Study On Synthesis And Properties Of Novel Polyurethane Packaging Materials

In this subject, IPDI and PTMG were used as main raw material to prepare a new type of WPU film, and the antibacterial film containing TNO was prepared which can be used in the packaging.At the beginning of the experiment, 4 factor 3 level orthogonal test table L9 (34) was designed to determine the reaction conditions. The result shows that the biggest impact factor is the R value, the second one is the reaction temperature, the reaction time (t1) of IPDI and PTMG is followed and the weakest impact factor is the time (t2) of performed stage after added DMPA. In this research, we find that when the R value is 1.8, the reaction temperature is 90℃, t1 is 6h, t2 is 2h, we can get WPU with excellent performance. The WPU films and the antibacterial films are characterized by IR spectrum. The results shows that synthesis reaction is carried out more thorough and thiotriazinone of TNO is found in the molecular chain. In addition, the HNMR is taken and it shows that the polyurethane prepolymer is synthesized successfully. What’s more, linear relationship was established between the solid content of the emulsion, the quality of the emulsion and the thickness of the film which has guiding significance to the following experiment. The mechanical properties, transmittance and barrier properties of films are tested, the results shows that with the increase of the R value, the tensile strength of films increases, the elongation at break decreased, the light transmittance decreased, oxygen permeability coefficient increased, water vapor permeability coefficient decreased and with the increase of the content of DMPA, the tensile strength of the film increased, elongation at break decreased, the light transmittance is improved, oxygen permeability coefficient decreases, the moisture coefficient increases.Along with the increasing of neutralization degree, tensile strength of the film increased,elongation at break decreased, light transmittance first increased and then decreased, oxygen permeability coefficient decreases, moisture coefficient increase and with the increase of the content of TNO, the tensile strength of the film increased, elongation at break decreased, the transmittance decreases, oxygen permeability coefficient decreases, the moisture coefficient decreases first, and then increases. We studied the inhibiting capacity of the antibacterial films to the Escherichia coli, Staphylococcus aureus, Bacillus subtilis and Gray mold, we found that the inhibiting capacity of films for each strain effect becomes obvious with the increase of content of antibacterial agent and the sensitive degree to all kind of bacterial species is different. Finally, we observe the section micro-structure and surface micro-structure of films by SEM and it shows that with the increase of content of antibacterial agent the micro-structure becomes rough.