Plastic materials for optical products are strongly required to exhibit high refractive index and low dispersion (with less chromatic aberration)

and the most convenient and effective way is to introduce sulfur element into polymer structures.Therefor

2

2' mercaptoethyl sulfide (MES) dimethacrylate (MESDMA) and p phenylthioethyl thiolmethacrylate (MEPSMA) were synthesized by normal phase transfer catalysis (PTC) and special PTC reaction (dropping caustic solution)

respectively.The double-bond containing monomers(MESDMA and MEPSMA) and their precursor thiols (MES and p-phenylthioethanethiol(MEPS) were characterized and corroborated by 1H-NMR and FTIR spectra.According to the analysis of 1H-NMR

the foreign substance in MES was caused by thiodiglycol (TDG)

and it can not be eliminated by distillation of MES or TDG.Due to the results of monomer synthesis and polymerization

the little amount of foreign substance in MES has no disadvantageous affect

through quality control

the MES can be used directly.It was proved by 1H-NMR and FTIR spectra that the addition reaction between the mercapto of MEPS and the double bond in normal PTC condition leads to the failure of double-bond containing monomer (MEPSMA) synthesis.In the condition of special PTC reaction

the thiolate(RS-anion)of MEPS is just appeared following with the dropping of caustic solution

its amount in the organic layer maintains lower and it is more easily to react with MC

which is large amount and freely to move

not with MEPSMA

which is big volume and difficult to move

so MEPSMA can be successfully synthesized by this way.The special PTC reaction

i.e.dropping caustic solution not MC

is the best way to prepare double-bond containing monomers from thiols and MC in characterizations of light color

high purity and high yield

especially for those double-bond containing monomers with higher molecular weight and difficult to refine.MESDMA/MEPSMA transparent copolymer resins with refractive index higher than 1.625 were obtained bu casting the monomers and initiator into glass molds

polymerized in an oven according to a definite curing program.Some basic properties of the resins

e.g.refractive index

Abbe number

density and impact strength etc.are measured finally.