Preparation and property study of novel composite epoxy-type optical resins

Bis (beta -epoxypropylthioethyl) sulfide (DGEMES) was synthesized from 2, 2 '-dimercaptoethyl sulfide (MES), and epichlorohydrin and it's structure was characterized by FTIR and MS. Ethylenediamine was used to cure the mixture of DGEMES and DGEBA, a novel optical resins with a high refractive index a nd low dispersion were obtained. The studies indicated that DGEMES is a goo d monomer for copolymerization. With increasing it's content, the refractiv e index and Abbe number of the copolymer can be increased at the same time. The cured resins of DGEMES/DGEBA/ethylenediamine have a higher refractive index 1. 59-1. '62 and a large Abbe's number 35-39; especially, when the co ntent of DGEMES is 40 % in weight, the cured copolymer has a high refractiv e index (n(d) > 1. 60) and a higher impact strength (22. 5 kJ/m(2)), and, o ther well-balanced properties, which is also important for optical material s. In addition, B-650 was used as a curing agent, the cured resins of DGEME S/DGEBA/B-650 were prepared, which possess middle degree of refractive inde x. The n(d) and nu (d) values of the resins, ranging between 1. 54-1. 56 an d 38-40, were measured by refractometer, the optical and mechanical propert ies of them were discussed in this paper.