Controlled modification of interphase and its influence on shear strength of polymer composites

abstract

English

Aims: The main point was the preparation of glass fiber (GF)/polyester composites using fibers with modified interphases. Based on plasma surface treatment of unsized GF, series of polymer composites were investigated. Methods: Plasma-enhanced chemical vapor deposition (PECVD) was used for interphase modification using pure tetravinylsilane (TVS) or its mixture with oxygen gas. The interlaminar shear strength (ILSS) of composites was acquired using short-beam-shear test. The ILSS was interpreted based on chemical composition and interface adhesion of plasma coatings measured using infrared (IR) spectroscopy and scratch test, respectively. Results: The ILSS was achieved ranging 26.2–34.9 MPa for 2–100 W power input and 32.0–44.1 MPa for 0–0.71 oxygen fraction in TVS/O2 mixture. While raising the generator power, IR spectra show a significant decrease in vinyl groups, accompanied with increasing number of CHx groups. With increasing oxygen content, a gradual increase of OH, C=O, Si–O–Si and Si–O–C groups has been observed. Conclusions: The addition of oxygen into plasma coatings had beneficial effects on the ILSS of GF/polyester composites by up to 26 % compared to fibers treated without oxygen and up to 192 % compared to unsized fibers. This indicates a direct chemical effect of oxygen on the ILSS, supported by acquired IR spectra. When using plasma treatment, the composite interphase and its mechanical properties could be modified according to the particular use of the composite.

plasma nanocoatings; glass fibers; polymer-matrix composites; interface/interphase; shear strength; adhesion

ZVONEK, M.; ŠIRJOVOVÁ, V.; BRÁNECKÝ, M.; PLICHTA, T.; ČECH, V.

8. 7. 2019

Bangkok

1