Design of novel plasticizers for nylon: from molecular modeling to experimental verification

Polyamides are semi-crystalline polymers useful in a wide range of applications in the plastics industry. Some applications require higher flexibility and workability of the polyamides. Therefore, plasticizers are added to ease compounding and processing procedures and produce the desired product properties. The goal of the present work was to study experimentally a series of four esters of 4-hydroxybenzoate with linear side chain as plasticizers for the random copolymer nylon 66/6 and to compare the experimental results to computational results that were obtained in a previous work. The plasticizers used were the methyl, ethyl, propyl, and butyl esters of 4-hydroxybenzoate (M4HB, E4HB, P4HB, and B4HB, respectively). Four properties of the plasticizer-polymer blends were examined: area under the loss modulus curve; impact energy; the decrease in Tg, which is related to the plasticization efficiency, and static modulus that serves as an indication to the mechanical properties or the polymer. It was found that P4HB and B4HB offer the optimal combination of plasticization efficiency and mechanical properties and that M4HB is inferior to the other three plasticizers, as was predicted computationally. This study verifies that computational design of plasticizers for nylon is valid and can serve as an important tool to develop new plasticizers specifically and new additives to polymers generally. Copyright (C) 2016 John Wiley & Sons, Ltd.