Synthesis And Exploration Of New Catalysts For Ring Opening Polymerization Of Epoxide Compounds

Ring-opening polymerization of epoxy compounds can provide both relatively low molecular weight polyethers and high molecular weight elastomers-polyether rubbers.Both these two materials are widely used and and have high industrial value.However,the existing catalytic systems all have their defects,which limit the industrial development of epoxy ring-opening polymerization.Therefore,two kinds of phosphorus-containing guanidine catalysts?Guanidyl phosphazene?and four kinds of Polycondensation catalysts,which were obtained from the reaction of organotin with phosphate ester,were synthesized in this work.Their structures,compositions and catalytic effecst on homogenization and copolymerization of epichlorohydrin was studied.The results of the study are as follows:?1?The GPC curves of domestic homopolymers and corresponding products in Japan are basically consistent,and this result is consistent with the fact that the performance of homopolymer products at home and abroad is not much different.Different batches of domestic copolymers have good repeatability.Therefore,the speculation that large differences in different batches of products cause differences in the performance of copolymers at home and abroad does not hold.The comparison of the GPC results of domestic and foreign copolymers with similar or equal Mooney viscosity shows that:?1?Domestic copolymers contain three molecular weight components,which contain two components of ultra-high molecular weight and low molecular weight in addition to the main peak.There is no ultra-high molecular weight component in Japanese products,and there is also a clear difference between the two small molecule components;?2?Under the same Mooney viscosity condition,the molecular weight of the main component from Japanese product is significantly higher than that of the domestic sample?Mn:146900>104300;Mw:1247000>514000?,and the molecular weight distribution width of the main component was greater than that of the domestic sample?8.48>4.92?;?3?The fundamental reason for the difference in the performance of domestic copolymer products is that 3%-4%of the ultra high molecular weight components in domestic products contribute a lot to the viscosity of the system,which makes the molecular weight of the main component in domestic copolymer is smaller under the same Mooney viscosity.Therefore,that mooney viscosity is used as a basis for product processing and application will lead large deviations.?2?Phosphorus trichloride and 1,1,3,3-tetramethylguanidine were used to synthesize tris?tetramethylguanidino?phosphine oxide[?tmg?3OP],and its composition and structure were verified by NMR,ultimate analysis and HPLC-MS,which composes the catalytic system together with triisobutylaluminum and solketal.Through the L₁₆?3⁴?orthogonal test,the following conclusions are drawn:The temperature has the greatest influence on the molecular weight and the molecular weight distribution of the product,and the time has the greatest influence on the conversion rate.It can be known from the orthogonal test expansion experiment that under the conditions of the catalytic system,although a suitable molecular weight polymer can be designed,the yield is not ideal.?3?It is hoped to design a catalyst of hexasubstituted derivatives of cyclotriphosp-hazene through different charge ratios of hexachlorocyclotriphosphazene and 1,1,3,3-te-tramethylguanidine.The results of NMR and MALDI-TOF showed that the obtained pr-oducts were all tetra-substituted derivatives of cyclotriphosphazene?tetrakis?tetramethyl-guanidino?cyclotriphosphazene[?tmg?₄HCCP].The molecular calculation of this substitut-eion reaction has explained the above phenomenon.When this tetra-substituted derivat-ive catalyzed the homopolymerization and copolymerization of epichlorohydrin,the de-sired polymer cannot be obtained.?4?According to the ratio of Bu₂SnO:Bu₃PO₄=1:1/1:2/1:3/1:4,four different kinds of polycondensation catalysts were obtained,and their compositions and structures were investigated by XPS,SEM,EDS-mapping.The results show that the composition and elemental valences of these four different polycondensation catalysts are the same,but their contents are not the same,and the distribution of surface elements is also very different,which leads to their different morphologies.We try to use them to catalyzed the homopolymerization and copolymerization of epichlorohydrin and it is failed to obtain the desired polymer due to the inability to explore suitable polymerization conditions.