Synthesis And Properties Of Sulfur-containing Polyether

In this thesis,a series of Sulfur-containing polymers were designed and synthesized by the nucleophilic substitution reaction of halogen elements attached to alkanes with mercapto groups on alkanes,and some important factors that may affect the reaction results were explored.The properties of these products were explored.The main results obtained are as follows:（1）Synthesis and characterization of sulfur-containing polyethers in main chainThe polythioether product is obtained by a nucleophilic substitution reaction of a dibromoalkane with a dithiol alkane.First,1,2-ethanedithiol was polymerized with1,2-dibromoethane under the action of three catalysts,Et₃N,NaH and K₂CO₃,to obtain the effect of different catalysts on the reaction.Then,using NaH as an catalyst,1,2-ethanedithiol and 1,6-hexanedithiol were respectively reacted with dibromoane having different carbon chain lengths to explore the relationship between the structure and properties of the products with different intervals of thioether bond.The results show that when the dithiol alkane used is 1,2-ethanedithiol,as the number of carbon chains of the dibromoalkane used increases,the interval between sulfur and sulfur becomes larger,and the decomposition temperature of the product gradually increases.The crystallization temperature also tends to increase gradually,but after the reaction of 1,2-dibromoethane with 1,2-ethanedithiol,the product repeat unit contains S-C-S bonds,making the product very stable,so its crystallization Temperature will show higher crystallization temperature than regularity.When the dithiol alkane used is1,6-hexanedithiol,the product exhibits the same tendency as the product of the1,2-ethanedithiol series.Due to the product obtained from the reaction of 1,6-hexanedithiol and 1,2-dibromoethane has a strong S-C-S bond,so it still has an abnormal law.（2）Synthesis and characterization of sulfur-containing polyethers in side chainFirst,a combination of Tetrabutylphosphoniunm Bromide and Triisobutylaluminum was used as a reaction initiator,and a toluene dryed from Calcium Chloride was used as a solvent to complete ring-opening polymerization of an epichlorohydrin and epibromohydrin monomer under a nitrogen atmosphere.On this basis,the reaction of polyepichlorohydrin and polyepibromohydrin with dodecyl mercaptan and benzyl mercaptan was studied,and the effects of three catalysts Et₃N,NaH and K₂CO₃ on the subsequent modification of polyepichlorohydrin and polyepibromohydrin were investigated.The K₂CO₃ which used as catalyst was chosen to continue exploring the effects of different temperatures on the reaction to obtain the relationship between the structure and properties.The results show that in the exploration of catalysts,the reaction of polyepichlorohydrin and polyepoxybromopropane with dodecyl mercaptan and benzyl mercaptan can be used to obtain side chain sulfur-containing polyether with NaH and K₂CO₃ as catalysts.Ether.But when Et₃N was used as the catalyst,the reaction could not proceed,and the obtained product was identical to the base polymer.Whether at room temperature or 80°C,sulfur-containing side chains can be successfully introduced into PERH to increase the decomposition temperature and thermal stability of polymer products.When the sulfur side chain is long chain alkyl,the products will appear at different melting and crystallization peaks of the raw materials,and the melting and crystallization temperatures will increase with the increase of reaction temperature.When the sulfur side chain is phenylmethyl,the glass transition temperature of the product increases compared with the raw material,and with the increase of reaction temperature,the glass transition temperature increases.