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Polylactic acid has good biocompatibility and bio-security, has become a hot research at home and abroad. But its poor hydrophilicity, the lack of the biologically active substances and other defects limit its application in the field of biomedical materials. To overcome these shortcomings, the study the modified material PITLA of a polylactic acid-based. In the D, L-lactide (D, L-LA), methacrylic anhydride (MAH) and itaconic anhydride (ITA) as raw materials, through a series of chemical reactions to prepare a hydrophilic strong, rich in active group PITLA, and Fourier transform infrared spectroscopy and nuclear magnetic resonance spectrometer to characterize the structure PITLA, multi-angle laser light scattering, differential scanning calorimeter and conventional methods of chemical analysis of its physical and chemical properties of the test, particularly its in vitro biodegradable and affinity / hydrophobic properties. Explored in order to further improve the properties of the polymer, the diamine modified products DPITLA, and its structure was characterized. The main contents and conclusions are as follows: 1, Sn (Oct) 2 as the initiator, to D, L-lactide material melting the open-loop system of PDLLA and PDLLA molecular weight is adjusted by the amount of Sn (Oct) 2 so that it is around 5000. Methacrylic anhydride and PDLLA reaction the PDLLA-MAH, to characterize its structure. ① The structure of the product was characterized by FTIR and 1 ~ H NMR spectra analysis showed that the MAH PDLLA successful polymerization to obtain PDLLA-MAH, the end groups containing double bonds. ② optimized, the optimal conditions to obtain a reaction conditions of the synthesis of PDLLA-MAH: polylactic acid and methacrylic anhydride molar feed ratio of 1:1.5, the reaction time was 1 h, the reaction temperature was 50 ° C, the entire reaction system Under a nitrogen blanket. 2, BPO as the initiator, in anhydrous toluene, to give the product PITLA. By orthogonal experimental synthesis conditions were optimized, and the structure of the PITLA IR, NMR characterization. ① of FTIR, 1 to H-NMR analysis showed that, of PDLLA-MAH and ITA successfully achieved a radical polymerization to form a copolymer PITLA. (2) with a rhodamine experimental determination PITLA ITA's content discovery With the the ITA amount of the increase, PITLA the ITA's content in multi-angle laser light scattering to measure the molecular weight, the decrease in molecular weight the ITA increased use of the resulting product. ③ adopted PITLA the molecular weight as the main evaluation indicators, taking into account the carboxyl content in PITLA know the optimal conditions of PITLA prepared by the statistical analysis of the results of the orthogonal experiment: reaction temperature 80 ° C, the reaction time of 8 h, ITA was 10%, BPO content is 5%, the entire reaction is carried out under nitrogen, the synthesized PITLA molecular weight Mw = 4.783 × 10 ~~ 4, wherein the content is 5.99% ITA. ④ DSC analysis shows PITLA the glass transition temperature and decomposition temperature are higher than the PDLLA, and appears in the 144.4 ° C melting endothermic peak. PITLA pro / hydrophobic properties and in vitro degradation properties were determined. Which investigated PITLA static water contact angle and water absorption, as pro / hydrophobic evaluation, and the degradation of performance using real-time degradation test to evaluate in vitro. The results showed that: ① ITA content increased, PITLA also will increase the hydrophilicity, considering the hydrophilicity and molecular weight of the material and other factors, to determine the ITA an amount of 10% synthetic PITLA optimal performance. ② PITLA degradation rate is faster than PDLLA the rapid degradation occur five to nine weeks, more than two weeks ahead of the rapid degradation of PDLLA expected to have certain advantages in the short-term treatment. 4, to solve the problem of PITLA degradants acidic, the reaction was carried out with hexamethylenediamine PITLA give the product DPITLA, the basic amino group is introduced in the molecule, FTIR, and 1 to HNMR of the analysis showed that the successful synthesis of DPITLA. Ninhydrin color experiment quantitatively detecting content of DPITLA the HMD and found consistent with the theoretical value, when PITLA in ITA contents were 4.59% and 5.99%, the synthetic DPITLA HMD graft rate corresponding to 4.23% and 5.79 %.
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