Further Progress in Functional Interlayers with Controlled Mechanical Properties Designed for Glass Fiber/Polyester Composites

Abstract

Compatible interlayers must be coated on reinforcing fibers to ensure effective stress transfer from the polymer matrix to the fiber in high-performance polymer composites. The mechanical properties of the interlayer, and its interfacial adhesion on both interfaces with the fiber and polymer matrix are among the key parameters that control the performance of polymer composite through the interphase region. Plasma-synthesized interlayers, in the form of variable materials from polymer-like to glass-like films with a Young’s modulus of 10–52 GPa, were deposited on unsized glass fibers used as reinforcements in glass fiber/polyester composites. Modulus Mapping (dynamic nanoindentation testing) was successfully used to examine the mechanical properties across the interphase region on cross-sections of the model composite in order to distinguish the fiber, the interlayer, and the modified and bulk polymer matrix. The interfacial shear strength for plasma-coated fibers in glass fiber/polyester composites, determined from the microindentation test, was up to 36% higher than those of commercially sized fibers. The effects of fiber pretreatment, single and double interlayers, and post-treatment of the interlayer on interfacial shear strength were also discussed. Functional interlayers with high shear yield strength and controlled physicochemical properties are promising for high-performance polymer composites with a controlled interphase.

The Formation of a Highly Oriented Structure and Improvement of Properties in PP/PA6 Polymer Blends during Extrusion-Stretching

“…However, these fibers, such as carbon fiber and glass fiber, could cause abrasive wear of the processing equipment. Additionally, some fibers could be broken down into fragments during processing, thereby reducing the performances of the composites [9,10]. Recently, the microfibrillated cellulose fibers have been used to modify polymer materials [11][12][13][14].…”

Hybrid Cellulose–Basalt Polypropylene Composites with Enhanced Compatibility: The Role of Coupling Agent

“…Despite the well documented positive effects on natural fibers and inorganic reinforcements, the effectiveness of the coupling agent depends on several factors, including the graft level, viscosity, fiber content and type [ 23 ]. This means that the properties of PP-based composites can be fine-tailored to meet diverse requirements, but this is still an up-to-date and unsolved issue, even for glass-based polypropylene composites [ 24 ], because MA-g-PP can increase the performance of PP-based composites only if it is able to wet the reinforcement, chemically react with it and interdiffuse within the polymer bulk [ 25 ]. The adhesion at the fiber interface is dictated by the surface energies of the materials and the chemical functional groups of the matrix and the fiber sizing.…”

Plasma Nanocoatings Developed to Control the Shear Strength of Polymer Composites

“…The polar groups, hydroxyl (–OH) and carbonyl (–C=O), improve wettability of the nanocoatings with polyester resin and the vinyl groups on the surface of the nanocoatings are responsible for covalent bonding with the polyester resin during the curing process [30]. It is known that a high concentration of Si–O–C species is responsible for the adhesion of the nanocoating to the glass surface [16,17].…”

“…Plasma coating is an alternative technology to wet chemical processes, which can significantly improve the functionality of reinforcements in polymer-matrix composites [15,16,17]. Plasma nanotechnology operated as plasma-enhanced chemical vapor deposition (PECVD) [18] employs non-thermal plasma, where the temperature of ions and neutral particles is less than 400 K, which retains the bulk properties even of polymer reinforcements.…”