阻燃处理瓦楞纸板的性能及表征

Properties and Characterization of Corrugated Paperboard by Flame-retardant Treatment

目的研究阻燃处理对瓦楞纸板阻燃性能和物理性能的影响。方法以磷酸胍、纳米二氧化硅、NH_4Cl改性4A分子筛、甲基纤维素、Cu(NO_3)_2改性4A分子筛共混制备无机无卤复合阻燃剂,利用超声波浸渍的方法制备阻燃型瓦楞纸板,根据国标对瓦楞纸板的主要物理性能进行测量,采用垂直燃烧实验和极限氧指数(LOI)测试瓦楞纸板的阻燃效果,采用热重分析(TG)、场发射扫描电镜(FE-SEM)、X射线能谱仪(EDS)和傅里叶红外光谱(FTIR)表征阻燃前后瓦楞纸热稳定性、残炭率、微观形貌、元素组成剂含量以及化学官能团的变化。结果经阻燃处理后,瓦楞纸板的吸水性、边压强度和耐破度分别提高了33.3%,53.7%,14.5%,剥离强度下降了4.5%;阻燃瓦楞纸板的炭化长度为20.3 mm,达到了GB/T 14656—2009中的阻燃纸板技术性能指标,氧指数达到28%(比对照样提高了47.4%);TG分析显示阻燃瓦楞纸板的成炭率提高了111.09%;FE-SEM、EDS和FTIR分析结果显示,阻燃瓦楞纸板的纤维表面存在微米级粒子,这些粒子中的元素除C和O外,还有N,P,Cu等阻燃剂成分。结论复合阻燃剂的施加可提高瓦楞纸板的阻燃性能和物理强度,阻燃剂的覆盖和燃烧时热分解产生的气体均对抑制燃烧起到了重要的凝固相阻燃和气相阻燃作用。

The work aims to study the influence of fire-retardant treatment on the flame retardancy and physical properties of corrugated paperboard. Inorganic halogen-free composite flame retardant was prepared by blending guanidine phosphate, nano-silica, 4 A molecular sieves which was modified by NH4Cl and Cu（NO3）2 and methyl cellulose. Flame-retardant corrugated paperboard was prepared by ultrasonic impregnation. According to the national standard, the main physical properties of corrugated paperboard were measured, and the flame-retardant effect of corrugated paperboard was tested by vertical combustion test and limiting oxygen index（LOI）. Thermo gravimetric analysis（TG）, field emission scanning（FE-SEM）, X ray energy spectrometer（EDS） and Fourier transform infrared spectroscopy（FTIR） were used to characterize thermal stability, carbon residue rate, micro morphology, element composition content and change of chemical functional groups before and after flame-retardant treatment. The water absorption, edge compressive strength and burst strength of corrugated paperboard were increased by 33.3%, 53.7% and 14.5%, respectively. The peeling strength was decreased by 4.5%. The char length of flame-retardant corrugated paperboard was 20.3 mm, which reached technical performance index of flame-retardant board in GB/T 14656—2009, and the oxygen index reached 28%（47.4% higher than the control）. TG analysis indicated that the carbon deposition rate of flame-retardant corrugated paperboard was in-creased by 111.09%. The results of FE-SEM, EDS and FTIR showed that there were micron-sized particles on the fiber surface of the flame-retardant corrugated paperboard. Other than C and O, the elements of these particles also included such components of flame retardants as N, P and Cu. The application of composite flame retardant can improve the flame retardancy and physical strength of corrugated paperboard. In addition, both the covering effect of flame retardant and the gas produced by the thermal decomposition during combustion play an important role in inhibiting the combustion with respect to the solidified phase flame resistance and the gas phase flame resistance.