Preparation of monomer of degradable biomaterial poly(L-lactide)

Abstract

L-lactide was prepared from L-lactic acid with stannous octoate as the catalyst. The effects of reaction temperature and pressure on the ingredient of crude lactide were investigated. The results show that the mass fraction of meso-lactide increases with the increasing reaction temperature. Crude lactide containing 85.4% L-lactide is obtained when the reaction temperature is 200 °C. High purity of L-lactide with a yield of 40.6% is obtained by synthetic purifying method. The properties of L-lactide are characterized by optical purity, infrared spectrum and gas chromatogram/mass spectrum. The L-lactide samples purified by recrystallization and synthetic purifying methods are polymerized with the catalyst of stannous octoate, and the corresponding viscosity average relative molecular masses of poly(L-lactide) are 2.85×10⁵ and 5.05×10⁵, respectively. This indicates that the optical purity of L-lactide has great influence on the relative molecular mass of poly(L-lactide).

Keywords

lactide / polylactide / purification / polymerization

References

[1] LeenslagJ W, NijenhuisA J, PenningsA J, et al.. Porous polyurethane — poly (L-lactide) composite for reconstruction of meniscus lesions [A]. Fifth International Conference: Polymers in Medicine and Surgery [C], 1986, London, Plastics & Rubber Inst: 101-102

[2] IlliO E, GitzelmannC A, GasserB. Five years of experience with biodegradable implants in paediatric surgery [J]. Journal of Materials Science: Materials in Medicine, 1994, 5(6): 417-423

[3] TaizoF, YoshitakaM, TsunoruY. Histomorphometric study on high-strength hydroxyapatite/poly (L-lactide) composite rods for internal fixation of bone fractures [J]. Journal of Biomedical Materials Research, 2000, 50(30): 410-419

[4] FreedL E, MarquisJ C, NohriaA. Neocartilage formation in vitro and in vivo using cells cultured on synthetic biodegradable polymers [J]. Journal of Biomedical Materials Research, 1993, 27(1): 11-23

[5] BergsmaJ E, RozemaF R, BosR R M. Poly (L-lactic) acid implants in repair of defects of the orbital floor. A five-year animal study [J]. Cells and Materials, 1994, 4(1): 31-36

[6] ChenLian-xi, JiangXin. The ring-opening polymerization of D, L-lactide initiated with stannous octoate[J]. Journal of Wuhan University of Technology (Materials Science Edition), 2001, 16(4): 10-13

[7] LouLing, YinJing-Bo, LiangQi-Zhi. Preparation and properties of L-lactide and poly (L-lactide) [J]. Polymeric Materials Science and Engineering, 2003, 19(2): 72-72(in Chinese)

[8] GeHai-xiong, SuiZheng-rong, PanXiao-chun, et al.. Studied on the synthesis and thermal stability of poly (L-lactide) [J]. Acta Scientiarum Naturalium Universitatis Pekinensis, 2001, 37(2): 251-254(in Chinese)

[9] JiangXin, ChenLian-xi, HeJian-hua, et al.. Study on synthesis and purification of lactide [J]. Journal of Wuhan University of Technology, 2002, 24(4): 42-44(in Chinese)

[10] SchindlerA, HarperD. Polylactide—II. viscosity-molecular weight relationships and unperturbed chain dimensions[J]. Journal of Polymer Science (Polymer Chemistry Edition), 1979, 17(8): 2593-2599

[11] KricheldorfH R. Polylactones — 6. Influence of various metal salts on the optical purity of poly(L-lactide)[J]. Polymer Bulletin, 1985, 14(6): 497-502

[12] NicholsonJ W, TawfikH, CzarneckaB, et al.. A study of cements formed by aqueous lactic acid and aluminosilicate glass [J]. Journal of Materials Science: Materials in Medicine, 2002, 13(4): 417-419

[13] Yamaguchi Y, Arimura T. Purifying method of lactide[P]. Japan: 657447, 1995-11-29.

[14] Suong-HyuH, JamshidiK, YoshitoI. Synthesis of polylactides with different molecular weights [J]. Biomaterials, 1997, 18(22): 1503-1508

[15] QuanDa-ping, YuanRun-zhang. Synthesis and thermal stability of poly (DL-lactide) [J]. Applied Chemistry, 2000, 17(3): 268-271(in Chinese)

[16] KricheldorfH R, Kreiser-saundersI, BoettcherC. Polyactones:31,Sn(II)octoate—initiated polymerization of L-lactide: a mechanistic study[J]. Polymer, 1995, 36(6): 1253-1259