Branda Francesco, Malucelli Giulio, Durante Massimo, Piccolo Alessandro, Mazzei Pierluigi, Costantini Aniello, Silvestri Brigida, Pennetta Miriam, Bifulco Aurelio
Department of Chemical Materials and Industrial Production Engineering (DICMaPI), University of Naples Federico II, P.le Tecchio 80, Naples 80125, Italy.
Department of Applied Science and Technology, Politecnico di Torino, Viale Teresa Michel 5, Alessandria 15121, Italy.
Polymers (Basel). 2016 Aug 22;8(8):313. doi: 10.3390/polym8080313.
In this paper, for the first time, inexpensive waterglass solutions are exploited as a new, simple and ecofriendly chemical approach for promoting the formation of a silica-based coating on hemp fabrics, able to act as a thermal shield and to protect the latter from heat sources. Fourier Transform Infrared (FTIR) and solid-state Nuclear Magnetic Resonance (NMR) analysis confirm the formation of ⁻C⁻O⁻Si⁻ covalent bonds between the coating and the cellulosic substrate. The proposed waterglass treatment, which is resistant to washing, seems to be very effective for improving the fire behavior of hemp fabric/epoxy composites, also in combination with ammonium polyphosphate. In particular, the exploitation of hemp surface treatment and Ammonium Polyphosphate (APP) addition to epoxy favors a remarkable decrease of the Heat Release Rate (HRR), Total Heat Release (THR), Total Smoke Release (TSR) and Specific Extinction Area (SEA) (respectively by 83%, 35%, 45% and 44%) as compared to untreated hemp/epoxy composites, favoring the formation of a very stable char, as also assessed by Thermogravimetric Analysis (TGA). Because of the low interfacial adhesion between the fabrics and the epoxy matrix, the obtained composites show low strength and stiffness; however, the energy absorbed by the material is higher when using treated hemp. The presence of APP in the epoxy matrix does not affect the mechanical behavior of the composites.
在本文中，首次将廉价的水玻璃溶液作为一种新型、简单且环保的化学方法，用于促进在麻织物上形成基于二氧化硅的涂层，该涂层能够作为热屏蔽层并保护麻织物免受热源影响。傅里叶变换红外光谱（FTIR）和固态核磁共振（NMR）分析证实了涂层与纤维素基材之间形成了⁻C⁻O⁻Si⁻共价键。所提出的水玻璃处理具有耐洗涤性，对于改善麻织物/环氧复合材料的燃烧性能似乎非常有效，与聚磷酸铵结合使用时也是如此。特别是，对麻织物进行表面处理并在环氧树脂中添加聚磷酸铵（APP），与未处理的麻/环氧复合材料相比，热释放速率（HRR）、总热释放量（THR）、总烟雾释放量（TSR）和比消光面积（SEA）显著降低（分别降低83%、35%、45%和44%），有利于形成非常稳定的炭，热重分析（TGA）也证实了这一点。由于织物与环氧基体之间的界面附着力较低，所得复合材料的强度和刚度较低；然而，使用经处理的麻时材料吸收的能量更高。环氧基体中APP的存在不影响复合材料的力学性能。
