Chemistry Reference
In-Depth Information
Recently we have carried out the first ATRP of rosin-derived monomers and employed
precise molecular engineering of rosin-containing polymeric materials and block
copolymers [4, 5]. ATRP is expected to be suitable for the synthesis of rosin-derived
polymers since this polymerisation method is compatible with a variety of vinyl
monomers and functionality under mild reaction conditions [59, 110]. ATRP has
been combined with ring-opening polymerisation (ROP) to prepare rosin-derived
block copolymers. We have also employed the RAFT technique to polymerise rosin
monomers. Details of the monomer synthesis and polymerisation are given below.
4.4.1 Synthesis of Acrylic Monomers
Dehydroabietic acid (DHAA) was chosen as the starting resin acid. After derivatisation
of DHAA into vinyl monomers, all impurities from the starting materials were readily
removed through simple column chromatography.
Dehydroabietic methyl acrylate
(DAMA) was prepared from acryloyl chloride and dehydroabietic alcohol, which
was obtained by the reduction of dehydroabietic acid with sodium borohydride.
2-Acryloyloxyethyl dehydroabietic carboxylate (AEDA), 4-acryloyloxybutyl
dehydroabietic carboxylate (ABDA), and 2-methacryloyloxyethyl dehydroabietic
carboxylate (MAEDA) were prepared by converting dehydroabietic acid into acyl
chloride under oxalyl chloride followed by an
in situ
esterification reaction with
hydroxyl groups of corresponding (meth)acrylates (
Figure 4.9
). The structures of all
monomers were confirmed by proton nuclear magnetic resonance (
1
H NMR).
Figure
4.10
shows clear evidence of the high purity of vinyl monomers, as confirmed by
chemical shifts of vinyl, aromatic and methylene protons as well as those protons
next to the aromatic ring. All integrations of NMR spectra matched very well.
