Preparation and degradability of poly(lactic acid)–poly(ethylene glycol)–poly(lactic acid)/SiO₂ hybrid material

Abstract

Poly(lactic acid)–poly(ethylene glycol)–poly(lactic acid) (PLA‐PEG‐PLA)/SiO2 hybrid material is prepared by sol–gel method using tetraethoxysilane (TEOS) and PLA‐PEG‐PLA as raw material. From Fourier transform infrared spectroscopy (FTIR) and X‐ray photoelectron spectroscopy (XPS) spectra, the hydroxyl groups of the silica sol derived from partially hydrolysis of TEOS and the unhydrolyzed ethoxy groups of TEOS can react with PLA‐PEG‐PLA. Differential scanning calorimetry (DSC) curves imply that the glass transition temperature (Tg) of PLA‐PEG‐PLA/SiO2 hybrid material is higher than that of PLA‐PEG‐PLA and increases with the increase of silica content. X‐ray diffraction (XRD) analysis results show that PLA‐PEG‐PLA and PLA‐PEG‐PLA/SiO2 hybrid material are both amorphous. Field scanning electron microscope (FSEM) photographs show that when PLA‐PEG‐PLA/SiO2 hybrid material has been degraded for 12 weeks in normal saline at 37°C, a three‐dimensional porous scaffold is obtained, which is available for cell growth and metabolism. Moreover, the hydroxyl (OH) groups on SiO2 of PLA‐PEG‐PLA/SiO2 hybrid material could buffer the acidity resulted from the degradation of PLA, which is beneficial to proliferation of cell in tissue repairing. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008

Synthesis, phase behavior, and simulated in vitro degradation of novel HTPB-b-PEG polyurethane copolymers

“…In Figure 1(b), a strong absorption band at about 1100 cm -1 is attributed to ether groups (C-O-C) stretching vibration of PEG. 29,31 The disappearance of the -NCO absorption at 2267-2373 cm -1 suggests that the coupling reaction occurs between -NCOterminated HTPB pre-polymers and PEG. New absorption peaks at around 1726 and 1770 cm -1 correspond to carbonyl stretching bands (amide band I) in urethane linkages, at about 1569 ascribed to the N-H bending mode (amide band II), 32 at 1453 cm -1 belonging to the CH 2 in-plane bending mode, at 1415 cm -1 assigned to the overlapping of the C-N stretching, the residual terminal -OH deformation vibration, and the -CH 2 bending and rocking vibration, 32 and at 1250 cm -1 reflecting the C-O stretching characteristic in the urethane linkage.…”

“…In addition, the absorption peaks at 2918, 2846 and 1442 cm -1 belong to the asymmetric, symmetric stretching vibration and bending vibration of -CH 2 , respectively. [28][29][30] The vibration band at 2267-2373 cm -1 is attributable to the characteristic absorption of isocyanate groups. 28 These findings imply that -NCOterminated HTPB pre-polymers are formed.…”

Synthesis and micellization of new biodegradable phosphorylcholine‐capped polyurethane

“…This is due to the absorption of ester carbonyl groups of PLA and LDI, free and hydrogen‐bonded carbonyl of urethane, respectively 36, 37. The absorption peaks at 2942 and 2872 cm −1 are corresponded to the stretching vibration of methyl and methylene 38. The peaks at 1253 and 1045 cm −1 , respectively, belong to COC symmetric and asymmetric stretching vibration of ester;28 1098, 1137, and 1192 cm −1 are attributed to ether group (COC) stretching vibration of PEG 38.…”

“…The absorption peaks at 2942 and 2872 cm −1 are corresponded to the stretching vibration of methyl and methylene 38. The peaks at 1253 and 1045 cm −1 , respectively, belong to COC symmetric and asymmetric stretching vibration of ester;28 1098, 1137, and 1192 cm −1 are attributed to ether group (COC) stretching vibration of PEG 38. Moreover, the peaks of PO groups at 1218 cm −1 can be clearly observed for PCPU series when the 1170–1235 cm −1 region is amplified in Figure 4(a).…”

Co‐electrospun composite nanofibers of blends of poly[(amino acid ester)phosphazene] and gelatin

“…Although biomaterials based on the polymers of lactic acid and glycolic acid and their copolymers are studied or used extensively in various biomedical applications, mainly as drug carriers and scaffolds in tissue engineering, concerns have been raised regarding their acidic degradation products, which could cause biocompatibility problems 1–3. This has prompted researchers to focus on developing novel biomaterials with improved biological properties.…”