Study On Modification Of Poly(Lactic Acid)

In recent years, as white pollutions are more and more serious, researching biodegradable materials have been achieved more attention in the world. Polylactide is chemical aliphatic thermoplastic polyester, produced from renewable resources. It has been regard to the most outlook biodegradable polymer in the medical field because of its excellent biodegradability, biocompatibility and bioabsorbability. Moreover, polylactide can also be used to package because of its high modulus and stiffness. Polylactide has interested more and more researches and observations under environmental protection pulling. It has been used to common plastics to take place of polyolefin.In the experiment, design and synthesize the terpolymer toughening agent. As a toughening agent, the structural monomers of the terpolymer are n-butyl acrylate, acrylic acid and styrene. A series of blends of the biodegradable polymers polylactide / St-BA-AA were prepared by melting blending. They were characterized by Rheological analysis, dynamic mechanical analysis (DMA) and strength-strain tests. The analyses by DMA showed that the PLA/ St25-BA45-AA4 blends are immiscible. When 20wt% St25-BA45-AA4 added, the elongation at break increased to 305.66%. rheological analysis showed that in the low frequency zone, the viscosity of the blend increased with the concentration of St25-BA45-AA4 and in the middle and low frequency zone, the storage modulus of the blend increased with the concentration of St25-BA45-AA4, which was favorable to the processing properties of PLA.In the experiment, design and synthesize the terpolymer toughening agent. As a toughening agent, the structural monomers of the terpolymer are n-butyl acrylate, acrylic acid and methyl methacrylate. The analyses by DMA showed that the PLA/ MMA25-BA45-AA4A blends are immiscible. A series of blends of the biodegradable polymers polylactide/MMA-BA-AA were prepared by melting blending. When 20wt% MMA25-BA45-AA4 added, the elongation at break increased to56.885%. When 30wt% MMA25-BA45-AA4 added, the impact strength increased from 4.8kJ/m of neat PLA to 10.1 KJ/m2 2.. The rheological measurement revealed that in the middle and low frequency zone, the storage modulus and complex viscosity of the blend increased with the concentration of MMA25-BA45-AA4.In the experiment, design and synthesize the terpolymer toughening agent. As a toughening agent, the structural monomers of the terpolymer are n-butyl acrylate, acrylic acid and ethyl acrylate. A series of blends of the biodegradable polymers polylactide/EA-BA-AA were prepared by melting blending. When 20wt% EA90-BA120-AA12 added, the elongation at break increased to106.93%. When 30wt% EA90-BA120- AA12 added, the impact strength increased from 4.8kJ/m2 of neat PLA to 10.5 KJ/m2. Rheological analysis showed that in the low frequency zone, the complex viscosity of the blend increased with the concentration of EA90-BA120-AA12 and in the low and middle frequency zone, the storage modulus of the blend increased with the concentration of EA90-BA120-AA12.