Faculty of Chemistry, University of Belgrade, Studentski Trg 12-16, Belgrade 11000, Serbia.
Institute of Chemistry, Technology and Metallurgy, University of Belgrade, Njegoševa 12, 11000 Belgrade, Serbia.
Carbohydr Polym. 2016 Dec 10;154:20-9. doi: 10.1016/j.carbpol.2016.08.001. Epub 2016 Aug 2.
Novel macromolecular graft copolymers were synthesized by reaction of the hydroxyl groups of the microbial polysaccharide levan, produced using Bacillus licheniformis, with polystyrene (Lev-g-PS). Synthesis was performed by the free radical reaction using potassium persulfate (PPS) as initiator. The prepared copolymer was characterized by FTIR, SEM, TG/DTA, XRD and (13)C NMR. The influence of the different conditions (reaction temperature, air or nitrogen atmosphere, reaction time, type of amines and ascorbic acid (AA) concentration) on the grafting reaction was investigated. Results showed that maximum percentage of grafting (58.1%) was achieved at a reaction temperature 70°C, in a nitrogen atmosphere and using dimethylethanolamine (DMEA) as the amine activator. On the basis of the obtained results, the likely reaction mechanism was proposed. Synthesized copolymers have better thermal stability in comparison with their initial components. Copolymers such as Lev-g-PS could potentially have many applications, such as compatibilizers and material for membranes.
新型大分子接枝共聚物是通过反应微生物多糖莱鲍迪苷的羟基与聚苯乙烯（Lev-g-PS）合成的，该多糖是由地衣芽孢杆菌产生的。合成是通过自由基反应，使用过硫酸钾（PPS）作为引发剂进行的。所制备的共聚物通过傅里叶变换红外光谱（FTIR）、扫描电子显微镜（SEM）、热重分析/差示扫描量热法（TG/DTA）、X 射线衍射（XRD）和（13）C 核磁共振（NMR）进行了表征。研究了不同条件（反应温度、空气或氮气气氛、反应时间、胺的类型和抗坏血酸（AA）浓度）对接枝反应的影响。结果表明，在 70°C 的反应温度、氮气气氛下，使用二甲基乙醇胺（DMEA）作为胺活化剂时，接枝率达到最大值（58.1%）。基于获得的结果，提出了可能的反应机制。与初始组分相比，合成的共聚物具有更好的热稳定性。Lev-g-PS 等共聚物具有作为增容剂和膜材料等多种潜在应用。
