Caracterización mediante espectroscopia FTIR del polietileno funcionalizado con anhídrido maleico y modificado con dos diaminas

MICHAEL LÓPEZ MUJICA; RITA TENÍA; BLANCA ROJAS DE GÁSCUE

Caracas

Congreso; XIII International Congress of Numerical Methods in Engineering and Applied Sciences; 2016

Universidad Simón Bolívar

Chemical modification is an alternative increasingly used to produce new materials looking for properties that are more specific. In the case of polymers, the condensation reaction has been used to transform previously functionalized polymers with certain molecules. In recent years, polyethylene (PE) functionalized with maleic anhydride (MAH) and modified with diamines has been studied in order to obtain new structures with applications as compatibilizing agent for blending with other polymers. In this sense, it arises the study through infrared spectroscopy (FTIR) of PE grafted with MAH (PE-g-MAH) and modified by condensation reaction with two different structures of diamines: aliphatic (1,12-diaminododecane, 1,12-DADD) and aromatic (4-aminopyridine, 4-AMPy). The functionalization of PE was carried out using the method proposed by Rojas de Gáscue et al., 2005. In a three-necked flask was placed under reflux 3 g of PE, 67 ml of o-dichlorobenzene, 0,07 ml of DBPH (initiator agent) and 0,3 g of MAH over a period of 67 min. After the reaction, the product was precipitated in cold acetone and purified by Soxhlet extraction for 9 h. The condensation reaction was carried out for 3 h, mixing the PE-g-MAH and the respective diamine. All polymers were characterized in a spectrophotometer Perkin-Elmer, Frontier model. The FTIR results of modified polymers with diamines showed the appearance of a band at 1770 cm- attributed to the stretching of the carbonyl group of imide, caused by cyclization of the acid and amide; also it appears a band at 1722 cm-1 corresponding to the symmetric stretching of the carbonyl group of the amide. This band overlapped with a band at 1715 cm-1, is attributed to the carbonyl group stretching of the carboxylic acid group, indicating that the acids units reacted and converted into secondary amides. Other characteristics bands of tensions in the N-H groups of secondary amides were identified, such as 1636 and 1590 cm-1. This results indicates that the modification of PE-g-MAH both the 1,12-DADD and 4-AMPy occurred in two stages: first the formation of amide and carboxylic acid, and then the imide and a release of a water molecule.