Preparation Of Poly （Lactic Acid）（Pla） Alloy With Ionic Liquid And Study Of Supercritical CO₂Foaming

Currently ionic liquid synthesis have been very matured, however poly(lactic acid’s)(PLA) was existed lots of shortcomings, so research on preparation of PLA alloy with ionic liquids was less. In this paper the focus was on compatibility and crystallization of PLA with ionic liquids, and supercritical CO2foaming of PLA was preliminary probe, the research results were as follows:1. Through ion exchange reaction, methacryloxyethyltrimethyl ammonium hexafluorophosphate ionic liquid monomer was synthetized, poly ionic liquid(PIL) was polymerized by using atom transfer radical polymerization, and the synthetic products were tested by mass spectrometry and1H nuclear magnetic spectra analysis, the results showed that they were the target products.Syntheses of [amim]Cl、[bmim]Br、[Omim]Br、[Domim]Br by the direct method,[bmim]PF6、[Omim]PF6、[Domim]PF6were carried out by one-step ion exchange method. In view of special structures of the imidazole ring, different anion and carbon chain length determined the synthetic products by FITR,1H NMR and ESI.2. With different processing method, PIL and PL A (3100D) solution blendings were ready for samples of SEM. Unique concave morphology which belongs to the micron level was observed, the size was0.5-1μm. The alloys were dissolved by different solvents, then different morphology of alloy was observed. After acetonitrile etching single homogeneous medium of alloy was formed.Mechanical melting blendings of [bmim]PF6、[Omim]PF6、[Domim]PF6and polylactic acid(2003D) were dissolved, then observed by electron microscope. They were all like similar bubble pore and phase separation structure. As the growth of the carbon chain, the sizes of bubble hole were bigger, and the compatibility was improved.3. XRD of PIL and PLA (3100D) solution blendings had shown PIL was amorphous polymer, PLA (3100D) was semicrystalline polymer. Isothermal and non isothermal crystallization tests were showed that: under20%and80%concentrations of PIL, PIL had heterogeneous nucleation effect, but the effect was not obvious.[bmim]Br、[bmim]PF6、[Domim]PF6didn’t possessed good heterogeneous nucleation effect, but [Domim] PF6showed plasticizing effect.4. The measurements of PIL’s CO2adsorption and releasing were carried out and showed that:Weight loss ratio was6.75%, the releasing time was above4h.According to variable method, CO2adsorption rate of [Domim]PF6and PLA blendings were tested in different pressure、temperature、 adsorption time. The best proper test condition was under50bar,110℃and adsorption time for1h. The adsorption rate was26.43‰, while the parsing process was extremely slow. Foaming of the blends were not successful, however supercritical CO2showed plasticizing effect. The foaming process should take consideration of foaming temperature、 equilibrium pressure、increasing the solubility and diffusion rate of CO2, both give consideration to the melt strength of poly lactic acid.