Thermal Stabilization of Recycled PET Through Chain Extension and Blending with PBT

Abstract

This study investigates the effect of using a multifunctional epoxide chain extender (Joncryl® ADR 4468) on the thermal stabilization and rheological properties of recycled polyethylene terephthalate (R-PET) and its blends with polybutylene terephthalate (PBT). The thermal stability of the melt blended samples was analyzed through small amplitude oscillatory shear (SAOS) rheological experiments. The structure of the samples was evaluated using a Fourier transform infrared (FTIR) spectrometer. While the dynamic rheological properties of R-PET were improved with the addition of Joncryl and by blending with PBT, during the SAOS rheological experiments, the complex viscosity of R-PET further increased due to the concurrent polycondensation of R-PET and the resumption of Joncryl reaction with R-PET molecules.These reactions during the rheological experiments were further expedited with increasing the testing temperature. On the other hand, in R-PET/PBT blends, the reactivity of Joncryl was more noticeable in blends with higher R-PET contents due to the higher available internal reactive sites of much shorter R-PET molecules. It was observed that the addition of only 0.2 wt.% Joncryl to the blends of R-PET/PBT (75w/25w) dramatically improves the thermal stability and dynamic rheological properties of R-PET and most likely its processability.

Thermal and Rheological Characterization of Recycled PET/Virgin HDPE Blend Compatibilized with PE-g-MA and an Epoxy Chain Extender

“…A comparison of the blends containing Joncryl ( Figure 3 ), indicates a significant increase in viscosity—almost double—and a slight decrease in the degradation rate during processing ( Figure 5 ) in PET and blends containing 75% PET, thus proving the efficiency of this additive towards PET. Guclu [ 40 ] investigated the effect of using a multifunctional epoxide chain extender (Joncryl ® ADR 4468) on the thermal stabilization and rheological properties of recycled polyethylene terephthalate and its blends with polybutylene terephthalate, and the reactivity of Joncryl was more noticeable in blends with higher recycled polyethylene terephthalate contents due to the higher available internal reactive sites of much shorter recycled polyethylene terephthalate molecules.…”

Investigation of the Reaction Kinetics of Poly(butylene terephthalate) and Epoxide Chain Extender

“…Torque max − Torque time Torque max − Torque min (2) The reaction rate constant can be calculated from the double logarithmic plot of ln [ − ln (Θ)] over ln(t). They found out that the reaction of Joncryl with PLA is generally faster than that with PBSA, due to the lower molecular weight of PLA used in that study.…”

“…Due to their excellent properties, polyesters such as poly (ethylene terephthalate) (PET) and PBT are classified as engineering DOI: 10.1002/mame.202200683 plastics. [1][2][3] In particular, their enhanced thermal stability and mechanical resistance qualify them for use as construction materials in areas such as the automotive and electrical industries. [1,4,5] For lightweight structures, polyesters are used as foams to save weight while maintaining reliable mechanical properties.…”

“…[3,[16][17][18] Chain extenders are multifunctional additives that can react with the terminal functional groups of the polymers. For polyesters, many different systems of substances are already known and studied that can be used as chain modifiers, such as isocyanides, [14,19] phosphites, [20,21] pyromellitic acid dianhydride, [3,[22][23][24] epoxides, [2,18,[25][26][27][28][29] and others, [30,31] with varying degrees of efficiency. As summarized in a recently published review article, one of the most commonly used chain extenders both in industry and academia is Joncryl ADR4468 from BASF.…”

Composition design ofPLA/TPUemulsion blends compatibilized with multifunctional epoxy‐based chain extender to tackle high impact resistant ductile structures

“…42,[82][83][84][85][86][87] This is due to its high reactivity with carboxyl acid and hydroxyl end groups that exist specifically in polyesters such as PLA and polyethylene terephthalate (PET) and polyamides. 87 Due to such high reactivity, the rheological properties of polyesters and polyamides could dramatically be improved 78,[87][88][89] and hence their processability could considerably be enhanced. 87,90 It has also been demonstrated that the use of small amount of Joncryl could significantly promote the crystallization of polyesters.…”