Influence of the addition of PEG into PCL‐based waterborne polyurethane‐urea dispersions and films properties

Abstract

In this work, segmented waterborne polyurethane‐urea (WBPUU) dispersions containing hydrophobic polycaprolactone (PCL) and hydrophilic poly(ethylene glycol) (PEG) in different molar ratios are synthesized and used for the subsequent preparation of films by casting. The molar ratio of PEG is gradually increased up to 0.20 in order to analyze the effect of low hydrophilic PEG content (from 1.7 to 7.1 wt %) on the properties of resulting dispersions and films. Regarding the dispersions, the addition of PEG results in an increase of the particle size, from 86 ± 1 in the case of pure PCL‐based system to 112 ± 15 for systems containing 7.1 wt % of PEG, as well as in the formation of a core–shell structure in the particles. Films show different behaviors depending on their PEG content. WBPUUs containing just PCL or very low content of PEG in the soft segment present higher stiffness. However, the addition of PEG in a content of 3.4 wt % or higher hinder the ability of the short‐range ordering of the hard segment, increasing the elongation at break from 842 ± 102 MPa for PCL‐based WBPUU to 1312 ± 84 MPa for the system with the highest PEG content. Systems with higher PEG content form nanoparticles with more segregated core–shell structures inducing to the film a higher hydrophilicity. Hence, the addition of PEG to a PCL‐based WBPUU allows to tune the properties of the resulting film increasing the range of application of these materials. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48847.

Thermally stable poly(urethane‐imide)s with enhanced hydrophilicity for waterproof‐breathable textile coatings

“…AFM was utilized to study the micro phase‐separation in PU46 and PUI46 films; scanning was performed in tapping mode on a 1.5 μm area. The AFM phase images are presented in Figure 4 where the dark and light areas represent the soft and hard phases, respectively 16 . As expected, both PU46 and PUI46 exhibit a phase‐segregated structure; however, the extent of phase separation was more pronounced in PUI46, which can be attributed to a lesser degree of hydrogen bonding between its hard and soft segments than PU46.…”

“…Crosslinking has been explored to improve the mechanical properties and waterproofness of polyurethanes, but it is generally at the expense of breathability 6,15 . Further, low‐thermal stability (thermal degradation starts around 200°C), drastic reduction in mechanical properties around 80–90°C along with excessive melt dripping, limit their usage in areas mandating high‐temperature stability such as constituent materials in fire protective clothing 16–19 …”

Design of a Waterborne Polyurethane–Urea Ink for Direct Ink Writing 3D Printing

“…A WBPUU with a PCL:PEG ratio of 0.8:0.2 was synthesized, following a procedure developed in a previous work [21]. Briefly, the synthesis consisted of a two-step reaction where the former comprised the formation of the prepolymer from PCL, PEG, DMPA, and IPDI, while the latter involved the chain extension with EDA in heterogeneous media once the phase inversion was carried out.…”

“…This incorporation of nanoentities can lead to the realization of a final printed piece with different properties or even new functionalities. Thus, WBPUU based inks with a PEG:PCL ratio of 0.2:0.8, according to previously optimized results [21], with solid contents ranging from 27 to 46 wt%, were synthesized. The different synthesized inks were extensively characterized from the rheological viewpoint in order to establish a relationship between the structural parameters of the WBPUU based inks, their rheological properties, and their printing performance.…”

Rheological experiment and fractional derivative model for aqueous polyurethane dispersion

“…Since environmentally friendly features, aqueous polyurethane dispersion (PUD) has been used in a wide range of industrial applications as versatile fluid. [1][2][3][4] Aqueous PUD is considered to be the most rapidly developing and active branches of PU chemistry and technology driven by their versatility. As an essential physical property, rheology of aqueous PUD has an important effect on the transfer process.…”