Modification of Low Refractive Index Polycarbonate for High Refractive Index Applications

Gunjan Suri,Geetha Seshadri,Rakesh Kumar Khandal,Gouri Shankar Jha

doi:10.1155/2009/836819

Gunjan Suri, Geetha Seshadri + Show 2 more

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https://doi.org/10.1155/2009/836819

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Abstract

Polycarbonates and polythiourethanes are the most popular materials in use today, for optical applications. Polycarbonates are of two types which fall in the category of low refractive index and medium refractive index. The present paper describes the conversion of low refractive index polycarbonates into high refractive index material by the use of a high refractive index monomer, polythiol, as an additive. Novel polycarbonates, where the properties of refractive index and Abbe number can be tailor made, have been obtained. Thermal studies and refractive index determination indicate the formation of a new polymer with improved properties and suitable for optical applications.

Highlights

Amongst the optical polymers used so far for optical applications, the most popular ones belong to polycarbonate chemistry
Only two types of polycarbonates are being used for spectacle lenses: (i) Diethylene glycol di(allyl carbonate) (DEGDAC) and (ii) Bisphenol A carbonate (BPAC)
The results indicate that the essential optical properties of DEGDAC can be tailor-made to a desired level by using different ratios of polymers as such and their combinations (PSH):DEGDAC

Summary

Introduction

Amongst the optical polymers used so far for optical applications, the most popular ones belong to polycarbonate chemistry. Polycarbonates currently used for optical applications are classified into two types based on the two different monomers produced by reacting carbonyl chloride (phosgene) with two different diols [1,2,3,4,5]. Depending upon the characteristics of the diol used, the polycarbonates of different properties can be obtained. For the last five decades, when for the first time, polycarbonates were developed for making spectacle lenses, there have been attempts to develop better materials than polycarbonates and to develop a process which can avoid the use of phosgene. Only two types of polycarbonates are being used for spectacle lenses: (i) Diethylene glycol di(allyl carbonate) (DEGDAC) (free radical polymerization) and (ii) Bisphenol A carbonate (BPAC) (condensation polymerization)

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