Chemistry Reference
In-Depth Information
Chapter 2
Cellulose Graft Copolymers: Synthesis,
Properties, and Applications
G
¨
lten G
¨
rda˘ and Shokat Sarmad
Abstract
Grafting of vinyl monomers onto cellulose is an important tool for the
modification of cellulose. Depending on the monomer grafted onto cellulose, it
gains new properties. The grafting can be performed in heterogeneous or homoge-
neous medium. In the grafting performed in heterogeneous medium, the reaction is
carried out in aqueous medium using a suitable initiator. As initiator, the radiation
or chemical initiators such as ceric ammonium nitrate (CAN), various persulfates,
azobisisobutyronitrile (AIBN), and Fenton reagent (Fe(II)-H
2
O
2
) are mostly used.
In case of CAN initiator, the grafting should be performed in acidic medium in
order to prevent its hydrolysis. In the homogeneous grafting reactions, either a
water-soluble cellulose derivative is used in the grafting or cellulose is dissolved in
a suitable solvent, and then the grafting is performed. Higher number of grafts per
cellulose chain is obtained in homogeneous grafting than those in heterogeneous
medium.
Keywords
Cellulose • Grafting • Homogeneous medium • Heterogeneous
medium • Grafting percentage • Grafting efficiency • Number of grafts per cellulose
chain • Ceric ammonium nitrate • Fenton reagent • Persulfates
2.1
Introduction
Cellulose is a naturally occurring polymer, and it is the most abundant and renew-
able polymer in the world. In addition, it is one of the most promising raw materials
due to its abundance, easy availability, and low cost. It is a linear polysaccharide
with long chains which consists of
β
-D-glucopyranose units joined by
β
-1,4
