Functional Interlayers Developed to Control Interfacial Adhesion in Polymer Composites Reinforced with Glass and Basalt Fibers

book chapter

English

In this chapter, attention was paid to hydrogenated amorphous carbon-silicon (a-CSi:H) and hydrogenated amorphous carbon-silicon oxide (a-CSiO:H) thin films deposited from tetravinylsilane or its mixtures with a different fraction of oxygen by plasma polymerization using Plasma-Enhanced Chemical Vapor Deposition (PECVD) deposition systems. These films were subjected to a nanoscratch test and thus, the critical normal load, as a measure of adhesion, was determined. However, since this test is influenced by many intrinsic and extrinsic parameters and films showed changes mainly in mechanical properties, it was found that the work of adhesion was a more appropriate parameter to characterize the adhesion. The same measure of adhesion was determined on the silicon substrate, planar glass substrate as well as glass fiber. Since the distribution of shear stress across the interphase in the case of composites indicates that interfacial adhesion at the interlayer/fiber interface is a key parameter, these films (as compatible interlayers) were deposited on the glass fibers to form a strong but tough bond between the fibers and the polymer matrix. Through controlled interlayer synthesis with tailored physicochemical properties, it was possible to ensure efficient stress transfer from the matrix to the fibers by improving interfacial adhesion at both interfaces – glass/interlayer and interlayer/matrix. Composite materials (glass-fiber reinforced composites – GFRCs) were prepared from glass fibers surface modified with oxygen-free and oxygen binding interlayers, which were then subjected to microindentation, push-out test and short-beam shear test. It was found that the interfacial shear strength exhibited a linear dependence on the short-beam shear strength, and at the same time, these were linearly dependent on the work of adhesion. Attention was given not only to the study of interlayers but also to fiber pretreatment and post-deposition treatment or bilayers. Using surface modification of the fibers, a composite with interfacial shear strength 36% higher than that of commercially sized glass fibers was prepared. In the case of basalt fibers and a suitable interlayer, the improvement in the short-beam shear strength was up to 181% compared to unsized basalt fibers. These results show the appropriateness of the application of these interlayers and their benefits; without a doubt, this is a promising route that will provide a number of significant improvements applicable not only in the industry.

a-CSi:H and a-CSiO:H thin film, glass fiber, polymer-matrix composite, interface/interphase, mechanical properties, critical normal load, work of adhesion, shear strength

PLICHTA, T.; ČECH, V.

16. 7. 2024

Wiley

USA

9781394238200

Progress in Adhesion and Adhesives

Vol.8

119

187

69

https://onlinelibrary.wiley.com/doi/10.1002/9781394238231.ch3