| Poly(citric acid-co-polyethylene glycol)was synthesized by a condensation reaction between cirtic acid and polyethylene glycol(PEG1000),which was used in modification of polylactic acid(PLA)toughness through melt blend.Fisrt of all,PEGCA with different extent of reaction was characterized by Fourier-transform infrared(FT-IR)transmission spectra,Nuclear magnetic resonance spectroscopy(NMR),Gel permeation chromatography(GPC)and Differential scanning calorimeter(DSC).PEGCA/PLA blends at different compositions were prepared by Torque Rheometer,the effect of different reaction extents and different compositions of PEGCA on properties of the blends was investigated.Thermal and thermal mechanical properties of PEGCA/PLA blends were studied by Differential scanning calorimeter(DSC)and Dynamic mechanical analyzer(DMA),PEGCA reduced the glass transition temperature,and improved the crystallization ability of PLA.PEGCA and PLA were partial miscible system through DSC data analysis,this result also was in accord with SEM photographes.On the mechanical performance,PEGCA could significantly improve the PLA’s toughness.In the proportion of 15%,elongation at break of PEGCA/PLA blends could reach 316%and impact strength increased to 103J/m.Through comprehensive performance comparison,the PEGCA with low reaction extent had better modification effect.The effect of different tensile conditions on the mechanics properties of blends was discussed,it indicated that tensile strength and modulus of blends increased along with the higher strain rate,the elongation at break remarkably decreased.What’s more,the biodegradation property of blends with 15%PEGCA was studied in PBS buffer solution,it indicated that PEGCA could promote the degradation of PLA. |
