Practical two‐step chain extension method to prepare sulfonated waterborne polyurethanes based on aliphatic diamine sulphonate

Abstract

We reported a novel synthesis route to fabricate sulfonated aliphatic waterborne polyurethane dispersions (SWPU) only based on 2‐[(2‐aminoethyl) amino] ethane sulphonate sodium (AAS‐Na) by two‐step chain extension method with the assistance of acetone and water cosolvent. When AAS‐Na was added, only less than 50% of AAS‐Na was incorporated into polyurethane chain in the first‐step chain extension and the residual AAS‐Na formed molecular aggregates which were insoluble in acetone due to the high polarity of AAS‐Na. Subsequently, the mixture of acetone and water was added, the residual AAS‐Na aggregates dissolved, undertaking the further second‐step chain extension reaction, and the ultimate reaction conversion of AAS‐Na rose to more than 90%. The mechanism for acetone and water cosolvent to affect the preparation of SWPU dispersions was studied, as well as the water resistance, mechanical properties and hydrolysis resistance of as‐prepared SWPU dispersions. With the decrease of AAS‐Na content from 2.0% to 1.2%, the peak area of the melting peaks for SWPU films increased, as well as the water resistance. And the as‐prepared polyester SWPU exhibited good hydrolytic stability.

Durable Polyurethane/SiO2 Nanofibrous Membranes by Electrospinning for Waterproof and Breathable Textiles

“…Si−OH vibration appeared at 952 cm −1 , and Si− O−Si stretching vibration appeared at 800 cm −1 , while the related intensity peaks of N−H (3327 cm −1 ) and C�O (1705 cm −1 ) were markedly weakened. 44 After the fiber membrane was treated with superhydrophobicity (Figure 4e FTIR spectrum, which also confirmed that the SiO 2 particles were all around the surface of the fiber membrane. 4i).…”

“…Figure e-III shows the FTIR spectrum of the PU/4,4′-MDI- 0.4 /APTES- 2 fiber membrane. Si–OH vibration appeared at 952 cm –1 , and Si–O–Si stretching vibration appeared at 800 cm –1 , while the related intensity peaks of N–H (3327 cm –1 ) and CO (1705 cm –1 ) were markedly weakened . After the fiber membrane was treated with superhydrophobicity (Figure e-IV), the characteristic peaks of Si–OH and Si–O–Si groups were markedly enhanced.…”

Fabrication and In Vitro Biological Assay of Thermo-Mechanically Tuned Chitosan Reinforced Polyurethane Composites

“…FTIR is a conventional technique to describe the development of important polymeric linkage. Particularly, it is used to observe the development of urethane linkage in the case of PU [43][44][45]. Some of the important linkages are provided in Table 1.…”

Design, Preparation and Properties of Polyurethane Dispersions via Prepolymer Method

“…Considering viscosity control of the prepolymer, the temperature of prepolymer is usually higher than 45 °C in industrial production, and the R value of the prepolymer process is usually ≥2, which is much different from the acetone method, meaning there will be amount of active NCO groups in prepolymer. After dispersion step, it is the most important issue to control the extremely fast chain-extension reactions between NCO groups and NH 2 groups [ 25 , 26 ]. It is well known that the reactivity of the NCO group toward NH 2 is very high especially when the temperature is above 40 °C and the NCO group concentration is high, which has a high possibility of leading to emulsification failure.…”

“…It is well known that the reactivity of the NCO group toward NH 2 is very high especially when the temperature is above 40 °C and the NCO group concentration is high, which has a high possibility of leading to emulsification failure. Molecular weight of polyurethane increases via the formation of urea linkages with NCO-terminated prepolymers and diamines in the chain extension step [ 25 , 27 ]. Therefore, for the prepolymer method, prepolymerization process is easy to control and not a difficulty, the emulsification and amine chain extension stage is difficult to control [ 28 ] because of the above reasons, which directly determines whether the emulsion can be obtained or not.…”