Structural Elucidation of the Polymeric Condensed Tannins of Acacia nilotica Subspecies by ^(13)C NMR, MALDI-TOF and TMA as Sources of Bioadhesives  

作　　者：Zeinab Osman Antonio Pizzi Bertrand Charrier 

机构地区：[1]Institute of Engineering Research and Materials Technology,National Center for Research,P.O.Box 2404,Khartoum,Sudan [2]ENSTIB-LERMAB,University of Lorraine,27 rue Philippe Seguin,Epinal,88000,France [3]Department of Materials Science and Engineering,Institute of Analytical Sciences and Physico-Chemistry for the Environment and Materials-Xylomat(IPREM-UMR5254),University of Pau and the Adour Region,E2S UPPA,CNRS,Mont de Marsan,40004,France

出　　处：《Journal of Renewable Materials》2024年第7期1291-1310,共20页可再生材料杂志（英文）

基　　金：the fund provided by NAPATA program,jointly funded by France campus and the Ministry of Higher Education and Scientific research,Sudan;Lab facilities provided by LERMAB which is supported by a grant of the French Agence Nationale de la Recherche(ANR)in the ambit of the laboratory of excellence(Labex)ARBRE is also aknowledged.

摘　　要：Tannin was extracted from different subspecies of Acacia nilotica,Acacia nilotica nilotica(Ann),Acacia nilotica tomentosa(Ant)and Acacia nilotica adansonii(Ana).The aim was to elucidate their structure and evaluate their reactivity as bioadhesives in the wood industry.The extracts were prepared by hot water extraction(90°C tem-perature).Their gel time with paraformaldehyde was used atfirst to compare their reactivity.The tannin contents and the percentage of total polyphenolic materials in different solutions of the extracts spray dried powder were determined by the hide powder method.Concentrated solutions(47%)were tested by both MALDI ToF,13CNMR.The thermomechanical analysis(TMA)was performed to evaluate their modulus of elasticity(MOE)at different pHs.The gel times of all the three tannin extracts showed that their reactivity and it was com-parable to other known procyanidin/prodelphinidin tannin extract types.Ana,Ann and Ant showed highest per-cent of total polyphenolic materials at 70%,64%,and 57%,respectively.The 13CNMR spectra showed that the three subspecies of condensed tannins were mainly constituted of procyanidins(PC)and prodelphinidins(PD)in slightly different ratios.Ann(56.5%PC and 43.4%PD),Ant(57%PC and 43%PD)and Ana(58%PC and 42%PD).MALDI–TOF spectra showed the presence offlavonoid monomers,and oligomers some of which linked to short carbohydrates monomers or dimers.TMA revealed that the three types of tannins had high MOE at their initial pH(5).

关 键 词：Acacia nilotica condensed tannins PROCYANIDINS prodelphinidins 13C NMR MALDI-TOF 

分 类 号：O63[理学—高分子化学]