Synergic effect of temperature and alkalinity on the long‐term durability of pure vinyl ester

Abstract

This paper presents an experimental approach to investigate the long‐term durability of vinyl ester (VE) used in civil/structural engineering. Various alkaline (pH = 7, 11, 12, and 13) and temperature (23, 40, and 60°C) conditions were considered for accelerated aging over 12 months. The test results reveal only slight changes in water absorption capacity (0.75–1.17%) and mass loss (~1%) for the aged VE, which can be explained by the unchanged glass transition temperature. Furthermore, significant hydrolysis reaction and severe microcracking at an elevated temperature resulted in a higher diffusion coefficient. The VE diffusion coefficient increases from 6.60 × 10−7 to 1.75 × 10−6 after 12‐month aging in 23°C water (pH = 7), but becomes 4.00 × 10−6 mm2/s as the water temperature rises to 60°C. Surface microcracks with a depth of ~8.46 μm and chemical hydrolysis reaction with a 74% increment of OH/CH ratio were observed in the 12‐month aged VE at 60°C. However, the diffusion coefficient was insensitive to alkalinity (pH = 7, 11, 12, and 13) regardless of the exposure time and temperatures, which could be attributed to the similar OH/CH ratio at different alkaline conditions. The results of this study shed light on understanding the VE degradation in harsh environments as applied in fiber‐reinforcement polymer (FRP) composites.

Functional Epoxy Elastomer Integrating Self-Healing Capability and Degradability for a Flexible Stretchable Strain Sensor

“…Comparatively, the PEG-SS 8 -ESO 0.2 and PEG-SS 10 -ESO 0.2 elastomers were partially degraded, and the surfaces turned pale. As illustrated in Figure e, the degradation of the epoxy elastomers was realized by the hydrolytic breaking of the inherent ester bonds in alkaline solution. , Due to slight swelling and hydrolysis of a small amount of ester bonds, some microcracks appeared on the surface of the PEG-SS 8 -ESO 0.2 elastomer after immersing in NaOH aqueous solution for 1 day (Figure S7). When the degradation time was prolonged to 6 days, the microcracks further expanded and formed an uneven corroded morphology (Figure f).…”

Experimental investigation on the low‐velocity impact response and the residual strength of CFRP tubes

“…Carbon fiber-reinforced polymer (CFRP) composites are widely used in aerospace, automobile, ship, civil engineering, and other fields due to their superior performance such as designable, lightweight, specific strength/stiffness, and corrosion/fatigue resistance. [1][2][3][4][5][6][7][8][9][10] Meanwhile, various complex structures of CFRP composites such as plain laminates, [11][12][13][14] curved laminates, 15 and T-shape joints [16][17][18][19][20][21][22] are employed depending on the different usage scenarios.…”

“…Carbon fiber‐reinforced polymer (CFRP) composites are widely used in aerospace, automobile, ship, civil engineering, and other fields due to their superior performance such as designable, lightweight, specific strength/stiffness, and corrosion/fatigue resistance 1–10 . Meanwhile, various complex structures of CFRP composites such as plain laminates, 11–14 curved laminates, 15 and T‐shape joints 16–22 are employed depending on the different usage scenarios. Especially, in many applications such as the transportation of natural gas and the transmission shaft in the transmission system, CFRP tubes have their non‐substitutable advantages as crucial structural element 23–26 …”

Experimental and simulative investigation on the mechanical behavior of GFRP T‐joints subjected to low‐velocity‐impact and post‐impact tensile loading

“…Composite structures are widely used in aerospace, machinery, and other fields owing to their outstanding advantages, such as high stiffness/strength-to-weight ratio, high fatigue resistance performance, and corrosion resistance. [1][2][3][4] Nevertheless, due to the manufacturing process limitations of the composite structures, it is a necessity for the connection of the parts to assemble complex structures. 5,6 Connection technology of composite structures involves adhesively bonded joints, bolted joints, and bonded/bolted hybrid joints.…”