摘要
随着人们对环境保护的高度重视,在评价、选择聚乙烯等聚烯烃材料性能时,除了考虑其阻燃性能外,低毒、低烟也是聚烯烃材料必不可少的指标。氢氧化镁是一种具有无毒、低烟、热稳定性好等优点的环保型无机阻燃剂,由于其表面呈亲水性,而聚乙烯表面呈疏水性,需要对氢氧化镁进行表面改性以改善其表面物理化学性质,增强其与聚乙烯材料的相容性,还需要提高阻燃聚乙烯复合材料的机械性能等。
采用干法处理工艺对氢氧化镁进行表面改性,考察了改性温度、改性剂用量和改性时间对氢氧化镁的活化指数的影响,结果表明,提高改性剂温度、增加改性剂用量和改性时间均可以提高氢氧化镁的活化指数。确定氢氧化镁改性的最优条件为：改性温度控制在80℃,改性剂硬脂酸镁和KH570的用量分别为待改性氢氧化镁粉体质量的2.5%、0.5%,改性时间达到3h。FTIR、XRD和SEM结果表明改性后的氢氧化镁的活化指数高达98%以上、粒子极性得以降低、分散性得到明显提高。文中也对氢氧化镁/硼酸锌复合体系的改性进行了初步研究。
将最优条件下改性前后的氢氧化镁与聚乙烯制成共混体系,随着氢氧化镁添加量的增加,氢氧化镁/聚乙烯共混体系的拉伸强度呈下降趋势,在添加量为20%时,与纯聚乙烯材料相比,改性前后氢氧化镁/聚乙烯共混体系的拉伸强度分别下降了8.22%、1.98%。氢氧化镁/聚乙烯共混体系的LOI值随着氢氧化镁添加量的增加逐渐增大,添加量为35%时,改性前后氢氧化镁/聚乙烯共混体系的LOI值分别为26.0、24.6。DSC、TGA和SEM结果表明改性氢氧化镁/聚乙烯共混体系相比未改性氢氧化镁/聚乙烯共混体系具有更好的热稳定性、加工性能且与聚乙烯基体有更好的相容性。
将最优条件下改性的氢氧化镁/硼酸锌复合体系与聚乙烯制备共混体系,在阻燃剂添加量为35%的情况下,改变氢氧化镁与硼酸锌的配比时阻燃聚乙烯材料的拉伸强度保持在19.0-20.6MPa之间；适当调整硼酸锌的比例阻燃聚乙烯的氧指数仍保持在25.0左右且阻燃聚乙烯的加工性能和热稳定性得以提高,SEM结果表明改性后氢氧化镁/硼酸锌复合体系与聚乙烯基体具有较好的相容性。
With the increasing attention to environmental protection, low toxicity and low smoke have become important factors in evaluating the flame retardant properties of polyethylene materials and other polyolefin. As the surface of magnesium hydroxide and polyethylene is hydroophilic and hydrophobic, respectively, surface modification of magnesium hydroxide is necessary to improve the surface physical and chemical properties and to enhance its compatibility with the polyethylene material, as well as to maintain the mechanical properties of flame-retardant polyethylene, and so on.
In this study, the dry process modification of magnesium hydroxide was conducted. The effects of modification temperature and the amount of modification agents and modification time on activation index of magnesium hydroxide have been studied. It's found that the activation index of modified magnesium hydroxide increases with the increasing of modification temperature and the amount of modification agents and modification time. The optimal modification conditions for magnesium hydroxide are modification temperature is controlled to be 80℃, the modifier amount of magnesium stearate and KH570 compared to the weight of modified magnesium hydroxide powder is 2.5% and 0.5%, respectively, and the modification time is 3h. The activation index of magnesium hydroxide powder modified in optimal modification conditions reaches 98% or more. It's found from FTIR, XRD and SEM that particle polarity of magnesium hydroxide modified has been reduced and dispersion of powder has been obviously improved. In this paper, the modification of magnesium hydroxide/zinc borate compound system has also been studied.
The modified magnesium hydroxide and polyethylene have been blend together. With the increasing addition of magnesium hydroxide, the tensile strength and the LOI value of magnesium hydroxide/polyethylene composites have been decreased and increased, respectively. When content of magnesium hydroxide is 20%, the loss tensile strength of modified magnesium hydroxide/polyethylene composites and unmodified magnesium hydroxide/polyethylene composites is 8.22% and 1.98%, respectively. When content of magnesium hydroxide reaches 35%, the LOI value of modified magnesium hydroxide/ polyethylene composites and unmodified magnesium hydroxide/polyethylene composites is 26.0 and 24.6, respectively. It's found from the result of DSC, TGA and SEM of tensile fracture that modified magnesium hydroxide has more good thermal stability, processing properties and has better compatibility with polyethylene composites.
In this study, the compound system of magnesium hydroxide and zinc borate has been blend with polyethylene. When the amount of flame retardant reaches 35% of the total mass of the composite, with the change of ratio between magnesium hydroxide and zinc borate the tensile strength of flame retardant PE change from 19.0 Mpa to 20.6MPa. With the ratio of zinc borate appropriate adjustments, the LOI value of blends remained at 25.0 or so. It's found from SEM and other tests that the properties of process and thermal stability of polyethylene have been effectively improved and the retardant particles has better compatibility with the matrix of polyethylene.
引文
[1]陶勇.氢氧化镁阻燃剂的表面改性研究现状.中国非金属矿工业导刊,2008,5：13-15.
[2]Howell B A. Thermal proerties of compounds possessing both solid-phase and gas-phase flame retardant potential. Jounal of Thermal Analysis and Calorimetry,2007,89(2):373-377.
[3]Deci R R, Saikia C N, Thakur A J, et al. Modification of rubber wood with styrene in combination with diethyl allyl phosphate as the flam-retardant agent. Journal of Applied Polymer Science,2007, 105:2461-2467.
[4]Faghihi K, Zamani K. Synthesis and properties of novel flame-retardant poly(amide-inide)s contain-ing phosphine oxide moieties in main chain by microwave irradiation. Journal of Applied Polymer Science,2006,101:4263-4269.
[5]Costa F R, Wagenknecht U, Jehnichen D, et al. Nanocomposites based on polyethylene and Mg-Al layered double hydroxide:charactersation of modified clay, morphological and rheological analysis of nanocomposites. Plastics,Rubber and Composites,2006,35(4):139-148.
[6]Wu K, Song L, Wang Z Z, et al. Prearation and characterization of double shell microencapsulated ammonium polyphosphate and its flame retardance in polypropylene. Journal of Polymer Research, 2009,16:283-294.
[7]Meng W Q, Li F, Evans D G, et al. Preparation and thermal decomposition of magnesium/iron(III) layered double hydroxide intercalated by hexacyanoferrate(III) ions. Journal of Materials Science, 2004,39:4655-4657.
[8]Chen X L, Jiao C M. Synergistic effects of hydroxyl silicone oil on intumescent flame retardant polypropylene system. J Polym Res,2009,16:537-543.
[9]Atikler U, Demir H, Tokatli F, et al. Optimisation of the effect of colemanite as a new synergistic agent in an intumescent system. Polymer Degradation and Stability,2006,91:1563-1570.
[10]Mills S L, Lees G C, Liauw C M, et al. Prediction of mechanical properties following the disper-sion assessment of flame retardant filler/polymer composites based on the multifractal analysis of SEM images. Journal of Macromolecular Science,2005,44:1137-1151.
[11]王苏娜,刘广建.聚乙烯阻燃改性研究进展.塑料,2002,31(4)：64-68.
[12]于丽丽.对HDPE/MTH阻燃体系的改性研究.青岛科技大学硕士论文,2005：1-2.
[13]Montezin F, Crespy A, Georlette P, et al. Flame retardant and mechanical properties of a copoly-mer PP/PE containing brominated compounds/antimony trioxide blends and magnesium hydroxide or talc. Fire and Materials,1997,21:245-252.
[14]Fang S L, Hu Y, Song L. Mechanical properties, fire performance and thermal stability of magnes-ium hydroxide sulfate hydrate whiskers flame retardant silicone rubber. J Mater Sci,2008,43: 1057-1062.
[15]Khusnutdinov V P, Isupov V P. Mechanochemical synthesis of a hydroxycarbonate form of layered magnesium sluminum hydroxides. Inorganic Materials,2008,44(3):263-267.
[16]王丽丽,潘炯玺,邱桂学.HDPE/Br-Sb/Mg(OH)2低卤阻燃电缆料的研制.塑料科技,2005,166(2)：20-23.
[17]王正洲,范潍澄,瞿保钧等.含氢氧化镁的阻燃硅烷交联聚乙烯.功能高分子学报,2000,13(1)：77-80.
[18]方征平,俞晓薇.高分子包覆剂对高填充聚乙烯/氢氧化镁体系动态力学行为的影响.高分子材料科学与工程,2000,16(5)：128-130.
[19]Velasco J I, Ardanuy M, Martinez A B, et al. The role of poly(ethylene terephthalate-co-isophth-alate) as interfacial agent in polypropylene-matrix composites. J Mater Sci,2007,42:2782-2791.
[20]Zheng X T, Wu D M, Meng Q Y, et al. Mechanical properties of low-density polyethylene/nano-magnesium hydroxide composites prepared by an in situ bubble seretching method. J Polym Res, 2008,15:59-65.
[21]李征征,李三喜,张爱玲等.氢氧化镁阻燃剂研究进展.塑料科技,2009,37(4)：83-87.
[22]张林进,张月琴,叶旭初.氢氧化镁的水热改性研究.盐业与化工,2009,38(2)：24-27.
[23]杨华明,周灿伟,李云龙等.氢氧化镁阻燃剂的现状和发展.中国非金属矿工业导刊,2004,5：81-84.
[24]Rothon R N, Hornsby P R. Flame Retardant Effects of Magnesium Hydroxide. Polymer Degrada-tion and Stability,1996,54(2):383-385.
[25]陈旭,虞鑫海,张怀礼等.氢氧化镁阻燃PP、PE、EVA材料的研究进展.绝缘材料,2010,43(1)：45-48.
[26]Chernev B, Olbrich M, Zipper P. Site-resolved X-ray investigations on injection-molded polypro-pylene filled with magnesium hydroxide. Composite Interfaces,2005,12(3-4):221-230.
[27]Rothon R N, Liauw C M, Lees G C, et al. Magnesium hydroxide filled EVA:the effects of filler surface modification on the strength of filler/matrix adhesion and the consequences for composite structure and properties. The Journal of Adhesion,2002,78:603-628.
[28]Liauw C M, Dumitru P, Lees G C, et al. Use of flow microcalorimetry and dynamic mechanical thermal analysis for probing interphase structure in poly(styrene-b-butadiene-b-styrene)/ magnesium hydroxide composites. Composite Interfaces,2003,10(6):593-607.
[29]Celasco J I, Morhain C, Santana O O, et al. Low-rate fracture behaviour of magnesium hydroxide filled polypropylene block copolymer. Polymer Bulletin,1998,41:615-622.
[30]李永泉,乔辉.Mg(OH)2的结构形态对LDPE阻燃性能的影响.北京化工大学学报,2003,30(3)：48-50.
[31]吴湘锋.阻燃型氢氧化镁的制备及其在聚丙烯中应用技术研究.中北大学硕士论文,2008：1-2.
[32]汪关才,卢忠远,胡小平等.无机阻燃剂的作用机理及研究现状.材料导报,2007,21(2)：47-50.
[33]Kiyoaki M. Development of environmentally-friendly electric wires for household and electro-appliances. SEI technical review,2002,54:80-85.
[34]Frank.C. Nanoengineering of Partiele Surfaces. Ady.Mater.2002,13:11-22.
[35]Merwe E M, Strydom C A. Quantitative thermogravimetric analysis of binary mixtures magnesium hydroxide and magnesium acetate. Journal of Thermal Analysis and Calorimetry,2004,76: 149-156.
[36]Larry K. Magnesium hydroxide:Halogen free flame retardant and smoke suppressant for polypro-pylene. Plastics Compounding,1985,9(4):402-441.
[37]Tai C M., Robert K Y. Studies on the impact fracture behaviors of flame retardant polymeric mate-rial. Materials and Design,2001,22(1):15-19.
[38]Sain M, Park S H, Suhara F. Flame retardant and mechanical properties of natural fibre-PP compo-sites containing magnesium hydroxide. Polymer Degradation and Stability,2004,83:363-367.
[39]郑水林编著.粉体表面改性.北京：建材工业出版社,1995.
[40]杜高翔,郑水林,李杨.阻燃用氢氧化镁及水镁石粉体的表面改性研究现状.非金属矿,2002,25(增刊)：10-13.
[41]张斌,胡德生.不同偶联剂对水镁石填料表面的改性研究.塑料工业,1995,23(5)：40-44.
[42]徐旺生,易爱国.阻燃剂型氢氧化镁生产新工艺研究.无机盐工业,2001,33(1)：13-14.
[43]李永泉.氢氧化镁及其阻燃增效剂阻燃LDPE的研究.北京化工大学硕士研究学位论文,2003：4-8.
[44]俞振海,卢晗锋,梁锦等.硅烷偶联剂对氢氧化镁表面改性及其在聚丙烯中的应用.无机盐工业,2010,42(2)：12-14.
[45]刘立华.硬脂酸镁改性氢氧化镁阻燃剂的实验研究.化工科技市场,2010,33(5)：17-21.
[46]罗士平等.氢氧化镁表面改性及其在EVA中的应用.江苏石油化工学院学报,1998,10(4)：4-7.
[47]Zhang Y, Yang J H, Peng Z L, et al. Effect of silicone oil on the mechanical properties of highly filled HDPE composites. Polymers and Polymer Composites,2000,8(7):77-80.
[48]安悦,靖凤梅.无机阻燃剂天然水镁石的表面改性机理.抚顺石油学院学报,1998,18(2)：22-24.
[49]王丽秋,李青山,刘莉莉等.纤维级氢氧化镁阻燃体系研究.功能高分子学报,1998,9(3)：351-354.
[50]冯嘉春,陈鸣才,张秀菊等.稀土偶联剂(REC)对PP/Mg(OH)2体系性能的影响.中国塑料,2000,14(10)：57-61.
[51]王选伦,冯建民,杨鸣波.氨基硅油对阻燃HDPE护套管的改性.塑料工业,2003,31(12)：16-18.
[52]王正洲,瞿保钧,范维澄等.表面处理剂在氢氧化镁阻燃聚乙烯体系中的应用.功能高分子学报,2001,14(1)：45-48.
[53]陈玉坤,郭伟男,贾德民等.不同表面活性剂包覆的LMH对LLDPE生能影响.合成树脂及塑料,2008,25(2)：31-34.
[54]陈一,赵芳,杨军红.表面改性对纳米氢氧化镁/高密度聚乙烯复合材料的影响.江南大学学报(自然科学版),2009,6,8(3)：355-359.
[55]Kodama K, Hyodo T, Shimizu Y, et al. Effects of surface modification of Mg(OH)2 with polysilo-xane oil and silica additive on the flame retardancy and mechanical properties of LDPE-Mg(OH)2 composites. Mater Res Soc Symp Proc Vol,2005,84(7):339-344.
[56]Ulutan U, Gilbert M. Mechanical properties of HDPE/magnesium hydroxide composites. Journal of Materials Science,2000,35(9):2115-2120.
[57]Yeh J T, Hsieh S H, Cheng Y C, et al. Combustion and smoke emission properties of poly (ethyl-ene terephthalate) filled with phosphorous and metallic oxides. Polymer Degradation and Stability, 1998,61(3):399-407.
[58]Gul B S, Mohammad F. Modification of polyethylene and incorporation of fillers for effective rein-forcement of mechanical and better flame retardant properties. Journal of Applied Polymer Science,2006,99(4):1928-1933.
[59]Laoutid F, Ferry L, Lopez-Cuesta J M, et al. Flame-retardant action of red phosphorus/magnesium oxide and red phosphorus/iron oxide compositions in recycled PET. Fire and Materials,2006, 30(5):343-358.
[60]王苏娜,刘广建.聚乙烯阻燃改性研究进展.塑料,2002.,31(4)：64-68.
[61]闫爱华,周志强,吴泽.可膨胀石墨/聚磷酸铵协同阻燃聚乙烯的研究.化学工程师,2006,126(3)：48-50.
[62]庞洪昌,叶俊伟,李俊强等.月桂酸键合改性氢氧化镁的制备及其在聚乙烯中的应用.中国科技论文在线,2008,3(6)：415-418.
[63]Fabien.C, Serge B, Michel L B, et al. Charring of fire retarded ethylene vinyl acetate copolymer-magnesium hydroxide/zinc borate formulations. Polymer Degradation and Stability,2000,69(1): 83-92.
[64]Kim S. Flame Retardancy and Smoke Suppression of Magnesium Hydroxide Filled Polyethylene. Journal of Polymer Science Part B:Polymer Physics,2003,41(9):936-944.
[65]吴洁,李建新.添加剂对无卤阻燃聚乙烯体系性能的影响.绝缘材料,2010,43(3)：55-59.
[66]Stanimirova T, Hibino T, Balek V, et al. Thermal behavior of Mg-Al-CO3 layered double hydro-xide characterized by emanation thermal analysis. Journal of Thermal Analysis and Calorimetry, 2006,84(2):473-478.
[67]Shashidhara G M, Biswas D, Pai B S, et al. Effect of PP-g-MAH compatibilizer content in polypro-pylene/nylon-6 blends. Polym. Bull.,2009,63:147-157.
[68]Sun C Y, Zhang Q B, Li Z B. The water resistance of surface-modified APP with melamine-TDI in LLDPE. J Polym Res,2007,14:505-509.
[69]Gilbert M, Sutherland I, Guest A. Characterization of coated particulate fillers. Journal of Materials Science,2000,35:391-397.
[70]Afonina G A, Leonov V G, Popova O N. Effect of the conditions of hydrolysis of tetraethoxysilane on the synthesis of forsterite. Glass and Ceramics,2008,65:11-12.
[71]Wang Z Z, Chen Z, Fan W C. Effects of surface modifiers on mechanical and rheological proper-ties of halogen-free flame retarded polyethylene composites. Polymer-Plastics Technology and Engineering,2006,45:191-196.
[72]Goncalves J P, Toleso R D, Fairbairn M R. Ecaluation of magnesium sulphate attack in mortarmet-alkaolin system by thermal analysis. Journal of Thermal Analysis and Calorimetry,2008, 94(2):511-516.
[73]王正洲,范维澄,瞿保钧.聚合物材料阻燃测试试验方法相关性研究进展.合成橡胶工业,2001,24(3)：178-181.
[74]Focke W W, Molefe D, Ramjee S, et al. The influence of stearic acid coating on the properties of magnesium hydroxide, hydromagnesite, and hydrotalcite powders. Journal of Materials Science, 2009,44:6100-6109.
[75]郭会仙,曾波,王国栋.氢氧化镁生产现状及市场分析.无机盐工业,2010,43(3)：7-10.
[76]付争兵.阻燃聚乙烯复合材料的制备及其性能研究.应用化工,2009,38(10)：1421-1423.
[77]张玉忠,郑水林,刘桂花.无机复合超细阻燃填料的表面改性.中国粉体技术,2010,16(2)：61-63.
[78]任鹏飞,陈建铭,宋云华等.水热合成制备超细氢氧化镁阻燃级.化工进展,2005,24(2)：186-189.