Study On The Synthesis Of A Novel POSS And Its Modification With Thermosetting Resins

With the rapid development of micro-electronic industry has brought increasing requirements on high performance insulating materials which are the key and basic materials for electronic components and electronic products. These high performance insulating materials must have excellent integrated properties, such as good processing characteristics、higher thermal stability、high mechanical strength、better moisture resistance, and outstanding dielectric property, and thus make it impossible for one type of material to meet these harsh requirements. Since last decade, inorganic/organic hybrids have attracted great attentions worldwide because they combine the advantages of both inorganic and organic phases, and show some new unique properties which are not possessed by either inorganic or organic phase. Bismaleimide (BMI) and cyanate ester (CE) resins are two representative sorts of heat resistant thermosetting resin, and are considered to be the most promising resins for fabricating high performance insulating materials. Unfortunately, these resins need to be cured at very high temperature; in addition, some performances of these resins still need to be improved to meet the harsh requirements of the increasing development of electric and electronic industries. Therefore, it is a great importance in both theory and application to developing high performance resins.Inorganic/organic hybrids have combined the advantages of both inorganic and organic phases; which provide an effective route for developing new materials. Among them, the hybrids composed of incompletely condensed POSS (IC-POSS) have attracted great interest owing to their unique structure and properties. Unfortunately, there are only a few kinds of IC-POSS, so that which can not meet the requirements of developing new high performance materials; which restrict the development and application of IC-POSS.In order to overcome the drawbacks of present resins, and meet the requirements of "high frequency and fast speed" for high performance insulating materials, this dissertation focuses on the study of novel thermosetting resin/IC-POSS hybrids. The targets of this dissertation include several aspects, such us design and synthesize new types of IC-POSS, preparing high performance hybrids based on IC-POSS and thermal resistant thermosetting resins, systematically investigating the effect of IC-POSS on the structure and properties of hybrids, and finally developing new high performance hybrids with attractive integrated performance, especially those with good processing characteristics, outstanding thermal and dielectric properties.First, a novel kind of incompletely condensed polyhedral oligomeric silsesquioxane (TAP-POSS) containing allyl groups was successfully synthesized, and its structure was characterized by fourier transform infrared, nuclear magnetic resonance (’H-NMR and29Si-NMR) and X-ray diffraction. In addition, TAP-POSS was hybridrized with2,2’-diallylbisphenol A (DBA) modified4,4’-bismaleimidodiphenylmethane (BDM) resin to develop a new kind of hybrids. The results indicate indicating that BDM/DBA/TAP-POSS prepolymer has the same curing mechanism as BDM/DBA prepolymer, but all hybrids have bigger p values than BDM/DBA resin, and thus leading to different structure and property. Three allyl groups exist on a nano cage structure of one TAP-POSS molecule, while two allyl groups exist in a relatively "long" molecular chain of DBA, consequently, the presence of TAP-POSS tends to shorten the distance between the cross-linked points, and thus increases the p value of the resultant network.. In addition, all hybrids show improved dielectric properties and thermal resistance. For example, the Tg of modified BDM/DBA resin with only3wt%TAP-POSS is330℃, which is36℃higher than that of pure BDM/DBA resin. On the other hand, the results show that the dielectric constant and loss of all hybrids not only are lower than those of BDM/DBA resin over the whole frequency (1-106Hz) and temperature (-50-300℃) range tested, but also exhibit smaller dependence on temperature and frequency.Second, in order to overcome the poor curing feature of CE resins, lots of researches have been conducted on the modifications of CE resin, and results show that co-polymerizing with epoxy compounds is an effective technique for developing high performance CE resins. In this article, a new incompletely condensed POSS containing epoxy groups (TEP-POSS) is designed and synthesized, moreover, which is used to prepare novel hybrids with CE resin. Results show that the performance of hybrids is greatly related with the content of TEP-POSS. CE/TEP-POSS hybrids have obviously decreased curing temperature than CE resin, improve the processing characteristics of CE resin. Compared with cured CE resins, CE/TEP-POSS hybrids exhibit decreased dielectric constant and loss as well as higher thermal stability.