Enhanced interfacial adhesion via interfacial crystallization between sisal fiber and isotactic polypropylene: direct evidence from single-fiber fragmentation testing

Abstract

Bioresource natural sisal fiber (SF) was used to prepare single fiber-reinforced isotactic polypropylene (iPP) composites. Three kinds of interfacial crystalline morphologies, spherulites, medium nuclei density transcrystallinity (MD-TC) and high nuclei density transcrystallinity (HD-TC), were obtained in the single fiber-reinforced composites by implementing quiescent or dynamic shear-enhanced crystallization and by modulating the compatibility interaction between SF and iPP. The development of interfacial shear strength (IFSS) during the interfacial crystallization process was demonstrated for the first time using a combination of single-fiber fragmentation testing and optical microscope observation. A close correlation between IFSS and morphological characteristics of interfacial crystallization was well elucidated. The increases in IFSS were very different for spherulitic, MD-TC and HD-TC morphologies. The highest IFSS obtained was 28 MPa, after the formation of HD-TC, which was about 62% of the tensile strength of neat iPP (45 MPa). These results offer powerful and direct evidence that interfacial crystallization could play an important role in the enhancement of interfacial adhesion of real SF/iPP composites.

Silane-Treated Basalt Fiber–Reinforced Poly(butylene succinate) Biocomposites: Interfacial Crystallization and Tensile Properties

“…Specially, the development of interfacial crystallization occurring in the interface between fiber and matrix would enhance interfacial adhesion [14][15][16][17][18][19][20]. It is generally accepted that the interfacial crystallization would substantially influence mechanical behavior [21][22][23][24].…”

Glass fiber coated with graphene constructed through electrostatic self‐assembly and its application in poly(lactic acid) composite

“…GO can be linked to the amino surfaces of glass fiber in the following way: protonation of the amine by the weakly acidic sites of the GO layers (COO − + H 3 NR) and electrostatic attraction between the oppositely charged ions . The graphene on the surface of GF obtained by the chemical reduction can act as nucleating agent to induce interfacial crystallization of polymer and improve the interfacial adhesion …”

Interface strength of glass fibers in polypropylene: Dependence on the cooling rate and the degree of crystallinity

“…GF/PP IFSS is compared in quenched (no transcrystallinity) and isothermally crystallized material and found that IFSS of transcrystalline specimens was much lower than of the quenched ones. The literature on the IFSS dependency on DoC of PP for carbon and natural (cellulosic) fibers is more broad (see a review of 2005 and later literature); however, analysis of this literature lies out of scope of this article.…”