SYNTHESIS AND PROPERTIES EVALUATION OF LIGNIN BASED PLASTICIZERS IN THE STABILIZATION OF POLY (VINYL CHLORIDE)

Abstract

From the synthesis, and properties evaluation of lignin-based plasticizers in the stabilization of PVC, the following conclusions can be drawn:

1.  The synthesis of lignin-based plasticizers was successfully carried out by reacting lignin with 34% HCL.
2.  FTIR analysis of PVC-Lignin confirmed lignin's integration into PVC matrices, as evidenced by the appearance of characteristic peaks in PVC-Lignin composite spectra, including the prominent C-O stretching vibration peak around 1090cm-¹. These findings demonstrate successful synthesis of lignin-based plasticizers and their potential to enhance PVC materials.
3.  The FTIR analysis of the PVC sample revealed characteristic peaks corresponding to various functional groups present in the polymer structure. Specifically, the medium peak observed at 3450.53 cm-1 suggests the presence of primary amine groups, while the strong peak at 615.83 cm-1 indicates the C-Cl stretching vibration in the PVC backbone, confirming the presence of chlorine atoms. Additionally, strong peaks at 689.37 cm-1, 16369.39 cm-1, 1251.27 cm-1, 1329.24 cm-1, 1096 cm-1, and 1251 cm-1 correspond to alkene, alkane, carboxylic acid, sulfone, secondary alcohol, and alkyl aryl ether functional groups, respectively. Comparing these observations with the expected FTIR spectrum of PVC, as documented by Shnawa in 2011, corroborates the consistency of the findings. Peaks at 615 cm-1 (C-Cl stretching), 689 cm-1 (alkene), 1251.27 cm-1 (carboxylic acid), and 1329.24 cm-1 (sulfone) align with the anticipated spectrum, further validating the analysis. Moreover, the peaks at 2913.42 cm-1 and 3450.53 cm-1 correspond to C-H stretching vibrations in the PVC backbone and residual water molecules, respectively, consistent with previous literature by Nakamoto in 2009.
4. The migration tests indicated that PVC-Lignin composite films exhibit hydrophilic properties, with minimal migration observed in water. Immersion in acetic acid resulted in minor material loss with 1.36% weight loss, suggesting relative stability under acidic conditions. However, exposure to sodium hydroxide led to slightly higher weight loss with 1.85%, indicating increased susceptibility to alkaline environments.