Factors affecting the use of dimethylol ethylene urea (DMEU) as a cross-linking agent in the textile industry

Dimethylol Ethylene Urea (DMEU) was synthesised using a previously reported method to produce three batches with different degrees of purity: DMEU 1, a literature synthesis, DMEU 2, with a synthesis temperature of 10° above that recommended in the literature, and DMEU 3, which was synthesised using a four-fold increase in the starting materials. The melting points of the products decreased in the following order: DMEU 1>DMEU 3>DMEU 2, involving temperature as an important factor in controlling the side-reactions. This was corroborated by FT IR analysis, which showed that DMEU I and 3 were very similar, whilst DMEU 2 displayed several absorbance values indicating the presence of impurities and the occurrence of self-condensation. Further evidence for the reduced purity of DMEU 2 was found by differential scanning calorimetry with the thermogram displaying poorly defined thermal events, indicative of a mixed system. The presence of impurities in DMEU 3 was reflected in the increased number of thermal events in comparison to DMEU 1. The implications of this study are that scaling up the DMEU synthetic reaction did not necessarily produce side-reactions that would be deleterious to the textile industry. However, the sensitivity of synthesis to increased temperature means that this parameter must be strictly regulated both during synthesis and when DMEU is used as a cross-linking agent. In the latter case, prolonged exposure to elevated temperatures (during extended curing) may result in deleterious side-reactions resulting in flawed or imperfect textiles.
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