Reactive Blending of Recycled Poly(ethylene terephthalate)/Recycled Polypropylene: Kinetics Modeling of Non-Isothermal Crystallization

Abstract

Plastics were developed to change our world for the better. However, plastic pollution has become a serious global environmental crisis. Thermoplastic polyesters and polyolefins are among the most abundant plastic waste. This work presents an in-depth non-isothermal crystallization kinetics analysis of recycled post-consumer poly(ethylene terephthalate) (rPET) and recycled polypropylene (rPP) blends prepared through reactive compounding. The effect of pyromellitic dianhydride (PMDA) on crystallization kinetics and phase morphology of rPET/rPP blends was investigated by differential scanning calorimetry (DSC) and microscopy techniques. DSC results showed that increasing rPP content accelerated rPET crystallization while reducing crystallinity, which indicates the nucleation effect of the rPP phase in blends. Further, it was found that the incorporation of PMDA increased the degree of crystallinity during non-isothermal crystallization, even though the rate of crystallinity decreased slightly due to its restriction effects. The non-isothermal crystallization kinetics was analyzed based on the theoretical models developed by Jeziorny, Ozawa, Mo, and Tobin. The activation energy of the crystallization process derived from Kissinger, Takhor, and Augis−Bennett models was found to increase in rPET/rPP blends with increasing PMDA due to hindered dynamics of the system. Rheological measurements revealed that rPET melt viscosity is remarkably increased in the presence of PMDA and reactive blending with rPP relevant for processing. Moreover, nanomechanical mapping of the rPP phase dispersed in the rPET matrix demonstrated the broadening of the interfacial domains after reactive blending due to the branching effect of PMDA. Findings from this study are essential for the recycling/ upcycling thermoplastics through non-isothermal fabrication processes, such as extrusion and injection molding, to mitigate the lack of sorting options.

Manipulation of Crystallization Nucleation and Mechanical Properties of PBAT Films by Octadecylamine-Cellulose

“…At a given cooling rate, the CRC results indicated an increase in crystallization with increased OMCC amount. Additionally, it was found that 3#OMCC had the fastest crystallization rate, which is well consistent with the our above and reported results …”

“…The crystallization properties of PBAT are mainly influenced in two ways: (1) one is introduction of nucleating agents . Inorganic and organic nucleating agents have been used to enhance the polymer properties.…”

“…The crystallization properties of PBAT are mainly influenced in two ways: (1) one is introduction of nucleating agents. 7 Inorganic and organic nucleating agents have been used to enhance the polymer properties. However, conventional inorganic nucleating agents such as silica, 8 titanium dioxide, and mica, clay 9 have poor compatibility with the PBAT matrix.…”

Crystallization Behavior of Copolyesters Containing Sulfonates

“…Moreover, at different temperatures, the curve fitted by the Ozawa equation has a large deviation, and the comparison between S0 and the parameters of S1.5 and S3.0 regarding the Ozawa equation has no reference value. Therefore, the Ozawa method does not apply to polymers with different crystallization processes [47], which is consistent with the results of previous studies [48].…”

Effect of mechanical recycling on crystallization, mechanical, and rheological properties of recycled high‐density polyethylene and reinforcement based on virgin high‐density polyethylene

“…According to previous studies, an increased content of rPP reduces the crystallinity of the rPET phase in blends, which indicates that invasive polymer influence the crystallization behavior of the virgin polymer. 47 In light of aforesaid result, it is indicates that more non-crystalline regions were formed by irregularly arranged chains in rHDPE compared to vHDPE films. Moreover, the addition of 25 wt%, 50 wt%, and 75 wt% V1 into rHDPE films of R2 results in the increasing of crystallinity by almost 2.8%, 5.9%, and 9.4%, respectively.…”