Abstract
A lack of renewable resources and their inefficient use
is a major challenge facing the society. Lignin is a
natural biopolymer obtained mainly as a by-product from
the pulp- and paper-making industries, and is primarily
burned to produce energy. However, interest for using
lignin in more advanced applications has increased
rapidly. In particular, lignin based nanoparticles could
find potential use in functional surface coatings,
nanoglue, drug delivery, and microfluidic devices. In
this work, a straightforward method to produce lignin
nanoparticles from waste lignin obtained from kraft
pulping is introduced. Spherical lignin nanoparticles
were obtained by dissolving softwood kraft lignin in
tetrahydrofuran (THF) and subsequently introducing water
into the system through dialysis. No chemical
modification of lignin was needed. Water acts as a
non-solvent reducing lignin's degrees of freedom causing
the segregation of hydrophobic regions to compartments
within the forming nanoparticles. The final size of the
nanoparticles depended on the pre-dialysis concentration
of dissolved lignin. The stability of the nanoparticle
dispersion as a function of time, salt concentration and
pH was studied. In pure water and at room temperature the
lignin nanoparticle dispersion was stable for over two
months, but a very low pH or high salt concentration
induced aggregation. It was further demonstrated that the
surface charge of the particles could be reversed and
stable cationic lignin nanoparticles were produced by
adsorption of poly(diallyldimethylammonium chloride)
(PDADMAC).
Original language | English |
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Pages (from-to) | 1416-1422 |
Journal | Green Chemistry |
Volume | 18 |
Issue number | 5 |
DOIs | |
Publication status | Published - 2016 |
MoE publication type | A1 Journal article-refereed |