The effect of long‐term ultraviolet light irradiation on polymer matrix composites

Abstract

This study reports the individual and combined effects of ultraviolet light and thermal shock on the physical properties of polymer matrix composites in air and in a "near-vacuum system." The longest exposure time was 180 days. It was found that the weight loss of composites increased with irradiation time. In the graphite/epoxy system, the weight loss in air was 2-3 times that in a "near-vacuum system." Similarly, the weight loss of the glass/epoxy system in air was 3-6 times that in a "near-vacuum system." The weight loss of the glass/epoxy system was always larger than that of the graphite/epoxy system. In all cases, the W irradiation and 1000 times thermal shock did not change the fracture mechanism-it was always brittle fracture in addition to fiber pullout. Surface erosion was observed in the irradiated surfaces by scanning electron microscopy. For both graphitelepoxy a n d glass/epoxy composites, the tensile strength decreased with increasing irradiation time irrespective of the irradiation environment. However, the decrease was not significant. By SEM, cracks could be observed in the up-surface and side-surface of the glass/epoxy system that was irradiated more than 1 month in air and through 1000 times thermal shock. Obviously, UV light cannot deeply penetrate the sample, and only the surface of the sample will be influenced. The UV radiation initiated microcracks, which propagated through the thermal shock.

Effects of compaction and UV exposure on performance of acrylate/glass‐fiber composites cured layer by layer

“…The DC reached 98% after three layers was added, and then kept a certain value. This suggested that the exposure dose should be controlled during curing process for every layer to pretend composite from over‐curing which would result in decrease of mechanics 21…”

“…This suggested that the exposure dose should be controlled during curing process for every layer to pretend composite from over-curing which would result in decrease of mechanics. 21 The effect of exposure dose on ILSS Like the effect of temperature on performance of composites in a thermal cure, UV exposure dose has a significant effect on the performance of UV curable composites. Figures 4 and 5 show the correlation between ILSS and UV exposure dose, ILSS and DC, respectively.…”

Environmental Degradation of Carbon Nanotube Hybrid Aerospace Composites

“…This alters the chemical structure by molecular chain scission or chain crosslinking and results in material deterioration (Ranby and Rabek 1975). For prolonged exposure to UV radiation, the matrix dominated properties, such as interlaminar shear strength, flexural strength, and flexural stiffness can suffer severe deterioration (Chin et al 1997;Liau and Tseng 1998;Shin et al 2000a, b;Kumar et al 2002;Signor et al 2003). Furthermore, degradation phenomena due to UV radiation and moisture when acting together can significantly accelerate the degradation process of the matrix.…”

Life-cycle performance model for FRP bridge deck panels

“…Temperature Creep/relaxation effects Gramoll et al (1990), Greenwood (1975), Hugo et al (1993), Panasyuk et al (1987) 10 Moisture Panasyuk et al (1987) 11 Loading cycle Ando et al (1997), Machida (1997) Loading cycle Mahfuz et al (2000), Datta et al (2002), Dzenis (2003), Karbhari et al (2003) 15 Temperature Liau and Tseng (1998), Steckel et al (1999), Kumar et al (2002) 16 Moisture UV exposure effect Steckel et al (1999), Busel and Lockwood (2000), Karbhari et al (2003), Kumar et al (2002) 17 Freeze and thaw Liau and Tseng (1998) 18 UV light Chin et al (1997), Liau and Tseng (1998), Kumar et al (2002) , Signor et al(2003) 19 Temperature Fire effects Busel and Lockwood (2000), Balázs and Borosnyói (2001), Mouritz (2002), Mouritz (2003), Sorathia et al (1993), Sorathia et al (1996), Mourtiz and Mathys (1999), Mourtiz and Mathys (2001), Mourtiz (2003) 20 Fire attack because of editorial constraints. For detailed information on the seven DMs, refer to Hong (2005).…”

“…For example, to determine the intensity of EFs, 'Temperature' for the city of West Lafayette, Indiana, the threshold level for temperature was assumed to be ≤4 • C (40 • F) and ≥20 • C (68 • F) when it could influence certain DMs. The limited range of temperature was determined according to the experimental conditions used by previous research projects related to the EF 'temperature' (Greenwood 1975, Watanabe 1979, Panasyuk et al 1987, Gramoll et al 1990, Dutta 1992, Hugo et al 1993, Bank et al 1995, Dutta and Hui 1996, Chin et al 1997, Liau and Tseng 1998, Steckel et al 1999, Haramis et al 2000, McBagonluri et al 2000, Datta et al 2002Karbhari et al 2002, Kumar et al 2002 …”