基于4-甲基愈创木酚的聚酰亚胺的合成与性能研究

Synthesis and Properties of Creosol-derived Polyimides

以木质素衍生物4-甲基愈创木酚为主要原料制备了3种生物基芳香二酐,并与石油基和生物基二胺聚合制备了3个系列的生物基聚酰亚胺,这些聚合物的生物基含量为31.8%～56.4%.利用FTIR、1H-NMR、DSC、DMTA、TGA和拉伸实验对聚合物的结构、热性能和力学性能进行了系统分析表征.双醚型生物基聚酰亚胺(PI-I和PI-II系列)的玻璃化转变温度(Tg)在213～235°C之间,5%热失重(T5%)在406～453°C之间;含有二苯并二氧六环结构的生物基聚酰亚胺(PI-III系列)的Tg最高可达424°C,T5%最高可达508°C.聚合物的拉伸强度、弹性模量和断裂伸长率分别为70～115 MPa、1.8～2.8 GPa和3.5%～20.4%.上述结果表明,基于4-甲基愈创木酚的生物基聚酰亚胺具有与石油基聚酰亚胺相当的热和机械性能.

The development of high-performance polymers using bio-renewable feedstocks will promote a sustainable society. However, it remains a challenge to fabricate polyimides rich in bio-based component while high in heat resistance. In this work, three types of bio-based dianhydrides were synthesized using bio-renewable creosol as the raw material, which were then applied for preparing three series of polyimides via polycondensation with petroleum- or bio-based diamines. The molecular weights of these bio-based polyimides were in the range of 14 – 233 kg mol^-1. The inherent viscosity of these polymers spanned a range 0.4–2.06 dL g^-1. Most of the polyimides were soluble in common organic solvents, and flexible films could be readily cast from their solutions. The bio-based contents of these polymers ranged from 31.8% to 56.4%. The temperatures at 5% weight loss (T5%) and the glass transition temperatures (Tg) of bio-based polyetherimides (PI-I and PI-II series) were 406–453 ℃ and 213–235 ℃, respectively, while PI-III series containing dioxin segments exhibited a T5% at 490–508 ℃ and Tg at 378-424 ℃ due to the existence of fused aromatic rings. The tensile strength, modulus, and elongation at break of these polyimides were 70–115 MPa, 1.80–2.8 GPa, and 3.5%–20.4%, respectively. The above mentioned results indicated comparable thermal and mechanical properties between the bio-based polyimies in this study and those made from petroleum-based monomers, such as Ultem^■ and Kapton^■. Due to an excellent combination of high bio-based contents and outstanding thermal and mechanical properties, these polyimides showed great potential in various applications as films and engineering plastics, replacing petroleum-based polyimides.