Effects of Dyeing Temperature and Molecular Structure on the Dye Affinity of Polyurethane Films containing Polyethylene Glycol Segments

Enomoto M,Tokino S

doi:10.4172/2165-8064.1000224

Abstract

The dyeing behavior of segmented polyurethane containing copolymerized polyethylene glycol soft segments was investigated. Four types of segmented polyurethane were prepared by controlling the aggregation of the hard segments and the mobility of polyethylene glycol in the soft segments. Dyeing rate curves and sorption isotherms were obtained for direct dyes at various temperatures along with the swelling ratios of the different segmented polyurethane samples. The sorption of CI Direct Red 28 by these samples is shown to decrease with increasing dyeing temperature, with the swelling ratio of the segmented polyurethane film also decreasing. Changes in the tensile strength of the films before and after dyeing with CI Direct Red 28 are shown to be related to the degree of aggregation of the hard segments, as well as to the amount of dye used.

Highlights

The high flexibility of polyurethane resin, even at low temperatures, and the fact that its molecular structure can be modified to produce fibers or films makes it an ideal material for cloth and interior linings
Affinity of the cast films for direct dye Dyeing rate curves: Figure 3 shows the sorption curves for films produced from Solution 1 when dyed with CI Direct Red 28 at different temperatures
Coordinated water molecules tend to discharge from the Segmented polyurethane (SPU) soft segments composed of polyethylene glycol (PEG) and MDI, with this increasing at higher dyeing temperatures

Summary

Introduction

The high flexibility of polyurethane resin, even at low temperatures, and the fact that its molecular structure can be modified to produce fibers or films makes it an ideal material for cloth and interior linings. SPU has been rendered responsive to acid dyes by synthesizing soft segments through copolymerization with polyethylene glycol (PEG) [1,2] or by introducing dyeing sites [3,4] through copolymerization with tertiary amino groups or tertiary nitrogen chain extenders. In a previous study [5] SPU films with soft segments prepared using different relative contents of PEG and polytetramethylene glycol (PTMG) were investigated in relation to their affinity to acid dyes. The affinity of the SPU films for acid leveling-type dyes was low, but the films with higher PEG contents were readily stained with millingtype dyes. A dyeing mechanism was proposed involving interactions between the dye and hydrophilic PEG groups in SPU soft segments [6] in which dyeing is presumed to occur through via van der Waals forces that exist between the dye and hydrophobic urethane moieties

Methods

Results

Conclusion