Polylactide with caprolactone

Narrow distribution in the backbone length as well as in the chemical composition or the branch frequency may be expected from a living-type copolymerization between a macromonomer and a comonomer provided the reactivity ratios are close to unity. This appears to have been accomplished to some extent with anionic copolymerizations with MMA of methacrylate-ended PMMA, 29, and poly(dimethylsiloxane) macromonomers, 30, which were prepared by living GTP and anionic polymerization, respectively [50,51]. Recent application [8] of nitroxide (TEMPO)-mediated living free radical process to copolymerizations of styrene with some macromonomers such as PE-acrylate, la, PEO-methacr-ylate, 27b, polylactide-methacrylate, 28, and poly(e-caprolactone)-methacrylate, 31, may be a promising approach to this end. 

All tris-P-diketiminato complexes 130-134 exhibited high catalytic activity for the ROP of e-caprolactone and L-lactide. a,co-dihydroxytelechelic polymers in high yield with high molar mass and moderate molar mass distributions (Mw/M = 1.38-1.89) were produced from the ROP of e-caprolactone (Scheme 8) catalyzed by 130-134.130-134 are highly active catalysts for the ROP of L-lactide to produce polylactide (Scheme 14). The electronic factor of the P-diketiminate ligand largely affects the catalytic activity of the complexes. 131 containing an... 

Polycaprolactone (PCL) is a biodegradable semicrystalline polyester that is synthesized from cap-rolactone using staimous octoate in a similar maimer to polylactide or polyglycolide. PCL has a very low modulus of around 50 ksi since it has a low Tg of —60 C. PCL degrades very slowly, and therefore, it is usually not used as a homopolymer. Caprolactone, however, is copolymerized with glycolide to make a flexible suture material (trade name Monocryl). ... 

Multiwalled CNTs were also used to improve the mechanical properties of polylactide-caprolactone copolymer. The composite with only 2 wt% of MWCNTs showed 100% improvement in the elastic modulus and a 160% enhancement in tensile strength [64]. Others showed significant reinforcement in bofli compressive modulus (74%) and flexural modulus (69%) with only 0.05 wt% of single-walled CNTs [65]. These results demonstrate favorable cytocompatibility for potential use as scafrbld for bone tissue engineering applications. 

Lahiri D, Rouzaud F, Namin S, Keshri AK, Valdes JJ, Kos L, et al. Carbon nanotube reinforced polylactide-caprolactone copolymer mechanical strengthening and interaction with human osteoblasts in vitro. ACS Appl Mater Interfaces 2009 1(11) 2470—6. 

PUs have been developed and thoroughly investigated for various industrial and biomedical applications [1-3], By alternately connecting soft and hard segments together through urethane bonds, assorted PUs, such as poly(E-caprolactone) (PCL) containing block PUs [21], polylactide (PLA)-based PUs [22], and poly(E-caprolactone-co-lactide acid) (PCLA)-based PUs [23], were prepared with useful shape-memory properties. 

The mechanisms of biodegradation of polylactide, polycaprolactone and caprolactone copolymers with dilactide copolymer, valerolactone copolymer, and decalactone copolymer in the rabbit were shown to be qualitatively similar. The rate of the first stage of the degradation process, non enzymatic random hydrolytic chain scission, was found to vary by an order of magnitude and was dependent on morphological as well as chemical effects. 17 refs. 

Aliphatic polyesters are biocompatible and biodegradable polymers that are widely used in biomedical applications. Within these, polylactides and poly(s-caprolactone) are two of the most studied ones (Fig. 2). These polyesters can be synthesized via ring-opening polymerization of the corresponding cyclic esters (s-caprolactone and lactide) and via polycondensation of lactic acid. In material science, both pure aliphatic polyesters and natural polysaccharides have limitations in some specific applications. These limitations can be overcome by the introduction of hydrophilic groups (carbohydrate compounds) into the aliphatic polyesters and modifications of natural polysaccharides with hydrophobic polyesters. 

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