(447d) Synthesis of High Biomass Content UV-Curable Epoxy Acrylate Oligomer with Cardanol

UV-curable
polymerization is widely used in industrial
applications for different purposes, such as decoration, protection, and some
other specific functions.¹ Conventionally, petroleum-based
materials are included in most UV-curing polymer.

This will be increasing
environmental concerns and limit for fossil feedstock.² Much effort
has been devoted to explore renewable materials to substitute non-renewable
organic chemicals.³ Among these, a cashew nut shell liquid (CNSL),
is a kind of sustainable, low-cost and largely available natural resources,
which is obtained as a byproduct of the cashew processing industry.⁴
Its extracted product, cardanol, is a phenol
derivative, which has a meta-substituent
of a C₁₅ unsaturated hydrocarbon chain with one to three double
bonds.⁵ This unique structure exhibits promising properties for
making tailor-made polymers of high value.⁶

Cardanol can be reacted with epichlorohydrin
(ECH) in order to introduce the epoxy group. Then the cardanol glycidyl ether
is synthesized and used in the next step. The unsaturated double bonds in the
molecular structure of the cardanol glycidyl ether can be oxidized by 3-Chloroperbenzoic
acid to form epoxide groups. The epoxide groups of the product were reacted with acrylic
acid in the presence of triphenyl phosphorus. High
biomass content UV-curable epoxy acrylate oligomers were synthesized.
Different contents of the modified Nano-silica were
added into the epoxy acrylate
oligomer to study the materials
property variations.

Fig 1 Synthesis sequence adopted for
the preparation of cardanol-based epoxy
acrylate oligomers

The structure of the prepared products
was analyzed by a nuclear magnetic resonance (NMR) and (FT-IR) spectroscopy. The
biorenewable content of UV-curable
epoxy acrylate oligomers is about 58.8% ~ 60.9%. The UV-cured coatings have high
gel content and good flexibility. The hardness value of the samples is form 3H to 5H. With the increasing of the modified Nano-silica content, the contact
angle values on the cured film surfaces and surface energy showed a great changes. The presences of 0.75% (relative to the
total mass) of the modified Nano-silica could lead to
a large decrease in the surface free energy. The scanning electron microscopy
(SEM) images were evident that the solubility of the UV-cured coatings was improved
with a small amount of modified Nano-silica addition.
We expect that our results will provide insight into the utilization of a new epoxy
acrylate oligomer for adhesive and coating
applications.

[1] H. Wang, W. Liu, Z. Yan, J. Tan and G. Xia-Hou,
RSC Adv., 2015, 5, 81838-81846.

[2] R. Liu, X. Zhang, J. Zhu, X. Liu, Z. Wang and J. Yan, ACS Sustainable
Chemistry & Engineering, 2015, 3, 1313-1320.

[3] R. Liu, G. Zhu, Z. Li, X. Liu, Z. Chen and S. Ariyasivam,
Green Chem., 2015, 17, 3319-3325.

[4] K. I. Suresh and V. S. Kishanprasad, Ind. Eng. Chem. Res., 2005, 44,
4504-4512.

[5] J. Chen, X. Nie, Z. Liu, Z. Mi and Y. Zhou, ACS
Sustainable Chemistry & Engineering, 2015, 3, 1164-1171.

[6] C. Voirin,
S. Caillol, N. V. Sadavarte,
B. V. Tawade, B. Boutevin
and P. P. Wadgaonkar, Polym. Chem., 2014, 5. 3142-3162.