Abstract
The texture and molecular weight of polymer drastically affect the adhesion or tack strength. Waterborne polyurethane dispersions (WBPU) have been prepared using two different macrodiols of hydroxyl terminated polybutadiene (HTPB; Mn = 2912 g/mol−1) and four compositions of Polypropylene glycol (PPG Mn = 425, 1000, 2000, 2700 g/mol−1). The contents of the macrodiols have been varied using HTPB as 5, 10 and 15 mol%. The prepolymer of HTPB and Poly propylene glycol (PPG) have been developed using 4,4-Methylene bis(cyclohexyl isocyanate) (H12MDI) which is extended using 1, 4 butanediol (BD) followed by the dispersion of polymers in deionized water. Fourier Transform Infra-red spectroscopy (FTIR) is used to confirm the desired PU linkage. The probe tack graphs for tack analysis have not shown any plateau indicating absence of fibrillation. Two different values of glass transition temperature (Tg) have been observed for each dispersion using Differential Scanning Calorimetry(DSC). Storage modulus (E′) up to 3.97 MPa and (tanδ/E′) from 0.01–0.30 MPa−1 has been observed via Dynamic Mechanical Analysis (DMA). Introducing the HTPB has resulted in a decrease in the values of (tanδ/E′). No adhesion favorable parameters have been retrieved, indicating the molar variation a key factor in the development of anti-tack dispersions.
Highlights
Among a diverse range of viscoelastic materials, the water borne dispersions (WBDs) are vibrant facilitator in a number of applications; in particular, its usage is indispensable in the field of medicine
The Fourier Transform Infra-red spectroscopy (FTIR) spectrum of final stage for the formation of waterborne polyurethane dispersions (WBPUDs) is given in Figure 2, which represents the dispersion of PU chains in the deionized water
The polymerization leading to the formation of good WBD is always a critical task which demands a lot of precautions to prepare the required material
Summary
Among a diverse range of viscoelastic materials, the water borne dispersions (WBDs) are vibrant facilitator in a number of applications; in particular, its usage is indispensable in the field of medicine. The unique operational properties of WBD allow it to be attached to the surface of a substrate with a slight pressure, which can even be applied with a finger, for a very short time, depending on the wettability of the adhesive and its potential substrate [1,2,3,4,5]. It is one of the abundantly used products in daily life [4,5,6,7]. The ideal WBD requires a perfect balance of viscoelastic properties
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