Enhancement of the processing window and performance of polyamide 1010/bio‐based high‐density polyethylene blends by melt mixing with natural additives

[EN] This work reports the enhancement of the processing window and the mechanical and thermal properties of biopolymer blends of polyamide 1010 (PA1010) and bio-based high-density polyethylene (bio-HDPE) at 70/30 (wt/wt) achieved by means of natural additives. The overall performance of the binary blend melt-mixed without additives was poor due to both the relatively low thermal stability of bio-HDPE at the processing temperatures of PA1010, that is, 210¿240 ºC, and the lack or poor miscibility between the two biopolymers. Gallic acid (GA), a natural phenolic compound, was added at 0.8 parts per hundred resin (phr) of biopolymer blend to enhance the thermal stability of the green polyolefin and therefore enlarge the processing window of the binary blend. Maleinized linseed oil (MLO), a multi-functionalized vegetable oil, was then incorporated at 5 phr to compatibilize the biopolymers and its performance was also compared with that of a conventional petroleum-derived copolymer, namely, poly(ethylene-co-acrylic acid) (PE-co-AA). The resultant biopolymer blends showed a remarkable enhancement in the thermal stability and also improved toughness when both natural additives were combined. This work can potentially serve as a sound base study for the mechanical recycling of similar blends based on bio-based but non-biodegradable polymers.
This research was funded by the Spanish Ministry of Science, Innovation, and Universities (MICIU) project numbers MAT2017-84909-C2-2-R and AGL2015-63855-C2-1-R. LQ-C and ST-G are recipients of an FPU grant (FPU15/03812) from the Spanish Ministry of Education, Culture, and Sports (MECD) and a Juan de la Cierva-Incorporacion contract (IJCI-2016-29675) from MICIU, respectively. The microscopy services at Universitat Politecnica de Valencia (UPV) are acknowledged for their help in collecting and analysing FESEM images.