[.sup.1]H NMR spectroscopy provides more conclusive evidence of the structure of WBPU and WBPSUU.
Table 3: Assignment of (1)H NMR and chemical shift of WBPU Assignment Chemical shift (ppm) NH(Ut) 7.18 NH(Ur) 7.10 H1 3.34 H2 1.65 H3 + H4 1.25 H5-H8 1.0-1.2 Ut, urethane; Ur, urea The molecular weight is considered to be one of the most important parameters of polyurethane.
The PTMG-based WBPU exhibited the maximum tensile strength and the Young's modulus among all of the samples.
Figure 5 shows the XPS survey scan of WBPU and WBPSUU.
Table 4: Relative peak area (%) contribution of various carbon functional groups evaluated from XPS Sample C-H/C-C C-N C-0 C=0 C-Si WBPU 62.5 16.0 15.0 6.5 ...
Seawater-immersion test of pure WBPU and WBPSUU coatings were carried out to confirm the antifouling property depending on the PDMS contents.
The IR spectrum of SAE with silicone monomer 3%, a hydroxyl value of 100 mg KON/g and the IR spectrum of 2K WBPU film were prepared from the above emulsion the Rhodocoat WT2102 with an-NCO/OH ration = 1.5 and are shown in Fig.
Two SEN photographs of 2K WBPU coatings consisting of SAE and hydrophilic modified polyisoeyanate Rhodocoat WT 2102 with and NCO/OH ratio of 1.5 are shown in Fig 2 It can be seen from these SEM photographs at different magnifications that some white particles still existed at the surface of the film, some of which were connected together, These were acrylic emulsion particles that had no reacted with the curing agent.
Figure 3 illustrates the TG-DSC curves of SAE (a), the 2K WBPU costing film consisting of SAE and curing agent Rhodocoat WT 2102 (b), the 2K WBPU coating film composed of the commonly used acrylic emulsion and curing agent Rhodocoat WT 2102(c), when NCO/OH = 1.5:1.
The silicone modification of the acrylic emulsion improved the properties of the resultant 2K WBPU paint.