摘要聚甲基丙烯酸甲酯（PMMA）具有良好的电绝缘性能、耐老化性能和后加工性能，其发泡材料中的泡孔使裂纹尖端钝化，保证了材料的力学性能。因此，发泡材料广泛应用在建筑、包装等方面。本文利用超临界CO2卸压法发泡PMMA，研究改变温度、压力和时间等工艺参数对发泡结构的影响；同时研究了PMMA/GPPS共混物的发泡性能，并与纯PMMA发泡产物进行了对比。研究表明：对PMMA发泡产物泡孔结构影响程度的顺序是发泡温度＞饱和压力＞保压时间；而对于PMMA/GPPS共混体系，相对于纯PMMA而言，共混体系的泡孔直径更小，泡孔密度更大，且GPPS含量越大影响越明显。因此，选择合适的温度、压力、时间及适当含量的共混物，有利于得到更好的发泡结构。64169

毕业论文关键词  聚甲基丙烯酸甲酯  超临界CO2  发泡温度  饱和压力  保压时间   PMMA/GPPS共混体系

毕业设计说明书（论文）外文摘要

Title Preparation of Polymethylmethacrylate Foam Using Supercritical Carbon Dioxide As Blowing Agent                          

Abstract

Polymethylmethacrylate (PMMA) has many excellent properties such as electrical insulating properties, ageing-resistant performance and handling characteristics. In addition, the tip of crack in PMMA foams can be passivated because of the existence of bubbles, thus ensuring the mechanical properties of PMMA foams. Therefore, they are widely used as building and packaging materials. Supercritical carbon dioxide was used as blowing agent to prepare polymethylmethacrylate foam in this paper. The effects of changes of temperature, dwell time, pressure have been studied. Moreover, the foaming properties of PMMA/GPPS blends were studied, and compared with the pure PMMA foam. The effects of three factors on the cell diameter of PMMA foams are listed in the order: Foaming temperature > Saturation pressure > holding time. Compared with the PMMA forms, the cell size of PMMA/GPPS blends is smaller，and cell density is greater. In conclusion, better foaming structure can be gotten with appropriate temperature, time and additives.

Keywords  polymethylmethacrylate，supercritical carbon dioxide，foaming temperature，saturation pressure，holding time，PMMA/GPPS blends

1.  绪论 1

1.1  研究背景 1

1.2  超临界CO2简介 1

1.3  聚甲基丙烯酸甲酯简介 2

1.4  微孔塑料的应用 2

1.5  发泡方法及原理 3

1.6  选题的目的与意义 4

2.  实验部分 5

2.1  实验仪器设备与药品 5

2.2  超临界流体注入系统 6

2.3  试样制备 7

2.4  实验步骤 7

2.5  测试与表征 8

3.  结果与讨论 10

3.1  聚合物的玻璃转化温度 10

3.2  发泡温度对泡孔结构的影响 11

3.3  发泡压力对泡孔结构的影响 14

3.4  保压时间对泡孔结构的影响 16

3.5  PMMA/GPPS共混体系对泡孔结构的影响