| Due to the quickly develop of electronics industry, dielectric packing substrate, which is a critical element to support and protect each kind of electrical circuits, is advancing at its highway. In order to meet the requirments of high density electronic packaging substrate material with high heat resistance, high mechanical properties, low thermal expansion coefficient, low dielectric constant, low water absorption, and other performance needs, new substrate matrix resin is urgent needed to be developed. With the requairment of green packaging, packaging substrate must have no halogen, and the solder must lead-free. The lead-free assembly lead to the rising of the peak temerature of the reflow solder to260℃, that make elavate the glass transition temeprature is indispensable. Polyimide, which is a kind of engineering plastic with good overall performances, has been widely used in flexible electronic packaging due to the excellent thermal and electrical properties, and is the first choice for electronic packaging substrate material. In this thesis, research was started from the molecular structure, processing performance, lower dielectric constant and water absorption were considered, a serial of polyimides and polyimide/quartz-fiber cloth laminite were developed, and in order to obtain a kind of thermo-plasitic polyimide,and to sumerize the rule of the relationship between molecular structure and melt property, the following work was carried out:1、A series of thermo-setting polyimides which derived from2,2’-Bis (trifluoromethyl)-4,4’-diaminobiphenyl (TFDB) and3,3’,4,4’-diphenyl ether dianhydride (ODPA), and endcapped by norbornene anhydride (NA), named as TOPIs were prepared with PMR method. And the thermal properties, processing properties and mechanical properties of these polyimide were examined. The results showed that two of these PIs TOPI-B and TOPI-C have good composite properties. The B-stage resin of these two kinds of Pis showed good processable properties, and the cured resins exibite better mechanical properties:the tensile strengths are75MPa and91MPa; and the glass transition temperature are higher than340℃, and the dielectric constants in range of1-12GHz frequency are lower than3.0, and the dielectric losses were less than0.007.2、TOPI-B was choosen to prepare a series of laminates to find out the proper curing temperature and resin constant of TOPI/quartz-fiber cloth laminate and then to prepare high quality laminate. The results show that the proper curing temperature is330℃/1h, and the best resin contant of laminate is49%. Processing temperature and resin content has been identified before was used to prepared TOPI-C/QF conposite laminate. The mechanical properties and thermal properties as well as the electrical properties were examined. And the results show that this series of laminates have excellent mechanical properties, thermal and electrical properties:the thermal expansion coefficient in the XY axis is bout9ppm/℃, and when test under the frequency in range of1-12GHz the dielectric constants of these two laminate are about3.2, and the dielectric loss are less than0.008.3、 Three series of thermo-plastic polyimides derived from a-BPDA、ODPA、 m-PDA、3,4’-ODA and4,4’-ODA, and end-capped by PA, in order to control the molecular weight of these resins, were prepared by high-temperature one-step method. The prepared thermo-plastic polyimide resin were in good high-temperature fusion, especially a-BTPI-C series, not only has a relatively low melt viscosity, also has good mechanical properties. Investigation of thermal properties and melt viscosities of these resins were carried out. The results shows that polyimide BTPI-C-15is the best one, which has composite properties, of these resins. Its melt viscosity at360℃is11610Pa·S, and the glass transition temperature is295℃, the tensile strength is71MPa, and the flexural strength is185MPa. |
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