Ya-Qi Wang,Qing He,Zhi-Yang Zhang,Lei Zhang,Na-Juan Yuan,Yong Liu,Hai-Tao Ren,Xu Han
Although the low molecular weight poly(2,6-dimethyl-1,4-phenyl oxide) (LMW-PPO) has been extensively applied in the field of 5G communication, the complicated procedures involved in the synthesis of LMW-PPO and efficient recovery of the homogeneous catalysts are still challenging nowadays. In this study, five ionic liquids (ILs) have been successfully synthesized, and LWM-PPO is directly synthesized using different Cu(OAc) 2 -ILs complexes as catalysts. Among them, Cu(OAc) 2 - IL(a) not only exhibits the high yield of LWM-PPO (83.68%, M n =3.6✕10 3 ) with the low 3,3’,5,5’-tetramethyl-4,4’-diphenoquinone (DPQ) yield (0.12%) and polydispersity index (PDI, 1.39) in methanol, but also maintains high stability after being recycled for 5 times. In addition, with increasing H 2 O contents in the system from 1.0% to 5.0%, the M n values of PPO decrease from 2.9✕10 3 to 2.4✕10 3 with the narrow PDI values in the range of 1.22-1.45, indicating that trace H 2 O effectively promotes the formation of binuclear Cu(II) complex between Cu(OAc) 2 ·H 2 O and ILs, which then polymerizes 2,6-dimethylphenol (DMP) to LMW-PPO. The synthesized LMW-PPO exhibits high thermostability ( T d5% =427.07-430.52°C), low glass transition temperature ( T g =167.6-180.3°C), and low dielectric constant ( D k =2.14-2.64, 1 GHz) and dielectric loss ( D f =2.83✕10 -3 -4.91✕10 -3 , 1 GHZ), indicating that it is more appropriate to be used in the field of 5G communication. This study provides new insight on the importance of ILs in direct synthesis of LMW-PPO with high performances.
Traditional free radical polymerization has poor controllability, and traditional petroleum-based lubricant additives have adverse effects on the environment. Poly (lauryl methacrylate (LMA)-soybean oil (SBO)) (P(LMA-SBO) was synthesized using Salen-Cu(II) complex as a catalyst and azodiisobutyronitrile (AIBN) as an initiator by the Schlenk techniques. The structure of P(LMA-SBO) was characterized by infrared spectroscopy (FT-IR), nuclear magnetic resonance (1H NMR), and gel permeation chromatography (GPC) followed by evaluating the solidification point depression performance by the Chinese standard method GB/T 510-2018, and the wax crystal morphology was studied by optical microscopy. The results show the catalytic activity could be 22.88 × 104 g·mol−1·h−1 and the number average molecular weight (Mn) of the copolymer is 8.71 × 104 with a low dispersity (Ɖ) of 1.37 under the optimal conditions, which indicates good controllability of the polymerization. Adding 1.0%(w) P(LMA-SBO) to the lubricating oil fraction (350–500 °C) could reduce the solidification point by 15 °C. Therefore, the Salen-Cu (II) catalyst was successfully applied to the controlled polymerization of LMA and SBO. The vegetable oil-based solidification point depressant of P(LMA-SBO) could be used as a potential alternative to replace the traditional solidification point depressant in the future.
危险品化学品经营许可证（带存储）