Synthesis And Propertys Of Crosslinkable Macrocycle-Containing Poly (Aryl Ether Ketone)s

In recent years there is a considerable interest in the aromatic polymer poly(aryl ether ketone)s among thermoplastic polymers because of their unique combination of toughness, stiffness, thermooxidative stability, electrical performance, flame retardancy and retention of physical properties at high temperatures. So far they have been successfully applied to many fields such as aviation, spaceflight, nuclear energy, communication, telecom, petroleum, machine manufacturing and traffic. However, with the booming development of new science and technology revolution in world, materials with high performance and functionality have been required extensively and urgently. In order to improve the characterization of poly(aryl ether keonte)s further, it is made them to take place crosslinking reaction. Before they are cured processed thermoplastic materials, which can be molded or casted,and then become thermoset through crosslinking reaction, so they have both kinds of advantage of materials. They're required to introduce crosslinking groups.The dissertation include three parts: crosslinkable fully aromatic poly(aryl ether ketone)s bearing macrocycle of aryl ether ketone; synthesis and crosslinking of poly(arel ether ketone)s bearing macrocycle pendants; synthesis and curing behaviors of aromatic poly(ether ether ktone)s with macrocycle pendent.A novel bisphenol monomer, (3-methoxy)phenylhydroquinone, was synthesized via a three-step synthetic procedure. The cyclization of the bisphenol monomer and 4,4-difluorobenzophenone was carried out under pseudo high dilution condition. Two types of fully aromatic poly(aryl ether ketone)s were prepared by copolymerization of macrocycle of aryl ether ketone (MACEK) containing hydroxyphenyl, 4,4-(hexafluoroisopropylidene) diphenol (HFBPA), and 4,4-difluorobenzophenone. The copolymers have high molecular mass, good solubility and high glass transition temperatures. The copolymers are crosslinkable in the presence of basic initiator and the glass transition temperatures of the copolymers increased greatly after the curing. These cured copolymers exhibit excellent thermal stability, and the 5% weight loss temperatures are around 500 oC in nitrogen.A novel bisphenol monomer, (2,5-methoxy)phenylhydroquinone, was synthesized via a three-step synthetic procedure. The cyclization of the bisphenol monomer and a di-fluoro monomer was carried out under pseudo high dilution condition. Two types of fully aromatic poly(ether ketone)s with macrocycle (MCPAEK) were successfully prepared by copolymerization of macrocycle of aryl ether ketone containing hydroxyphenyl groups, (hexafluoroisopropylidene)diphenol (HFBPA), and 4,4-difluorobenzophenone. The copolymers had high molecular mass, good solubility and high glass transition temperatures. The MCPAEKs exhibited excellent thermal stability due to their wholly aromatic structures. In the presence of CsF, the crosslinking reaction of MCPAEKs could afford fully aromatic thermoset poly(aryl ether ketone)s by ring-opening reaction driven by entropy. After crosslinking, the glass transition temperatures increased greatly. These cured copolymers presented an excellent thermal stability, and the temperatures at the 5% weight loss were above 510 oC in nitrogen. The cured copolymers even possessed good tensile properties and the elongations at break were up to 20%.Novel fully aromatic macrocycle-terminated poly(aryl ether ketone)s (MCPAEK) were prepared by condensation of macrocyclic aryl ether ketone dimers containing hydroxyphenyl groups and fluorine end-capped poly(aryl ether ketone)s oligomers. The MCPAEKs exhibited highly thermal stability due to their wholly aromatic structures. Compared to liner poly(aryl ether ketone)s, MCPAEKs showed much lower melt viscosities at low temperature. In the presence of cesium fluoride (CsF), the crosslinking reaction of MCPAEKs could afford fully aromatic thermoset poly(aryl ether ketone)s by ring-opening reaction. After crosslinking, the glass transition temperatures and complex melt viscosities of the polymers both increased greatly. Though there were some residual CsF or phenoxides produced by ring-opening reaction, the obtained thermoset poly(aryl ether ketone)s had good thermal stability with 5% -Td above 475 oC.