Preparation and properties of poly(siloxane‐ether‐urethane)‐acrylic hybrid emulsions

Abstract

Poly(siloxane-ether-urethane)-acrylic (PU-AC) hybrid emulsions were prepared by introducing different hydroxyethoxypropyl-terminated polydimethylsiloxane (PDMS) content into the acrylic-terminated poly(ether-urethane) backbone and then in situ copolymerizing with methyl methacrylate and butyl acrylate via emulsion process. The effects of PDMS on the particle size and viscoelastic behavior of the hybrid emulsions were investigated. Meanwhile, the hydrogen bonding, mechanical and thermal mechanical properties, water resistance, the surface gloss, and wettability of the resultant hybrid films were also studied. The results showed that all the hybrid emulsions showed shear-thinning behaviors, and the introduction of PDMS resulted in the formation of the hybrid emulsions with increased average particle size and decreased viscosity. The chemical bonds built between PU and AC yielded higher than 73% crosslinking fraction in all the hybrid materials, but this value decreased with increasing PDMS content because PDMS reduced the hydrogen bonding interactions and enhanced the phase separation. As a result, an increase in the PDMS content led to an increase in the elongation, water resistance, surface roughness, and water hydrophobic of the films, but the tensile strength, hardness, storage modulus, and glass transitions temperature decreased. It is suggested that introduction of PDMS can provide the hybrid materials with the improved flexibility, water resistance, and surface hydrophobicity, which has potential application value in the fouling-release coatings, biomaterials, and surface fishing.

Preparation of Polydimethylsiloxane-Modified Waterborne Polyurethane Coatings for Marine Applications

“…PS-WPU 1 without PDMS exhibits the highest storage modulus, and the storage modulus of the PS-WPU samples decreases with increasing PDMS content. The storage modulus is a measure of material stiffness [39][40][41], and the incorporation of PDMS into the soft segment of the WPU decreases the stiffness because of the high flexibility of the PDMS. Figure 5b displays the tan δ curves, which are directly related to the T g of the PS-WPU samples.…”

“…When the films are immersed in water, the water fills the microcavities and they swell due to the interaction between the hydrophilic groups and water, resulting in the absorption of water. However, incorporating hydrophobic PDMS creates a hydrophobic barrier on the surface to prevent water absorption and reduce the interaction between hydrophilic groups and water [31,41,53,54]. Thus, it can be concluded that by incorporating hydrophobic PDMS into the soft segment of the PU chains, the water resistance of the PS-WPU films was enhanced.…”

In Situ Incorporation of Diamino Silane Group into Waterborne Polyurethane for Enhancing Surface Hydrophobicity of Coating

“…This is primarily caused by the Si–O–Si network structure [42,43]. During the film formation and crosslinking process, the presence of siloxane with low polarity can provide a thermodynamic driving force for its surface migration, decrease the surface energy, and make the surface hydrophobic [44], which leads to the observation shown in Figure 8. In the studies by Zhao et al [17] and Lei et al [29], the maximum water contact angle reached respectively 79.25° and 77.6°.…”

Preparation and properties of room-temperature-vulcanized silicone rubber using modified dopamine as a crosslinking agent

“…Low-polarity silicon-oxygen chains act as a barrier to prevent water from entering the silicone rubber. Silicon-oxygen chains can form a siloxane (Si-O-Si) network structure, which can shield hydrophilic groups and reduce the interaction between water and hydrophilic groups [38,39]. It can be found from the results that even with a relatively small amount of IDA, the hydrophobicity of the modified silicone rubber is still enhanced.…”