropylene

“…Recently, Zhang et al [12,13] used pimelic acid supported nano-sized CaCO 3 as β-nucleating agent. β-iPP has several advantageous properties compared to the traditional α-form, like higher impact resistance, ductility and better weldability [4,14,15]. The high impact resistance of β-form resulted in increased industrial interest in the past decades and simultaneously the number of available β-nucleating agents increased as well.…”

A review on techniques for improving the mechanical properties of fusion welded joints

“…The stress relief effect with an eccentric circulating vibrator was better than that obtained using a magnetic telescopic vibrator. Varga et al (2008) describes propylene homo-and copolymers (both random and block types) with and without beta nucleation were injection moulded and the related plaques joined by linear vibration welding. The melt flow index (MFI) of the polypropylenes was different.…”

Experimental investigation, modeling and simulation of the deformation behavior of vibration welded nanocomposites

“…The process of vibration welding and its impact on properties of the welded parts have been widely investigated in different studies [1,2,3,4]. Reaching the quasi-steady stage of vibration welding as well as using low welding pressures is of high importance for maximizing welding strength, as an increase in welding pressure results in lower weld strength [5].…”