Crosslinked poly(ester anhydride)s based on poly(ε‐caprolactone) and polylactide oligomers

Abstract

Resorbable poly(ester anhydride) networks based on ε‐caprolactone, L‐lactide, and D,L‐lactide oligomers were synthesized. The ring‐opening polymerization of the monomers yielded hydroxyl telechelic oligomers, which were end‐functionalized with succinic anhydride and reacted with methacrylic anhydride to yield dimethacrylated oligomers containing anhydride bonds. The degree of substitution, determined by 13C NMR, was over 85% for acid functionalization and over 90% for methacrylation. The crosslinking of the oligomers was carried out thermally with dibenzoyl peroxide at 120 °C, leading to polymer networks with glass‐transition temperatures about 10 °C higher than those of the constituent oligomers. In vitro degradation tests, in a phosphate buffer solution (pH 7.0) at 37 °C, revealed a rapid degradation of the networks. Crosslinked polymers based on lactides exhibited high water absorption and complete mass loss in 4 days. In ε‐caprolactone‐based networks, the length of the constituent oligomer determined the degradation: PCL5‐AH, formed from longer poly(ε‐caprolactone) (PCL) blocks, lost only 40% of its mass in 2 weeks, whereas PCL10‐AH, composed of shorter PCL blocks, completely degraded in 2 days. The degradation of PCL10‐AH showed characteristics of surface erosion, as the dimensions of the specimens decreased steadily and, according to Fourier transform infrared, labile anhydride bonds were still present after 90% mass loss. © 2003 The Authors. Journal of Polymer Science Part A: Polymer Chemistry Published by Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 3788–3797, 2003

Synthesis of Poly(ester‐anhydrides) Based on Different Polyester Precursors

“…As is well known, in the presence of co-initiators containing hydroxyl groups, ring-opening polymerisation yields hydroxyl-terminated polymers with molecular weight depending on the ratio of monomer to co-initiator. Like the 1,4-butanediol initiated polymers we discussed earlier, [21] the ricinoleic acid initiated polymers followed the trend of lower molecular weight with higher co-initiator concentration, which indicates that the hydroxyl group of ricinoleic acid is active in initiation. The presence in ricinoleic acid of about 15% non-hydroxy impurities incapable of coinitiating the polymerisation explains why ROA initiated prepolymers have molecular weights slightly higher than 1,4-butanediol initiated polymers.…”

“…[21] Ricinoleic acid initiated oligomers were first polymerised in test tubes; 5 g of monomer was polymerised with ricinoleic acid (3, 5, 10, 15 and 20 mol-%) and Sn(Oct) 2 (0.02 mol-%) at 140 8C for 20 h. The most promising compositions were then polymerised on larger scale by weighing the monomers (100-150 g) into a batch reactor with 5, 10, or 15 mol-% of ricinoleic acid and 0.02 mol-% of Sn(Oct) 2 . For example, PCL-ROA15-OH was synthesised by polymerising 100 g of e-CL (0.876 mol) with 46.14 g of ROA (0.155 mol) and 0.075 g of Sn(Oct) 2 (0.18 mmol).…”

Structure and Properties of Poly(ε‐caprolactone) Networks with Modulated Water Uptake

“…[10] PCL networks were prepared via the ring opening polymerization of e-caprolactone monomer, and were then end functionalized with succinic anhydride and reacted with methacrylic anhydride to yield dimethacrylate oligomers. [11] In this work, a PCL macromonomer was synthesized through the reaction of PCL diol with methacrylic anhydride to get methacrylate end capped PCL able to self crosslink. The synthesis of the macromonomer was assessed by FT-IR and 1 H NMR.…”

Synthesis and Hydrolysis Behaviour of Poly(ester anhydrides) from Polylactone Precursors Containing Alkenyl Moieties

“…[20,28] In brief, the monomers (150-250 g) were weighed into a batch reactor with 5 or 10 mol-% of 1,4-butanediol and 0.02 mol-% of Sn(Oct) 2 . For example, PCL-BD5-OH was synthesised by polymerising 200 g of e-CL (1.752 mol) with 8.31 g of 1,4-BD (0.092 mol) and 0.149 g of Sn(Oct) 2 (0.35 mmol).…”

“…[28,29] Functionalisation of the hydroxyl groups to carboxylic acids was carried out without a catalyst. [20] According to 1 H NMR studies, the hydroxyl groups of PCL reacted completely with the alkenylsuccinic anhydrides within 3 h at 140 8C, whereas those of PLA reacted more weakly.…”