Synthesis And Properties Of Novel Vanadium(â…¤)Complexes, And Cross Metathesis Reaction Of Gutta-percha

The basic task of polymer chemistry is that exploring new catalytic system and new type of polymerization, synthesizing new structures and functional polymers. Olefin metathesis reaction is a extremely effective method to changing structure of polymers, optimizing the performance of polymers, since olefin metathesis was found in1950s, it has been a research focus in the field of polymer synthesis. Olefin metathesis is a process that two olefins exchange double bond groups to generate new olefin. Olefin metathesis was usually divided into two parts:metathesis reaction and metathesis polymerization. Metathesis reaction contains olefins cross metathesis (CM), ring-opening metathesis (ROM), and so on. Metathesis polymerization includes ring-opening metathesis polymerization (ROMP) and acyclic diene metathesis (ADMET) polymerization. The catalysts for olefin metathesis are much different with that of traditional coordination polymerization in the field of structure e of catalyst, reaction mechanism and structure of polymer chains. This thesis mainly relates to catalyst of olefins metathesis and cross metathesis (CM), the specific contents and results are as follows:In the second chapter, synthesize three kinds of vanadium complexes with ligands of hydroxyl quinolone derivatives. The introduction of polar groups and the enlargement of the space steric hindrance of complexes could contribute to the activity and stability, and help to explore one or two kinds of vanadium catalysts which are efficient, stable, have definite structures and single active centers.In the third chapter, nature rubber (NR) and gutta-percha (GP) with different proportion carried out cross-metathesis reaction by using Grubbs Ru-I as catalyst. The products could be characterized by gel permeation chromatography (GPC), differential scanning calorimetry (DSC), X-ray diffraction (XRD) and tensile testing. GPC results showed the products all had unimodal and DSC detection showed a single Tg data belonging to all products which both shew that cross metathesis reactions were complete. DSC and XRD data shew the crystallinity of products become lower along with the increase of natural rubber, and the products were all homogeneous which were the biggest different between the products of CM and the mixture. The above experimental data proved that cross metathesis could change the physical and chemical properties of rubbers by changing the structure of molecular chain.