High performance and dendritic polybenzoxazines: Molecular structure designs and characteristic behavior investigations

• Main Authors: Ruey-Chorng Lin, 林瑞崇
• Other Authors: Shiao-Wei Kuo
• Format: Others
• Language: en_US
• Published: 2018
• Online Access: http://ndltd.ncl.edu.tw/handle/7fq38q

博士 === 國立中山大學 === 材料與光電科學學系研究所 === 106 === Polybenzoxazines are developed for more than two decades and gained many attentions for academic researches and industrial applications. In this study, it focuses on the investigations of the high performance benzoxazine-base polymers and the dendritic benzoxazine-base polymers. For incorporating some functional groups (e.g., COOH and coumarin) into the benzoxazine monomers, the thermal stabilities of the polybenzoxazines can be enhanced significantly by using the hydrogen bonding interactions of the COOH moieties through blending with PVP [poly(N-vinyl-2-pyrrolidione)] and the crosslinking density increments through [2π + 2π] cycloaddition of the coumarin moieties upon UV irradiation as well as the multivalent strategies. A series of novel dendritic TPA-BZ monomers are synthesized successfully by using the triphenylamine as the branching group through facile one-pot Mannich condensations with a unique feeding approach. 1H and 13C NMR, UV-Vis absorption, and PL emission spectra can be used effectively to monitor the chemical constructions (conformations) of the dendritic TPA-BZ monomers, especially in the signal splitting behavior of oxazine rings for asymmetrical hyperbranched TPA-BZs and the effective conjugation length increment as the triphenylamine group increasing. Interestingly, the polymerized TPA-BZ dendrimers possess higher thermal stabilities than those of their hyperbranched counterparts, suggesting that the segmental mobilities in the polymer networks are restricted by the dendrimer core groups and their symmetrical chemical constructions. The temperatures of the exothermic peaks for all benzoxazine derivatives in this study are lower than that of the conventional Pa-type benzoxazine monomer (263 oC), resulting in improvement of the benzoxazine curing temperature too high issue.