Characterization of henequen cellulose microfibers treated with an epoxide and grafted with poly(acrylic acid)

A two step method for grafting polyacrylic acid, PAA, onto henequen cellulosic microfibers, CM is discussed. Initially, the CM is treated with an epoxide that contains a terminal double bond. The epoxide reacts at the surface with the cellulosic fibers that become functionalized with a terminal double bond. The next step is the grafting of the PAA onto the cellulosic fibers using a solution polymerization reaction initiated with potassium persulfate. The grafting of PAA onto the cellulosic fibers was confirmed by FTIR with a peak that presents a maximum at 1725 cm−1 that is characteristic of the C–O bond of the PAA which was not present in the pure CM. Gravimetric measurements and FTIR characterization indicate that the amount of grafting depends on the concentration of the initiator present in the reaction medium. The best conditions for the grafting reaction were found when the initiator was 0.4% respect to the weight of the fiber. It is also shown that cellulosic fibers grafted with a 21% by weight of PAA increase their water sorption capacity by up to three times.