无卤阻燃增韧聚乳酸3D打印材料的制备及性能研究

发布时间：2018-04-22 20:24

本文选题：聚乳酸 + 3D打印　；参考：《沈阳工业大学》2017年硕士论文

【摘要】：聚乳酸(PLA)作为热塑性的生物可降解脂肪族聚酯材料,因其具有优良的生物相容性、高透明性、高模量和高强度等特性,近年来受到人们的广泛关注。而随3D打印技术的发展,作为环境友好型材料的PLA在3D打印领域具有广阔的应用前景。然而,作为3D打印耗材要求材料具有良好的加工流动性和韧性,这样可以防止在打印过程中发生喷头堵塞,同时避免在牵引力作用下发生断丝现象。由于PLA韧性差、流动性差和易燃等缺点,限制了PLA在3D打印领域的广泛应用。本文首先系统性综述了近年来PLA在阻燃、增韧和3D打印领域的研究情况。其次,采用聚乙二醇(PEG)、聚丁二酸丁二醇酯(PBS)、乙烯-醋酸乙烯共聚物(EVA)、聚磷酸铵(APP)和液晶聚合物(LCP)对PLA同时进行阻燃和增韧改性,并通过极限氧指数测试、垂直燃烧测试、热重分析、差示扫描量热分析、力学性能测试、扫描电镜分析和熔融指数分析等对PLA复合材料进行性能表征。主要研究工作如下:(1)通过熔融共混的方法制备了PLA/PEG/APP/LCP阻燃增韧体系。极限氧指数和垂直燃烧测试表明添加15%的APP后复合材料的极限氧指数达到30.1%,达到难燃级别,通过UL-94 V-0标准。热重分析发现,LCP的添加降低了复合材料最大分解速率所对应的温度。力学性能测试发现,PEG的添加使PLA的韧性得到明显改善,添加15%PEG使复合材料的断裂伸长率由4.1%提高到75.2%,随LCP添加量的增加复合材料的断裂伸长率逐渐降低,添加1.0%LCP时,断裂伸长率由57.1%降低到19.38%。对拉伸断裂面进行SEM测试发现,PEG与PLA相容性较好,体现明显的韧性断裂,APP与PLA发生相分离现象。通过熔融指数分析发现,LCP的添加可以明显改善复合材料的加工流动性,MFR由7.01g/10min提高到14.09g/10min。(2)通过熔融共混的方法制备了PLA/PBS/APP阻燃增韧体系。极限氧指数和垂直燃烧测试表明,APP添加量为20%时LOI达到31.5%,通过UL-94 V-0标准。热重分析发现,改性后复合材料初始分解温度提高了10℃,残炭率随APP含量的增加由0.2%提高到16.8%。力学性能测试发现,添加PBS后复合材料的冲击强度和断裂伸长率明显提高,随APP含量的增加复合材料的拉伸强度、冲击强度和断裂伸长率逐渐降低。对拉伸断裂面进行SEM测试发现,PLA和PBS未完全相容,APP与PLA发生相分离现象。通过熔融指数分析发现,随APP含量的增加复合材料MFR先增大后减小,APP含量为15%时达最大值27.41g/10min。(3)通过熔融共混的方法制备了PLA/EVA/APP阻燃增韧体系。极限氧指数和垂直燃烧测试表明,当APP添加量为20%时LOI达到28.3%,达到难燃材料级别,通过UL-94V-0标准。热重分析发现,改性后复合材料初始分解温度提高了10℃左右,残炭率随APP含量的增加由1.34%提高到20.26%。力学性能测试发现,添加EVA后复合材料的冲击强度和断裂伸长率明显提高,随APP含量的增加复合材料的拉伸强度、冲击强度和断裂伸长率逐渐降低。对拉伸断裂面进行SEM测试发现,PLA和EVA相容性较差,APP与PLA发生相分离现象。熔融指数分析发现,随APP含量的增加复合材料MFR先增大后减小,APP含量为10%时达最大值22.51g/10min。
[Abstract]:Poly (lactic acid) (PLA), as a thermoplastic biodegradable aliphatic polyester material, has attracted wide attention in recent years because of its excellent biocompatibility, high transparency, high modulus and high strength. With the development of 3D printing technology, PLA as environmentally friendly material has a broad application prospect in the field of 3D printing. As the 3D printing consumables, the material has good processing fluidity and toughness, which prevents the nozzle blockage in the printing process and avoids the breaking of wire under the action of traction force. Because of the disadvantages of poor PLA toughness, poor fluidity and flammability, the wide application of PLA in the field of 3D printing is limited. The research situation of PLA in the field of flame retardancy, toughening and 3D printing in recent years is reviewed. Secondly, the flame retardancy and toughening modification of PLA with polyethylene glycol (PEG), polybutylene succinate (PBS), ethylene vinyl acetate copolymer (EVA), ammonium polyphosphate (APP) and liquid crystal polymer (LCP) are also carried out at the same time, and through the test of the limit oxygen index, the vertical combustion test and the heat. The properties of PLA composites were characterized by reanalysis, differential scanning calorimetry, mechanical properties test, scanning electron microscope analysis and melt index analysis. The main research work is as follows: (1) the PLA/PEG/APP/LCP flame retardant toughening system was prepared by melt blending. The limit oxygen index and vertical combustion test showed that the composite after adding 15% of APP The limit oxygen index of the material reaches 30.1%, reaching the refractory grade. Through the UL-94 V-0 standard, the thermogravimetric analysis shows that the addition of LCP reduces the temperature corresponding to the maximum decomposition rate of the composite. The mechanical properties test shows that the addition of PEG makes the toughness of PLA obviously improved, and the elongation at break of the composite material is increased from 4.1% to 7 by adding 15%PEG. 5.2%, with the addition of LCP, the elongation at break of the composite gradually decreased. When 1.0%LCP was added, the elongation at break decreased from 57.1% to 19.38%. to the tensile fracture surface, and SEM test found that the compatibility of PEG and PLA was better, it showed obvious ductile fracture, and APP was separated from PLA. The addition of LCP can be found by the melt index analysis. In order to improve the processing fluidity of the composite obviously, MFR was raised from 7.01g/10min to 14.09g/10min. (2) to prepare the PLA/PBS/APP flame-retardant toughening system by melt blending. The limit oxygen index and vertical combustion test showed that LOI reached 31.5% when the APP addition amount was 20%, through the UL-94 V-0 standard. The initial decomposition temperature increased by 10 degrees C, the residual carbon rate increased from 0.2% to the APP content from 0.2% to the mechanical properties test. After adding PBS, the impact strength and elongation at break increased obviously. With the increase of APP content, the tensile strength of the composite material, the impact strength and the elongation at break gradually decreased. The tensile fracture surface was measured by SEM. It is found that PLA and PBS are not completely compatible, APP and PLA are separated. Through the melting index analysis, it is found that the composite MFR first increases and then decreases with the increase of APP content, and the maximum value 27.41g/10min. (3) when the APP content is 15%. The PLA/EVA/ APP flame retardant toughening system is prepared by the melt blending method. The test shows that when the addition of APP is 20%, LOI reaches 28.3%, reaching the grade of refractory material. Through the UL-94V-0 standard, it is found that the initial decomposition temperature of the modified composite is raised about 10 degrees C, the residual carbon rate increases from 1.34% to the 20.26%. mechanical properties by the increase of APP content, and the impact strength and fracture of the composites after adding EVA are found. With the increase of APP content, the impact strength and elongation at break gradually decreased with the increase of the tensile strength of the composite. The SEM test of the tensile fracture surface showed that the compatibility of PLA and EVA was poor and the APP and PLA were separated. The melting index analysis found that with the increase of APP content, the composite MFR increased first and then decreased, APP content contained. When the amount is 10%, the maximum value is 22.51g/10min.

【学位授予单位】：沈阳工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ323.41

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