Effect of the Process Parameters on the Adhesive Strength of Dissimilar Polymers Obtained by Multicomponent Injection Molding

Abstract

The growing demand in the consumer market for products with sustainable technologies has motivated new applications using overmolded natural fiber composites. Therefore, studies have been conducted mainly to understand the adhesive properties of overmolded parts. In the present study, a polypropylene (PP) composite with 30% coconut fibers without additives was developed with the aid of a corotating twin screw extruder. Subsequently, a multicomponent injection mold was developed based on the geometry of the ISO 527 type I specimen, in which samples overmolded with PP and PP–coconut-fiber composite, with the overlap in the central area, were obtained to evaluate the adhesive strength of dissimilar materials. The objective of this study was to evaluate the bond between PP and PP–coconut-fiber composite under different processing conditions using an adhesive strength testing device to perform a pure shear analysis. The experimental conditions followed a statistical design considering four factors in two levels and a significance level of 5%. The results indicated that adhesive strength increased significantly as the overlap area increased. It was observed that temperature and injection flow rate were the factors that most contributed to strengthening the bonds of dissimilar materials.

Selective Reinforcement of Joining Interface Using Nanofibers in Single-Lap Joints of Thermoplastic Composites Fabricated by the Injection Overmolding Process: Creep Deformation Behaviour

“…From the viewpoint of molding conditions, the higher cylinder temperature and higher injection speed increased lap shear strength. Pisanu et al [16] also reported that higher holding pressure, cylinder temperature and injection speed increased the joining strength.…”

Strength of Onyx-based composite 3D printing materials according to fiber reinforcement

“…The tensile test standard used in this study was performed by citing the international test standard ISO 527-4, which defines test conditions for isotropic and orthotropic fiber-reinforced plastic composites. ISO 527-4 presents a standardized size for tensile testing of specimens (Pisanu et al, 2021). According to the above standard, the size of the test specimen was set as shown in Figure 1A.…”

Hemocompatibile Thin Films Assessed under Blood Flow Shear Forces

“…High, biocorrosion-resistant adhesion of such hard coatings on the elastic TPU and controlled biofunctionality require adequate ion plasma pretreatment [ 31 , 32 , 33 ] and fluoridization or oxidation post-treatments [ 34 , 35 , 36 , 37 , 38 , 39 ]. The manufacturing of a fragile titanium is inserted with a flexibility that is based on the local mesh-width and thickness requires sophisticated high-precision milling and laser cutting [ 40 , 41 , 42 , 43 , 44 ], vacuum heat treatment to control the proper mechanical properties of the titanium, and surface finishing by electropolishing. The novelty and scientific contribution to the discipline comes from the development of materials in the form of thin coatings characterized by low hemocompatibility for long-term direct contact with blood for the desired application in the form of silent heart valves dedicated to the new generation of cardiac assist chambers.…”