Photosensitive polymers. II: Synthesis and properties of arylazido polycondensates

Abstract

SynopsisPhotosensitive polymers containing arylazido groups were obtained by interfacial polycondensation of azido-substituted acid chlorides with diols and diamines. The light sensitivity was studied with the polyester synthesized by condensation of m-azidoisophtaloylchloride and 4,4 '-dihydroxydiphenylpropane. The qualitative determination of the sensitivity on a relative scale was based on a standardized technique of irradiation of coated layers. The study of the influence of the degree of substitution on the photosensitivity showed a threshold substitution value indicating some loss of reticulating points at lower degrees of substitution and a levelling of the sensitivity about 50% substitution. The addition of sensitizers of the carbonyl type was able to increase the sensitivity of the arylazido polycondensates. An optical sensitization by triplet-triplet energy transfer was put forward a s a possible explanation. Measurements of the photolysis rate and of the crosslinking threshold decomposition value allowed us to check the validity of the hypothesis of a decreased crosslinking capacity due to side reaction of the imido intermediates.

UV-Curable Biobased Polyacrylates Based on a Multifunctional Monomer Derived from Furfural

“…Cross-linking via photodimerization of functional monomers proceeds readily with or without the addition of a photosensitizer and thus does not require any additional, often toxic additives such as initiators or cross-linkers to achieve network formation. Several functional groups that can undergo photocycloadditions have been incorporated in polymers, some of which include coumarin, − cinnamic acid, , conjugated furanes, or anthracene − groups.…”

Tetramethyl biphenyl-3,5,3′,5′-tetracarboxylate benzene sesquisolvate

“…The title compound was synthesized according to literature methods (Burton & Kenner, 1923;Grahl, 1895;Delzenne & Laridon, 1969) with the following modi®cations. Dimethyl 5-iodoisophthalate (2 g, 0.0062 mol) was ground together with copper powder (2 g, 0.031 mol) in a mortar and placed in an autoclave at 503 K for 20 h. A hard pellet was formed which dissolved in dichloromethane.…”

Synthesis and spectroscopic characterisation of fluorescent indicators for Na+ and K+

“…Convergent route. Design of the fluorophore.-The fluorophore building block dimethyl 5-(5-tributylstannyl-2-thienyl)isophthalate 7 (Scheme 2) was synthesised starting from 5-aminoisophthalic acid 2, which was converted into 5-iodoisophthalic acid 3 by diazotization, 18 followed by a Sandmeyertype reaction. 19 The corresponding ester 4 20 was then coupled at room temperature to 2-(tributylstannyl)thiophene in a crosscoupling reaction under air in DMF, catalysed by 2 mol% of the ligandless catalyst bis(acetonitrile)dichloropalladium() 21 to give compound 5 in high yields.…”

“…The diazonium salt of 2 was prepared according to the procedure described by Delzenne and Laridon. 18 For the Sandmeyer-type reaction, the conditions reported by Grahl 19 were followed, yielding 5-iodoisophthalic acid 3 (80%); mp 285-287 ЊC (lit., 19 Dimethyl 5-iodoisophthalate 4. 5-Iodoisophthalic acid 3 (24 mmol) was esterified by reflux in thionyl chloride followed by addition of methanol.…”