Papers by Keyword: Water Repellents

Abstract: The treatment of resist water and oil by low-temperature plasma technology for recycled polyethylene terephthalate(PET)fiber automotive interior carpet was studied.The best process conditions were optimized:low-temperature plasma processing power was 150W,vacuum was 30Pa, time was 10 min,perfluorooctylsulfonyl amide(C₈H₂F₁₇NO₂S)monomer concentration was 15%.With angle measurement instrument,scanning electron microscopy and infrared spectroscopy,the performance of PET interior carpet on the condition of optimum process was tested and analysed.The result showed:there was cross-linked esterification between C₈H₂F₁₇NO₂S monomer and PET molecules,some C-F groups with low surface energy appeared on the fiber surface.Namely, C₈H₂F₁₇NO₂S monomer was effectively grafted onto the surface of PET fiber.The PET interior carpet had a better effect on resisting water and oil.

Abstract: Two different viscous coating materials, which are Polydimethylsiloxane (PDMS) mixed with 10%wt of Dicumylperoxide (DCP), and Semifluorinate Silane (SFS), were applied to silicon micro-asperity. The cosine’s Young and viscosity of those coating materials are -0.3584,-0.3496 and 3.176x10-3, 1.339 x10-3 Pas, respectively. The rough surfaces with nine asperity shapes were studied. The results shown that, pillar shape has an effect on water contact angle (WCA): Stripe asperity cannot make the average WCA greater than 150. When consider the pillar asperity, the WCA falls between 152 and 157, which exhibits a superhydrophobic surface property. However, actual WCA of the micro-asperity coated with PDMS+10%wt of DCP is lower than that coated with SFS around 1 to 7. High viscous material makes the asperity size bigger than the design and decreases the WCA: the low viscous material is more suitable for coating on the asperities.

Abstract: Reinforced concrete structures are often conceived for a certain time span of serviceability. Due to the superposition of different kinds of loads and particularly due to the presence of aggressive substances the resistance of construction materials is insufficient in numerous cases. Hence, many structures have to be repaired before the end of their designed life span. In case of reinforced concrete structures these repair measures are not only very expensive but they also consume high amounts of energy and materials which causes strong environmental impacts. The main challenge in developing reliable concrete technologies is the capability to enhance the life span of new and already repaired structures to a reasonable maximum. When aiming this objective not only durability related material properties have to be accomplished but their environmental impact has to be minimized simultaneously. This paper evaluates different concrete technologies and materials from diverse perspectives: Durability (simulating expected life span using numerical analyses), ecology (product life cycle and environmental impact assessments) and economy (estimating life cycle costs by investment appraisals). This kind of combined analysis facilitates the efficient design of structural elements and repair measures and provides the possibility to significantly increase the life span of new and repaired concrete structures.