聚酰亚胺/纳米MgO复合材料的制备与性能研究

Studies on Preparation and Properties of Polyimide /Nano-MgO Composites

采用直接分散法将纳米MgO颗粒均匀分散在聚酰胺酸溶液中,经旋涂、热亚胺化制得聚酰亚胺/纳米MgO复合材料.利用傅里叶变换红外光谱(FTIR)、X射线衍射(XRD)、扫描电子显微镜(SEM)、紫外可见光谱(UV-Vis)、热重分析(TGA)和纳米划痕等测试技术对复合材料的结构和性能进行了表征.结果表明,平均粒径约为20 nm的纳米MgO颗粒均匀地分散在聚酰亚胺基体中,有机无机两组分相容性良好;复合材料在可见光区具有优良的光学透明性,在近紫外光区随着纳米MgO含量的增加呈现出了显著的紫外屏蔽性能;纳米MgO的加入能大幅提高复合薄膜的抗划伤性能,在100μN的划痕力下,划痕深度由纯聚酰亚胺的57.4 nm降至10 nm左右,且划痕的宽度也明显减小;尽管复合材料的热稳定性能较纯聚酰亚胺略有下降,但在300℃以下仍具有较好的热稳定性.

Polyimide /nano-MgO composites without using any coupling agents or surface modifiers were prepared successfully by direct dispersing nano-MgO particles into the polyamic acid solution followed by spin coating and thermal imidization. The structures and properties of the composites were characterized by means of Fourier transform infrared spectroscopy（ FTIR）,X-ray diffraction（ XRD）,scanning electron microscopy（ SEM）,Ultraviolet-visible spectroscopy（ UV-Vis）,thermal gravimetric analyses（ TGA） and nano-scratch test. The results showed that nano-MgO particles with average size of ca. 20 nm were well dispersed in the polyimide matrix,and the compatibility between the organic and inorganic components was good. The asprepared composites exhibited excellent optical transparency in the visible region and good UV-shielding properties in the near ultraviolet region. The UV-shielding properties of the composites increased with increasing amount of nano-MgO. It was found that the anti-scratch properties of the composites were enhanced substantially with the addition of nano-MgO. Under a scratching force of 100 μN,the scratching depth dropped from 57. 4 nm of pure PI to about 10 nm of PI /nano-MgO composites,and the width of the scratches also decreased significantly. Although the thermal stability of the composites was slightly inferior to pure PI,they still possessed fairly good thermal stability under the temperature of 300 ℃.