W50 eht

The feedstock for the self-manufactured filament F4 was prepared in a mixer–kneader compounder (W50-EHT, Brabender GmbH, Duisburg, Germany) with a rotation speed of 30 rpm, a compounding temperature of 125 °C and a processing time of 1 $\mathrm{h}$ . The produced feedstock was then extruded into filaments with a diameter of $2.85$   $\mathrm{m}$ $\mathrm{m}$ using a Noztek single-screw extruder (Noztek pro, Noztek, UK). Further, the temperature- and shear-rate-dependent melt flow was characterized by a high-pressure capillary rheometer (Rheograph 25, Goettfert Werkstoff-Pruefmaschinen GmbH, Buchen, Germany).

The obtained fiber was prepared and made into short fiber through sequential phases: (1) The fiber threads were manually picked according to their purity, length, and strength, (2) the selected threads underwent a crushing phase and were cut into small pieces using a crushing machine, (3) the crushed fibers further endured a grinding process, finally, (4) the fibers were refined and sieved using a 200–250 micron sieve analyzer. The obtained short sugar palm fibers (SSPFs) were naturally dried and prepared for the mixing process. The SSPFs and PVDF were mixed using a Brabender measuring mixer, model: W 50 EHT (Brabender, Duisburg, Germany). As recommended in several studies, the loading of fiber in composites was 30%. This percentage ensures better mechanical, environmental, and technical properties such as hardness, tensile strength, flexural strength, impact strength, enhanced interfacial bonding, abrasion resistance, and thermal stability. Such enhanced properties will provide adequate reinforcement in composites [18 ,19 (link),20 (link),21 (link)]. The composites then underwent a hot and cold press accomplished through successive phases. First, the specimens experienced a preheat of 10 min, hot-pressed for five minutes, and then cold-pressed for 1 min at a maximum pressure of 160 Bar. The used mold measurement was 150 mm (L) × 150 mm (W) × 2 mm (T).

Before melt compounding, all materials were dried overnight (PP and all modifiers at 70 °C, and the AII filler was dried at 100 °C). PP–AII composites were obtained by melt compounding at 220 °C, using a Brabender bench scale internal mixer (W50EHT, Plastograph EC, Brabender GmbH &. Co. KG, Duisburg, Germany) equipped with “came” blades. Conditions of processing: feeding at 30 rpm for 4 min, followed by melt mixing at 100 rpm for 10 min. For the sake of clarity, the codes and compositions of filled PP composites produced with internal mixers are shown in Table 1. Neat PP processed under similar conditions has been used as one key reference. The so-obtained PP composites were processed by compression molding (CM) at 210 °C, using an Agila PE20 hydraulic press to obtain plates (100 mm × 100 mm~3 mm thickness). More specifically, the material was first maintained at low pressure for 180 sec (3 degassing cycles), followed by a high-pressure cycle at 150 bars for 120 sec. Then, the cooling was realized under pressure (50 bars) for 300 sec using tap water (temperature slightly > 10 °C). The plates produced by CM were used to obtain specimens for mechanical characterizations. Throughout this contribution, all percentages are given as weight percent (wt.%).

A torque recording mixer-kneader (W50-EHT, Brabender GmbH, Duisburg, Germany) was applied for the new polar feedstock compounding. The blade’s rotating speed was set to 30 rpm, which is equivalent to a maximum shear rate of 36 1/s for 1 h compounding time. The compounding temperature was set to 110 °C (PEG/PVB) and 160–170 °C (PEG/PMMA) according to the different glass transition temperatures of the high molecular weight polymer. Further details can be found in [36 (link)].

All feedstocks were prepared in a mixer-kneader compounder (W50-EHT, Brabender GmbH, Duisburg, Germany) with simultaneous torque recording during mixing. The blade’s rotating speed was set to 30 rpm, and the processing time to 1 h. The compounding temperature depended on the binder composition and was set to the following values: LDPE/wax: 125 °C, HDPE/wax, and HDPE/LDPW/wax: 160 °C. The sequence of material added to the mixing chamber (volume 45 mL) was identical for all feedstock compositions guaranteeing identical processing conditions.

PLA or PBAT was simultaneously modified into a masterbatch using an initiator and grafting materials after drying in a vacuum oven at 50 °C for 24 h to remove moisture. By using the MAH-modified masterbatch, PLA-g-MAH/PBAT and PLA/PBAT-g-MAH composites were fabricated. These processes were conducted by melt-mixing methods using a Plasti-Corder Lab-Station with a melt mixer (W50 EHT, Brabender, Duisburg, Germany) equipped with a counter-rotating twin-screw compounder with a bowl volume of 55 cm³ and roller blades. A barrel temperature of 180 ± 5 °C with a rotation speed of 50 rpm and a total residence time of 10 min were utilized. Table 1 summarizes the compositions of the PLA and PBAT composites.
The prepared compounds were cut into small pieces and shaped into 140 mm × 120 mm rectangles with a thickness of 1 mm using a hydraulic laboratory press (Model 3851, Fred S. Carver Inc., Menomonee Falls, WI, USA). Preheating at 180 °C for 4 min, followed by molding at a pressure of 2000 psi for 2 min and cooling, afforded the desired modified PLA materials.