Russian Journal of Applied Chemistry, 2011, Vol. 84, No. 9, pp. 1616−1622.
Pleiades Publishing, Ltd., 2011.
Original Russian Text © A.A. Alalykin, R.L. Vesnin, D.A. Kozulin, 2011, published in Zhurnal Prikladnoi Khimii, 2011, Vol. 84, No. 9, pp. 1567−1574.
AND POLYMERIC MATERIALS
Preparation of Modiﬁ ed Hydrolysis Lignin and Its Use
for Filling Epoxy Polymers and Enhancing
Their Flame Resistance
A. A. Alalykin, R. L. Vesnin, and D. A. Kozulin
Vyatka State University, Kirov, Russia
Received March 18, 2011
Abstract—The reaction of hydrolysis lignin with orthophosphoric acid and urea under the conditions of reactant
fusion without a solvent was studied. The inﬂ uence of the reactant ratio and of the reaction temperature and time on
the degree of chemical binding of phosphorus and nitrogen with lignin was examined. The modiﬁ cation products
can be used as ﬁ re-retardant ﬁ llers for epoxy compounds.
Growing attention is given today to integrated
processing of wood raw materials with the aim to reduce
their loss, and also to the development of production
processes ensuring as full utilization of natural resources
and materials as possible and excluding or considerably
mitigating the environmental impact. Useful utilization
of by-products from wood processing without formation
of harmful substances is appropriate from not only
economical, but also environmental viewpoint.
The development of hydrolysis and alcohol industry
involves a serious problem of utilization of a large-
tonnage solid waste, hydrolysis lignin (HL), which
is a potential source of annually renewable organic
raw material. Of much interest is the use of HL as
dispersed ﬁ ller for polymer compounds. However, the
physicochemical properties of lignin do not always meet
the requirements imposed on ﬁ llers.
The chemical composition, structure, physicochemical
properties, and technological characteristics of HL can
be substantially changed by its chemical modiﬁ cation.
In particular, introduction of phosphorus-containing
groups imparts to the products a number of valuable
properties, the most important of which is decreased
Phosphorylation of lignins is usually performed with
phosphorus acid derivatives and is successful when
carried out under the conditions of minimal moisture
content (as a rule, in organic solvents) . The ﬁ nal step
most frequently involves recovery of valuable products
from the reaction mixture and their puriﬁ cation.
These facts impose certain limitations on industrial
implementation of the synthesis of phosphorylated
lignins. Therefore, search for economical procedures for
HL modiﬁ cation, with minimal expenditures for the raw
material pretreatment and target product preparation in
the form suitable for further use, is a topical problem.
One of the cheapest, most readily available, and
environmentally safest phosphorylating reagents is
orthophosphoric acid (OPA). However, it ﬁ nds limiting
use in the process because of relatively low activity and
pronounced dehydrating action on organic substances
The phosphorylating power of OPA is considerably
enhanced in the presence of certain compounds, in
particular, of urea . In the process, intermediate active
OPA derivatives are generated directly in the reaction
medium. At elevated temperatures, OPA undergoes
condensation with urea to form reactive amido
phosphates, which are the basis of the well-known KM
ﬁ re retardant intended for composite wood and cellulose
materials . The efﬁ ciency of the combined use of
KM ﬁ re retardant with HL to enhance the mechanical