Ingeo 2500hp

Linseed cake was purchased from a local supplier and fractioned using an Analysette sieve shaker (Fritsch, Weimar, Germany) equipped with a 630 μm mesh. To investigate the influence of linseed oil on the tribological properties of the composites, the filler was subjected to partial defatting in acetone. As a result of the procedure described in our previous study [19 (link)], 5 grades of linseed cake with 0.9, 4.6, 17.7, 30.4 and 39.8 wt % of natural oil were obtained and used to produce the composites.
A multipurpose PLA grade Ingeo 2500HP (Natureworks, Minnetonka, MN, USA) characterized by a density of 1.24 g/cm³ and melt flow index of 8 g/10 min (210 °C, 2.16 kg) was chosen as the matrix of the composites.

A PLA crystallization investigation was conducted using Ingeo 2500HP obtained from NatureWorks LLC (Plymouth, MN, USA). The extrusion grade of PLA contains PLLA blended with <2% PDLA and can be fabricated into semi-crystalline samples. The material, provided in pellet form, was dried at 40 °C for 12h before any characterization. Table 1 summarizes the main properties of the commercial PLA.
Two nucleating agents were considered to promote crystallization as follows: (1) 97% anhydrous orotic acid (OA) from MilliporeSigma (Burlington, MA, USA), and (2) N,N’-ethylene bis stearamide (EBS) from Acme-Hardesty Co. (Blue Bell, PA, USA). Both nucleating agents were received as white powders and dried separately at 100 °C for 2h. The nucleating agents were mixed with the PLA according to the concentrations shown in Table 2. The batch names indicate the selected nucleating agent and the weight concentration.

Poly(lactic acid) Ingeo^® 2500 HP was supplied by NatureWorks LLC (Minnetonka, MN, USA) in the form of granules (density = 1.24 g/cm³, melt flow rate at 210 °C and 2.16 kg = 8 g/10 min ) and used as received. High-molecular-weight poly(ethylene 2,5-furandicarboxylate) (PEF) was synthesized via a 2-stage melt polycondensation procedure. The resulting PEF had an intrinsic viscosity of 0.42 dL/g and after solid state polycondensation at 210 °C for 5 h was increased to 0.69 dL/g [64 (link)], which implies a molecular weight close to 30000 g/mol. The availability of PEF for this trial was approx. 63 g. The employed compatibilizer was Joncryl^® ADR 4468 (density = 1.08 g/cm³, glass transition temperature = 59 °C). Joncryl was purchased by BASF GmbH (Ludwigshafen am Rhein, Germany) in the form of flakes and used as received. The other three commercial compatibilizers were the DuPontTM Entira™ Strong 1002 polymer modifier (DuPont Packaging & Industrial Polymers, Wilmington, DE, USA), and the poly(ethylene-co-methyl acrylate-co-glycidyl methacrylate) (EMA-GMA) and poly(ethylene-co-glycidyl methacrylate) (E-GMA), both provided by Sigma-Aldrich (Saint Louis, MO, USA).

PLA used in this work was of a commercial-grade and was supplied by NatureWorks^® LLC (Ingeo^TM 2500HP, NatureWorks^® LLC, Minnetonka, MN, USA). According to the data supplier datasheets [45 ], glass transition temperature T_g is about 55–60 °C, melting temperature T_m is about 150–180 °C, and decomposition temperature is 250 °C. For melt processing, temperatures between 190 °C and 210 °C are recommended. In this work, three different compatibilizers, named C1, C2, and C3, were used (Figure 1).

Ingeo^TM 2500HP, supplied by NatureWorks^® LLC (Minnetonka, MN, USA) in pellet form, was the PLA used in this work. According to the producer’s technical datasheet, it was characterized by a specific gravity of 1.24 g/cm³, a melt flow index (MFI) of 8 g/10 min (210 °C, 2.16 kg) and a melting temperature of 165–180 °C. Polymer granules of PBAT Technipol^® Bio 1160 were purchased from Sipol Spa (Mortara, PV, Italy). According to the supplier datasheet, its specific gravity was 1.23 g/cm³, the MFI was 20 g/10 min (160 °C, 2.16 kg) and melting temperature was about 115 °C.