Synthesis and evaluation of N,N-dibutylundecenamide as new eco-friendly plasticizer for polyvinyl chloride

Tertiary fatty amide, namely N,N-dibutylundecenamide (DBUA), has been synthesized and evaluated as potential plasticizer for polyvinyl chloride (PVC). Homogeneous PVC/DBUA composite films containing 20, 30 and 40 wt% of DBUA were prepared by solvent casting. Infrared analysis of PVC/DBUA blends indicated molecular interactions between polar –CH–Cl group of PVC and carbonyl group of tertiary amide. According to results of mechanical testing, PVC/DBUA films containing 30 and 40% of DBUA have significantly increased elasticity with reduced Young’s modulus of over 90%, as well as increased elongation at break of approximately 130% compared with neat polymer. Good plasticizing efficacy of DBUA toward PVC has also been revealed by differential scanning calorimetry analysis. Thus, the introduction of DBUA (20% and 30%) into PVC significantly reduced its glass transition temperature by 64.8 and 91.4 °C, respectively. The results of thermal gravimetric analysis revealed reduced thermal stability of PVC/DBUA blends compared to neat PVC, as well as polymer compositions containing common plasticizer bis(2-ethylhexyl)phthalate (BEHP). However, the thermal degradation point of plasticized material (217 ºC) still remained higher than the actual temperature of its processing by common methods. DBUA plasticizer was also found to have higher volatility, but better resistance to migration from PVC films, compared to PVC/BEHP blends. The biodegradability of DBUA determined by primary biodegradation test CEC L-33-A93 was found to be 92.6% after 21 days. Overall, the obtained results indicate that tertiary fatty amide DBUA is promising eco-friendly plasticizer for PVC which combines good low-temperature performance, high biodegradability, as well as resistance to migration from polymer matrix.