Study On High Performance Polyphenylene Oxide/Thermosetting Resins

Copper clad laminate (CCL) is the key base material for electrical industry,its property determines the performance of electric products. Since the beginning of this century, high frequency CCLs have been the trend for the development of CCLs'market because faster speed and larger capacity for delivering information have been increasingly demanded by modern information-related electrical products. Hence, the resins used for preparing high frequency CCLs need better excellent dielectric properties, lower dielectric constant and loss.Cyanate ester (CE) resin and bismaleimide (BMI) resin are representatives of high performance thermosetting resins, which have been regarded as the candidates to fabricate advanced functional/structural materials for high frequency CCL. However, low impact resistance is the intrinsic disadvantage of thermosetting resins. In this thesis, polyphenylene oxide (PPO), an amorphous thermoplastic polymer with excellent dielectric properties (extremely low dielectric constant and loss), outstanding moisture resistance, and desirable toughness, is used to modify above two thermosetting resins.First, a high performance resin system based on commercial PPO and 2, 2'–bis(4-cyanatophenyl) isopropylidene (BADCy), coded as PPO-n/BADCy, is developed. The effect of PPO on the key properties including dielectric and thermal properties, water-resistance as well as toughness of cured resins is intensively investigated. Results show that PPO can not only catalyze the curing reaction of BADCy, but also react with BADCy to form a single-phase structure. Furthermore, compared with cured BADCy resin with 1phr epoxy resin as catalyst, cured PPO-n/BADCy resins have significantly increased impact strength, decreased dielectric constant and loss as well as water-resistance. The reasons behind these desirable improvements are discussed from the view of structure–property relationship. These results suggest that PPO-n/BADCy system has great potential to be used as the matrix for high frequency CCLs or other advanced composites. Second, PPO was used to modify bismaleimide-triazine resin (BT), and the effect of PPO on the key properties of modified resin was investigated. Results show that PPO can not only significantly increase the impact strength and moisture absorption of the resin, but also further reduce the dielectric constant and loss of the resin.Third, a new resin system (PPO-n/BD) based on PPO, BDM, and 2,2'-diallylbisphenol A (DBA) was prepared usingγ-(2,3-Epoxypropoxy) propyltrimethoxysilane (KH560) as the compatibilizer to improve the miscibility of different components. The effect of the content of KH560 on the dielectric property and impact resistance was discussed, and results show that 2phr of KH560 is the optimal content for compatibilization. In addition, the effects of PPO on the dielectric property and water-resistance as well as the effect of absorbed water on the dielectric property are also intensively investigated. Results show that the addition of PPO can significantly improve the dielectric property and water resistance of BD resin. The absorbed water can not be completely desorbed from the resin, so the absorbed water will increase the dielectric constant and loss, however, the enlarged values still meet the requirement of high performance matrices for high performance CCLs.