As a consequence
of their excellent barrier properties vinyl chloride/vinylidene chloride copolymers
have long been prominent in the flexible packaging market. While these polymers
possess a number of superior characteristics, they tend to undergo thermally-
induced degradative dehydrochlorination at process temperatures. This degradation
must be controlled to permit processing of the polymers. Three series of N-substituted
maleimides (N-alkyl-, N-aralkyl, and N-aryl) have been synthesized, characterized
spectroscopically, and evaluated as potential stabilizers for a standard vinyl
chloride/vinylidene chloride (85 mass%) copolymer. As surface blends with
the polymer, these compounds are ineffective as stabilizers. However, significant
stabilization may be achieved by pretreatment of the polymer with N-substituted
maleimides. The most effective stabilization of the polymer is afforded by
N-aralkyl- or N-arylmaleimides, most notably, N-benzylmaleimide and N-p-methoxyphenylmaleimide.
Authors:Rajesh Munirathinam, Andrea Leoncini, Jurriaan Huskens, Herbert Wormeester, and Willem Verboom
Cinchona alkaloid and proline derivatives as enantioselective catalysts were covalently attached onto the inner walls of a microreactor using glycidyl methacrylate polymer brushes. The successful formation of the organocatalyst-functionalized brush layers on flat silicon oxide surfaces was confirmed by several techniques such as Fourier transform infrared (FT-IR), ellipsometry, and X-ray photoelectron spectroscopy (XPS). The applicability of the cinchona alkaloid (cinchonidine or quinidine)- and proline-containing polymer brushes in a microreactor was demonstrated for the Diels–Alder reaction between anthrone and N-substituted maleimides, and the aldol reaction between 4-nitrobenzaldehyde and cyclohexanone, respectively, which showed moderate conversions (up to 55% and 23%, respectively) and moderate to good enantioselectivities (up to 55% and 93%, respectively). The pristine catalytic activity of the microreactor was intact even after 1 month.
of maleic anhydride (MAH) onto ABS backbone has been studied in many literatures and it is proved MAH was successfully introduced onto the rubber phase [ 8 – 12 ].
In recent years, N -substitutedmaleimides have been selected as the most