Polyanhydride Networks from Thiol−Ene Polymerizations

Abstract

Thiol−ene photopolymerization was used in the synthesis of elastomeric polyanhydrides. Side reactions involving the addition of thiol to the anhydride were observed but take place at a much slower rate than photoinitiated thiol−ene polymerization. The thermomechanical properties, including the glass transition temperature (T g) as well as tensile and compressive modulus, of the cross-linked material were studied using dynamic mechanical analysis. T g values ranged from −15 to approximately −50 °C and were dependent on the degree of cross-linking. The Young’s and compressive modulus measurements confirm that these types of networks are a soft rubber-like material at room and body temperature and become softer as the cross-linking density is reduced. The hydrophobicity/hydrophilicity of these networks was analyzed by water contact angle measurements. The polyanhydrides were moderately hydrophobic, with water contact angle averages ranging from 82° to 92°. This hydrophobicity, coupled with the high reactivity of the anhydride groups, results in the material eroding via the surface erosion mechanism.

Quantitative and qualitative toxicological evaluation of thiol-ene “click” chemistry-based polyanhydrides and their degradation products

“…S1, Supporting Information) and FT‐IR (Fig. S2, Supporting Information) and were found to be consistent to our earlier reports …”

“…However, most of these PAH materials are typically synthesized under relatively harsh reaction conditions via polycondensation reactions, which may involve high heat, vacuum and potentially tedious monomer synthesis . More recently, we have developed a relatively mild and facile method for making photocurable PAHs, which may be linear or cross‐linked, using thiol‐ene “click” reactions (Scheme ). These materials are moldable and can be easily adapted for localized delivery of drugs, have recently been demonstrated to perform as reconfigurable shape memory polymer composites and can be formulated into nanoparticles .…”

Dual‐Responsive Polydimethylsiloxane Networks

“…In contrast, the degradation of hydrophobic polymers via ester hydrolysis follows a surface erosion mechanism as has been observed for polyanhydride networks . It should be noted that regarding PDMS‐ 1 , a part of the anhydride groups was not consumed during the thermal curing with the bifunctional crosslinker.…”

Polyanhydrides of Castor Oil–Sebacic Acid for Controlled Release Applications

“…Several biodegradable polymers exhibited hydrophobicity, such as cross-linked polyanhydrides obtained by thiolene-polymerization were found to be hydrophobic in nature with a contact angle in the range of 82−92°. 44 Poly(CPP-SA) system with higher content of CPP eroded very slowly because of the hydrophobic nature of the monomer CPP. 9 An increase in the castor oil content in castor oil− mannitol−citric acid−sebacic acid based polyesters showed an increase in contact angle values.…”