Substantially crosslinked polycarbonate articles
View Patent ↗Polycarbonate articles having improved properties due to their substantially cross-linked nature are disclosed. The substantially cross-linked articles are formed by forming a product from a polymeric composition comprising a cross-linkable polycarbonate resin containing a photoactive group derived from a benzophenone, and exposing the formed product to an effective dosage of ultraviolet radiation to cause substantial cross-linking throughout the article. Such cross-linking can also be used to obtain films having good scratch resistance properties.
1. A substantially cross-linked article, wherein the article is formed by:
forming a product from a polymeric composition comprising:
a cross-linkable polycarbonate resin containing a photoactive group derived from a benzophenone; and
exposing the formed product to an effective dosage of ultraviolet radiation to cause substantial cross-linking of the polycarbonate resin throughout the formed product, producing the substantially cross-linked article,
wherein the substantially cross-linked article has an insoluble mass percentage of at least 90%.
2. The article of claim 1 , wherein the article is a film, a fiber, a foam, a powder, or a molded article having at least one wall with a thickness of 0.6 mm or less.
3. The article of claim 1 , wherein the benzophenone from which the photoactive group is derived is a monohydroxybenzophenone or a dihydroxybenzophenone.
4. The article of claim 3 , wherein the cross-linkable polycarbonate resin is formed from a reaction of:
the monohydroxybenzophenone;
a diol chain extender; and
a first linker moiety comprising a plurality of linking groups, wherein each linking group can react with the hydroxyl groups of the monohydroxybenzophenone and diol chain extender.
5. The article of claim 3 , wherein the cross-linkable polycarbonate resin contains from about 0.5 mole % to about 5 mole % of endcap groups derived from the monohydroxybenzophenone.
6. The article of claim 1 , wherein the article has a water contact angle of 80° or less.
7. The article of claim 1 , wherein the cross-linkable polycarbonate resin has a polydispersity index of 2.0 to 3.0.
8. The article of claim 1 , wherein the article is a film, a fiber, or a foam.