Page 67 - 摩擦学学报2025年第5期

第 5 期 李东伟, 等: 基础油分子结构对多孔聚酰亚胺含油特性及两者复合体系润滑机理的影响 701

lubrication oils. Therefore, oil content and oil retention, which are both determined by the porous structure of polyimide
have a heavy influence on their long-term lubrication. However, there is a holdback to obtaining OPPI with both higher
porosity and smaller pore size according to the present method by cold-pressing and hot sintering. To break through this
limitation, researchers have conducted various attempts including design with different molecular structures of polyimide,
adjusting internal pore size, and optimizing the lubricants. However, it is easy to ignore the interaction between different
base oils and PPI molecular structure, but particularly crucial to oil absorption and release. As well we know, there is a
lack of systematic investigations into this field. In this work, we prepared and obtained porous YS-20 (PPI) with a
certain pore size (1.46 μm) and porosity (22.63%) by utilizing an established pore-making process. We investigated the
effects of the molecular structure of the base oils on the capacity of oil storage and recyclable smart-lubrication of
porous YS-20. Three base oils (PAO10, DIOS, PEG400) with different polarity and viscosity were selected. The
intrinsic correlation between the molecular structure of the base oil on the oil-containing characteristics and stimulus-
response behavior of the porous YS-20 was revealed. The higher polarity base oil PEG400 was found to greatly improve
the oil content and oil retention of porous YS-20. Herein, QCM-D was further used to characterize the adsorption
properties between YS-20 and different structural base oils, revealing the intrinsic connection between them. It was
found that the adsorption of PEG400 on the surface of YS-20 was stronger and the adsorption film was thicker compared
with that of PAO10 and DIOS. At the same time, porous YS-20 containing different base oils was used as the friction
material to realize the stimulation response of the porous oil-containing polyimide material by varying the load and
speed, thus providing a lubrication effect. Porous YS-20 impregnated with PEG400 was found to have excellent friction
reduction and anti-wear properties. By characterizing and analyzing the morphology and composition of porous YS-20
and steel ring wear surfaces after friction experiments, the intrinsic lubrication mechanism of porous YS-20 impregnated
with base oils of different polarities was elucidated. In conclusion, this study could provide some theoretical support for
the design of porous polyimide self-lubricating materials for future high-end equipment.
Key words: porous polyimide; base oils; molecular structure; lubrication mechanism; solid-liquid duplex lubrication

聚合物含油润滑材料主要包括简易混合型 [1-3] 、微 减小有利于含油保持率的提升. 由于传统粉末冶金成型
胶囊型 [4-6] 和多孔含油型 [7-10] 3种形式，其中，通过润滑 工艺的局限性，现有的多孔PI材料的制备方法难以实
[16]
剂浸入基体内部孔隙结构的多孔含油自润滑材料是 现多孔PI材料高含油率的同时满足高含油保持率 .
[11]
1种典型的可循环润滑材料 . 多孔材料通过自身形 孔径过大或孔隙率过高，均难以确保润滑剂的长期持
[17]
成的三维贯通多孔网络，在外力的驱使下吸附并储存 续供应，同时也会降低材料的自身机械强度 . 为了
一定量的液体润滑剂，并在热和机械力的作用刺激下 改善多孔含油PI的润滑性能，研究人员进行了多种方
及时释放，当外界刺激消除之后，释放的润滑剂又可 案探索，具体包括PI材料结构设计、孔结构调节以及
以通过多孔孔道的毛细力作用而重新回收到多孔基体 润滑油优化. 其中，通过对聚酰亚胺自身结构改性设
[12]
内部，进而实现循环润滑 . 聚酰亚胺(PI)由于自身刚 计，提高其含油润滑性能的研究很多，例如Wang等 [18]
性苯环结构的存在，分子链之间相互作用极强，使得PI 首次制备了多孔热固性含苯并咪唑芳香族聚酰亚
具有优异的耐热性能、机械强度、耐腐蚀和耐辐射性 胺(PIB)材料，该材料的玻璃化转变温度高达336 ℃，
[13]
能 . 同时，其在高低温条件下还表现出了独特的润滑 优异的热稳定性进一步提高了其耐磨性. 与GCr15轴承
[14]
性能，易于满足苛刻工况下的长寿命润滑需求 . 多孔 钢在300 ℃下的摩擦系数和磨损率分别为0.038和1.41×
−6
3
[19]
含油聚酰亚胺自润滑材料以其稳定的极低摩擦系数 10 mm /(N·m). Wang等 用氨基硅油(UMIDA)直接
和近零磨损性能，被广泛应用于机械传动的关键部件. 修饰聚酰亚胺孔道内部结构，改性后样品对硅油的
含油率(孔隙率)和含油保持率(孔径大小)是多孔PI 含油保持率从52%提高到87% (离心条件3 000 r/min，
[20]
[15]
含油自润滑材料的2个重要的性能参数 ，高含油率 120 min)；在孔结构调节方面，Chen等 利用砂纸和三
保证了润滑油的充分补给，是满足传动部件长寿命润 氧化二铝浆料先后对多孔PI表面进行预抛光，得到表
滑的必要条件；高含油保持率有利于多孔基体对储存 面具有纳米级孔道，内部具有微米级别的梯度多孔PI，
在其内部的润滑油进行更有效的控制与释放，进而实 有效控制了润滑油的释放，进而提升了多孔PI的润滑
[21]
现“长时常效”润滑，同时也能减少环境污染和资源浪 性能. Tao等 利用热等静压法制备2种孔径的多孔聚
费. 高含油率要求多孔材料的孔隙率增大，而孔径的 酰亚胺，该结构对PAO10的含油率达15%以上，含油