Graft Copolymerization of Acrylic Acid onto Sawdust Using KMnO₄as Initiator

Abstract

The oxidation of sawdust (Picea abies) with potassium permanganate in diluted aqueous solution creates active sites for its Copolymerization with acrylic acid in hexane. Acrylic acid copolymerized and non copolymerized sawdusts were examined in a scanning electron microscope and presented strong morphological differences. Separation and analysis by FTIR and 13 CP/MAS NMR of lignin and holocellulose by respective delignification with sodium chlorite and hydrolysis of holocellulose with concentrated sulfuric acid, of modified and unmodified sawdusts, showed that lignin was more reactive to grafting than holocellulose. 13 CP/MAS NMR investigations allowed to propose a suitable grafting mechanism.

Preparation and use of sawdusts bearing quaternary ammonium groups for removal of anionic dyes from water

“…Grafting of [2-(methacryloyloxy)ethyl]-trimethylammonium chloride, carried out according to a previous procedure (Marchetti et al 1998), allows to obtain highly modi®ed sawdust. The results are given in Table 1.…”

“…In previous studies, we have reported the synthesis and use of modi®ed sawdusts bearing carboxyl group for the adsorption of heavy metal (Marchetti et al 1996 and1998). Graft copolymerisation of acrylic acid onto sawdust using KMnO 4 as initiator allowed to obtain inexpensive materials which have been used successfully to trap heavy metal ions from water (Geay et al 1999).…”

Converting date seed biomass into highly absorbing hydrogel

“…First, homopolymerization of the added monomers is carried out in a competitive form with grafting onto polysaccharide (the desired reaction), which causes decreased grafting efficiency as well as the production of homopolymers as by-products [13]. The second limitation is the presence of lignin in the polymerization media which can deactivate free radicals through absorbing radicals (by free phenolic hydroxyl group into quinoid structures) and by increasing the chances of termination reactions; as a result, both the velocity and efficiency of graft polymerization reaction are reduced [13]. Therefore, prior to application, the biomasses must be subjected to different preparation stages, especially delignification reaction which is an expensive and time-consuming process.…”

Localisation and Characterization by TEM and EELS of Man-ganese Species during Graft Copolymerization of Acrylic Acid onto Sawdust Using KMnO4 as Initiator

“…KMnO 4 is an efficient initiator for the grafting of vinyl monomers onto lignocellulosic fibers (Lanfang et al 1989;Zheng et al 1995;Marchetti et al 1998). Indeed, permanganate ions are able to react with a reducing substrate to produce highly reactive free macroradicals which initiate graft polymerization.…”

“…Indeed, permanganate ions are able to react with a reducing substrate to produce highly reactive free macroradicals which initiate graft polymerization. In this paper, we report the use of electron energy loss spectroscopy (EELS) to determine the ionization state of the manganese absorbed on wood before and after graft copolymerization of acrylic acid (Marchetti et al 1998) in order to confirm the participation of an electron transfer process from wood to the oxidant species during the reaction. This higher reactivity may be partly attributed to benzylic C-H bond and a-carbonyl carbon or to aromatic nuclei which could be converted via oxidative mechanism to macroradicals.…”