Ion Sabina, Opris Cristina, Cojocaru Bogdan, Tudorache Madalina, Zgura Irina, Galca Aurelian C, Bodescu Adina M, Enache Madalin, Maria Gabriel-Mihai, Parvulescu Vasile I
Department of Organic Chemistry, Biochemistry and Catalysis, Faculty of Chemistry, University of Bucharest, Bucharest, Romania.
Laboratory of Optical Processes in Nanostructured Materials, National Institute of Materials Physics, Magurele, Romania.
Front Chem. 2018 Apr 20;6:124. doi: 10.3389/fchem.2018.00124. eCollection 2018.
A novel and efficient one-pot system for green production of artificial lignin bio-composites has been developed. Monolignols such as sinapyl (SA) and coniferyl (CA) alcohols were linked together with caffeic acid (CafAc) affording a polymeric network similar with natural lignin. The interaction of the dissolved SA/CA with CafAc already bound on a solid support (S/S-CafAc) allowed the attachment of the polymeric product direct on the support surface (S/S-CafAc-L and S/S-CafAc-L, from CA and SA, respectively). Accordingly, this procedure offers the advantage of a simultaneous polymer production and deposition. Chemically, oxi-copolymerization of phenolic derivatives (SA/CA and CAfAc) was performed with HO as oxidation reagent using peroxidase enzyme (2-1B mutant of versatile peroxidase from ) as catalyst. The system performance reached a maximum of conversion for SA and CA of 71.1 and 49.8%, respectively. The conversion is affected by the system polarity as resulted from the addition of a co-solvent (e.g., MeOH, EtOH, or THF). The chemical structure, morphology, and properties of the bio-composites surface were investigated using different techniques, e.g., FTIR, TPD-NH, TGA, contact angle, and SEM. Thus, it was demonstrated that the SA monolignol favored bio-composites with a dense polymeric surface, high acidity, and low hydrophobicity, while CA allowed the production of thinner polymeric layers with high hydrophobicity.
一种用于绿色生产人造木质素生物复合材料的新型高效一锅法系统已被开发出来。芥子醇（SA）和松柏醇（CA）等单木质醇与咖啡酸（CafAc）连接在一起，形成了一个类似于天然木质素的聚合物网络。溶解的SA/CA与已经结合在固体载体上的CafAc（S/S-CafAc）之间的相互作用使得聚合物产物直接附着在载体表面（分别来自CA和SA的S/S-CafAc-L和S/S-CafAc-L）。因此，该方法具有同时进行聚合物生产和沉积的优点。从化学角度来看，酚类衍生物（SA/CA和CAfAc）的氧化共聚反应是以HO作为氧化试剂，使用过氧化物酶（来自的多功能过氧化物酶的2-1B突变体）作为催化剂进行的。该系统对SA和CA的转化率最高分别达到71.1%和49.8%。转化率受添加共溶剂（如甲醇、乙醇或四氢呋喃）所导致的系统极性影响。使用不同技术（如傅里叶变换红外光谱、程序升温脱附-氨、热重分析、接触角和扫描电子显微镜）对生物复合材料表面的化学结构、形态和性能进行了研究。因此，结果表明SA单木质醇有利于形成具有致密聚合物表面、高酸度和低疏水性的生物复合材料，而CA则允许生产具有高疏水性的较薄聚合物层。
