Impact of rapid ozone degradation on the structure and properties of polypropylene using a reactive extrusion process

Abstract

In this work, rapid ozone degradation of polypropylene (PP) was developed for the aim of rheology control using a reactive extrusion process. Experiments were carried out in a co-rotating intermeshed twin-screw extruder with varied polymer throughput and reaction temperature. Ozone was introduced into the extruder to rapidly oxidize molten PP in just several seconds period. The oxidized PP was characterized through melt flow index (MFI), rheological measurement, differential scanning calorimetry (DSC), and Fourier transform infrared (FTIR) spectroscopy tests. The influence of reactive temperature and polymer throughput on the degradation reaction was studied. It was noted that molten PP could be fast and successfully degraded during this reactive extrusion process. The oxidized PP had higher MFI than that of the origin PP resin, indicating the decrease of molecular weight of PP. Carbonyl groups were formed on the PP molecular chains. This rapid oxidization process has higher reaction efficiency than the ozone degradation of PP in solid state and no harmful byproduct would be generated from this ozonizing reaction.

Ozone as an alternative decontamination process for N95 facemask and biosafety gowns

“…fibers at shorter exposure times. However, the appearance of the carbonyl group signal in the FTIR spectra for the samples treated at 120 (8 cycles) and 180 min indicate the outset of degradation [32] , [33] , [34] , [35] .

Fig.

…”

Oxidization and Chain‐Branching Reaction for Recycling HDPE and Mixed HDPE/PP with In‐situ Compatibilization by Ozone‐Induced Reactive Extrusion

“…In Figure 9a, it can be seen that the complex viscosity of PE-PP-O 3 experiences a notable decrease, which can be attributed to the degradation of PP. [50] While the potential branching of PE leads to an increase in molecular weight, it is unable to fully compensate for the decrease in molecular weight of PP. With the addition of TMPTA, the complex viscosity of the mixture recovers close to its origin value.…”

In situ ozonolysis of polypropylene during extrusion to produce long-chain branches with the aid of TMPTA

“…The same screw conguration and ozone generator had previously been used for production of controlled rheology PP in our last report. 38 A le-handed screw element was set just before the reaction zone for PP melt pressure building-up and uniformity improvement. It was proved to be effective for ozone to induce PP degradation reaction.…”

“…[33][34][35][36][37] Previously, we used ozone to initiate molecular breakdown and oxidization of PP macromolecules with highly efficiency during extrusion process. 38 In this work, the production of LCB-PP via in situ ozonolysis during reactive extrusion process in the presence of multi-functional monomers (trimethylolpropane triacrylate, TMPTA) is reported. The introduction of ozone gas as initiator into molten PP extrusion process can initiate macroradicals at the gas/melt interface.…”