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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

A novel biopolymeric photoinitiator based on chitosan and thioxanthone derivative: Synthesis, characterization and efficiency in photopolymerization

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Author(s):
Valandro, Silvano R. [1] ; Poli, Alessandra L. [1] ; Venancio, Tiago [2] ; Pina, Joao [3] ; de Melo, J. Seixas [3] ; Burrows, Hugh D. [3] ; Schmitt, Carla C. [1]
Total Authors: 7
Affiliation:
[1] Univ Sao Paulo, Inst Quim Sao Carlos, Caixa Postal 780, BR-13560970 Sao Carlos, SP - Brazil
[2] Univ Fed Sao Carlos, Dept Quim, Caixa Postal 676, BR-13565905 Sao Carlos, SP - Brazil
[3] Univ Coimbra, Coimbra Chem Ctr, Dept Chem, P-3004535 Coimbra - Portugal
Total Affiliations: 3
Document type: Journal article
Source: JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY A-CHEMISTRY; v. 327, p. 15-20, AUG 15 2016.
Web of Science Citations: 4
Abstract

A novel biopolymeric photoinitiator was synthetized from N-phthaloyl chitosan. The 10-oxo-10H-dibenzene thiopyran-3-4-dicarboximide/chitosan (TXICh) structure was characterized by 1D (H-1 and C-13) and 2D ((HH)-H-1-H-1 COSY, (HC)-H-1-C-13 HSQC and (HC)-H-1-C-13 HMBC) NMR experiments. TXICh showed absorption in a wide region of the visible, with bands at 385, 450 and 540 nm. Fluorescence measurements showed three emitting states with lifetimes of 3, 0.612 and 0.021 ns. Transient lifetimes of the same magnitude were found for TXICh by femtosecond time-resolved pump-probe transient absorption spectroscopy. TXICh triplet formation was observed by flash photolysis. This excited state is responsible for producing radicals, which initiate photopolymerization. The efficiency of TXICh as a biopolymeric photoinitiator was checked by photopolymerization kinetics of TEGDMA using photocalorimetry (photo-DSC). The ability and efficiency of TXICh to act as photoinitiator radical in different wavelengths was confirmed. (C) 2016 Elsevier B.V. All rights reserved. (AU)

FAPESP's process: 12/19656-0 - Photoinitiation of polymerization and degradation of polymers multicomponent
Grantee:Carla Cristina Schmitt Cavalheiro
Support Opportunities: Regular Research Grants