Effects of core‐shell structured rubber on biobased polyamide 56 with stiffness and toughness balance

Abstract

There is great social awareness concerning the use of biobased materials of diminishing the rapid resource depletion and suppressing global warming. The inherent drawbacks of biobased polyamide 56 (PA56) such as poor notched impact strength limit its applications. Core‐shell structured impact modifiers consisting of a soft glycidyl methacrylate grafted poly(ethylene–octene) (POE‐g‐GMA) shell and a rigid polypropylene core were synthesized through the differences in interfacial tensions. Core‐shell rubber (CSR) particles were used to toughen biobased PA56 by melt blending. PA56/CSR composites exhibited a 560% increase in the impact strength, while the tensile performance loss was slight. This desirable toughness of biobased PA56 is attributed to the cavitation that occurred in POE‐g‐GMA shell which can induce shear bands and shear yielding, forming the fibrils. Characterizations, including X‐ray diffraction (XRD), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), melt rheological tests, and dynamic mechanical analysis (DMA) were conducted to study the toughening mechanism. The results indicated the massive shearing yielding, the cavitation of the CSR and interfacial debonding between the POE‐g‐GMA and the PP were the principal toughening mechanisms.

Improvement of mechanical properties of highly ZnO‐filled polyethylene composites by dual‐compatibilizer for hydrogen sulfide permeation inhibition

“…The addition of PE‐ g ‐MAH to the composites is effective in increasing the yield strength, while introduction of POE‐ g ‐MAH is more favorable for raising the elongation at break. Incorporation of the elastomer rubber‐based soft phase in the composites inevitably reduce the yield strength of the composites 48 . Moreover, for the HDPE/ZnO composites modified by POE‐ g ‐MAH, the relatively weak compatibility between compatibilizers and HDPE matrix results in a weak interfacial adhesion between the compatibilizers and HDPE.…”

“…Incorporation of the elastomer rubber-based soft phase in the composites inevitably reduce the yield strength of the composites. 48 Moreover, for the HDPE/ZnO composites modified by POE-g-MAH, the relatively weak compatibility between compatibilizers and HDPE matrix results in a weak interfacial adhesion between the compatibilizers and HDPE. The weak interfacial adhesion facilitates the debonding of the interface between compatibilizer-encapsulated fillers and the HDPE matrix, leading to a reduction of yield strength.…”

Bio‐based Polyamide 56: Recent advances in basic and applied research

“…Xu et al 74 measured the impact strength of PA56 to be 4.92 kJ/m, the tensile strength to be 86.23 MPa and the elongation at break to be 27.3%. Zhang et al 75 measured the notched impact strength of PA56 to be 4.9 kJ/m 2 , whereas PA66 has a tensile strength of 160 MPa and a notched impact strength of 12 kJ/m 2. 76 Researches show that it is difficult to replace PA66 by bio‐based PA56 in high‐strength and high‐toughness applications.…”

“…The current approach to toughening PA56 is mainly through blending grafted elastomers and organic–inorganic synergistic “core‐shell.” Zhang et al 87 showed that bio‐based PA56/poly (octene‐co‐ethylene) grafted glycidyl methacrylate (POE‐g‐GMA) composites were mixed through twin‐screw extrusion in the toughener range of 0–25 wt% and the notched Izod impact strength was increased by a factor of nearly 17. Yuhui Zhang 75 synthesized a core‐shell structural impact modifier consisting of a soft glycidyl methacrylate grafted poly (ethylene‐octene) (POE‐g‐GMA) shell and a rigid polypropylene core. Core‐shell rubber (CSR) particles were used to toughen bio‐based PA56 by melt blending.…”

“…Xu et al 74 measured the impact strength of PA56 to be 4.92 kJ/m, the tensile strength to be 86.23 MPa and the elongation at break to be 27.3%. Zhang et al 75 measured the notched impact strength of PA56 to be 4.9 kJ/m 2 , whereas PA66 has a tensile strength of 160 MPa and a notched impact strength of 12 kJ/m 2.76 Researches show that it is difficult to replace PA66 by bio-based PA56 in high-strength and hightoughness applications. In order to expand the application of bio-based polyamides and to replace the market of petroleum-based polyamides, many scientists have conducted intensive researches in the field of PA56 reinforcement and toughening.…”