Andres Sustic

Surface photografting of polymerizable 2-(2-hydroxyphenyl)2H-benzotriazoles as ultra-violet stabilizers☆

Abstract Films of low-density polyethylene (LDPE), high-density polyethylene (HDPE) and polypropylene (PP) have been surface photografted with different polymerizable 2-(2-hydroxyphenyl)2 H -benzotriazole monomers [2-(2-hydroxy-4-acryloxyphenyl)2 H -benzotriazole (BDHA), 2-(2-hydroxy-4-methacryloxyphenyl)2 H -benzotriazole (BDHM), 2-(2-hydroxy-5-vinylphenyl)2 H -benzotriazole (2H5V) and 2-(2-hydroxy-5-isopropenylphenyl)2 H -benzotriazole (2H5P)] in the presence of benzophenone as the photo-initiator using 254 nm ultra-violet irradiation. Photografted films of polyethylene (LDPE and HDPE) have much higher resistance towards photoageing (tested in a Weather-O-meter) than non-stabilized samples. Photografted films of polypropylene (PP) have a tendency to be photodegraded faster than non-grafted samples. This is interpreted as a result of destructive photo-oxidative degradation caused by traces of benzophenone that have not been completely removed from the grafted films by extraction.

FUNCTIONAL POLYMERS 65. SYNTHESIS AND BRIEF CHARACTERIZATION OF SURFACE ACTIVE 2(2-HYDROXYPHENYL)2H-BENZO-TRIAZOLE ULTRAVIOLET STABILIZERS

A number of 2(2-hydroxyphenyl)2H-benzotriazoles substituted in the 5-position with reactive hydroxyl and carboxyl groups have been synthesized. They include compounds with a tert butyl substitution in the 3-position or without substitution. The latter compounds were subjected to a reaction with N-hydroxy-methyl-(meth)acrylamide to form acrylic polymerizable 3(meth)acrylamidomethyl-2(2-hydroxyphenyl)2H-benzotriaz-oles. Hydroxyl reactive compounds were allowed to react with long chain acids, compounds with carboxyl groups with long chain hydrocarbon, fluorocarbon or silicon oligomer alcohols. The polymerizable 2(2-hydroxyphenyl)2H-benzotriazoles were then copolymerized with methyl methacrylate. Films made from such polymers showed by contact angle measurements, substantial migration of the fluorocarbon or silicon component to the surface of the film.

Functional Polymers. LIX. Synthesis and Polymerization of 2(2-Hydroxyphenyl)2H-benzotriazole-Based Glycidyl Methacrylate Derivatives

Abstract Three 2(2,4-dihydroxyphenyl)2H-benzotriazole derivatives were reacted with glycidyl methacrylate on the 4-hydroxyl group of the benzotriazole molecules to give the corresponding acrylic monomers. The new monomers were copolymerized with methyl methacrylate. In another approach, copolymers of methyl methacrylate and glycidyl methacrylate were allowed to react with the same three 2(2,4-dihydroxyphenyl)2H-benzotriazole derivatives and gave the corresponding 3-methacryloxy-2-hydroxypropyl derivatives. The monomers and polymers were characterized by the usual characterization techniques. The greatest emphasis was placed on the ultraviolet spectra in various solvents stressing the local proximity of the neighboring groups.

Functional polymers. LV. Photochemical behavior of 2(2-hydroxyphenyl)2H-benzotriazole derivatives: 3. Effects of the position of the substituents

SummaryPolymerizable 2(2-hydroxyphenyl)2H-benzotriazole ultraviolet absorbers have the normal hydrogen bonded λ maximum at 340 nm. When more than one ortho-hydroxy group capable of hygen bonding is present in the molecule the extinction coefficient increases dramatically; the fluorescence spectra are also affected. It is expected that these compounds are very effective ultraviolet stabilizers.

Functional polymers 60. Chemical structure/ultraviolet spectrum relationship of 2(2-hydroxyphenyl)2H-benzotriazoles: synthesis of novel 2(2-hydroxyphenyl)2H-benzotriazoles

Abstract The synthesis of several u.v. absorbers of the 2(2-hydroxyphenyl)2H-benzotriazole category is reported. The compounds are of three types: 2(2-hydroxyphenyl)2H-benzotriazoles with one or two substituents located in the benzotriazole moiety of the molecule; 2(2-hydroxyphenyl)2H-benzotriazoles with a substituent in the hydroxy-containing phenyl part of the molecule; and a naphthalene derivative. Syntheses of the 2(2-hydroxyphenyl)2H-benzotriazoles were carried out by the diazotization of a 2-nitroaniline derivative followed by reduction and cyclization, yielding the products in moderate yield. The characterization of the products was carried out by i.r., u.v. and 13 C n.m.r. spectroscopy, and included the determination of their molecular weights by elemental analysis and potassium ionization of desorbed species.

Functional Polymers. 61. Ultraviolet Spectral Behavior of Selected 2(2-Hydroxyphenyl)2H-Benzotriazoles

Abstract Ultraviolet spectra of a number of 2(2-hydroxyphenyl)2H-benzotriazoles were studied in nonpolar, polar, and hydrogen bonding solvents. The effect of substituents located in the 4-position of the benzotriazole ring was investigated, and the effect on the UV absorption characteristics of 2(2-hydroxyphenyl)2H-benzotriazoles was determined. Substituted resorcinol or phloroglucinol-based 2(2-hydroxyphenyl)2H-benzotriazole derivatives were investigated with special emphasis on UV absorption characteristics that were expected to be useful as polymerbound UV stabilizers in optical lens applications.

FUNCTIONAL POLYMERS 64. POTASSIUM IONIZATION OF DESORBED SPECIES (K+IDS) OF 2(2-HYDROXYPHENYL)2H-BENZOTRIAZOLES

Mass spectrometry using the potassium ionization of desorbed species (K+IDS) technique was found to be an unusually fruitful method to characterize 2(2-hydroxyphenyl)2H-benzotriazole derivatives. This class of compounds has the proper molecular weight range of 200 up to more than 1000 daltons (Da) and the proper volatility to show readily desirable concentrations in the mass spectrometer. This class of compounds is stable under the conditions of measurement which allows the determination of their purity. 2(2-Hydroxyphenyl)2H-benzotriazoles have recently been used most extensively for the ultraviolet stabilization of polymeric materials. In this work, over 100 2(2-hydroxyphenyl)2H-benzotriazoles have been characterized by K+IDS mass spectrometry.

Functional polymers. LIV. Photochemical behavior of 2(2-hydroxyphenyl)2H-benzotriazole derivatives

SummaryThe absorption spectra of 2(2-hydroxyphenyl)2H-benzotriazoles derivatives substituted with electron-donating and withdrawing groups in various positions on the phenyl ring allowed to estimate the relative stability of the hydrogen-bonded structures as evidenced by the ɛ 340 nm/ɛ300 nm ratio.Photodegradation studies of poly-cis-1,4-butadiene-1,3 with and without 2(2-hydroxyphenyl) benzotriazole absorbers with various substituents show that compounds with R=H are better photostabilizers than those with R≠H.