Chain extension of poly (ethylene terephthalate) by reactive extrusion with secondary stabilizer

Abstract

Poly(ethylene tereftalate) (PET) is a polymer highly susceptible to the hydrolytic reactions that occur during applications and mainly in thermomechanical processing. These reactions lead to the decrease of molecular weight of the polymer, limiting the recycling number of the material. The reactive extrusion of the PET in presence of chain extenders is an alternative to recover mechanical and rheological properties that were depreciated by the polymer degradation. In this study, PET wastes from nonwoven fabrics production were extruded in presence of the secondary stabilizer Irgafos 126 (IRG) on variable concentrations. The results showed that Irgafos 126 increased molecular weight, decreased crystallinity and changed processing behavior of the PET, similarly to the effects produced by the well-known chain extender pyromellitic dianhydride (PMDA), showing that the secondary stabilizer Irgafos 126 can also act as a chain extender for the PET.

Plasma-Etching for Controlled Modification of Structural and Mechanical Properties of Electrospun PET Scaffolds

“…Solution viscosity measurements were performed with pristine and plasma‐etched ePET samples, to determine their intrinsic viscosity and molecular weight . In accordance with ASTM‐D 4603, a Cannon‐Ubbelohde viscometer was used for this purpose: A solvent mixture of phenol/1,1,2,2‐tetrachloroethane (60/40 w/w) was employed to dissolve 0.125 g of the PET samples in 25 mL of solvent at 110 °C for 1 h. Once the samples were completely dissolved, the solutions were first filtered, then tested at 30 °C in a water bath, as follows: From the flow times of the pure solvent mixture ( t 0 ) and the polymer solutions ( t , at least three measurements), inherent and intrinsic viscosities were determined from the following equations: where:…”

Recycling of poly(ethylene terephthalate) by chain extension during reactive extrusion using functionalized block copolymers synthesized by RAFT polymerization

“…In the extrusion process, the polymer molecules are melted and mixed. Once melted, the reaction of PET end groups with the chain‐extension compound can then take place …”

Control of thermal degradation of poly(lactic acid) using functional polysilsesquioxane microspheres as chain extenders

“…Recently, “chain extenders,” the functional additives that are used to link the end groups of these low‐molecular‐weight PLA to obtain high‐molecular‐weight PLA, are considered to be an easy‐to‐apply alternative for many industries and have attracted much attention . Generally, the chain extenders have two or more functional groups, such as isocyanate, anhydride, amine, and epoxy, to couple the two end groups of low‐molecular‐weight polymer chains. Chain extenders not only offer an opportunity to enhance the physical and chemical properties of PLA by increasing the molecular weight but also introduce new functional groups into the PLA backbone paving the way for preparation of composites, laminates, coated items, and blends/alloys with improved properties and cost effectiveness …”