Synthesis And Characterization Of The Polyphenylene Ether. Pay

Polyphenylene ether (PPE) is a useful engineering plastic because of its mechanical properties, electric properties, thermal resistance , chemical resistance and self-extinguishing characteristics. Especially it's dielectric constant and loss are very low .As for materials for use in an electric field, as the speed of transmission signal increases, a low dielectric constant and a low dielectric loss are desired for utilizing a high-frequency wave. So studying on PPE is becoming a focus in many countries. However, this resin is thermoplastic, which is a problem. It is soluble in a aromatic hydrocarbons solvent such as toluene, benzene or xylene and an halogenated hydrocarbon solvent such as methylene chloride or chloroform. It can't bear high temperature (>260℃) during PCB manufacture. It has a high molecular weight and high melt viscosity so that molding process ability is poor. Therefore PPE need to be modified.Now there are usually two ways to modify thermoplastic PPE into thermosetting polymer. In the first, some Japan company brings allyl groups on PPE chains , but the synthetic route involving butyl lithium is troublesome. The other, like GE corporation, adopts IPN to develop new thermosetting PPE.In the paper, we study the synthesis and characterization of PPE, PPE containing allyl group and PPE containing epoxy group. Meanwhile, we optimize our experiments in the synthesis and characterization of thermosetting PPE. The main results of our work are summarized as following:1 Poly(2,6-dimethyl-1,4 phenylene oxide)(PPE) with low molecular weight and low Mw/Mn was made using hydrogen peroxide as oxidizing agent and mixed solvent of water and 1,4-dioxane instead of nitrobenzene . It is an environmentally friendly process, also reduces the cost of PPE.2 We can choose water to 1, 4-dioxane ratio to control the PPE molecular weight and Mw/Mn. 3 We optimize our experiments of PPE and got low molecular weight about 10000 and low Mw/Mn.4 PPE containing allyl group with high yield was synthesized successfully in one step reaction. This procedure is much simpler and safer than the old way with butyl lithium catalyst. Its molecular weights (Mn) from 15557 to 43150 and Mw/Mn from 2.3 to 8.5 have been achieved. Both Td10 of thermosetting PPE and 10% weight loss temperature have been increased by 7-45℃. Glass transition temperature (Tg) of PPE containing allyl group is lower than traditional thermalplastic PPE.5 The cured PPE has a solubility of 28.2% in chloroform, and 17.8% in xylene.6 We study synthesis and characterization of PPE having epoxy group on the its main chain, and produced the sample successfully.