Influence of aggressive environmental aging on mechanical and thermo-mechanical properties of Ultra Violet (UV) Cured in Place Pipe liners

Abstract

Ultraviolet light cured-in-place pipe is a popular trenchless rehabilitation technology used to repair existing buried pipelines without soil excavation. A polymer composite liner is manufactured directly in the field. After curing is complete, the new liner is placed in service to convey flowing water. Long-term water exposure has the potential to degrade the fiber reinforced cured-in-place pipe liners. Like other composites, liner hygrothermal stability could be a major challenge, especially for undercured materials. The objective of this study was to investigate the effect of aggressive environmental conditions such as water, salt solution, and simulated concrete pore solution at 50℃ on cured-in-place pipe liner mechanical and thermo-mechanical performance. Liners were exposed to aqueous solutions ranging from a typical exposure environment to a very aggressive alkaline environment. Cured-in-place pipe liner samples were collected from New York storm sewer installation sites. Specimens were assessed for the degree of curing as determined by differential scanning calorimetry and TGA. Samples were then immersed in aforementioned solutions for investigating the stability of the liners as a function of degree of cure. Both interlaminar shear strength and thermo-mechanical properties significantly differed based on the degree of cure. Cured-in-place pipe liner mechanical and thermo-mechanical properties were significantly impacted by water, salt, and pore solutions exposure. Long-term exposure to salt and alkaline environments may have a detrimental effect on the performance of cured-in-place pipe liners and desires additional scrutiny.

Structure–Property Relationship of Cellulose Nanocrystal–Polyvinyl Alcohol Thin Films for High Barrier Coating Applications

“…In polymer films, the diffusion process is largely controlled by the size of the existing free volume, whereas the solubility of gas molecules is dictated by the density of free volume in the polymer Figure shows that PVA and EVOH have the highest gas barrier performance (e.g., low permeability) when compared with other polymers such as high-density polyethylene, PVC, PET, and so forth, as they have the lowest free volume. , The CNC–PVA coatings developed here have even better barrier performance (e.g., lower gas permeability) than EVOH films. Our substrate in this study, PP, was chosen as it is widely used for packaging applications due to its associated low manufacturing cost, high degree of clarity, chemical resistance, and superior water barrier properties .…”

“…Generally, lower permeability is observed for O 2 gas compared to CO 2 , due to the higher kinetic diameter of O 2 ( d O2 = 0.346 nm) than CO 2 ( d O2 = 0.330 nm) . Because of the quadrupole moment of CO 2 , the interaction between CO 2 and CNCs and PVA is strong, leading to a higher CO 2 solubility and, therefore, its higher permeability than O 2 in this case. ,, As shown in Figure a, P CO2 for PVA and CNC films are 1.32 × 10 –16 and 5.47 × 10 –16 cm 3 ·cm/cm 2 ·s·Pa, respectively. As expected, P CO2 is higher than P O2 for CNC films, showing the CO 2 interaction with CNC.…”

“…Aqueous 11.9 wt % CNC suspension (0.99 wt % sulfur on dry CNC, Batch# 014-FPL-065) was purchased from the University of Maine (Orono, Maine, USA). The length and width of CNCs were 100 ± 25 and 5 ± 1.5 nm, respectively. ,, The zeta potential of the CNC suspensions and crystallinity of the CNCs were −47.4 ± 2 mV and 85.5%, respectively. ,, The polypropylene film (trade name: Bicor 70HSH) was kindly provided by Jindal films.…”

Processing and Characterization of Food-Grade Plasticizer-Compatibilized Cellulose Nanocrystals and Ethylene Vinyl Alcohol Copolymer Nanocomposites

“…Cellulose nanomaterials are an interesting option for blending with EVOH. As a result of their biocompatibility, cellulose-based nanomaterials have found significant use in the food industry as additives for packaging, stabilizers, and as direct food additives. , Cellulose nanomaterials can be extracted as cellulose nanocrystals (CNCs) and cellulose nanofibers (CNFs) from wood and agricultural residues. − CNCs, in particular, are attractive for packaging applications due to their high aspect ratio and excellent mechanical properties. , Furthermore, their crystalline structure imparts unique barrier properties; gas molecules and moisture are impermeable through individual CNCs . Chowdhury et al and Nuruddin et al.…”

“…Chowdhury et al and Nuruddin et al. investigated this behavior and demonstrated that CNC films have excellent gas barrier performance because of their high crystallinity. − With these advantages, CNCs have been employed as filler materials in polymers including PVA, alginate, starch, chitosan, poly­(ethylene oxide) (PEO), xylan, methyl cellulose, etc . Unfortunately, CNCs still present a challenge to disperse in many hydrophobic polymer matrices, including EVOH, which has been attributed to an assumed polar character of CNCs.…”