【作者】 马金玲；

【导师】 张兴华；

【作者基本信息】 广东工业大学 ， 高分子化学与物理， 2012， 硕士

【摘要】 快速成型技术在现代的制造领域中的竞争力越来越强,选择性激光烧结技术作为快速成型技术的一种,已经受到越来越多的关注。烧结材料是该领域研究的重点之一。本论文主要研究选择性激光成型技术的一种重要烧结材料聚苯乙烯(PS)及PS微球的制备,并比较了两种不同的烧结原料形状不规则的PS粉末和PS球形粉末在激光烧结过程中的表现。首先采用传统的悬浮聚合法制备PS微球,并对聚合工艺参数中的搅拌速度及引发剂含量对微球的尺寸及分布的影响做了相关研究。研究表明,随着搅拌速度的增加,微球的粒径变小并且当搅拌速度为600转／分时,微球的形貌及分散性较佳。随着引发剂含量的增加,微球的粒径逐渐增加且当引发剂的含量占单体总量的1.5%时,微球的形貌及分散性较佳。本文开发出了一种由粉碎的PS粉末制备PS微球的新工艺,利用光学显微镜详细阐述了由形状不规则的PS粉末到球形PS粉末这一变化过程,并对原粉以及制得的微球的扫描电镜图片、堆积密度等进行了对比。结果表明,原粉的堆积密度为0.464g/cm3,制得的微球粉末的堆积密度为0.688g/cm3,微球粉末的堆积密度比原粉的堆积密度提高了48.4%。通过对微球粉末的热失重分析,比较三种不同的后处理方法对聚苯乙烯微球粉末的除杂效果,相比较而言,50℃蒸馏水煮的方法有一定的效果但不是特别明显,采用50℃酒精煮以及在50℃真空干燥箱中干燥的方法效果都比较好。分别以形状不规则的PS粉末和PS球形粉末为烧结原料,根据电脑中设计的相同的三维CAD图形在激光快速成型上进行烧结实验,比较烧结工艺复杂度、烧结制件的精度并对烧结制件断面进行了扫描电镜分析。相比之下,以PS微球粉末为烧结原料时,烧结工艺简单,可以节省大量的人力物力降低了生产成本,同时烧结制件的尺寸精度也有了很大的提高。更多还原

【Abstract】 The competitive power of Rapid Prototyping (RP) is becoming stronger and stronger in the field of modern manufacturing. One important branch of RP is selective laser sintering (SLS), which has attracted increasing attention. One of the research key points in this field is sintering raw materials. In this paper, the sintering materials polystyrene (PS) and the preparation of PS microspheres were studied. Two different kinds of sintering materials including irregularly shaped PS powder and PS spherical powder were used in SLS technology in order to find out their different performance.First, Polystyrene (PS) microspheres with different sizes were prepared by suspension polymerization. The effect of initiator concentration and stirring speed on the average size and size distribution was evaluated. The results showed that the average size of PS microspheres reduced with the increase of the stirring speed. When the stirring speed was600RPM the surface appearance and size distribution of PS microspheres were relatively good. The average size of PS microspheres increased with increasing initiator content, the surface appearance and size distribution of PS microspheres were relatively good when the mass ratio of BPO to styrene was1.5:100.In this paper, a novel method which can prepare PS microspheres from irregularly shaped PS powder was explored. Optical microscopy with a camera was used to describe the whole change process. The SEM figure and bulk density of the original PS powder and prepared PS spherical powder were studied. The bulk density of original PS powder was0.464g/cm3, while the bulk density of PS spherical powder was0.688g/cm3increasing by48.4%. In addition, three different post treatment methods were adopted to remove the impurities within PS microspheres. The first one was heating PS microspheres in50℃distilled water for10hours, the second one was heating PS microspheres in50℃ethanol for10hours, the third one was heating PS microspheres in50℃vacuum oven for24hours. The thermogravimetric analysis results showed that the second and the third one can remove most of the impurities which were more effective than the first one. The irregularly shaped PS powder and PS spherical powder were sintered respectively according to the same three-dimensional CAD graphic. And then the sintering process, the accuracy of sintered parts and the SEM graphic of sintered parts section were also studied. In contrast, when the sintering raw material was PS spherical powder, the sintering process was more convenient so the production cost was lower, and the dimensional accuracy of sintered parts was better.更多还原