超细氢氧化镁在硬质PVC阻燃板材中的应用

Application of Superfine Magnesium Hydroxide in Rigid PVC Flame Retardant Board

利用物理研磨法制备了3000目的氢氧化镁(MH)(GY-3000)、6000目的MH(GY-6000),通过硅烷偶联剂R-903对GY-3000进行改性,得到活性MH GY-3000,并对它们的物理性能进行对比。用这三种不同牌号的MH来替代Sb_(2)O_(3),可以大幅降低成本,提高抑烟性能。将三种粉体按照4份MH代替1份Sb2O3的比例,制备了一系列的聚氯乙烯(PVC)/MH复合材料,并对其热性能、极限氧指数、烟密度、拉伸性能、冲击性能进行了研究。研究结果表明,当用12份GY-6000代替3份Sb_(2)O_(3)制备的PVC复合材料表现出最佳的综合性能,该种MH具备可替代部分Sb_(2)O_(3)的潜力,其复合材料的极限氧指数上升明显,可达到47.0%,烟密度下降显著,其复合材料的最大烟密度为74.64%,还可以有效改善复合材料的热稳定性和最终残炭率,其800℃残炭率最高达到37.3%,没有对复合材料力学性能造成不良影响,反而具有最佳拉伸强度和缺口冲击强度,分别为28.9MPa和5.42kJ/m^(2)。

The 3000 mesh magnesium hydroxide(GY-3000)and 6000 mesh magnesium hydroxide(GY-6000)were prepared by physical grinding method.GY-3000 was modified by silane coupling agent(R-903)to obtain active GY3000 magnesium hydroxide,and their physical properties were compared.Using these three different brands of magnesium hydroxide to replace Sb_(2)O_(3) can greatly reduce the cost and improve the smoke suppression performance.A series of polyethylene(PVC)magnesium/hydroxide(MH)composites were prepared with four parts of magnesium hydroxide instead of one part of Sb_(2)O_(3).Their thermal properties,oxygen index,smoke density,tensile properties and impact properties were studied.The results show that when PVC composite prepared with 12 parts GY-6000 instead of 3 parts Sb_(2)O_(3)shows the best comprehensive properties,this kind of magnesium hydroxide has the potential to replace part of Sb2O3.The limiting oxygen index of the composite increases significantly,reaching 47%,and the smoke density decreases significantly.The maximum smoke density of the composite is 74.64%,which can also effectively improve the thermal stability and final carbon residue rate of the composite.The highest residual carbon rate at 800℃is 37.3%,which has no adverse effect on the mechanical properties of the composites.On the contrary,it has the best tensile properties and impact properties,which are 28.9 MPa and 5.4 kJ/m^(2)respectively.