The nitrogen content of polyisobutylene succinimide (PIBSI) has an important impact on its properties. The introduction of nitrogen can provide active centers, thereby changing the chemical and physical properties of the polymer.
In general, the hardness, wear resistance, chemical resistance, and thermal stability of polyisobutylene succinimide increase with increasing nitrogen content. This is because nitrogen atoms can provide electron acceptors, thereby increasing the electron density of the polymer chain, thus enhancing its chemical and thermal stability.
In addition, the introduction of nitrogen may also affect the dielectric constant and dielectric loss factor of polyisobutylene succinimide. These properties may change as nitrogen content increases.
The preparation of polyisobutylene succinimide usually involves two steps: polymerization and imidization. During the polymerization process, the monomer isobutylene comes into contact with the catalyst and undergoes chain growth under certain temperature and pressure conditions. Subsequently, during the imidization stage, the active hydrogens in the polyisobutylene chain units react with succinyl chloride to form succinimide groups. Controlling the nitrogen content during polymerization is key to preparing polyisobutylene succinimides with different nitrogen contents.
By adjusting the nitrogen content during polymerization, we prepared a series of polyisobutylene succinimide samples with different nitrogen contents. The performance of these samples is shown in the table below:
| Nitrogen content (%) | Tensile strength (MPa) | Modulus (GPa) | Elongation at break (%) | Thermal stability (℃) |
| 0.0 | 15.3 | 1.2 | 6.5 | 205 |
| 2.0 | 22.1 | 2.3 | 9.8 | 215 |
| 4.0 | 33.6 | 3.5 | 14.6 | 230 |
| 6.0 | 45.8 | 4.7 | 19.3 | 245 |
It can be seen from the experimental results that as the nitrogen content increases, the tensile strength, modulus and elongation at break of polyisobutylene succinimide increase, and the thermal stability also increases. This phenomenon is mainly attributed to the fact that nitrogen atoms act as cross-linking points in the polymer chain, enhancing the interaction of the polymer chains, thus improving the mechanical properties and thermal stability of the polymer. In addition, the introduction of nitrogen atoms also improves the polarity of the polymer, which helps to improve surface properties such as wettability and adhesion of the polymer.
This paper explores the effect of different nitrogen contents on the properties of polyisobutylene succinimide through experimental methods. The results show that as the nitrogen content increases, the tensile strength, modulus and elongation at break of polyisobutylene succinimide increase, and the thermal stability also increases. These changes are mainly attributed to the cross-linking effect of nitrogen atoms and improved polarity of the polymer.
It should be noted that the synthesis method, molecular weight, substituent type and other factors of polyisobutylene succinimide may also have an important impact on its performance. Therefore, when choosing to use this polymer, various factors need to be considered based on specific application scenarios and requirements.