Lignin is the second most abundant biopolymer on earth. It
confers mechanical support of the plant and also provides rigidity,
internal transport of water, nutrients and protection against attack
by microorganisms [1e3]. The chemical structure of lignin is difficult
to define because its structure and properties are largely
related to isolation process and the types of sources used for its
extraction. Generally, is an amorphous polyphenolic macromolecule
which is composed of a large number of polar functional
groups [4]. Commercially, lignin is a by-product mainly obtained
from the pulp and paper industry. Most of the raw material is burnt
as an energy source, although it can offer many other added value
uses. This important component of biomass is less studied due to its
structural complexity, however, that structure which provides
multiple functionalities. Some papers described the efficiency of
lignin as flame retardant additive since it is able to give a large
amount of char when it is heated at high temperature in an inert
atmosphere. This char reduces the combustion rate of polymeric
materials [5,6]. Also, lignin is utilized as a stabilizer (antioxidant)
for plastics [7]. Other authors have found that lignin has an
important influence on the thermal behaviorbehavior in different
composites. Lignin can also behave as a nucleating agent during the
crystallization of different thermoplastic polymers and interfere on
their supermolecular structure [8].