Preparation Of Two Kinds Of Polythiophene Polythiols And Their Application In Transparent Polyurethane

Polyurethane optical materials have developed rapidly in recent years due to their high wearing resistance,low density,and ease of processing.They have been used in many fields instead of inorganic optical materials.Among them,optical plastics are one of the most important parts of optical materials,and their development is more and more important.They are widely used in organic optical fibers,optical substrates,contact lenses,lenses and so on.In this kind of optical device,the increase of the refractive index can reduce its mass,further reduce the curvature of the device,and produce a lighter and thinner material,and the improvement of the thermal stability can increase the safety of its use and expand its scope of use.Based on the improvement of the previous synthesis method,two kinds of thiopolythiols were obtained using organic solvent-free method:2,3-bis(2-mercaptoethylthio)-1-propanethiol(M1)and 3-(2-mercaptoethylthio)-1,2-propanedithiol(M2).The refractive index of its monomers reached 1.636 and 1.634,respectively.Through the preparation of polythiocarbothiols by mercaptoethanol and thiourea,the method used is simpler than other methods,the used raw materials are easy to prepare,the price is low,the byproducts are inorganic salts and water,and no other harmful substances are produced in the reaction process,which was in line with the concept of green chemistry.The effect of chain extenders on the light transmission of IPDI-based polyurethanes was investigated before adding Ml and M2 to the polyurethane.In the commonly used chain extenders 1,4-butanediol,1,3-butanediol,ethylene glycol,1,2-propylene glycol,1,3-propanediol,and ethylene glycol.We found that adding 1,4-butanediol as a chain extender gives a polyurethane with high light transmittance,and with the change of time,and it has the property that the yellow is relatively stable.Based on the above research basis,1,4-butanediol was selected as the chain extender.The above two kinds of thiopolythiols were added as additives to the polyurethane.The transmittance and refractive index of the polyurethane with different content of additives were examined.So as the effect of thermal stability.After adding mercaptan,the transmittance of the obtained polyurethane is greatly increased,the measured value reaches a maximum of 90.22%,and the thermal stability is also improved.And we found that when the amount of Ml added was 4.76%,the refractive index reached 1.660.When the amount of M2 added was 3.80%,the refractive index reached 1.664.