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Preparation and Characterization of the Grafted Copolymer of Acrylic-Starch/PLA Blends

Author: GuiLei
Tutor: PanLiJun
School: Hefei University of Technology
Course: Agricultural Products Processing and Storage
Keywords: Modified starch Polylactic acid Graft copolymer - blend Characterization
CLC: R318.08
Type: Master's thesis
Year: 2009
Downloads: 296
Quote: 4
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Abstract


Starch / PLA biodegradable polylactic acid composite material combines excellent performance and low cost advantages of starch, not only able to partially replace traditional petroleum-based plastics, but to expand non-food uses of starch, is a highly promising new development can be degradable plastics. The problem of improving the molecular weight of polylactic acid starting, Direct Polycondensation of polylactic acid homopolymer and then by the solid phase method further increase its molecular weight; grafting method using modified starch, prepared starch - acrylic acid (AA) Composites ; the eventual adoption of graft copolymer - prepared by blending acrylic - starch graft / PLA composites; through tensile strength testing, infrared spectroscopy, X-diffraction, differential scanning calorimetry, scanning electron microscopy analysis of the prepared mechanical properties, thermal properties, hydrophilicity and degradation changes were characterized. The main results are as follows: 1. Single factor test and orthogonal test method, draw direct polycondensation synthesis of poly lactic acid optimum conditions as follows: reaction temperature 170 ℃, reaction time 11h, adding 0.5% stannous , p-toluenesulfonic acid added in an amount of 0.3%, which is synthesized under conditions of polylactic acid molecular weight of about 11,000, yield was 88.06%. (2) the second solid-phase condensation method homopolymer molecular weight copolymerized acid ultimately increased to 21100, the yield of the final product up to 80.09%; the products for testing and degradation of the infrared test results show that the sample material is polylactic acid, and has excellent degradation of performance. 3 orthogonal acrylic acid grafted starch to obtain optimum conditions: M AA / M starch = 1/1, reaction temperature 80 ℃, reaction time 1.5h, the amount of cerium ammonium nitrate added to 11mmol / L, at this time the graft ratio, the grafting efficiency, the monomer conversion rate was 167.4%, 94.71%, 98.90%; grafted starch crystallinity decreases, absorbent improved; FTIR results show that acrylic acid has been successfully grafted onto the starch backbone. 4 to prepare a composite tensile strength of the graft copolymer as index - blending the test, obtained modified starch / polylactic acid prepared in optimum condition for the amount of 30% of modified starch is added, blending temperature 80 ℃, the best blending solvent is dimethyl sulfoxide (DMSO). Test results show that after starch grafted acrylic acid / polylactic acid composite tensile strength increased crystallinity decreases, increasing the hydrophilic properties; SEM analysis showed that after scanning after acrylic acid grafted starch and polylactic acid between compatibility with a greater increase, slowing the degradation rate.

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CLC: > Medicine, health > Basic Medical > Medical science in general > Biomedical Engineering > General issues > Biomaterial
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