Abstract
In this study water-soluble polyurethane (WSPU) was synthesized from isophorone diisocyanate (IPDI), and polyethylene glycol (PEG), 2-bis(hydroxymethyl) propionic acid or dimethylolpropionic acid (DMPA), butane-1,4-diol (BD), and triethylamine (TEA) using an acetone process. The water solubility was investigated by solubilizing the polymer in water and measuring the contact angle and the results indicated that water solubility and contact angle tendency were increased as the molecular weight of the soft segment decreased, the amount of emulsifier was increased, and soft segment to hard segment ratio was lower. The contact angle of samples without emulsifier was greater than 87°, while that of with emulsifier was less than 67°, indicating a shift from highly hydrophobic to hydrophilic. The WSPU was also analyzed using Fourier transform infrared spectroscopy (FT-IR) to identify the absorption of functional groups and further checked by X-ray photoelectron spectroscopy (XPS). The molecular weight of WSPU was measured using size-exclusion chromatography (SEC). The structure of the WSPU was confirmed by nuclear magnetic resonance spectroscopy (NMR). The thermal properties of WSPU were analyzed using thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC).
Highlights
A need for water-soluble polyurethane arises as it is advantageous for adhesion to various dispersions, resistance to chemicals, solvents, and water, resistance to abrasion, high flexibility and toughness, non-flammability, easy water cleanup product, low volatile organic compounds (VOC) less pollution and fast dry products increase [1,2,3,4,5,6,7,8,9].To ensure water solubility of polyurethane (PUR), the PUR’s molecular weight and viscosity should not be too high, and the concentration of polar groups must be high enough
The results reveal that there was a difference in contact angle depending on the content of hard segment and molecular weight of polyethylene glycol (PEG)
Isophorone were used as soft segments and hard segments respectively to produce isophorone diisocyanate weretogether used aswith soft dimethylolpropionic segments and hard segments to produce water-soluble polyurethanes acid as anrespectively emulsifier through the water-soluble polyurethanes together with dimethylolpropionic acid as an emulsifier through acetone process
Summary
To ensure water solubility of polyurethane (PUR), the PUR’s molecular weight and viscosity should not be too high, and the concentration of polar groups (carboxylic groups, sulfuric acid groups, and tertiary amine groups) must be high enough. Water-soluble polyurethanes (WSPU)s can be divided into two classes of polymer stabilization: (1) external emulsifiers and (2) hydrophilic centers in the polymer (nonionic groups like polyethylene oxide chains, cationic groups as alkylated or protonated tertiary amines and anionic groups including carboxylate or sulfonate groups) [1,3,4,10]. Polyurethanes are prepared using a low to medium molecular weight isocyanate prepolymer from di or polyols with di- or poly-isocyanates, followed by chain extending and dispersing the prepolymer in water by introducing hydrophilic solubility groups [10,11,12,13]. WSPUs produced from aromatic DI degrade in ultraviolet (UV) radiation, while the aliphatic DI-based WSPUs are Polymers 2019, 11, 1915; doi:10.3390/polym11121915 www.mdpi.com/journal/polymers
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