@Article{jrm.2021.015827,
AUTHOR = {Rumeng Li, Guozhu Zhan, Qi Ma, Yunhe Yang, Xiaoyun Liu, Yitong Zhang, Qixin Zhuang},
TITLE = {The Spatial and Electronic Effects of Substituent Groups on the Thermal Curing of Bio-Based Benzoxazines},
JOURNAL = {Journal of Renewable Materials},
VOLUME = {9},
YEAR = {2021},
NUMBER = {12},
PAGES = {2093--2117},
URL = {http://www.techscience.com/jrm/v9n12/42982},
ISSN = {2164-6341},
ABSTRACT = {To explore the influence of substituent groups on thermally induced curing, eight new bio-based benzoxazines
containing different substituent groups with different electron negativity and volumes were synthesized. The thermal curing of these bio-based benzoxazines was studied in detail. Combined with the curing reaction kinetics,
simulation and calculation of Highest Occupied Molecular and Lowest Unoccupied Molecular values, the spatial
and electronic effects of different substituent groups on the curing of benzoxazine was explored. It was found that
when the substituent was located at the position directly connected to the N atom, the steric hindrance effect of
the group was dominant. When the substituent group was located on the benzene ring connected to the O atom,
both the electronic effect and the spatial effect influenced the curing of benzoxazine. When an electron-withdrawing group was connected ortho position to the O atom, the curing reaction was promoted due to the decreased
electron cloud density of O- on the oxazine ring, making the C-O bond easier to break. When an electron-donating
group was connected to the meta position of the O atom it also promoted the curing reaction, possibly because it
increased the electron cloud density of the <sup>+</sup>
CH<sub>2</sub> reaction site and thereby facilitated electrophilic substitution via
attack of <sup>+</sup>
CH<sub>2</sub> on the cross linking reaction centre. This work provides a deeper understanding of how spatial
and electronic effects of substituents affect the curing of benzoxazine.},
DOI = {10.32604/jrm.2021.015827}
}