Synthesis And Characterization Of Polylactide/silica Hybrid Organic-inorganic Materials

Polylactide/SiO2 hybrid material was prepared with lactic acid and tetraethoxysilane(TEOS) by one-step and two-step method respectively.The affections of water, temperature and pH on the gel time was discussed in one-step method and the optimized technology parameters were determined. As organic unit dispersed in hybrid network in low molecular polymer form, the result hybrid material was transparent and brittle.An active monomer, 3-amimoproplytriethoxysilane (APTES) was added as a coupling agent in the process of two-step method and the effecting factor on the size and the growing rate of the inorganic particle was studied through absorbency. It was found that the addition of APTES could lower the size of the particles and stabilized it.It was confirmed that the organic and inorganic phrases were connected with covalent bonds by IR and the result of elution. It was observed that the hybrid material prepared was homogeneous through TEM; The DSC result showed that the glass transition temperature (Tg) was increased with increasing SiO2 content and it was found there was a closer distance between molecules in the hybrid material than in PLA by the XRD result.It was showed that the sol fractions of the result material decreased with the increasing of the addition of APTES, the temperature and the reaction time.It was found that water absorption of the hybrid material was dramatically increased and got saturation after about 70 hours. The weight of the hybrid material equably decreased in the first month in normal saline and the weight loss of the hybrid material was much lower than PLA after about one month.