Synthesis And Characterzation Of Property Of Lactic Acid/aspartic Acid

Poly (lactic acid) (PLA) has fine biological compatibility and biological degradability, but PLA is a kind of hydrophobic material, degrades slowly, and lacks reactivity function groups on the molecular chain. These properties have limited it in applications of biological and medicine fields. Poly (amino acids) have good biological compatibility and degradability, and includes responsable active groups such as the hydroxyl, the carboxyl group, the amino group etc. Because there are many hydrogen bonds between intramolecular and intermolecular chains, they cannot dissolve in many organic solvents, and their processing performance is poor. Copolymerization of lactic acid(LA) and amino acid could obtain copolymers with good biological compatibility, adjustable degeneration speed, reactive active groups, and good processing performa nce. The copolymers' degeneration speeds and hydrophilic properties can be adjusted by changing the raw material's formulae and copolymerization conditions.Poly(aspartic acid-lactide) (PAL) was synthesized by simply heating a mixture of aspartic acid (Asp) and lactic acid(LA) without additional any catalyst or solvent. The copolymerization conditions of the there formulae had determined respectively, which are including Asp solution temperature, copolymerization temperature and reaction time. The unique branched architecture comprising succinimide units and lactic acid units was confirmed by infrared spectrum (IR) and nuclear magnetic resonance spectrum (NMR). The thermal properties are determined by differential scanning calorimetry (DSC), and the molecular weight and the distribution was determined by gelatin chromatograph (GPC). The PAL was soluble in many organic solvents, and has the good processing formation performance. PAL and the blends with PLA have different hydrophilic properties which are changing along with the component.PAL can make PLA hydrolysis faster.Through making PLA/PAL samples in various proportions,we can observe the change of the samples' mechanical properties, crystallization and surface topography;calculate the samples' loss of quality and molecular weight. Arrival at a conclusion:PAL can make PLA hydrolysis more effectively. At the same time,PAL could make the most Polyeaster hydrolysis faster.The degradation of blending films made by PLA/PAL is faster than pure PLA films.We could conclude that PAL dose not only make the hydrolysis of PLA faster,but also the degradation.