Rheological Behaviour of PP/PET and Modified PP/PET Blends. II. Dynamic Viscoelastic Properties

Abstract

The increasing amount of post-consumer waste leads to a search for effective recycling methods. Compatibilisation of immiscible blends of polypropylene (PP) and polyethylene terephthalate (PET) represents one such novel approach that allows recycling of significant scrap materials without any need for separation steps. The intention of this paper is to investigate the dynamic viscoelastic properties of unmodified and modified PP/PET blends. To study the effect of the matrix, three polypropylenes differing in flow properties were chosen. The compatibilisation was carried out by both one- or two-step reactive in situ techniques. In the former case, the addition of 1 wt.% of maleic anhydride, and in the latter, polypropylene supplied already modified by the producer were employed. The measurements were performed by using a rotational cone and plate rheometer at temperatures of 265 °C and 245 °C. Since PET is not melted at the lower temperature, completely different behaviour is observed in the two cases. The rheological functions generally decrease with PET content at 265 °C (conventional blend behaviour), while they increase at 245 °C, in a manner reminiscent particle-filled systems (including the yield behaviour). The positive effect of compatibilisation can be deduced not only from the results of the morphological study (dispersed phase size reduction, strengthened interfacial adhesion), but also through increased values of the viscous and elastic characteristics, which suggests enhanced interactions between the blend components. Comparing steady shear and dynamic viscoelastic properties, the extent of deformation applied during both types of measurements leading to different material responses should be considered.

Reactive Extrusion of Maleic-Anhydride-Grafted Polypropylene by Torque Rheometer and Its Application as Compatibilizer

“…This behavior is because of the presence of MAH-g-PP in PET and PP blends, which allowed physical interaction between the components and the partially homogenous blends’ formation. The area under the peak also enhanced in all prepared blends as compared to pure PP, which revealed high impact bearing properties of blends [ 36 , 37 , 38 ]. Figure 14 clarifies the effect of temperature on the value of storage modulus of prepared compatibilized blends in contrast to pure PP and pure PET.…”

Rubber toughened recycled polyethylene terephthalate for material extrusion additive manufacturing

“…[11][12][13] While PET has a tensile strength and modulus in the range of polymers commonly used in MEAM (30-100 MPa and 1.3-3.5 GPa, respectively), it suffers from low notched impact strength. 14,15 An effective way to improve impact behavior is through rubber toughening or the incorporation of an elastomeric material into the matrix. The dispersed rubber particles need to have two functions to successfully increase fracture toughnessconcentrate local stresses and debond to alter the stress state of the matrix material, enabling overall matrix deformation to occur.…”

Effect of silicon carbide particles on the mechanical, thermal and structural properties of recycled high-density polyethylene

“…9 Environmentalists worry that recycling plastic garbage will not only use less energy and virgin resources, but also less post-consumer waste and the disposal of post-industrial plastic trash. 10 Numerous scientists are investigating the blending of recycled plastic, including Avila and Duarte 11 worked in recycled PET/HDPE composites. It describes thermosmechanical properties of recycled plastic bottles that are made of polyethylene terephthalate (PET) blends with HDPE for engineering purposes.…”

“…9 Environmentalists worry that recycling plastic garbage will not only use less energy and virgin resources, but also less post-consumer waste and the disposal of post-industrial plastic trash. 10…”