Merighi Stefano, Mazzocchetti Laura, Benelli Tiziana, Giorgini Loris
Department of Industrial Chemistry "Toso Montanari" and INSTM UdR-Bologna, University of Bologna, Viale Risorgimento 4, 40136 Bologna, Italy.
Interdepartmental Center for Industrial Research on Advanced Applications in Mechanical Engineering and Materials Technology, CIRI-MAM, University of Bologna, Viale Risorgimento 2, 40136 Bologna, Italy.
Polymers (Basel). 2020 Dec 20;12(12):3054. doi: 10.3390/polym12123054.
In this work, Adenine is proposed, for the first time, as a cross-linker for epoxy resins. Adenine is an amino-substituted purine with heterocyclic aromatic structure showing both proton donors, and hydrogen bonding ability. DSC studies show that adenine is able to positively cross-link a biobased DGEBA-like commercial epoxy precursor with good thermal performance and a reaction mechanism based on a H NMR investigation has been proposed. The use of such a formulation to produce composite with recycled short carbon fibers (and virgin ones for the sake of comparison), as well as jute and linen natural fibers as sustainable reinforcements, leads to materials with high compaction and fiber content. The curing cycle was optimized for both carbon fiber and natural fiber reinforced materials, with the aim to achieve the better final properties. All composites produced display good thermal and mechanical properties with glass transition in the range of HT resins ( > 150 °C, E' =26 GPa) for the carbon fiber-based composites. The natural fiber-based composites display slightly lower performance that is nonetheless good compared with standard composite performance ( about 115-120 °C, E' = 7-9 GPa). The present results thus pave the way to the application of adenine as hardener system for composites production.
在本研究中，首次提出将腺嘌呤用作环氧树脂的交联剂。腺嘌呤是一种具有杂环芳香结构的氨基取代嘌呤，兼具质子供体和氢键结合能力。差示扫描量热法（DSC）研究表明，腺嘌呤能够有效地交联一种具有良好热性能的生物基类双酚A型环氧树脂商业前体，并基于核磁共振氢谱（¹H NMR）研究提出了一种反应机理。使用这种配方来制备以回收短碳纤维（以及作为对照的原始碳纤维）以及黄麻和亚麻天然纤维作为可持续增强材料的复合材料，得到了具有高压实度和纤维含量的材料。针对碳纤维和天然纤维增强材料对固化周期进行了优化，目的是获得更好的最终性能。所制备的所有复合材料均表现出良好的热性能和机械性能，基于碳纤维的复合材料的玻璃化转变温度在高温树脂范围内（> 150°C，储能模量E' = 26 GPa）。基于天然纤维的复合材料性能略低，但与标准复合材料性能相比仍然良好（约115 - 120°C，E' = 7 - 9 GPa）。因此，目前的研究结果为腺嘌呤作为复合材料生产的固化剂体系的应用铺平了道路。
