Development of hydrophobic polyurethane film from structurally modified castor oil and its anticorrosive performance

Abstract

Hydrophobic polyurethane (PU) films are widely used for various commercial and industrial applications due to their excellent water repelling and self-cleaning property. Nevertheless, achieving appreciable hydrophobicity in PU film is quite a challenge. Herein, we report on the development of a novel hydrophobic PU (fluorinated polyurethane [FCO-PU]) film and comprehensively evaluate its anticorrosive property. The FCO-PU was prepared by structural modification of castor oil (CO) through attachment of long fluorocarbon chains as pendant groups onto the backbone of CO. A model PU film (CO-PU) was also prepared from unmodified CO to compare the properties of FCO-PU film. All intermediate compounds, FCO-PU and CO-PU films were characterized by various spectroscopic techniques. Morphological, thermal and mechanical properties of the PU films were analyzed by field emission scanning electron microscopy (FESEM), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and dynamic mechanical thermal analysis (DMTA) studies. Successful introduction of long fluorocarbon chains into the FCO-PU film is reflected by its high hydrophobicity with a water contact angle of 119.1 , compared to the model CO-PU film with a water contact angle of 84.4 . Anticorrosive properties of the PU films were evaluated by polarization technique and electrochemical impedance spectroscopy under corrosive environment and the obtained results reveal a significant corrosion resistance (corrosion rate: 6.72 Â 10 À6 mm/year) behavior by the FCO-PU film. This work represents an effective strategy for the backbone modification of CO to develop novel functional PU materials.

Fully Biobased Self-Healing and Recyclable Covalent Adaptable Networks Prepared via a Catalyst-Free Aza-Michael Reaction

“…In the case of the ACO-DA-0.90 film, the presence of more amine content exerts a plasticizing effect that mitigates the rigidity of the film, which is reflected by the lower storage modulus of ACO-DA-0.90. The presence of more amine might remain as a pendant group or act as a spacer between the cross-linked network that disrupts the interchain interaction and plasticizes the CAN network. , As shown in Figure a, a drop in the storage modulus was observed in both the CAN films when the temperature was gradually increased to T α . The T α values for ACO-DA-0.75 and ACO-DA-0.90 were found to be reliable and comparable with the observed DSC analysis data.…”

Role of Silicoaluminophosphate as a Corrosion Inhibiting Nanocontainer and Filler in Environmentally Benign Bio-Based Hybrid Coatings

“…The Nyquist plots for COPU (Figure S4b), MoS5-COPU-0.5 (Figure 6f), MoS5-COPU-1 (Figure 6j), and MoS5-COPU-2 (Figure S5b) show that the anticorrosive performance of the prepared coating is judged from the lower frequency region of the impedance modulus. 7 All the plots of COPU, MoS5-COPU-0.5, MoS5-COPU-1, and MoS5-COPU-2 show only one time constant, which indicates that corrosion is still in the way of electron transfer. The EIS data is fitted with an equivalent circuit containing one time constant, and the fitted data are displayed in Table 3, where R ct represents the charge transfer resistance, R s represents the solution resistance, and Q represents the coating capacitance (inset in Figure 6b).…”

“…13−15 Additionally, the presence of hydroxyl functionality in the castor oil makes it a suitable bio-based polyol resin that can commonly be used as a precursor for the synthesis of polyurethanes. 7 Further, with the advancement of new chemical technologies for the uplift of new materials, integration of inorganic moieties into the organic polymer matrix emerged as a new area of research. 16 This approach allows the usage of both the components in their distinctive ways; the organic part provides flexibility and improves compatibility with the polymer segment while the inorganic content provides thermal, mechanical, and structural stability in addition to high ductility and superior adhesion to the metal substrate.…”

Synthesis, Structure, Properties, and Applications of Fluorinated Polyurethane

“…Up to now, FPU with targeted performance can be synthesized precisely by designing fluorochemicals including fluorinated isocyanates, fluorinated capping agents, and fluorinated chain extenders as hard segments; fluorinated polyester polyols and fluorinated polyether polyols as soft segments; and fluorinated acrylate as additives. The methods of introducing fluorinated chain segments and their corresponding product characterization are shown in Table 3 [44][45][46]. Although typical PU has a high mechanical strength, high elastic modulus, and high abrasion resistance, the enrichment of polar groups (hydrophilics) on its surface leads to poor weather resistance as well as humidity and heat resistance, which limit its applicational range.…”

“…Up to now, FPU with targeted performance can be synthesized precisely by designing fluorochemicals including fluorinated isocyanates, fluorinated capping agents, and fluorinated chain extenders as hard segments; fluorinated polyester polyols and fluorinated polyether polyols as soft segments; and fluorinated acrylate as additives. The methods of introducing fluorinated chain segments and their corresponding product characterization are shown in Table 3 [44][45][46]. Table 3.…”