Low temperature-dependence of N,N-dimethyl-3-methylbenzamide (DEET) release from a functional paper containing paraffin–DEET composites prepared using interfacial polymerization

• We prepared a polyamide paper coating containing paraffin–DEET composites.
• The polyamide film was directly prepared using interfacial polymerization.
• The functional paper containing paraffin released DEET for a long period.
• DEET release from the functional paper had a low temperature dependence.
• Paraffin was important in achieving the sustained release of DEET.

An interfacial polymerization reaction was used to prepare a functional paper with a polyamide film containing paraffin–N,N-dimethyl-3-methylbenzamide (DEET) composites, which gave a sustained release of DEET with a low temperature dependence. Preparing the polyamide film using an interfacial polymerization reaction eliminated the need for preparing microcapsules and coating the paper with a binder, which is the typical functional paper preparation method. Filter paper impregnated with an oil–water emulsion (composed of ethylenediamine and paraffin microcapsules prepared using methyl methacrylate polymer) was left in a beaker containing a cyclohexane solution of terephthaloyl chloride. The polyamide film containing paraffin–DEET composites could attach itself to the treated paper surface. We studied the release of DEET from the paper with and without paraffin, and its temperature dependence. The functional paper with paraffin showed the sustained release of DEET at high temperatures, but the release was usually inefficient. However, the sustained release of DEET was not temperature dependent, and this was found to be caused by the release of DEET being controlled by the paraffin melting. The optimum paraffin/DEET ratio was 9:1, taking into consideration the amount of DEET released from the paper and the low temperature dependence of the sustained release of DEET.