Biodegradable polymer, and preparation method
A biodegradable polymer technology, applied in the field of new biodegradable polymers and their preparation, can solve the problems of uncontrollable reaction, long reaction time, and long reaction time, and achieve the degree of crosslinking and glass transition temperature that are easy to control, The effect of good biocompatibility and simple synthesis process
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[0039] The preparation method of 5-hydroxylevulinic acid:
[0040] In a three-necked flask with stirring, dropping funnel and condenser, add 58 g of levulinic acid and 500 mL of methanol, place it in a water bath at 30°C, and add 80 g of liquid bromine dropwise with stirring. After the dropwise addition, the reaction was continued at 30-40°C for 8 hours, and then the reaction was continued for 1 hour under reflux. Methanol was distilled off under reduced pressure, 500 mL of ether and 100 mL of water were added, and the layers were separated. The ether layer was washed with excess saturated sodium bicarbonate solution, and dried over anhydrous sodium sulfate and 4A molecular sieves. Diethyl ether was distilled off to obtain the brominated mixture. The bromination mixture was added to a mixed solvent of V (ether): V (cyclohexane) = 1:1, and recrystallized at a low temperature (-20°C to -40°C) to obtain 5-bromoacetylpropane in the form of white needles Methyl ester crystals. M...
Embodiment 1
[0042] Add 5 grams of 5-hydroxylevulinic acid and 4.51 grams of 1,4-butanediol (1:1 molar ratio) into a 50ml flask, stir and mix evenly, and carry out dehydration and esterification reaction at 130°C for 3 hours , to obtain a viscous prepolymer.
[0043] Add a stannous chloride / p-toluenesulfonic acid composite catalyst in an equimolar ratio of 0.7wt% of the total monomer mass to the prepolymer, and after mixing evenly, add the reaction mixture to the polytetrafluoroethylene preheated to 130°C In the vinyl mold, the reaction was continued at 150°C for 37 minutes to obtain a biodegradable polymer prepared from 5-hydroxylevulinic acid and 1,4-butanediol with a gel content of 97.8% and a glass transition temperature of 22 ℃. Its infrared spectrum is shown in Figure 1. at 1405cm -1 The deformation vibration absorption peaks of the methylene group appear nearby, and the absorption peaks of the hydroxyl and carboxyl groups of the polymer are at 3440cm -1 nearby, 1172cm -1 It is ...
Embodiment 2-5
[0045] Other conditions are the same as in Example 1, but the molar ratios of 5-hydroxylevulinic acid (5-HLA) and 1,4-butanediol (BDO) are respectively 1: 0.2, 1: 0.4, 1: 0.67, 1: 1.5, 1:2.3, 1:4, 1:6, the gel contents of the obtained biodegradable polymers were 97.2%, 96.3%, 95.8%, 97.6%, 91.3%, 91.1%, 89.6%, and the glass The melting temperatures are 60.1°C, 46.3°C, 30.4°C, 14.8°C, -9.2°C, -15.4°C, -31.4°C, respectively. 5-Hydroxylevulinic acid and 1, the DSC curve of the biodegradable polymer obtained under the condition of 1:4 is that the mol ratio of 4-butanediol is shown in Fig. 2, and the polymer obtained under different monomer proportioning conditions The relationship between glass transition temperature and monomer ratio is shown in Figure 3. Tg data from Example 1 is also included in FIG. 3 .
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