聚电解质化聚磷酸铵对木塑复合材料性能的影响  

Effect of polyelectrolyte ammonium polyphosphate on the flame retardancy and mechanical properties of wood fiber⁃polyethylene composites

作　　者：张帅 张隐 张蕤[2] 潘明珠 ZHANG Shuai;ZHANG Yin;ZHANG Rui;PAN Mingzhu(College of Materials Science and Engineering,Nanjing Forestry University,Nanjing 210037,China;College of Chemical Engineering,Nanjing Forestry University,Nanjing 210037,China)

机构地区：[1]南京林业大学材料科学与工程学院,南京210037 [2]南京林业大学化学工程学院,南京210037

出　　处：《林业工程学报》2020年第4期52-59,共8页Journal of Forestry Engineering

基　　金：国家自然科学基金(31670556);江苏省“青蓝工程”(2018)。

摘　　要：以聚磷酸铵(APP)为原料,通过酸碱滴定法(t1-APP、t2-APP)、NaCl改性法(n-APP)和聚乙烯亚胺(PEI)改性法(p-APP)分别使APP聚电解质化,将制得的APP聚电解质加入木塑复合材料(WPC)中制备得到阻燃WPC。采用TEM、FT-IR对APP聚电解质的形貌及化学结构进行表征,采用TG、LOI及力学性能测试探讨APP聚电解质对WPC热性能、阻燃性能及力学性能的影响。结果表明:聚电解质化处理对APP形貌及晶体结构产生显著影响。经聚电解质化处理后APP结晶度及粒径尺寸下降,分散性显著提高,部分NH4+以NH4Cl形式析出;且热解初始温度和峰值温度均有所提前,700℃下残余质量显著提高。聚电解质化处理后APP保持了其良好的阻燃性能,当添加15%APP聚电解质时,t1-APP、t2-APP、n-APP和p-APP的WPC极限氧指数分别为24.9%, 23.8%, 24.7%和24.8%,与同添加量未改性APP(25.0%)保持在同一水平。同时,添加15%APP聚电解质的WPC力学性能得到显著改善,其中添加15%p-APP的WPC综合性能表现最佳,拉伸强度和模量分别为19.48和4 853 MPa,拉伸断裂伸长率和冲击强度分别为13.85%和7.72 kJ/m^2,与添加15%未改性APP相比,分别提高了18.2%, 57.0%, 39.7%和15.9%。经PEI改性后获得的APP聚电解质可以同步实现WPC阻燃和增韧。当WPC中p-APP添加量继续增加至20%和25%时,阻燃性能将进一步提高,LOI分别达到25.7%和26.7%,但强度和韧性均有所下降。Wood plastic composite(WPC)exhibits excellent mechanical properties,environment friendly,excellent weather resistance and outstanding dimensional stability.It is widely used for outdoor flooring,guardrails,garden chairs,automotive interior decoration,decoration board veneer,etc.With a wide application of WPC in various fields,its flame-retardant properties have received broadly attention.Ammonium polyphosphate(APP)is a commonly used high-efficiency halogen-free flame retardant in WPC.However,due to its poor compatibility with WPC,it would reduce the toughness of WPC.More effective methods are required to improve the flame retardancy of WPC.Polyelectrolyte complex is a class of new effective additives to improve the flame-retardant properties.As a kind of anionic polyelectrolyte,APP is often combined with the opposite charged polyelectrolyte for flame-retardant treatment of fibres or fabrics,showing excellent flame-retardant performance.It should be meaningful to investigate the flame-retardant and mechanical performance of the ionized polyelectrolyte APP in WPC.In this study,the polyelectrolyte APP was prepared by the APP treated with NaCl,PEI(polyethyleneimine)or the acid-base titration method.The transmission electron microscope(TEM)and Fourier transform infrared spectroscopy(FT-IR)tests were used to analyse it s morphology and structure.Then polyelectrolyte APP was added to wood plastic composite(WPC),limiting oxygen index(LOI),and the thermogravimetric analysis(TG)and mechanical properties tests were applied to analyse the flame retardancy and mechanical properties of WPC.Results indicated that,during the modification process,the size of APP decreased significantly and showed better dispersity in WPC.The thermal degradation process of the polyelectrolyte APP changed significantly as the initial decomposition temperature and the maximum decomposition temperature were all increased.After the addition of the APP polyelectrolyte,the LOI of WPC was improved.The LOIs of WPC/t 1-APP 15%,WPC/n-APP 15%,and WPC/p-APP 1

关 键 词：聚电解质 聚磷酸铵 木塑复合材料 增韧 阻燃 

分 类 号：S785[农业科学—林学]