【作者】 刘姝君；

【导师】 储富祥；

【作者基本信息】 中国林业科学研究院 ， 木基复合材料科学与工程， 2013， 博士

【摘要】 竹基纤维复合材料是以纤维化竹单板为构成单元,按顺纹组坯、经热压(或冷压)胶合而成的板材或方材,这种材料突破了竹材人造板加工利用的竹材径级限制难题,并使竹材的一次利用率从20%-50%提高到了90%以上,实现了竹材人造板从室内地板、家具、水泥模板等中低端应用领域到高强度风电叶片基材、高耐候性户外材料等高附加值领域的跨越。然而,因组成竹基纤维复合材料的基本单元——纤维化竹单板属于易燃材料,不经阻燃处理很难达到相关防火规范的要求,存在着一定的火灾隐患。对竹基纤维复合材料进行阻燃处理,研究材料的燃烧特性,必将成为扩展竹基纤维复合材料使用范围以及实现竹基纤维复合材料产品多样化的重要手段。开展竹基纤维复合材料阻燃性能的系统研究,不仅可以扩宽竹基纤维复合材料的应用领域,同时还可以为相关标准的制定及竹基纤维复合材料产品的开发提供基础的理论依据,这对提升我国竹材产业的整体竞争力、推广竹基纤维复合材料产品、提高其附加值都具有重要的意义。本论文主要以毛竹(Phyllostachys pubescens)、慈竹(Neosinocalamus affinis)为研究对象,以聚磷酸铵(APP)、磷酸氢二铵(DAP)为阻燃剂,将纤维化竹单板进行阻燃处理后,制备了阻燃型竹基纤维复合材料,并利用万能力学试验机、锥形量热仪、热重-差热联用分析仪、扫描电镜-能谱连用仪等,对材料的力学性能、燃烧性能和热解行为特征等进行分析表征,重点分析了纤维化竹单板中阻燃元素的分布状态,研究了竹基纤维材料制备工艺对材料性能的影响,探讨了竹基纤维复合材料性能随阻燃剂用量的变化规律,并揭示了阻燃剂对竹基纤维复合材料阻燃性能的影响机理,为阻燃型竹基纤维复合材料的应用提供了基础研究数据。主要研究结论如下：(1)通过对阻燃剂处理后纤维化竹单板的载药率的研究,分析了纤维化竹单板的竹种来源、浸渍阻燃剂的种类、浸渍处理的工艺等因素对阻燃处理效果的影响,得出了阻燃处理纤维化竹单板的制备工艺。纤维化竹单板的载药率随纤维化竹单板竹种来源的变化不大,慈竹纤维化竹单板的载药率与毛竹纤维化竹单板的载药率基本相同；载药率随浸渍阻燃剂的种类而变化,DAP处理纤维化竹单板的载药率略低于APP处理纤维化竹单板的载药率；载药率随浸渍处理的工艺而变化,高浓度阻燃剂处理的纤维化竹单板的载药率高于低浓度阻燃剂处理的纤维化竹单板的载药率。纤维化竹单板的断面电镜和元素分析表明,阻燃处理后新增的N、P两种元素已均匀地分布在竹材的组织中,当使用浓度为25%的APP对慈竹纤维化竹单板浸渍处理后,N元素含量由处理前的0.23%增大到处理后的9.59%,P元素含量由处理前的0.24%增大到处理后的14.81%。为适应复合材料的生产工艺要求,阻燃剂浸渍时间统一定为3h,当使用浓度为25%的APP对慈竹纤维化竹单板浸渍处理后,纤维化竹单板的载药率可达到最大值19.29%。(2)当以DAP作为竹基纤维复合材料阻燃剂时,纤维化竹单板的竹种来源、DAP阻燃剂的浸渍浓度、竹基纤维复合材料的密度等因素对材料的静曲强度、弹性模量、内结合强度、抗压强度、水平剪切强度、吸水宽度膨胀率、吸水厚度膨胀率、热解性能等产生不同的影响。以慈竹为原料制备的竹基纤维复合材料的静曲强度、弹性模量、抗压强度、水平剪切强度、吸水宽度膨胀率、吸水厚度膨胀率等均高于以毛竹为原料制备的竹基纤维复合材料,而慈竹竹基纤维复合材料的内结合强度则低于毛竹竹基纤维复合材料；当DAP阻燃剂的浸渍浓度增大时,板材的静曲强度、弹性模量、内结合强度、抗压强度、水平剪切强度等均减小,吸水宽度膨胀率、吸水厚度膨胀率则增大；当竹基纤维复合材料的密度增大时,板材的静曲强度、弹性模量、内结合强度、抗压强度、水平剪切强度等均增大,吸水宽度膨胀率、吸水厚度膨胀率则减小。竹基纤维复合材料的热降解过程可分为四个阶段,材料的热解性能随DAP阻燃剂的浸渍浓度而变化,当DAP阻燃剂的浸渍浓度增大时,材料600℃质量残留率增大,由10%增大至25%。(3)当以APP作为竹基纤维复合材料的阻燃剂时,纤维化竹单板的竹种来源、APP阻燃剂的浸渍浓度、竹基纤维复合材料的密度等因素对材料的静曲强度、弹性模量、内结合强度、抗压强度、水平剪切强度、吸水宽度膨胀率、吸水厚度膨胀率、热解性能等产生不同的影响。以慈竹为原料制备的竹基纤维复合材料的静曲强度、弹性模量、抗压强度、水平剪切强度、吸水宽度膨胀率、吸水厚度膨胀率等均高于以毛竹为原料制备的竹基纤维复合材料,以慈竹为原料制备的竹基纤维复合材料的内结合强度则低于以毛竹为原料制备的竹基纤维复合材料；当APP阻燃剂的浸渍浓度增大时,板材的静曲强度、弹性模量、内结合强度、抗压强度、水平剪切强度等均减小,吸水宽度膨胀率、吸水厚度膨胀率则增大；当竹基纤维复合材料的密度增大时,板材的静曲强度、弹性模量、内结合强度、抗压强度、水平剪切强度等增大,吸水宽度膨胀率、吸水厚度膨胀率则减小。材料的热解性能随APP阻燃剂的浸渍浓度而变化,当APP阻燃剂的浸渍浓度增大时,材料600℃质量残留率增大,由10%增大至24%。对比表明,经APP阻燃剂处理的竹基纤维复合材料的力学性能均高于经DAP处理的材料,经APP处理材料的600℃质量残留率与经DAP处理材料的质量残留率基本相同。(4)当以按不同比例混合的DAP、APP作为竹基纤维复合材料的阻燃剂时,板材的力学性能、耐水性能、热解性能等随DAP与APP的混合比例而变化,板材的静曲强度、弹性模量、内结合强度、抗压强度、水平剪切强度、600℃质量残留率等随APP比例的增大呈先增大后减小的趋势,而吸水宽度膨胀率、吸水厚度膨胀率等则随APP比例的增大呈先减小后增加的趋势。当DAP:APP=1:1时,板材的力学性能最大,吸水膨胀率最小,热解残留率最大；当DAP:APP=3:1时,板材的力学性能最小,吸水膨胀率最大,热解残留率最小。材料的热释放速率、热释放总量、有效燃烧热、发烟总量等随着APP含量的增大而有所减小,当DAP:APP=1:3时,材料的热释放速率为25.65kW/m2,热释放总量为46.11MJ/m2,有效燃烧热为4.31MJ/kg,发烟总量为1.63m2。(5)当DAP、APP加入竹基纤维复合材料中,其磷化物和氮化物具有阻燃功效,并产生磷-氮的协效阻燃作用,在燃烧过程中发生吸热发应,分解生成不燃气体以及不燃的液态膜,在高温下形成膨胀碳层,从而阻止材料的持续燃烧。材料的热解动力学参数随阻燃剂的浸渍浓度而变化,经25%浓度的DAP、APP处理后,材料热解的表观活化能分别为45.03KJ/mol、50.68KJ/mol,竹基纤维复合材料的燃烧过程接近于一级反应。经DAP、APP处理后,材料燃烧的引燃时间延长,热释放速率、热释放总量均大幅度地降低。当阻燃剂的浸渍浓度增大时,材料的平均释热速度减小,热释放总量减小。两种阻燃剂对比表明,经APP处理后材料的平均释热速度、热释放总量等均低于经DAP处理后的材料；而经APP处理后的材料的发烟总量则高于经DAP处理后的材料。更多还原

【Abstract】 Bamboo-based fiber composite material was made through assemble, press and glue. The problem of utilization of bamboo diameter limit was solved by this method, and utilization rate was increased from20%-50%to90%. The material had been used from the low-end applications such as indoor flooring, furniture to high value-added field such as wind turbine blades, high weatherability outdoor materials. However, because of the bamboo mat was flammable materials, it was hard to meet the fire safety requirements without flame retardant treatment, there was a fire hidden danger in certain. So it will become an important means to make product diversified through studying on fire-retardant treatment and combustion characteristics of the material. To carry out studying of flame-retardant properties of bamboo-based fiber composite materials, not only can be extended the application of the field of materials, but also can provide the relevant standards and theoretical basis. There was a great significance to enhance competitiveness of China’s bamboo industry, promote bamboo-based fiber composite products and improve the added value.In this paper, Phyllostachys pubescens and Neosinocalamus affinis were chosen as research object, flame retardant bamboo-based fiber composites was made as the bamboo mat was treated by APP and DAP respectively. Mechanical properties, combustion performance and pyrolysis behavior characteristics were characterized. The distribution state of flame retardant elements in bamboo mat, effect of preparation process to material properties, variation of properties with flame retardants concentration, and the mechanism of flame retardant to bamboo-based fiber composites was analyzed respctively. It will provide a basis data for research of flame retardant bamboo-based fiber composite materials.The main conclusions were as follows:(1) The effect of species of bamboo, types of flame retardant, and treatment process on treatment effect were analyzed. For dug loading of bamboo mat, there was no obviously change in species of bamboo. Bamboo mat drug loading rate with high concentrations treated was slightly higher than with low concentrations treated. The surface electron microscopy and elemental analysis showed that:fire-retardant elements of N, P were distributed in the organization of the bamboo uniformly. When the bamboo mat was impregnated by25%APP, N element content was increased from0.23%to9.59%, P element content was increased from0.24%to14.81%. In order to meet the process requirements, flame retardant impregnation time is unified at3h. When the bamboo mat of Neosinocalamus affinis was impregnated by25%APP, drug loading rate to a maximum of19.29%.(2) When DAP was chosen as fiber retardant, the factors such as species of bamboo, impregnation of DAP concentration and density of materials effected the mechanical properties, water resistance properties and pyrolysis performance. Expect to IB, mechanical properties and water resistance properties of Neosinocalamus affinis’s bamboo-based fiber composite was respectively higher than Phyllostachys pubescens’s bamboo-based fiber composite. When DAP impregnation concentration increased, the MOE, MOR, IB, compressive strength and shear strength were reduced, while WS and TS were inceseaed. When bamboo-fiber composite material’s density was increased, the MOE, MOR, IB, compressive strength and shear strength are inceseaed, while WS and TS were reduced. Thermal degradation of bamboo-fiber composite material can be divided into four stages, the pyrolysis of the material was varied with DAP concentration, mass residual was increased from10%to25%as DAP concentration increased.(3) When APP was chosen as fiber retardant, the factors such as species of bamboo, impregnation of APP concentration and density of materials effected the mechanical properties, water resistance properties and pyrolysis performance. Expect to IB, mechanical properties and water resistance properties of Neosinocalamus affinis’s bamboo-based fiber composite was respectively higher than Phyllostachys pubescens’s bamboo-based fiber composite. When APP impregnation concentration was increased, the MOE, MOR, IB, compressive strength and shear strength were reduced, while WS and TS were inceseaed. When the bamboo-fiber composite material’s density was increased, the MOE, MOR, IB, compressive strength and shear strength are inceseaed, while WS and TS were reduced. The pyrolysis of the material were varied with APP concentration, mass residual was increased from10%to24%as APP concentration increased.The result showed that:the mechniacl properties of APP treated was higher than DAP treated, and mass residual with APP treated was basically as same as DAP treated.(4) When DAP and APP were mixed as fiber retardant, the mechanical properties, water resistance properties and pyrolysis performance were changed as mix rate changed. MOE, MOR, IB, compressive strength and shear strength and mass residual at580℃were increases first and then decreases with the proportion of APP increases, while WS and TS were decreases first and then increases. When DAP and APP were mixed with1:1, the mechanical properties and mass residual at580℃was highest, while water resistance was lowest, when DAP and APP were mixed with3:1, the mechanical properties and mass residual at580℃was lowest, while water resistance was highest. HRR, THR, EHC and TSP were decreases with the proportion of APP increases. When DAP and APP were mixed with1:3, HRR was25.65kW/m2, THR was46.11MJ/m2, EHC was4.31MJ/kg, and TSP was1.63m2.(5) When DAP and APP were added in bamboo-based fiber composite, there were a flame retardant effect in phosphide and nitride, meanwhile, a synergistic flame retardant effect of phosphorus-nitrogen was producted. In combustion process, there was a endothermic reaction occurred in phosphide and nitride, and non-combustible gases as well as non-combustible liquid film was generated, these substance could prevent the material continued to burn. The pyrolysis kinetic parameters were changed with flame retardant concentrations. Activation energy of bamboo-based fiber composite was45.03KJ/mol and50.68KJ/mol with DAP and APP treated respectively. Bamboo-based fiber composite material combustion process were closed to a first-order reaction. After DAP and APP treated respectively, bamboo-based fiber composite material’s TTI, HRR and THR were significantly reduced. When the concentration of the flame retardant impregnation increased, HRR and THR were decreases. Comparied to DAP treated, bamboo-based fiber composite material’s HRR and THR with APP treated were lower, while bamboo-based fiber composite material’s TSP with APP was higher.更多还原